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Identifying New Persistent and Bioaccumulative Organics Among Chemicals in Commerce II: Pharmaceuticals
Abstract
The goal of this study was to identify commercial pharmaceuticals that might be persistent and bioaccumulative (P&B) and that were not being considered in current wastewater and aquatic environmental measurement programs. We developed a database of 3193 pharmaceuticals from two U.S. Food and Drug Administration (FDA) databases and some lists of top ranked or selling drugs. Of the 3193 pharmaceuticals, 275 pharmaceuticals have been found in the environment and 399 pharmaceuticals were, based upon production volumes, designated as high production volume (HPV) pharmaceuticals. All pharmaceuticals that had reported chemical structures were evaluated for potential bioaccumulation (B) or persistence (P) using quantitative structure property relationships (QSPR) or scientific judgment. Of the 275 drugs detected in the environment, 92 were rated as potentially bioaccumulative, 121 were rated as potentially persistent, and 99 were HPV pharmaceuticals. After removing the 275 pharmaceuticals previously detected in the environment, 58 HPV compounds were identified that were both P&B and 48 were identified as P only. Of the non-HPV compounds, 364 pharmaceuticals were identified that were P&B. This study has yielded some interesting and probable P&B pharmaceuticals that should be considered for further study.
... Wide use of amiodarone combined with high toxicity of this drug resulted in its classification as a high-risk compound, whose environmental monitoring is particularly demanded and should be prioritized (Besse and Garric, 2008;Chinnaiyan et al., 2018;Escher et al., 2011;Howard and Muir, 2011). Although reports concerning detection of amiodarone in the environmental samples are scarce as of this moment, the Predicted Environmental Concentration levels (PEC), calculated by some authors are relatively high. ...
... It is not clear why, despite quite high estimated PEC, amiodarone is not frequently detected as a contaminant in aquatic samples. However its low polarity (K ow = from 7.57 to 8.81, depending on the information source (Besse and Garric, 2008;Howard and Muir, 2011)), leading to an extensive adsorption on a solid phase, may partially answer this questionthus no wonder that amiodarone was found in the sediments taken from various sampling sites along Sava river in Slovenia and Croatia (at concentration over 100 ng g − 1 ) (Babić et al., 2018). Another factor underlying such state of things may be poor efficiency of amiodarone recovery reported in simultaneous determination of pharmaceutical pollutants using solid-phase extraction (SPE) method (Grabic et al., 2012). ...
... Moreover, observed disruption of Bacillus stearothermophilus growth indicates that this pharmaceutical may be harmful also to the lower level organisms (Rosa et al., 2000). The second factor influencing environmental troublesomeness of amiodarone are its unfavorable physicochemical propertiesdue to presence of two iodine atoms, its molecule is distinctively lipophilic, inducing its very high bioconcentration factor (BCF), which, in connection with high toxicity, yields high position in the persistence-bioaccumulation-toxicity (PBT) ranking (Babić et al., 2018;Howard and Muir, 2011). Taking into account high metabolic rate of amiodarone, knowledge of the toxic properties of its biotransformation products is crucial to holistically evaluate the impact of this drug on the natural environment. ...
In the present study the photochemical fate of organoiodine compound – amiodarone was performed. The drug turned out to be highly susceptible to UV–Vis irradiation, especially in the presence of humic substances and organic matrix. Qualitative LC-MS analysis revealed formation of twelve – mainly previously unreported – transformation products (TPs). Four major TPs were submitted to the toxicity analysis with the use of D. magna. All of the tested TPs presented higher toxic potential than the parent compound. The phenolic TPs were approximately 100 times more toxic than amiodarone. Toxic properties of the major TPs resulted in steadily increasing toxic potential of the photo-generated mixture over the time of irradiation. Moreover, the experimental toxicity data, concerning the TPs, were compared with results estimated by 6 in silico models with the use of a multivariate chemometric analysis. The results showed that the applied computational methods were able neither to correctly predict toxic properties of the studied compounds, nor the trends in change of their toxic parameters. Additional validation of in silico models ability to predict toxicity of iodinated organic compounds showed that the studied computational methods do not present sufficient prediction ability. Therefore their estimations concerning organoiodines should be verified using experimental tests.
... Extensive field investigations have demonstrated the wide distribution of pharmaceuticals in various environmental matrices worldwide (Arpin-Pont et al. 2016;Bu et al. 2013b;Daughton 2010;Ebele et al. 2017;Liu and Wong 2013;Sui et al. 2015). For example, since 1990 over 100 pharmaceuticals have been detected in surface water and sediment in China (Bu et al. 2013b), and up to approximately 300 have been detected around the globe (Howard and Muir 2011). ...
... According to the environmental risk assessment (ERA) proposed by the European Medicines Agency, persistence (P), bioaccumulation (B), and toxicity (T) are inherent properties of pharmaceuticals that were usually used in hazard-based screening procedure (Li et al. 2020). Multiple prioritization exercises have been performed based on these inherent properties during past few years (Berninger et al. 2016;Howard and Muir 2011;Sangion and Gramatica 2016) It has merit that the screening results could be directly applicable in other countries or regions. However, risk-based screening schemes were preferred as they were more realistic as environmental concentrations were usually considered. ...
... Firstly, hazard assessment was conducted to identify P and B antibiotics, as well as those with high production volumes (HPV). Toxicity was not considered because it is still a major lack of chronic ecotoxicity data to assess impacts of the most pharmaceuticals in aquatic environments (Howard and Muir 2011). Secondly, these identified antibiotics were ranked by scoring their production volumes and P and B potential. ...
The goal of this study was to identify antibiotics with potential risk in river water of the megacity Beijing, China. This was accomplished by using a tiered approach that combined hazard (phase I) and monitoring-based risk (phase II) assessment. Ninety-five candidate antibiotics were screened and 31 was identified as hazardous during phase I assessment. Of these hazardous antibiotics, 29 were identified as persistent and 7 were identified as bioaccumulative antibiotics. Fluoroquinolones, macrolides, sulfonamides, and aminoglycosides account for over 80% of these hazardous antibiotics. During phase II, four antibiotics (erythromycylamine, cefotaxime, ampicillin, and fusidic acid) that were not previously reported were detected in the surface water sampled from four major rivers in Beijing, with concentrations ranging from not detected to approximately 300 ng/L. The ecological risk assessment showed that erythromycylamine, cefotaxime, and ampicillin posed low to high levels of risk to the aquatic organisms. To summarize, erythromycylamine, cefotaxime, and ampicillin were identified as priority antibiotics in rivers in Beijing, China. Our results demonstrated the necessity of conducting monitoring-based verification process in identification of priority antibiotics in a specific region.
... SER was detected in effluents at a concentration of up to 1 µg L −1 [8]. SER and FLX were considered potential bioaccumulative compounds [7,9,10]. In our previous study, SER was found to be the most bioaccumulative antidepressant in the protozoan Spirostomum ambiguum with the bioaccumulation factor of 34,092 L/kg [11]. ...
... Many studies have reported the bioaccumulation of antidepressants in protozoa, invertebrates, and fish [11,12,36]. Due to their high lipophilicity, SER, PAR, and FLX were classified as potentially bioaccumulative compounds [9,12], and it is highly likely that they adsorb to organic matter, e.g., sediments and suspended microparticles. However, the sorption of antidepressants to abiotic material has rarely been tested in the literature. ...
Antidepressants, especially selective serotonin re-uptake inhibitors, which are among the most commonly used pharmaceuticals, are ubiquitous in effluents and freshwaters. Microparticles, including microplastics, show sorption properties to different compounds, thus becoming a potential vector of toxic substances. This study aimed to evaluate the effects of four antidepressants on the protozoan Spirostomum ambiguum in the presence of four types of microplastics and baker’s yeast. The Spirotox, measuring the acute toxicity, and food uptake inhibition assay were applied. The microparticles did not influence the toxicity of the tested antidepressants in the acute toxicity assay. Moreover, they did not adsorb the drugs during a seven-day incubation in dark. However, sublethal levels of sertraline and duloxetine decreased the number of food vacuoles formed by the protozoa. The highest effect was observed in the case of the suspension of edible particles of baker’s yeast, where a significant decrease in the number of food vacuoles was observed in the sertraline concentration as low as 0.025 mg L−1. A lower but statistically significant effect was observed when wettable microparticles of phenolic resin were used as the artificial food source. These results indicate that serotonin re-uptake inhibitors can interfere with the feeding processes of ciliates.
... A large number of chemicals have been released into the environment by human activities, such as agriculture, industrial productions, and their relative byproducts. Once these chemicals enter the environment, transformation products (TPs) can be produced through hydrolysis, photosynthesis, and biological metabolism [1][2][3][4][5][6]. Most of these chemicals and their TPs are missing molecular and/or structure information. ...
... Thus, these chemicals' human and environmental risk assessments remain an open question [6][7][8][9][10][11][12]. Although most legacy pollutants have been banned for decades in many countries, they can still be detected at trace-level in the environment [2,[13][14][15]. The known pollution is only the tip of the iceberg compared to the number of environmental hazards [1,13,14]. ...
High-resolution mass spectrometry is a promising technique in non-target screening (NTS) to monitor contaminants of emerging concern in complex samples. Current chemical identification strategies in NTS experiments typically depend on spectral libraries, chemical databases, and in silico fragmentation tools. However, small molecule identification remains challenging due to the lack of orthogonal sources of information (e.g., unique fragments). Collision cross section (CCS) values measured by ion mobility spectrometry (IMS) offer an additional identification dimension to increase the confidence level. Thanks to the advances in analytical instrumentation, an increasing application of IMS hybrid with high-resolution mass spectrometry (HRMS) in NTS has been reported in the recent decades. Several CCS prediction tools have been developed. However, limited CCS prediction methods were based on a large scale of chemical classes and cross-platform CCS measurements. We successfully developed two prediction models using a random forest machine learning algorithm. One of the approaches was based on chemicals’ super classes; the other model was direct CCS prediction using molecular fingerprint. Over 13,324 CCS values from six different laboratories and PubChem using a variety of ion-mobility separation techniques were used for training and testing the models. The test accuracy for all the prediction models was over 0.85, and the median of relative residual was around 2.2%. The models can be applied to different IMS platforms to eliminate false positives in small molecule identification.
... However, prioritization is of utmost priority to accelerate the detection and tentative identification of suspects. Such prioritization was subsequently achieved by referring to predicted toxicity, information on uses and consumption pattern, environmental occurrence frequency, persistence nature, and extent of bioaccumulation (Howard and Muir 2011;Gosetti et al. 2015). As discussed earlier, searching for unknowns through the databases is the quickest and commonly used approach for the initial screening of compounds present in environmental samples. ...
... Some of the miscellaneous pathways of PPCPs could be from seepage from effluent conduits, leaky septic tanks, infiltrations from wastewater treatment units, and atmospheric depositions. Apart from aforementioned sources and pathways of PPCPs, most of the veterinary drugs may reach the environment through terrestrial runoff from animal sheds and wind-borne migration of chemicals applied to crops (Howard and Muir 2011). In a nutshell, PPCPs once used or refused or released enter carriers like wastewater, soil, or air, depending on its mobility, reach, or accumulate in any of the natural components. ...
Naphthalene is a ubiquitous polycyclic aromatic hydrocarbon listed as a priority pollutant by the United States Environmental Protection Agency (USEPA). In this study, we have studied adsorption of naphthalene on biochar produced from sugarcane bagasse and ultrasonically removed the adsorbed naphthalene by low-frequency ultrasonication in a customized reactor. Biochar was produced from sugarcane bagasse (SB) at a pyrolytic temperature of 400 °C. UV and HPLC results suggest that 100% adsorption of naphthalene takes place in 75 min. X-ray diffraction results showed that SB biochar particles were amorphous. A known quantity of naphthalene adsorbed on 10 mg of SB biochar was subjected to ultrasonication in a customized cylindrical reactor (10 cm depth, 5.6 cm diameter) using low-frequency (40 kHz) sonication. More than 80% of naphthalene was desorbed from the biochar in 45 min. Therefore, low-frequency ultrasonication can be used as an effective treatment for the removal of such trace organic pollutants present in contaminated sites.KeywordsNaphthaleneBiocharAdsorptionUltrasonication
... environment. Of those, 92 were rated as potentially bioaccumulative and 121 were rated as persistent (Howard and Muir, 2011). These findings applied to numerous hormones, antibiotics, and commonly detected analgesics such as diclofenac, ibuprofen, naproxen, fluoxetine, and norfluoxetine (Howard and Muir, 2011). ...
... Of those, 92 were rated as potentially bioaccumulative and 121 were rated as persistent (Howard and Muir, 2011). These findings applied to numerous hormones, antibiotics, and commonly detected analgesics such as diclofenac, ibuprofen, naproxen, fluoxetine, and norfluoxetine (Howard and Muir, 2011). In addition, bioaccumulation can be assessed by the bioaccumulation factor (BAF), the ratio of the chemical in an organism to the concentration in the environment, or by using a bioconcentration factor (BCF), defined as the accumulation of a compound in an organism relative to the concentration in the water. ...
Pharmaceuticals and personal care products (PPCPs) are found in wastewater, and thus, the environment. In this study, current knowledge about the occurrence and fate of PPCPs in aquatic systems—including wastewater treatment plants (WWTPs) and natural waters around the world—is critically reviewed to inform the state of the science and highlight existing knowledge gaps. Excretion by humans is the primary route of PPCPs entry into municipal wastewater systems, but significant contributions also occur through emissions from hospitals, PPCPs manufacturers, and agriculture. Abundance of PPCPs in raw wastewater is influenced by several factors, including the population density and demography served by WWTPs, presence of hospitals and drugs manufacturers in the sewershed, disease burden of the population served, local regulations, and climatic conditions. Based on the data obtained from WWTPs, analgesics, antibiotics, and stimulants (e.g., caffeine) are the most abundant PPCPs in raw wastewater. In conventional WWTPs, most removal of PPCPs occurs during secondary treatment, and overall removal exceeds 90% for treatable PPCPs. Regardless, the total PPCP mass discharged with effluent by an average WWTP into receiving waters (7.35 – 20,160 g/day) is still considerable, because potential adverse effects of some PPCPs (such as ibuprofen) on aquatic organisms occur within measured concentrations found in surface waters.
... Several authors claim these drugs are persistent and bioaccumulative, considering them as emerging pharmaceutical contaminants (Daughton, 2014;Howard and Muir, 2011;Zurita et al., 2005). Ramesh et al. (2018) reported in his study many histopathological changes in vital organs, such as gills, liver and kidneys in groups of Cyprinus carpio organisms treated with CQ, indicating that the drug has toxic effects on non-target organisms. ...
... Potentially persistent and bioaccumulative properties Howard and Muir (2011) Good solubility and low biodegradation Gosu et al. (2016) Hydroxychloroquine Toxic effects on non-target organisms Ramesh et al. (2018) Ivermectin Antiparasitic ...
On March 11, 2020, the World Health Organization (WHO) declared COVID-19 a pandemic. The outbreak caused a worldwide impact, becoming a health threat to the general population and its professionals. To date, there are no specific antiviral treatments or vaccines for the COVID-19 infection, however, some drugs are being clinically tested. The use of these drugs on large scale raises great concern about their imminent environmental risk, since the elimination of these compounds by feces and urine associated with the inefficiency of sewage treatment plants in their removal can result in their persistence in the environment, putting in risk the health of humans and of other species. Thus, the goal of this work was to conduct a review of other studies that evaluated the presence of the drugs chloroquine, hydroxychloroquine, azithromycin, ivermectin, dexamethasone, remdesivir, favipiravir and some HIV antivirals in the environment. The research indicated the presence of these drugs in the environment in different regions, with concentration data that could serve as a basis for further comparative studies following the pandemic.
... During covid 19 pandemic situation, for the treatment of patients and post vaccine, antiviral and painkiller drugs were generally used [1,2]. Hydroxychloroquine persists in the environment due to its bio accumulative properties in vegetation through the polluted soil and groundwater [3,4,5]. Even natural degradative products of hydroxychloroquine have more toxicity due to their bio resistance [6]. ...
Water-soluble medications that are present in the environment have negative effects on species that are not their intended targets. The pharmaceuticals acetaminophen (paracetamol, APAP) and hydroxychloroquine are emergent micro pollutants during and after Covid. To reduce the influence of pharmaceutical micropollutants on the ecosystem, it is preferable to remove them from the environment with the aid of microorganisms. In this investigation, microorganisms from industrial effluent that could withstand acetaminophen and hydroxychloroquine were identified. Biochemical analysis and the 16s rRNA sequencing method were used to identify the isolate as Bacillus velezensis (GenBank accession number OQ932827.1). A combination of spectrophotometric and high-performance liquid chromatographic methods was used to study the biodegradation of acetaminophen and hydroxychloroquine. The degradation of paracetamol (1500 ppm) and hydroxychloroquine (200 ppm) by Bacillus velezensis was 80.2% and 40%, respectively with simple first order degradation kinetic. Degradative products were reported based on the High-resolution mass spectroscopy data. Based on high resolution mass spectroscopy data, hydroquinone and maleic acid were identified as the acetaminophen's degradative components. The biodegradative metabolite of the parent chemical, 7 Chloroquinoline 4 amine, is suggested by the HRMS chromatogram data for the hydroxychloroquine biodegradative product. Due to their affordability and environmental friendliness, biologically based methods (industrial, hospital, and municipal) for the removal of medicines from wastewater are ideal.
... molar absorption coefficient (ε), quantum yield (Φ), and rate constant of hydroxyl radical (K OH* ) is provided in Table S2 in SI. The 75 OMPs were selected based on environmental relevance (Howard et al., 2011), previous studies (Lienert et al., 2007;Wols et al., 2013;Yu et al., 2019) availability of analytical standards and analytical performance of the substances. ...
Urine dehydration is one of the technological approach to recover nutrients in concentrated form from source separated urine. When drying fresh urine, nitrogen loss occurs due to hydrolysis of urea into ammonia unless methods to inactivate urease enzyme are employed. In addition, concerns arise when using urine-derived fertiliser due to the potential presence of organic micropollutants (pharmaceuticals). This thesis evaluated ultraviolet (UV) treatment as an alternative chemical-free nutrient stabilisation (urease inactivation) and organic micropollutant (OMP) degradation technology. Urease inactivation and OMP degradation in water and in urine (synthetic urine, real urine from human subjects) were studied in a photoreactor equipped with a low-pressure mercury UV lamp emitting light predominantly at 185 and 254 nm. Exposure of real urine to 80 min of UV irradiation resulted in more than 90% degradation of 18 out of 75 OMPs and 1-90% degradation of the remaining OMPs. Enzymatic activity fell below the detection limit for real urine exposed to 71 min of UV irradiation. However, electrical energy demand for reducing enzymatic activity below the detection limit in real fresh urine was 52-fold higher than for inactivation in synthetic fresh urine (without urea), while electrical energy demand was more than 10-fold higher for 90% OMP degradation in real fresh urine than in water. The inactivation and OMP degradation observed were probably due to direct photolysis and photo-oxidation. Presence of organic substances in real urine was the likely reason for less efficient inactivation of urease and OMP degradation, as such substances can competitively absorb incoming UV light and scavenge the free radicals formed during UV treatment. Although 20% urea was lost after UV treatment, there was no decrease in total nitrogen. In summary, UV treatment can stabilise urea-N and degrade OMPs in fresh urine and has potential for integration into urine diversion sanitation systems.
... For example, Serra-Compte et al. (2018) reported mussel concentrations ( ± SD) of 12.9 ± 2.1 µg/g dw after a 20-day exposure to 5 µg/L (BAF ≈ 2500, compared to 1390-1610 L/Kg in this study) [35]. According to its log K OW (3.74 [37]), as moderately hydrophobic pharmaceutical in its neutral form, citalopram represents a medium concern for bioaccumulation [51]. ...
Pharmaceuticals and microplastics constitute potential hazards in aquatic systems, but their combined effects and underlying toxicity mechanisms remain largely unknown. In this study, a simultaneous characterization of bioaccumulation, associated metabolomic alterations and potential recovery mechanisms was performed. Specifically, a bioassay on Mediterranean mussels (Mytilus galloprovincialis) was carried out with polyethylene microplastics (PE-MPLs, 1 mg/L) and citalopram or bezafibrate (500 ng/L). Single and co-exposure scenarios lasted 21 days, followed by a 7-day depuration period to assess their potential recovery. PE-MPLs delayed the bioaccumulation of citalopram (lower mean at 10 d: 447 compared to 770 ng/g dw under single exposure), although reaching similar tissue concentrations after 21 d. A more limited accumulation of bezafibrate was observed overall, regardless of PE-MPLs co-exposure (<MQL-3.2 ng/g dw). Metabolic profiles showed a strong effect of pharmaceuticals, generally independent of PE-MPLs co-exposure. Alterations of the citrate cycle (bezafibrate exposure) and steroid and prostaglandin metabolism (citalopram and bezafibrate exposures) were highlighted. PE-MPLs alone also impacted metabolic pathways, such as neurotransmitters or purine metabolism. After depuration, relevant latent or long-lasting effects were demonstrated as, for instance, the effect of citalopram on neurotransmitters metabolism. Altogether, the observed molecular-level responses to pharmaceuticals and/or PE-MPLs may lead to a dysregulation of mussels' reproduction, energy metabolism, and/or immunity.
... molar absorption coefficient (ε), quantum yield (Φ), and rate constant of hydroxyl radical (K OH* ) is provided in Table S2 in SI. The 75 OMPs were selected based on environmental relevance (Howard et al., 2011), previous studies (Lienert et al., 2007;Wols et al., 2013;Yu et al., 2019) availability of analytical standards and analytical performance of the substances. ...
In household wastewater, a large proportion of organic micropollutants (OMPs) load is attributed to human urine. OMPs could pose a risk to human and environmental health when urine collected in source-separating sanitation systems is recycled as crop fertiliser. This study evaluated degradation of 75 OMPs in human urine treated by a UV-based advanced oxidation process. Fresh urine and water samples were spiked with a broad range of OMPs and fed into a photoreactor equipped with a UV lamp (185 and 254 nm) that generated free radicals in situ. Degradation rate constant and the energy required to degrade 90% of all the OMPs in both matrices were determined. At a UV dose of 2060 J m-2, average ΣOMP degradation of 99% (±4%) in water and 55% (±36%) in fresh urine was achieved. The energy demand for removal of OMPs in water was <1500 J m-2, but for removal of OMPs in urine at least 10-fold more energy was needed. A combination of photolysis and photo-oxidation can explain the degradation of OMPs during UV treatment. Organic substances (e.g. urea, creatinine) likely inhibited degradation of OMPs in urine by competitively absorbing UV-light and scavenging free radicals. There was no reduction in the nitrogen content of urine during treatment. In summary, UV treatment can reduce the load of OMPs to urine recycling sanitation systems.
... Hydroxychloroquine persists in the environment due to its bio accumulative properties in vegetation through the polluted soil and groundwater [30][31][32]. It also has been reported to cause depletion of ozone [33]. ...
Acetaminophen and hydroxychloroquine are widely used drugs during COVID situations. Residual concentrations of acetaminophen and hydroxychloroquine have been detected in pharmaceutical industry wastewater, effluent treatment plants, and surface water. The present study was carried out on the bioremediation of acetaminophen (paracetamol) and hydroxychloroquine by using the bacterial isolate Kosakonia cowanii JCM 10956(T) (GenBank: OQ733302.1). Identification of the isolate was done using the 16S rRNA sequencing technique. The LC50 values for bacteria were determined for acetaminophen and hydroxychloroquine as 2186.70 and 1735.13 ppm, respectively. Isolate was found to degrade acetaminophen (1500 ppm) into hydroquinone after five days of incubation with an 81% biodegradation rate. Hydroxychloroquine (1000 ppm) was found to be degraded into oxalic acid with 7-chloroquinoline-4-amine and 4-aminoquinoline-7-ol as intermediates. After 15 days of incubation, 60% of hydroxychloroquine was found to be degraded. Acetaminophen and hydroxychloroquine biodegradation followed a first-order kinetic model with a rate constant of 0.339 d − 1 and 0.0618 d − 1 , respectively. Half-lives for acetaminophen and hydroxychloroquine were found to be 2.05 and 11.2 days, respectively. Based on the analytical techniques of UV-visible spectra, HPLC, mass spectra, and proton nuclear magnetic spectroscopy (1H NMR) studies, biodegradative metabolites were identified. Ecotoxicological testing of the parent drug and degradative product was done using algal inhibition and shrimp lethality assays. The biodegradative product of acetaminophen, hydroquinone, has more algal toxicity and less toxicity against shrimp as compared to the parent drug. Whereas for the hydroxychloroquine biodegradative product, oxalic acid has less algal toxicity and more toxicity against shrimp compared to the parent drug. Industrial applications of hydroquinone and the metal leaching role of oxalic acid will give new insight into the bioconversion of expired paracetamol and hydroxychloroquine into value-added products.
... toxicity) [2,3]. Most of the chemicals in the human exposome are structurally unknown and therefore there is little known about their occurrence, fate, and potential health impact [4][5][6][7][8][9]. ...
Non-target analysis combined with liquid chromatography high resolution mass spectrometry is considered one of the most comprehensive strategies for the detection and identification of known and unknown chemicals in complex samples. However, many compounds remain unidentified due to data complexity and limited number structures in chemical databases. In this work, we have developed and validated a novel machine learning algorithm to predict the retention index (r\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_i$$\end{document}i) values for structurally (un)known chemicals based on their measured fragmentation pattern. The developed model, for the first time, enabled the predication of r\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_i$$\end{document}i values without the need for the exact structure of the chemicals, with an \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R^2$$\end{document}R2 of 0.91 and 0.77 and root mean squared error (RMSE) of 47 and 67 r\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_i$$\end{document}i units for the NORMAN (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n=3131$$\end{document}n=3131) and amide (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n=604$$\end{document}n=604) test sets, respectively. This fragment based model showed comparable accuracy in r\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_i$$\end{document}i prediction compared to conventional descriptor-based models that rely on known chemical structure, which obtained an \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R^2$$\end{document}R2 of 0.85 with an RMSE of 67.
Supplementary Information
The online version contains supplementary material available at 10.1186/s13321-023-00699-8.
... Furthermore, MEM has a low affinity for the adsorption to soil and sediment [6] and is likely to be persistent in the water column. In addition, due to the absence of chromophores, MEM is persistent to abiotic degradation pathways, such as photodegradation, and does not undergo hydrolysis, and is likely persistent to microbial degradation pathways [7]. To complicate matters, MEM is poorly metabolized in the human body and is therefore excreted largely unchanged [8]. ...
... Log K OW > 3 was interpreted as "potential to bioaccumulate in aquatic organisms". In 2011, Howard and Muir (2011) rated 92 out of 275 PhACs commonly detected in the environment as potentially bioaccumulative, using quantitative structure property relationships (QSPR). ...
There is increasing evidence that the presence of certain pharmaceuticals in the environment leads to biota exposure and constitute a potential risk for ecosystems. Bioaccumulation is an essential focus of risk assessment to evaluate at what degree emerging contaminants are a hazard both to the environment and the individuals that inhabit it. The main goals of the present review are 1) to summarize and describe the research and factors that should be taken into account in the evaluation of bioaccumulation of pharmaceuticals in aquatic organisms; and 2) to provide a database and a critical review of the bioaccumulation/bioconcentration factors (BAF or BCF) of these compounds in organisms of different trophic levels.
Most studies fall into one of two categories: laboratory-scale absorption and purification tests or field studies and, to a lesser extent, large-scale, semi-natural system tests. Although in the last 5 years there has been considerable progress in this field, especially in species of fish and molluscs, research is still limited on other aquatic species like crustaceans or algae. This revision includes >230 bioconcentration factors (BCF) and >530 bioaccumulation factors (BAF), determined for 113 pharmaceuticals. The most commonly studied is the antidepressant group, followed by diclofenac and carbamazepine. There is currently no reported accumulation data on certain compounds, such as anti-cancer drugs. BCFs are highly influenced by experimental factors (notably the exposure level, time or temperature). Field BAFs are superior to laboratory BCFs, highlighting the importance of field studies for reliable assessments and in true environmental conditions. BAF data appears to be organ, species and compound-specific. The potential impact on food web transfer is also considered. Among different aquatic species, lower trophic levels and benthic organisms exhibit relatively higher uptake of these compounds.
... In this study, we aimed to develop DGT devices for the monitoring of pharmaceuticals in surface waters. We selected high-priority pharmaceuticals identified for monitoring and risk assessment in multiple prioritization exercises (Bu et al., 2021;Bu et al., 2020;Howard and Muir, 2011;Huang et al., 2022;Li et al., 2019). Recently, the outbreak of coronavirus disease 2019 (COVID-19) has become a global health emergency (Fang et al., 2020). ...
Pharmaceutical contaminants in surface water have raised significant concerns because of their potential ecological risks. In particular, coronavirus disease 2019 (COVID-19)-related pharmaceuticals can be released to surface water and reduce environmental water quality. Therefore, reliable and robust sampling tools are required for monitoring pharmaceuticals. In this study, passive sampling devices of diffusive gradients in thin films (DGTs) were developed for sampling 35 pharmaceuticals in surface water. The results demonstrated that hydrophilic–lipophilic balance (HLB) was more suitable for DGT-based devices compared with XAD18 and XDA1 resins. For most pharmaceuticals, the performance of the HLB-DGT devices were independent of pH (5.0–9.0), ionic strength (0.001–0.5 M), and flow velocity (0–400 rpm). The HLB-DGT devices exhibited linear pharmaceutical accumulation for 7 days, and time-weighted average concentrations provided by the HLB-DGT were comparable to those measured by conventional grab sampling. Compared to previous studies, we extended DGT monitoring to include three antiviral drugs used for COVID-19 treatment, which may inspire further exploration on identifying the effects of COVID-19 on ecological and human health.
... Once HCQ has a high potential to persist, bioaccumulate, and transfer to living organisms, even in small quantities, the concern becomes greater, given the large amount of wastewater contaminated with hydroxychloroquine, which can reach aquatic matrices, persisting in the environment and causing damage to living beings (Dabić et al., 2019;Gosu et al., 2016;Howard and Muir, 2011;Ramesh et al., 2018). This perspective leads to studying efficient and lowcost processes that can eliminate these compounds . ...
The presence of drugs on a large scale in aquatic matrices raises concern and requires the study of efficient technologies to remove these compounds. This study investigated the adsorption capacity of the natural zeolite clinoptilolite (CP) in removing the drug hydroxychloroquine (HCQ). Zeolite was characterized by BET, XRD, FT-IR, SEM, and pHpzc techniques. The kinetic model that best fits the experimental data was the pseudo-first-order and the SIPS isotherm provided the best fit. The Langmuir isotherm RL separation factor (> 0.01) indicated that the adsorption process was favorable and the Freundlich isotherm (n > 1) suggested that the adsorption mechanism occurred mainly by physisorption, with intraparticle diffusion as the step limiting the process. The process was spontaneous (ΔG°ads < 0), endothermic (ΔH°ads > 0), and with increased randomness at the solid-solution interface (ΔS°ads > 0). The initial pH variation of the effluent was not favorable for the adsorption process and the zeolite was easily regenerated for later use. The ecotoxicological tests with Artemia salina and Lactuca Sativa proved that the final effluent did not show toxicity after the adsorption treatment. Based on the results obtained in this work, clinoptilolite zeolite is a potential adsorbent for reducing HCQ toxicity in aquatic matrices.
Supplementary information:
The online version contains supplementary material available at 10.1007/s11270-022-05787-3.
... However, prioritization is of utmost priority to accelerate Blaženović et al. (2018) the detection and tentative identification of suspects. Such prioritization was subsequently achieved by referring to predicted toxicity, information on uses and consumption pattern, environmental occurrence frequency, persistence nature, and extent of bioaccumulation (Howard and Muir 2011;Gosetti et al. 2015). As discussed earlier, searching for unknowns through the databases is the quickest and commonly used approach for the initial screening of compounds present in environmental samples. ...
Pharmaceutical compounds are nowadays ubiquitously detected in various environmental compartments around the world. As these compounds are present as complex mixtures and numerous other natural and anthropogenic chemicals, their transformation products (TPs), possible bio-conjugated counterparts, and their detection, quantification, and risk assessment prove extremely difficult. Recent advancements in mass spectrometry coupled with liquid chromatography (LC-MS) have enabled the detection of polar compounds with better reliability, precision, and accuracy. However, detecting trace levels of pharmaceuticals from complex matrices requires highly sensitive and selective techniques and sophisticated sample preparation steps to avoid analyte loss during sample preparation or in transit. Additionally, target analysis involves the use of expensive pharmaceutical standards and the corresponding isotope-labelled internal standards (ISs). Hence, before target analysis, it is much more viable to conduct suspect or nontarget analyses to obtain a more holistic understanding of the nature and composition of such contaminants present in environmental samples. This chapter aims to compare and compile the recent trends in suspect and nontarget screening of pharmaceuticals present in the water and wastewater matrices. Detailed information on the various mass banks, mass analyzers, and workflows for the screening of such contaminants are discussed here in detail.KeywordsPharmaceuticalsWastewaterSurface waterSuspect screeningNontarget screening
... toxicity). 2,3 Most of the chemicals in the human exposome are structurally unknown and therefore there is little known about their occurrence, fate, and potential health impact [4][5][6][7][8][9] Non-target analysis (NTA) combined with high-resolution mass spectrometry (HRMS) is considered one of the most comprehensive strategies for the detection and identification of the unknown chemicals of emerging concern (CECs) in complex biological and environmental samples. 2,8,[10][11][12][13][14][15][16] The NTA experiments are reliant on generic experimental conditions as they aim to cover as wide a portion of the sample chemical space as possible. ...
Non-target analysis combined with high resolution mass spectrometry is considered one of the most comprehensive strategies for the detection and identification of known and unknown chemicals in complex samples. However, many compounds remain unidentified due to data complexity and limited structures in chemical databases. In this work, we have developed and validated a novel machine learning algorithm to predict the retention index (r$_i$) values for structurally (un)known chemicals based on their measured fragmentation pattern. The developed model, for the first time, enabled the predication of r$_i$ values without the need for the exact structure of the chemicals, with an $R^2$ of 0.91 and 0.77 and root mean squared error (RMSE) of 47 and 67 r$_i$ units for the Norman and amide test set, respectively. This fragment based model showed comparable accuracy in r$_i$ prediction compared to conventional descriptor-based models that rely on known chemical structure, which obtained a $R^2$ of 0.85 with and RMSE of 67.
... Polar PhCs are generally water-soluble, so they easily disperse in aquatic environments. In aquatic environments, the spread of hydrophobic PhCs is relatively restricted and much slower, since they tend to accumulate in organisms' fatty tissues (Howard and Muir, 2011). ...
... Thanks to its anti-inflammatory and antiviral effects, HCQ has been recently proposed as a possible treatment for Coronavirus (Sinha and Balayla 2020;Gautret et al. 2020) and the interest in its potential therapeutic use continues to grow. HCQ is classified among the pharmaceutical contaminants of emerging concern due to its persistence, bioaccumulation and possible transfer to living organisms (Howard and Muir 2011;Gosu et al. 2016). This emphasizes the need for efficient degradation technologies able to eliminate HCQ from water. ...
One of the advanced oxidative processes is gamma irradiation, an efficient technique for removing pesticides and pharmaceutical products. Radiolytic degradation leads to free radical's formation, which facilitates molecular lesion and breaks the chemical bonds. The use of pharmaceutical compounds, such as hydroxychloroquine (HCQ), is increasing nowadays due to the Covid 19 pandemic situation. This study focused on gamma radiation-induced degradation of HCQ in aqueous solution. The degradation was monitored by High-Performance Liquid Chromatography (HPLC) using an Eclipse XDB-C18 column (150 × 3.0 mm, 3.5 µm) and a mobile phase composed of 94% water (phosphate buffer at pH = 3.6) and 6% acetonitrile, with a DAD detection at λ = 343 nm. The effect of different gamma radiation doses (from 0.05 to 3 kGy) was investigated. Chromatographic analysis shows that 1 kGy dose is effective to degrade completely HCQ at 20 ppm and following a first-pseudo-kinetic order with a dose constant corresponding to 4.2 kGy-1. A comparison was done between gamma degradation and other methods. LC-QToF-MS/MS identified the intermediate products, and their kinetic constants were determined. A mechanism pathway was proposed for HCQ degradation under gamma irradiation.
Graphical abstract:
... However, it is unclear whether these CAEs are present in food; therefore, it is critical to assess this aspect and the human health risk associated with CAE intake via diet. Recently, high-resolution mass spectrometry (HRMS)-based suspect and non-target screening has become an effective tool for identifying overlooked site-specific and potentially hazardous substances, such as pharmaceuticals (Howard and Muir, 2011;Singer et al., 2016;Vergeynst et al., 2015), registered pesticides and associated transformation products (Lopez et al., 2016;Moschet et al., 2014), illegal additives (Fu et al., 2016), and OPEs Ye et al., 2021) in environmental samples. A recent study on the screening of potential CAEs in indoor dust developed an integrated target, suspect, and characteristic fragment-dependent screening strategy to identify novel CAEs or CAE-like chemicals, which led to the identification of TBA, a frequent and abundant CAE (Zhang et al., 2021). ...
An increasing number of studies on the toxicities of citric acid esters (CAEs)—a class of so-called “safe” alternative plasticizers—have highlighted the urgent need to understand their contamination profiles in foodstuffs and the corresponding potential risks to human health. This study determined the concentrations of 8 target CAEs in 105 foodstuff samples, grouped into 6 food categories, collected from Nanjing City, China, in 2020. All eight CAEs were detected in at least one of the analyzed samples and had detection frequencies (DFs) of 5–47%. The DFs and distribution profiles of the target CAEs varied between the different food categories; for example, cereals had the highest DF (92%), while meat/fish contained the highest mean total concentration of CAEs (8.35 ng/g wet weight (ww)). Among the target CAEs, acetyl tributyl citrate (ATBC) had the highest DF (47%), and tributyl citrate (TBC) exhibited the highest mean concentration (1.24 ng/g ww). Based on the food ingestion route, the estimated total daily intake (EDI) values of the target CAEs for adults under average- and high-exposure scenarios were 38.3 ng/kg of body weight (bw) and 111 ng/kg bw, respectively, which were attributed to the high percentage contributions of TBC (50.6%) and ATBC (23.7%). In addition, a suspect and characteristic fragment-dependent screening strategy was applied to the foodstuff data, and a novel CAE, monoethyl citrate (MEC, CAS: 4552-00-5), with a DF of 34% was tentatively identified. Overall, this study provides novel and comprehensive information regarding the pollution status of CAEs in foodstuffs.
... The highest concentration of ACV in surface waters was measured in the United States at 1,410 ng L À1 (Bradley et al. 2014). The concentration levels of EFV indicate that it is a recalcitrant antiviral drug (Schoeman et al. 2017); the drug has a high volume of production and is likely to be persistent and/or bioaccumulative (Howard & Muir 2011). EFV was detected in effluents at concentrations of 17.4 to 34 μg L À1 (Schoeman et al. 2015;Abafe et al. 2018) and in surface waters at a maximum concentration of 2.45 μg L À1 (Mtolo et al. 2019). ...
Antiviral drugs are a class of medications used for treating viral infections. Due to their widespread use, especially in cases of pandemics and limited human metabolism, antivirals have been detected in multiple environmental matrices. This study aims to evaluate the chronic effects of acyclovir, efavirenz, lamivudine and zidovudine using Ceriodaphnia dubia and Raphidocelis subcapitata. The results with R. subcapitata showed the following toxicities: zidovudine (IC50 = 5.442 mg L−1) < acyclovir (IC50 = 3.612 mg L−1) < lamivudine (IC50 = 3.013 mg L−1) < efavirenz (IC50 = 0.034 mg L−1). The results of the chronic bioassay with C. dubia demonstrated that zidovudine is the least toxic (EC50 = 5.671 mg L−1), followed by acyclovir (EC50 = 3.062 mg L−1), lamivudine (EC50 = 1.345 mg L−1) and efavirenz (EC50 = 0.026 mg L−1). Both species have been shown to be sensitive to efavirenz. A risk quotient (RQ) was calculated, and efavirenz had an RQ greater than 1 for both species, and lamivudine had an RQ greater than 1 for C. dubia, representing a high ecological risk for these organisms. Antivirals pose a significant environmental risk to aquatic organisms and should be taken into consideration in future monitoring of water sources.
HIGHLIGHT
Very few studies have been published about antivirals toxicity in aquatic organisms. This study is important not only to increase the availability of ecotoxicological data, but also improves the relevance of environmental risks. Results found that Efavirenz was the most toxic for species, suggesting that environmental concentrations can affect the exposed biota. We declare that this manuscript is original.
... Due to long and highly branched side chains, and sulfate, nitrogen or halogen groups, these compounds had different risk patterns from other drugs of this class. These environmentally high-risk drugs were not commonly included in prioritization exercises; however, chlorpromazine was on priority lists reported previously (Howard and Muir 2011;Sangion and Gramatica 2016). Frédéric and Yves (2014) identified chlorpromazine as one of the 15 most high-riskdrugs in hospital wastewater (Frédéric and Yves 2014). ...
This research aimed to identify high-risk pharmaceutically active compounds (PhACs) by analyzing occurrence (O), persistence (P), bioaccumulation (B), and toxicity (T) of 62 drugs which are widely used in Iran. A comprehensive approach was taken in risk assessment of the selected PhACs and in their prioritization using multiple-criteria decision analysis (MCDA) such as utility functions and principal component analysis (PCA). In practice, assigning weight to each criterion (i.e., O, P, B, and T) for risk assessment of PhACs is a challenge. In this research, the impact of giving both equal and unequal weight to each criterion by using a quantitative entropy method was studied. For risk assessment, two exposure approaches (consumption rate and occurrence of PhACs) and three MCDA approaches (PCA and utility functions with and without equal weights for each criterion) were compared. The utility function using equal weights for all O, P, B, and T criteria showed that thioridazine, pimozide, chlorpromazine, sertraline, clomipramine, and aripiprazole were at the highest level of risk, with concern score of 0.75, 0.75, 0.67, 0.58, 0.58, and 0.58, respectively. Unequal weight approach included additional compounds such as fluoxetine, citalopram, and methadone as a priority. All three MCDA approaches showed that sedatives and antidepressants were prevalent PhACs in the risk-based priority lists. However, the exposure-based approaches showed antibiotics and analgesics as the pharmaceutical of the highest priority. Overall, selection of the high priority concern pharmaceuticals depends on the prioritization approach employed. However, the utility function using unequal weights is a more conservative and effective approach for prioritization.
... It is worth to mention that, several compounds included in the 3rd revision of the EU watch list of water pollutants (i.e., imazalil, clotrimazole, miconazole, venlafaxine and its O-demethylated form) were identified in sludge using the non-target DDA mode. Other species included in Table 3, such as levomethadone/methadone, amiodarone, lamotrigine, raloxifene, cyclobenzaprine, trazodone and chlorhexidine are included in the list of high production volume pharmaceuticals (Howard and Muir, 2011). To the best of our knowledge, pharmaceuticals as carvedilol, cinnarizine, cyclobenzaprine, dextorphan, octamylamine and raloxifene; and the fungicides amorolfine and hexetidine, are reported in sludge for the first time. ...
Sludge from sewage treatment plants (STPs) is recognized as a sink of moderate to high lipopHilic compounds resistant to biodegradation. Herein, we investigate the presence of emerging pollutants in sewage sludge combining the information provided by mass spectrometry detection, following ultra-performance liquid chromatography (UPLC), with the use of an accurate spectral database of pesticides and pharmaceuticals. In a first step, the performance of matrix solid-phase dispersion, as sample preparation technique, and two non-target data acquisition strategies (data dependent, DDA, and data independent analysis modes, DIA), used in combination with a UPLC quadrupole time-of-flight system, are assessed using a selection of deuterated compounds added either to freeze-dried sludge samples, or to sludge extracts. Possibilities and limitations of both modes are discussed. Following the DDA approach, a group of 68 micropollutants was identified in sludge from different STPs. Some of them are reported in this compartment for the first time. Finally, semi-quantitative concentration data are reported for a group of 37 pollutants in samples obtained from 16 STPs. Out of them, 10 pharmaceuticals, showing detection frequencies and median sludge residues above 50% and 100 ng g⁻¹, respectively; are highlighted as pollutants to be monitored in sludge in order to understand their behaviour during the wastewater treatment.
... PhACs can affect ecosystems even at low concentrations. They may cause adverse effects, since some of them are cytotoxic, carcinogenic, mutagenic, ecotoxic, embryotoxic, act as endocrine disruptors or promote the spread of antibiotic resistant genes/organisms; undesired effects can be enhanced when considering chronic exposure, bioaccumulation and mixtures of several compounds (B artíkov a et al., 2016;Charuaud et al., 2019;Couto et al., 2019;Daughton and Ternes, 1999;Desbiolles et al., 2018;Howard and Muir, 2011;Larsson, 2014;Majumder et al., 2019;Pomati et al., 2006;Puckowski et al., 2016;Williams-Nguyen et al., 2016;W€ ohler et al., 2020;Zhang et al., 2020). ...
The presence of pharmaceuticals in the environment is known to have multiple origins; livestock activities comprise one scarcely studied source, both globally and specially in Latin-America. This work aims to study the occurrence of pharmaceuticals in wastewater from swine farms and their surrounding surface waters, in a highland livestock production area of Costa Rica. The monitoring of 70 pharmaceutical active compounds resulted in the detection of 10 molecules in farm wastewater (influents and effluents of the on-farm treatment system), including compounds of animal and human use. A 57% of effluents showed high hazard (ΣHQ>1), mainly due to the compounds risperidone, ketoprofen, ibuprofen and naproxen. Additionally, ecotoxicological tests with Daphnia magna and Microtox classified at least 21% of the effluents as very toxic (10<TU≤100); likewise, 86% of effluents exhibited germination index (GI) inhibition values over 90% for Lactuca sativa. Seven molecules were detected in surface water, six of them of human use (1,7-dimethylxanthine, caffeine, cephalexin, carbamazepine, gemfibrozil, ibuprofen) and one (acetaminophen) of dual (human and veterinary) use; nonetheless, most of the detections were found in sampling points closer to human settlements than animal farms. Considering the set of molecules and their distribution, the livestock influence on surface water seems minimal in comparison with the urban influence. Only 16% of surface water samples showed high risk, mainly due to ibuprofen, gemfibrozil and caffeine; similarly, 45% samples presented GI inhibition >20% (no toxicity was determined towards Daphnia magna or Microtox). These findings in surface water suggest an incipient environmental risk in the area.
... Thus, a research need exists to determine the concentrations of pharmaceuticals, PFAS, and microplastics in lamprey. Both human-use pharmaceuticals and veterinary medicines from intensive livestock treatments and aquaculture have been found in aquatic ecosystems (Benotti et al., 2009;Howard and Muir, 2011). PFAS are synthetic compounds used in a variety of industrial and consumer products, including stain-resistant fabric and carpet treatments, oil-resistant coatings for food packaging, hydraulic fluids, and aqueous film forming foams (AFFF) used during firefighting training exercises (Harris et al., 2017;Hu et al., 2016;Lescord et al., 2015). ...
Environmental contamination is of global concern. Lamprey are scientifically, ecologically, culturally, and economically important fishes. Our study represents the first synthesis ever on environmental contamination in lamprey. Objectives of this study include: (1) evaluate lethal and sublethal effects of environmental contaminants on lamprey, thereby providing insight into the potential for environmental contaminants to affect lamprey abundance, (2) highlight the unique characteristics of contaminant accumulation in lamprey, (3) determine whether spatial and temporal trends observed in contaminant concentrations of other top predators of aquatic food webs are reflected in the spatial and temporal trends of contaminant concentrations of lamprey, (4) identify key environmental contaminants affecting consumption advisories for people eating lamprey, and (5) identify important gaps in our knowledge of environmental contamination in lamprey. The geographic scope of this synthesis is worldwide. We conclude that, in general, the environmental contaminant concentrations that have been experienced by lamprey in the wild appear to be nonlethal to lamprey. However, environmental contaminants exert sublethal effects on lamprey. Sea lamprey (Petromyzon marinus) and Pacific lamprey (Entosphenus tridentatus) are relatively high in total mercury (Hg) concentration compared with other fishes. Compared with other top predators, lamprey are relatively low in polychlorinated biphenyl (PCB) concentration and concentrations of organochlorine pesticides. We also conclude that regulations on the use of PCBs, beginning in the 1970s, were effective in dramatically reducing PCB concentration in lamprey since the 1970s. Emerging contaminants, such as pharmaceuticals, microplastics, and per- and polyfluorinated alkyl substances (PFAS), have yet to be studied in lamprey.
Early identification of new and emerging risk chemicals (NERCs) is critical in protecting human and environmental health while chemical invention and production is growing on a global market. Chemicals market data is information on the production, import, and use of chemicals in materials and products. By integration of chemicals market data with suspect screening strategies NERCs could potentially be detected early. In silico tools play an important role in this integration to identify blind spots in current analytical approaches and in identification of the potentially most hazardous chemicals. This chapter starts with a brief presentation of the term “chemicals market data.” The integrated approach is then presented in three steps: (1) Data collection and curation, (2) Scoring, ranking, and filtering, and (3) Suspect screening. Each step is first presented conceptually and then exemplified with use cases from the authors. The use of chemicals market data provides a solid basis for identification of true NERCs with confidence, and true and false negative findings can more confidently be distinguished. Chemicals market data should be provided to authorities and researchers so that early warning systems for NERCs can be installed and analytical blind spots identified and addressed.
Exposure to environmental organic pollutants has triggered significant ecological impacts and adverse health outcomes, which have been received substantial and increasing attention. The contribution of unidentified chemical components is considered as the most significant knowledge gap in understanding the combined effects of pollutant mixtures. To address this issue, remarkable analytical breakthroughs have recently been made. In this review, the basic principles on recognition of environmental organic pollutants are overviewed. Complementary analytical methodologies (i.e., quantitative structure-activity relationship prediction, mass spectrometric nontarget screening, and effect-directed analysis) and experimental platforms are briefly described. The stages of technique development and/or essential parts of the analytical workflow for each of the methodologies are then reviewed. Finally, plausible technique paths and applications of the future nontarget screening methods, interdisciplinary techniques for achieving toxicant identification, and burgeoning strategies on risk assessment of chemical cocktails are discussed.
The application of chloroquine (CLQ) due to its antibacterial/antiviral nature and high potential of being persistent and bioaccumulative poses a significant environmental threat. In this study, the electro-Fenton (EF) process with pyrite (FeS2)-modified graphite felt (FeS2/GF) as the cathode (EF-FeS2/GF), capable of providing a stable acidic environment with a solution pH of 3.0 was constructed and found to (i) achieve 83.3 ± 0.4% 60 min CLQ removal and (ii) maintain about 60.0% CLQ removal during consecutive batch tests. FeS2 loading amount, current density applied, and spacing between electrodes all influenced the efficacy of EF-FeS2/GF, with the optimum CLQ removal obtained at 10 mg, 150 mA, and 2.0 cm, respectively. Adsorption and electrocatalysis were both observed to contribute to the CLQ removal while the EF process with the verified functioning of ·OH played a dominant role. Based on the detected intermediates with identified ecotoxicities, two main paths were postulated to describe the degradation processes which led to the mineralization of CLQ. These findings supported that the EF-FeS2/GF could be an efficient technology to treat wastewater contaminated with CLQ.
Seasonally ice-covered reservoirs have both freeze-thaw and artificial regulation characteristics which could cause the accumulation of antibiotics. Florfenicol, one of the most widely used veterinary antibiotics, with an environemental persistence due to its fluorinated substituents has been detected in the suburban drinking water source reservoris. In this study, a four-level fugacity model that is appropriate for ice-water-sediment systems was developed to predict the fate of florfenicol and assess its ecological risk in seasonally ice-covered reservoirs. The effects of freeze-thaw and artificial regulation processes on the volume variation of ice and water were considered by the model. The simulation accuracies in ice and water in the model were improved by 3.9% and 17.7%, respectively, compared with the traditional model. The results of mass transfer analysis showed that the inflow of florfenicol in tributaries and the volume variation of ice and water were the major factors influencing the concentration variation of florfenicol in the seasonally ice-covered reservoir. Additionally, ecological risk analysis showed that the values of risk quotients ranged from 0.019 to 0.038 which was consistently at a low ecological risk level. Our findings provide a modeling tool for predicting the fate of antibiotics with persistence and assessing their ecological risks in seasonally freeze-thaw reservoirs in cold regions.
The European and U.S. chemical agencies have listed approximately 800k chemicals about which knowledge of potential risks to human health and the environment is lacking. Filling these data gaps experimentally is impossible, so in silico approaches and prediction are essential. Many existing models are however limited by assumptions (e.g., linearity and continuity) and small training sets. In this study, we present a supervised direct classification model that connects molecular descriptors to toxicity. Categories can be driven by either data (using k-means clustering) or defined by regulation. This was tested via 907 experimentally defined 96 h LC50 values for acute fish toxicity. Our classification model explained ≈90% of the variance in our data for the training set and ≈80% for the test set. This strategy gave a 5-fold decrease in the frequency of incorrect categorization compared to a quantitative structure-activity relationship (QSAR) regression model. Our model was subsequently employed to predict the toxicity categories of ≈32k chemicals. A comparison between the model-based applicability domain (AD) and the training set AD was performed, suggesting that the training set-based AD is a more adequate way to avoid extrapolation when using such models. The better performance of our direct classification model compared to that of QSAR methods makes this approach a viable tool for assessing the hazards and risks of chemicals.
This study investigated the properties of bioaccumulation, tissue-specific accumulation, and depuration of liquid crystal monomers (LCMs) in adult zebrafish (Danio rerio) exposed to a mixture of 39 LCMs for 19 days followed by depuration for 12 days. Tissue-specific accumulation of LCMs was examined at the time point of day 19, and we observed that the distribution of LCMs varied among different tissues with the following order of Σ39LCM concentrations, the intestine > brain > gill > liver > muscle. We also observed that the bioaccumulation potential of LCMs varied among LCM groups with different functional groups, and LCMs with the cyan group were prone to accumulate in zebrafish. Among the 39 target LCMs, nine exhibited bioconcentration factors (BCFs) >1000, indicating their great bioaccumulation potential in aquatic environments. The experimental BCFs of 22 LCMs in the present study were lower than the theoretical values predicted by the Estimation Programs Interface (EPI) Suite software developed by U.S. Environmental Protection Agency (USEPA), suggesting that their bioaccumulation potential might be overestimated by theoretical estimation techniques. Another interesting finding was the significant positive correlation relationship in both sexes of zebrafish (p < 0.01, r² = 0.66 for male; p < 0.01, r² = 0.41 for female) between logBCFww and logKow values of LCMs. Overall, this study provides fundamental information regarding the bioaccumulation potentials of LCMs, which could be helpful for further investigating the health risks of LCMs in aquatic environments.
The European Chemicals Agency (ECHA) and US Environmental Protection Agency (EPA) have listed approximately 800k chemicals that must be further investigated for their potential environmental and/or human health risk. A significant number of these chemicals have large enough global volumes of consumption (e.g. industrial and agro- chemical) to reach the limits of detection of our analytical chemistry methods in en- vironmental samples, but experimental data on their environmental fate and toxicity are largely missing. Filling these data gaps experimentally for such a large number of chemicals is practically impossible, making model approaches to predict chemical property data highly relevant. However, the currently available models suffer from limited training sets, linearity and continuity assumptions. In this study we present a supervised direct classification model that directly connects the molecular descriptors of chemicals to their toxicity. As a proof of concept we used 907 experimentally defined 96h LC50 values for acute fish toxicity. Classification was performed into two typesof toxicity categories: 1) categories derived via k-means clustering from the experimental dataset and 2) hazard categories defined by the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), via machine learning. Our direct classification model explained ≈ 90% of variance in our data for the training set and ≈ 80% for the test set. Direct comparison of our classification model with the conventional strategy (i.e. QSAR regression model) resulted in a 5 fold decrease in the wrong chemical categorization for our model. The optimized model was employed to predict the toxicity categories of ≈ 32k chemicals (from the Norman SusDat). Finally, a comparison between the model based applicability domain (AD) vs the training set AD was performed, suggesting that the training set based AD is a more adequate way to avoid extrapolation when using such models. The better performance of our direct classification model compared to conventionally employed QSAR methods, makes this approach a viable tool for hazard identification and risk assessment of chemicals.
The European Chemicals Agency (ECHA) and US Environmental Protection Agency (EPA) have listed approximately 800k chemicals that must be further investigated for their potential environmental and/or human health risk. A significant number of these chemicals have large enough global volumes of consumption (e.g. industrial and agro- chemical) to reach the limits of detection of our analytical chemistry methods in en- vironmental samples, but experimental data on their environmental fate and toxicity are largely missing. Filling these data gaps experimentally for such a large number of chemicals is practically impossible, making model approaches to predict chemical property data highly relevant. However, the currently available models suffer from limited training sets, linearity and continuity assumptions. In this study we present a supervised direct classification model that directly connects the molecular descriptors of chemicals to their toxicity. As a proof of concept we used 907 experimentally defined 96h LC50 values for acute fish toxicity. Classification was performed into two typesof toxicity categories: 1) categories derived via k-means clustering from the experimental dataset and 2) hazard categories defined by the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), via machine learning. Our direct classification model explained ≈ 90% of variance in our data for the training set and ≈ 80% for the test set. Direct comparison of our classification model with the conventional strategy (i.e. QSAR regression model) resulted in a 5 fold decrease in the wrong chemical categorization for our model. The optimized model was employed to predict the toxicity categories of ≈ 32k chemicals (from the Norman SusDat). Finally, a comparison between the model based applicability domain (AD) vs the training set AD was performed, suggesting that the training set based AD is a more adequate way to avoid extrapolation when using such models. The better performance of our direct classification model compared to conventionally employed QSAR methods, makes this approach a viable tool for hazard identification and risk assessment of chemicals.
Most chemicals present in the human and environmental exposome are structurally unknown (i.e. ≤ 1%). The European Chemicals Agency (ECHA) and US Environmen- tal Protection Agency (EPA) have listed approximately 800k chemicals that must be further investigated for their potential environmental and/or human health risk. A sig- nificant number of these chemicals have large enough global volumes of consumption (e.g. industrial and agrochemical) to reach the limits of detection of our analytical chemistry methods and may be toxic. In this study we present a supervised classification model that directly connects the molecular descriptors of chemicals to their toxicity. As a proof of concept we used 907 experimentally defined LC50 values for acute fish toxicity. Our classification model explained ≈ 90% of variance in our data for the training set and ≈ 80% for the test set. Direct comparison of our classification model with the conventional strategy (i.e. QSAR regression models) resulted in a 5 fold decrease in the wrong chemical categorization for our model. This optimized model was employed to predict the toxicity categories of ≈ 32k chemicals (from the Norman SusDat). Finally, a comparison between the model based applicability domain (AD) vs the training set AD was performed, suggesting that the training set based AD is a more adequate way to avoid extrapolation when using such models. The better performance of our direct classification model compared to conventionally employed QSAR methods, makes this approach a viable tool for hazard identification and risk assessment of chemicals.
In the race of technological advancement for better health and better lifestyle, research has founded a strong base to bring out new antibiotics, vaccines, generic medications, and personal care products (PCPs) for the people. On the other hand, the risk and effects concerning residues of pharmaceuticals and personal care products (PPCPs) in the urban environment are a vital challenge to combat. The biotic components of the environment are most vulnerable to the impacts induced by PPCPs. Though the PPCPs are detected in the range of nanograms per liter to micrograms per liter in water, air, and soil, they are potential endocrine disruptors and carcinogens, environmentally persistent, and hostile. Correlations between urban lifestyles, healthcare infrastructures, and PPCPs clearly pose threatening images on the fate, transport, and effects of PPCPs. Hence, this chapter individually focuses on the origin of PPCPs in the environment, the fate and transport of PPCPs in urban environment, and eco-toxicological impacts on aquatic and human genera by providing strong evidence and finally presents the prospective on PPCPs and plausible future trends in urban environments.KeywordsPPCPsWastewaterAntibioticsUrban environmentsFate and transport
Recent studies have suggested that liquid crystal monomers (LCMs) are emerging contaminants in the environment, and knowledge of this class of substances is very rare. Here, we reviewed existing LCM-related documents, i.e., publications and patents, and established a database involving 1173 LCMs. These 1173 LCMs were further calculated for their physicochemical properties, i.e., persistence (P), bioaccumulation (B), long-range transport potential (LRTP), and Arctic contamination and bioaccumulation potential (ACBAP). We found that 476 out of them were P&B chemicals (99% of them were halogenated), and 320 of them could have ACBAP properties (67% of them were halogenated). This LCM database was further applied for suspect screening of LCMs in n = 33 sediment samples by use of gas chromatography coupled to quadrupole time-of-flight mass spectrometry (GC-QTOF/MS). We tentatively identified 26 LCM formulas, which could have 43 chemical structures. Two out of these 43 suspect LCM candidates, 1-butoxy-2,3-difluoro-4-(4-propylcyclohexyl) benzene (3cH4OdFP) and 1-ethoxy-2,3-difluoro-4-(4-pentyl cyclohexyl) benzene (5cH2OdFP), were fully confirmed by a comparison of unique GC and MS characteristics with their authentic standards. Overall, our present study expanded the previous LCM database from 362 to 1173, and 1173 LCMs in this database were calculated for their physicochemical properties. Meanwhile, taking n = 33 sediment samples as an exercise, we successfully developed a suspect screening strategy tailored for LCMs, and this strategy could have promising potential to be extended to other environmental matrices.
The first half of the chapter deals with two emerging trace organic micropollutants (OMPs), namely pharmaceutically active compounds (PhACs) and endocrine disrupting chemicals (EDCs). Their residues in the environment may pose greater ecological risks to aquatic biota as they are in direct contact with wastewater contaminants. The environmental behavior of both PhACs and EDCs has not been very much explored, especially in tropical coastal marine systems. There is an urgent need for interdisciplinary research involving point source emission locations, coastal hydrodynamics, and exposure risks of these OMPs in coastal environments.
The second half illustrates the origin, characteristics, and concentrations of the priority pollutants such as hexachlorocyclohexane (HCH) isomers (HCHs), dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDTs), hexachlorobenzene, and congeners of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons in the intertidal sediments of the coastal regions of Indian Sundarban wetland. In addition, a class of organobromine compounds (polybrominated diphenyl ethers) and the organofluorine compound (perfluorinated compounds) has also been discussed along with their suitable and sustainable remedial strategies.
The use of antimicrobials for the treatment of plant diseases is limited due to efficacy, availability, economic feasibility, and human and environmental concerns. In plants, diseases caused by bacteria are less common than the issues caused by viruses and fungi. Antimicrobial agents such as livestock and poultry are used in agriculture since the 1950s for the treatment of plant infections and improvement of growth. The utilization of antimicrobial agents in agriculture which are also used in humans increases the chances of resistance or cross-resistance development to the drugs used in human medicines which can potentially affect the treatment of human disease. The monitoring and surveillance of drug resistance are not done routinely which makes this problem more severe. The World Health Organization (WHO) has recommended not using antimicrobial growth promoters in agriculture that are used in humans as antimicrobial class drugs. Only streptomycin and oxytetracycline antimicrobials are currently registered by the Environmental Protection Agency (EPA) for their use in plant agriculture. The appropriate and effective use of antimicrobial agents needs combined and collaborative efforts from agricultural, medical, veterinary, and public health communities. Replacements to antimicrobial agents like transgenic plants, biocontrol agents, and novel chemicals are being developed; however, their practical applications, efficacy, and safety over time are yet to be determined.
Since the phase-out of traditional halogenated flame retardants (HFRs), interests of research are gradually being shifted to organophosphate flame retardants (OPFRs), and this can be reflected by the increasing number of publications on OPFRs year by year. Here, an extensive survey is conducted in an attempt to generate a list of OPFRs that are being produced in factories, and to investigate the annual production volume (APV). This survey suggests that at least n = 56 OPFR monomers and n = 62 OPFR mixtures are being currently produced in 367 factories around the world, and 201 out of them are in Mainland China. APV of OPFRs was estimated as 598,422 metric tons, and this number could be underestimated due to the limitation of available information. We also notice that current researches are confined to a limited number of OPFRs, especially for OP esters (OPEs), and other OPFRs with different structures from OPEs has been rarely studied. Based on all the collected datasets, we provide five recommendations for how to proceed with future research to more comprehensively understand the currently-produced OPFRs in the environment.
Planetary boundaries delimit a ‘safe operating space for humanity’ that should not be overstepped to maintain stable Holocene-like conditions on Earth. Some chemical pollutants have the potential to pose a planetary boundary threat to the functioning of vital Earth system processes as so-called ‘novel entities’. Recently, an exposure-based prioritization scheme was developed that uses model-estimated data on persistence and degree of mobility in air and water to identify and prioritise chemical substances that may be planetary boundary threats. As a case study, chemicals of emerging Arctic concern identified by the Arctic Monitoring and Assessment Programme (AMAP) were used to develop the scheme. The exposure-based prioritization scheme cannot address all scenarios for a chemical to pose an unknown planetary boundary threat, but it does allow for prioritization of chemicals according to environmental fate and exposure profiles. A key limitation of the scheme is that the quantity of chemical potentially released to the environment was not considered in the prioritization. Here, we use data on chemical production and use reported under the European chemicals regulation REACH, and an emission scoring system developed by the European Food Safety Authority (EFSA) to attempt to add information about estimated emissions to the exposure-based prioritization scheme. Using REACH data and the EFSA scoring system, we ranked the AMAP substances according to their potential for environmental release and combined that information with the previously reported exposure-based prioritization that considers persistence and long-range transport potential. Our method successfully assigned ‘high priority’ to known ozone-depleting substances (methyl chloride and dichloromethane) and identified chemicals of concern recently under consideration for nomination as persistent organic pollutants under the Stockholm Convention (octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane). The EFSA scoring system offers a useful starting point that provided useful additional information in the case study for chemicals of emerging Arctic concern, but lack of information to estimate potential releases of chemicals was a major limitation.
Liquid crystal monomers (LCMs) were recently proposed as persistent, bioaccumulative, and toxic substances; however, there is a dearth of information regarding their experimental octanol-water partition coefficients (KOW). In the present study, we determined the experimental KOW values of these 39 LCMs by use of a classic shake-flask method. We observed that experimental KOW values of LCMs largely varied depending on their specific structures, and the Log transformed KOW generally fall in the range of 4.94-7.62. The experimental KOW values were further compared with those predicted by Estimation Programs Interface (EPI) Suite software. Interestingly, we observed that experimental and estimated Log KOW values were generally comparable for LCMs containing two benzene or cyclohexane rings; however, the estimated values gradually deviated from the experimental ones as the number of benzene or cyclohexane rings of LCM structures increased. Based on the experimental Log KOW values of 39 LCMs, we established a quantitative structure activity relationship (QSAR) model for predicting Log KOW values of other LCMs, for which authentic standards are not available. Adjusted square of determination coefficient (R2) of the developed model is 0.810, indicating its goodness-of-fit for estimation of Log KOW values of other substances with similar backbone structures. Overall, our present study provides the first insight on experimental Log KOW values of LCMs, and suggests that LCMs are inclined to accumulative in the fatty tissue of organisms in the aqueous environments.
The present work focuses on the ecotoxicological effects of montelukast sodium (MTL) and its photoproducts, obtained under environmentally-like conditions. Despite of the potential presence in surface waters and the common use of MTL as asthma drug, limited data has been published for its photodegradation, while no information is available for its ecotoxicity. Light-induced degradation is an effective way for drugs to degrade in aquatic environments, and MTL is highly photosensitive, even by exposure to sunlight. In this study, solar-simulated irradiation of the drug in water was investigated. The drug was quickly converted into a series of photoproducts that were spectroscopically characterized. The possible photoreaction pathways were proposed. Ecotoxicity tests were performed on parent compound and mixture of photoproducts towards two bioindicators (Raphidocelis subcapitata and Daphnia magna). Results evidenced that effects of MTL on D. magna (EC50 = 16.4 mg/L) were greater than effects on R. subcapitata (EC50 = 195.7 mg/L). Microscopy observations revealed that MTL had mainly accumulated in the gut of daphnia. Toxicity data on photolysed solutions highlighted the presence of residual toxicity in all samples, evidencing that no complete mineralization occurred. Future research should focus on monitoring of MTL concentrations in the environment and study its effects in bioaccumulation tests.
The presence and fate of antifungal agents in the environment have hardly been investigated. This is despite the increased usage of antifungal agents and higher prevalence of antifungal resistance. Stereochemistry of antifungal agents has been largely overlooked due to lack of analytical methods enabling studies at the enantiomeric level. This paper introduces a new analytical method for combined separation of achiral and chiral antifungal agents and their metabolites with the utilization of chiral chromatography coupled with triple quadrupole tandem mass spectrometry to enable comprehensive profiling of wide-ranging antifungal agents and their metabolites in environmental matrices. The method showed very good linearity and range (r2 > 0.997), method accuracy (61-143%) and precision (3-31%) as well as low (ng L-1) MQLs for most analytes. The method was applied in selected environmental samples. The following analytes were quantified: fluconazole, terbinafine, N-desmethyl-carboxyterbinafine, tebuconazole, epoxiconazole, propiconazole and N-deacetyl ketoconazole. They were predominantly present in the aqueous environment (as opposed to wastewater) with sources linked with animal and plant protection rather than usage in humans. Interestingly, chiral fungicides quantified in river water were enriched with one enantiomer. This might have consequences in terms of their ecological effects which warrants further study.
In the past half-century, scientists were mostly concerned with polychlorinated compounds (dioxins, polychlorinated biphenyls (PCBs), etc.). But in the last decades, polybrominated compounds [especially polybrominated diphenyl ethers (PBDE) present in various materials as flame retardants] became more and more present in the environment, causing a new set of problems, and subsequently challenges. Therefore researchers focused on PBDE degradation processes, one of them being the microbiological one. However, there are other brominated compounds polluting the environment (e.g., hexabromocyclododecane, tetrabromobisphenol A, etc.) that suffer similar or different fates during various biota processes (photodegradation, phytoremediation, or microbiological decontamination). We are making a short literature screening of these naturally occurring processes destined to remove such an alternative threat.
A comprehensive, non-targeted analysis of polar organic pollutants using high resolution/accurate mass (HR/AM) mass spectrometry approaches has been applied to water samples from San Francisco (SF) Bay, a major urban estuary on the western coast of the United States, to assess occurrence of emerging contaminants and inform future monitoring and management activities. Polar Organic Chemical Integrative Samplers (POCIS) were deployed selectively to evaluate the influence of three contaminant pathways: urban stormwater runoff (San Leandro Bay), wastewater effluent (Coyote Creek, Lower South Bay), and agricultural runoff (Napa River). Grab samples were collected before and after deployment of the passive samplers to provide a quantitative snapshot of contaminants for comparison. Composite samples of wastewater effluent (24 hours) were also collected from several wastewater dischargers. Samples were analyzed using liquid-chromatography coupled to high resolution mass spectrometry. Resulting data were analyzed using a customized workflow designed for high-fidelity detection, prioritization, identification, and semi-quantitation of detected molecular features. Approximately 6,350 compounds were detected in the combined data set, with 424 of those compounds tentatively identified through high quality spectral library match scores. Compounds identified included ethoxylated surfactants, pesticide and pharmaceutical transformation products, polymer additives, and rubber vulcanization agents. Compounds identified in samples were reflective of the apparent sources and pathways of organic pollutant inputs, with stormwater-influenced samples dominated by additive chemicals likely derived from plastics and vehicle tires, as well as ethoxylated surfactants.
In recent years, concern about the release of anthropogenic organic micropollutants referred to as contaminants of emerging concern (CECs) has been growing. The objective of this study was to find potential CECs by means of an analytical screening method referred to as comprehensive target analysis with an automated identification and quantification system (CTA-AIQS), which uses gas and liquid chromatography combined with mass spectrometry (GC-MS and LC-QTOF-MS). We used CTA-AIQS to analyze samples from a sediment core collected in Beppu Bay, Japan. With this method, we detected 80 compounds in the samples and CTA-AIQA could work to useful tool to find CECs in environmental media. Among the detected chemicals, three PAHs (anthracene, chrysene, and fluoranthene) and tris(isopropylphenyl)phosphate (TIPPP) isomers were found to increase in concentration with decreasing sediment depth. We quantified TIPPP isomers in the samples by means of targeted analysis using LC-MS/MS for confirmation. The concentration profiles, combined with previous reports indicating persistent, bioaccumulative, and toxic properties, suggest that these chemicals can be categorized as potential CECs in marine environments.
This study developed a comprehensive ranking system, for the first time as per authors' knowledge, for prioritizing the monitoring of pharmaceuticals and personal care products and endocrine-disrupting chemicals (together termed as EOCs, hereafter; a total of 100 EOCs considered) in U.S. stream water/source water and finished drinking water (termed as "EOCRank," hereafter). The EOCRank system was developed using a total of 4 criteria: (1) occurrence, (2) treatment in drinking water treatment plants, (3) ecological effects, and (4) health effects and characterized using 7 attributes: prevalence, frequency of detection, removal, bioaccumulation, ecotoxicity (for fish, daphnid, and algae aquatic indicator species), pregnancy effects, and health effects. The health effects attribute was characterized using 7 sub-attributes: carcinogenicity, mutagenicity, impairment of fertility, central nervous system acting, endocrine effects, immunotoxicity, and developmental effects. Rank scores of EOCs were calculated as summations of multiplications of importance weights and utility functions of multiple criteria and were arranged to highlight EOCs needing immediate attention. Two different ranking lists of EOCs were developed for U.S. finished drinking water and stream water/source water and observed to differ with each other, indicating the effect of water type on ranking of EOCs. A ranking list of priority EOCs, developed using a particular criterion, was observed to differ with that, developed using multiple criteria. Health effects and treatment criteria were observed to be important criteria influencing overall data gap rank scores and need further data collection. The generalized nature of the system could be customized for specific geographical locations (occurrence information and importance weights of different components). The developed database of the EOCRank system is available on: http://www.egr.msu.edu/~xagorara/research.html).
Pharmaceuticals from a wide spectrum of therapeutic classes are used in human medicine worldwide. Pharmaceutically active
compounds are defined as substances used for prevention, diagnosis or treatment of a disease and for restoring, correcting
or modifying organic functions (Daughton and Ternes 1999). Pharmaceuticals include more than 4000 molecules with different
physico-chemical and biological properties and distinct modes of biochemical action (Beausse 2004). Most medical substances
are administrated orally. After administration, some drugs are metabolised, while others remain intact before being excreted.
Therefore, a mixture of pharmaceuticals and their metabolites will enter municipal sewage and sewage treatment plants (STP;
Kümmerer 2004).
It is argued that chemical substances can be meaningfully ranked or classified according to their persistence (P), bioaccumulation (B), toxicity (T), and potential for long-range transport (LRT) only if these attributes can be shown to be intensive, as distinct from extensive, properties of the substance, i.e., they are independent of quantity of substance. It is shown that P, B, and LRT can be considered intensive or quasi-intensive properties, but toxicity is more problematic. To obtain an intensive metric of toxicity requires selection of one of several possible extensive quantities that define exposure or dose. Ranking of a group of chemicals by toxicity is shown to be very dependent on which quantity is selected. It is suggested that toxicity metrics, such as lethal concentration to 50% of the population (LC50), lethal dose to 50% of the population (LD50), and threshold limit value (TLV) suffer the severe disadvantage of being dependent on the efficiency of delivery of the substance to the site(s) of toxic action in the organism. The use of measured or calculated internal dose is a preferable measure of toxicity since it reduces ambiguities inherent in the other metrics. Also, the primary concern is not the quasi-intensive property of toxicity; rather, it is the risk of toxic effects, an extensive quantity. To adequately assess the risk of toxic effects, both the toxic hazard and the degree of exposure must be characterized. Since exposure cannot be estimated without knowledge of the emission rate of chemicals to the environment, a compelling case can be made that screening to identify priority P, B, T, and LRT substances should be expanded to include quantity released to the environment as an additional factor.
Pharmaceutical residues are environmental contaminants of recent concern and the requirements for analytical methods are mainly dictated by low concentrations found in aqueous and solid environmental samples. In the current article, a review of the liquid chromatography-tandem mass spectrometry (LC-MS/MS) based methods published so far for the determination of pharmaceuticals in the environment is presented. Pharmaceuticals included in this review are antibiotics, non-steroidal anti-inflammatory drugs, beta-blockers, lipid regulating agents and psychiatric drugs. Advanced aspects of current LC-MS/MS methodology, including sample preparation and matrix effects, are discussed.
In the present study, the concentrations and fate of contaminants such as organophosphate flame retardants and plasticizers, musk compounds such as galaxolide (HHCB), tonalide (AHTN), musk ketone and musk xylene, the bactericide triclosan, as well as the metabolites HHCB-lactone and triclosan-methyl were compared in the aqueous phase of the German Bight (North Sea). The concentrations of these compounds were around 1 to 10 ng/L in nearshore areas, and the concentrations were lower in the more pristine areas. The highest concentrations were determined for tris-(2-chloro-isopropyl) phosphate in the North Sea with concentration exceeding 10 ng/L even for the offshore samples. The samples contained 1 to 20 ng/L chlorinated organophosphates, approximately 1 ng/L nonchlorinated organophosphates, and 0.3 to 3 ng/L fragrance compounds. Some samples from Lake Ontario (Canada) were analyzed in comparison. Per capita emissions were calculated for both regions. These emissions were compared and turned out to be very similar for the Canadian and German locations. For the North Sea, some observations concerning stability, dilution, and degradation, as well as sources of the respective substances, were performed. These data indicate that the chlorinated organophosphates and some musk fragrances exhibit half lives exceeding the residence times and thus can be considered to be persistent in this ecosystem. In the German Bight, the river Elbe is the dominating source for the more hydrophilic compounds, such as chlorinated organophosphate flame retardants, which are diluted only into the North Sea. However, for the more lipophilic compounds such as the musk fragrances, different input patterns as well as distribution patterns are relevant, though the river Elbe is still a major source of pollution to the German Bight of the North Sea. The data seem to indicate either relevant inputs further west of the sampling area or mobilization from the sediments.
Substances that accumulate to hazardous levels in living organisms pose environmental and human-health risks, which governments seek to reduce or eliminate. Regulatory authorities identify bioaccumulative substances as hydrophobic, fat-soluble chemicals having high octanol-water partition coefficients (K(OW))(>/=100,000). Here we show that poorly metabolizable, moderately hydrophobic substances with a K(OW) between 100 and 100,000, which do not biomagnify (that is, increase in chemical concentration in organisms with increasing trophic level) in aquatic food webs, can biomagnify to a high degree in food webs containing air-breathing animals (including humans) because of their high octanol-air partition coefficient (K(OA)) and corresponding low rate of respiratory elimination to air. These low K(OW)-high K(OA) chemicals, representing a third of organic chemicals in commercial use, constitute an unidentified class of potentially bioaccumulative substances that require regulatory assessment to prevent possible ecosystem and human-health consequences.
In order to help prioritize future research efforts within the US, risks associated with exposure to human prescription pharmaceutical residues in wastewater were estimated from marketing and pharmacological data. Masses of 371 active pharmaceutical ingredients (APIs) dispensed in the US in 2004 were estimated from marketing data, and then divided by therapeutic dose rate to normalize for potency. Metabolic inactivation of the 50 most dispensed APIs was estimated from published data, and active metabolites were tabulated. Comparing maximum likely average wastewater concentrations of API-associated activity to exposure rates that produce therapeutic effects in humans suggests that the threat to healthy human adults from aquatic exposure is low, even when likely mixture effects are considered. Comparing predicted wastewater concentrations to human therapeutic plasma concentrations suggests that some APIs may be present at sufficient concentrations to affect organisms which eliminate them inefficiently. Comparing predicted antimicrobial concentrations to published minimum inhibitory concentrations suggests that antibacterial APIs in wastewater, but probably not antifungal APIs, may select for low-level antimicrobial resistance. The taxonomic distribution of molecular targets of the 50 most dispensed APIs suggests that potential effects of some APIs are likely restricted to vertebrates, while other APIs can probably affect many eukaryotic and prokaryotic clades.
Benzothiazole, tri-n-butylphosphate, fn's(2-chloroethyl)phosphate, tris(ß-chloropropyl) phosphate and two isomers of this last chemical were detected in all archived water extracts collected from permanent sampling stations located at Fort Erie, Niagara-on-the-Lake and Wolfe Island. The archived samples initially extracted using a Goulden large sample extractor (GLSE) after centrifuging, were analyzed using gas chromatography/atomic emission detection (GC-AED) for P-, S-, and N-containing compounds. All samples also contained atrazine and metolachlor whose concentrations had previously been determined using gas chromatography/mass spectrometry (GOMS). The concentration values of atrazine in the 38 archived samples as determined by the AED method were similar to those determined by the GC/MS method. However, the concentrations of metolachlor in the 38 archived samples calculated from the GC/AED generally differed by a factor of 2 relative to concentrations determined for the extracts by GC/MS. The atrazine and metolachlor concentrations determined by GC/AED were in the range 12-141 ng/L compared to 10-89 ng/L determined using GC/MS. The trialkylphosphate concentrations were in the range 5-23 ng/L and the benzothiazole concentrations were in the range 1-10 ng/L. Other archived samples from the St. Lawrence River above and below Montréal also contained the above five trialkylphosphates and benzothiazole, as did fresh samples from the eastern and western basins of Lake Erie. Nonpolar fractions from silica gel cleanup of the St. Clair River sample extracts contained none of the compounds of interest, but the compounds were found in the methanol eluates of the cleanup column material. One sample collected from the middle of Lake Huron contained tris(2-chloroethyl)phosphate. Rain samples collected about Lake Ontario contained benzothiazole and the alkylphosphates.
In Europe, under the framework of environmental legislation, various protocols have been developed for assessing the environmental risk of chemicals. For the “new chemicals,” environmental risk assessment (ERA) was introduced at 1980s. A decade later, pharmaceuticals were considered in the discussion for further ERA studies. Pesticides and biocides undergo a rigorous assessment following Directives 91/414/EEC and 98/8/EC. Registration, Evaluation, Authorisation of Chemicals (REACH) is the most important development in this field. REACH covers nanotechnology-based materials, but present methodologies may not be appropriate. The authors give a critical overview of the approaches under European water legislation, which cover the ERA frameworks for emerging contaminants.
1,3,6,8-Tetrabromopyrene reacted with 1-tert-butyl-4-vinylbenzene to afford the luminescent monomer M. In addn., the reaction of 1,6-dibromopyrene with 1,4-didodecyloxy-2,5-divinylbenzene yielded a poly(p-phenylenevinylene) (PPV) deriv. P. M dissolved partially in chloroform and completely in THF. P showed an excellent soly. being readily sol. in common org. solvents. M emitted intense blue-green light in THF soln. with photoluminescence (PL) max. at 507 nm and green-yellow light in thin film with PL max. at 570 nm. Polymer P displayed in THF a PL max. at 464 nm and a shoulder at 513 nm. Thin film of this polymer exhibited PL max. at 572 nm. Both M and P emitted from excimers in solid state. The PL emission quantum yields in THF were 0.35 for M and 0.32 for P. The emission max. of M thin film was red shifted by 9 nm after annealing at 150° for 24 h as a result of conformational changes of the mols. with increase in temp. [on SciFinder(R)]
The current widespread use of poly(dimethylsiloxane)s (PDMS) in a broad range of applications leads to their release into soil environments where they degrade to monomeric products, primarily dimethylsilanediol, most of which enter the atmosphere by volatilization. The major degradation pathway of volatile organosilicon compounds in the atmosphere is expected to be a reaction with hydroxyl (OH) radicals. In this work, the kinetics of the gas-phase reactions of dimethylsilanediol, trimethylsilanol, and tetramethylsilane with the OH radical were measured using a relative rate method which employed the N2H4 + O3 reaction as a nonphotolytic source of OH radicals, with analysis by Fourier transform infrared (FT-IR) spectroscopy in a 5870 L chamber. The measured values of the OH radical reaction rate constants (cm3 molecule-1 s-1) at 298 ± 2 K are as follows: dimethylsilanediol, (8.1 ± 1.0) × 10-13; trimethylsilanol, (7.2 ± 0.8) × 10-13; and tetramethylsilane, (8.5 ± 0.9) × 10-13. These values lead to an estimate of tropospheric lifetimes with respect to reaction with the OH radical of ca. 15 days for these organosilicon compounds. FT-IR spectroscopy and atmospheric pressure ionization mass spectrometry (API-MS) were employed to analyze the products of OH radical- and Cl atom-initiated photooxidations of dimethylsilanediol and trimethylsilanol. Infrared signatures of the probable formate ester intermediate products from both silanols were detected. API-MS analyses indicated the formation of methylsilanetriol from dimethylsilanediol, of both dimethylsilanediol and methylsilanetriol from trimethylsilanol, and of the corresponding intermediate formate esters. Possible reaction mechanisms are discussed.
The article contains sections titled:
Two new predictive models for assessing a chemical's biodegradability in the Japanese Ministry of International Trade and Industry (MITI) ready biodegradation test have been developed. The new methods use an approach similar to that in the existing BIOWIN© program, in which the probability of rapid biodegradation is estimated by means of multiple linear or nonlinear regression against counts of 36 chemical substructures (molecular fragments) plus molecular weight (mol wt). The data set used to develop the new models consisted of results (pass/no pass) from the MITI test for 884 discrete organic chemicals. This data set was first divided into randomly selected training and validation sets, and new coefficients were derived for the training set using the BIOWIN fragment library and mol wt as independent variables. Based on these results, the fragment library was then modified by deleting some fragments and adding or refining others, and the new set of independent variables (42 substructures and mol wt) was fit to the MITI data. The resulting linear and nonlinear regression models accurately classified 81% of the chemicals in an independent validation set. Like the established BIOWIN models, the MITI models are intended for use in chemical screening and in setting priorities for further review.
Silicones (polydimethylsiloxanes) find use in a wide variety of industrial and consumer product applications because of their outstanding properties. Potential human exposure to silicones occurs at the work place during manufacturing and product formulation, as well as through the normal use of consumer products containing them.
The entry of silicones into various environmental compartments raised health and safety concerns from potential exposure and mandated numerous environmental and toxicological studies. Such studies require qualitative and quantitative determination of silicone species at trace levels. However, the ubiquitous presence of silicones coupled with their unique chemistry renders their analysis at trace levels challenging.
This paper provides a consolidated account of various aspects silicones that must be borne in mind to obtain reliable data. The following are some of topics discussed: differences in the chemistry of silicones vs carbon; precautions in sample handling to avoid losses and inadvertent chemical transformation; potential sources for artifacts and interferences that could lead to systematic errors and data misinterpretation; sources for background and the need for matrix matched blank experiments; distinguishing silicones from silicates to avoid overestimation; potential for incorrect structural assignments; preventing inadvertent contamination; questionable claims on the presence of silicones in biological matrices including that of silicone implants.
As part of the studies to elucidate the environmental consequences from bacteriostat usage the extent of biodegradation of 3,4,4′-trichlorocarbanilide, TCC®, in sewage systems was examined. TCC samples uniformly labeled in either the p-chloroaniline ring (14C PCA TCC) or the dichloroaniline ring (14C DCA-TCC) were monitored in activated sludge systems by measurements of 14CO2 evolution. As was expected, the p-chloroaniline (PCA) ring of TCC was more rapidly degraded than the dichloroaniline (DCA) ring. In a continuous flow activated sludge system (10 h retention time, 200 μg1−1 TCC) acclimation to primary biodegradation was readily gained. 14CO2 evolution from 14C PCA TCC was consistent with complete metabolism of the PCA ring while that from 14C-PCA-TCC indicated about 50% biodegradation of the DCA ring. Analysis of effluents from continuous flow activated sludge units established that TCC undergoes primary biodegradation to its chloroaniline components which are in turn biodegraded.
The present work describes the development of a fully automated method, based on on-line solid-phase extraction (SPE)-liquid chromatography-electrospray-tandem mass spectrometry (LC-MS-MS), for the determination of 74 pharmaceuticals in environmental waters (superficial water and groundwater) as well as sewage waters. On-line SPE is performed by passing 2.5 mL of the water sample through a HySphere Resin GP cartridge. For unequivocal identification and confirmation two selected reaction monitoring (SRM) transitions are monitored per compound, thus four identification points are achieved. Quantification is performed by the internal standard approach, indispensable to correct the losses during the solid phase extraction, as well as the matrix effects. The main advantages of the method developed are high sensitivity (limits of detection in the low ng L(-1) range), selectivity due the use of tandem mass spectrometry and reliability due the use of 51 surrogates and minimum sample manipulation. As a part of the validation procedure, the method developed has been applied to the analysis of various environmental and sewage samples from a Spanish river and a sewage treatment plant.
A large number of xenobiotics including pharmaceuticals and personal care products are continuously released into the environment. Effluents from sewage treatment plants are well known to be the major source for introduction of pharmaceuticals and personal care products into the aquatic system. In recent years, reliable methods have been established for residue analysis of these pollutants down to low ng/L levels. In this review, the different approaches to their trace determination are reviewed with special attention being paid to sample preparation procedures, state-of-the-art high-performance separation methods hyphenated with mass spectrometry, and immunochemical methods.
Upon partial degradation of polar organic micropollutants during activated sludge treatment, transformation products (TPs) may be formed that enter the aquatic environment in the treated effluent. However, TPs are rarely considered in prospective environmental risk assessments of wastewater-relevant compound classes such as pharmaceuticals and biocides. Here, we suggest and evaluate a tiered procedure, which includes a fast initial screening step based on high resolution tandem mass spectrometry (HR-MS/MS) and a subsequent confirmatory quantitative analysis, that should facilitate consideration of TPs formed during activated sludge treatment in the exposure assessment of micropollutants. At the first tier, potential biotransformation product structures of seven pharmaceuticals (atenolol, bezafibrate, ketoprofen, metoprolol, ranitidine, valsartan, and venlafaxine) and one biocide (carbendazim) were assembled using computer-based biotransformation pathway prediction and known human metabolites. These target structures were screened for in sludge-seeded batch reactors using HR-MS/MS. The 12 TPs found to form in the batch experiments were then searched for in the effluents of two full-scale, municipal wastewater treatment plants (WWTPs) to confirm the environmental representativeness of this first tier. At the second tier, experiments with the same sludge-seeded batch reactors were carried out to acquire kinetic data for major TPs that were then used as input parameters into a cascaded steady-state completely-stirred tank reactor (CSTR) model for predicting TP effluent concentrations. Predicted effluent concentrations of four parent compounds and their three major TPs were corroborated by comparison to 3-day average influent and secondary effluent mass flows from one municipal WWTP. CSTR model-predicted secondary effluent mass flows agreed within a factor of two with measured mass flows and confidence intervals of predicted and measured mass flows overlapped in all cases. The observed agreement suggests that the combination of batch-determined transformation kinetics with a simple WWTP model may be suitable for estimating aquatic exposure to TPs formed during activated sludge treatment. Overall, we recommend the tiered procedure as a realistic and cost-effective approach to include consideration of TPs of wastewater-relevant compounds into exposure assessment in the context of prospective chemical risk assessment.
An analytical method for the quantification of thyroid hormones (3,5,3',5'-tetraiodo-L-thyronine, 3,3',5-triiodo-L-thyronine, 3,3',5'-triiodothyronine, 3,5-diiodothyronine, 3,3'-diiodothyronine) in different water matrices has been developed. The method, consisting of solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), was validated for tap and surface water as well as raw and treated waste water. The limits of quantifications (LOQs) were lowest in tap water, where they ranged from 1.1 to 13.3 ng L(-1), and highest in raw wastewater (10.5-84.9 ng L(-1)). Of the target analytes 3,5,3',5'-tetraiodo-L-thyronine (T(4)) could be quantified in the influent and effluent of a waste water treatment plant (WWTP) in Finland. The study showed that despite a relatively high removal rate during treatment (66%), part of the incoming T(4) will reach the aquatic environment and, due to the high endocrine activity of this compound, further studies are needed in order to assess its environmental fate and impact on natural ecosystems.
The goal of this study was to identify commercial chemicals that might be persistent and bioaccumulative (P&B) and that were not being considered in current Great Lakes, North American, and Arctic contaminant measurement programs. We combined the Canadian Domestic Substance List (DSL), a list of 3059 substances of "unknown or variable composition complex reaction products and biological materials" (UVCBs), and the U.S. Environmental Protection Agency (U.S. EPA) Toxic Substances Control Act (TSCA) Inventory Update Rule (IUR) database for years 1986, 1990, 1994, 1998, 2002, and 2006 yielding a database of 22263 commercial chemicals. From that list, 610 chemicals were identified by estimates from U.S EPA EPISuite software and using expert judgment. This study has yielded some interesting and probable P&B chemicals that should be considered for further study. Recent studies, following up our initial reports and presentations on this work, have confirmed the presence of many of these chemicals in the environment.
The contamination of wastewater and sewage sludge has been examined for three phosphodiesterase type V inhibitors sildenafil, vardenafil and tadalafil, active agents of Viagra, Levitra and Cialis, respectively. Sensitive quantification methods based on solid-phase extraction (SPE) and pressurized liquid extraction (PLE) followed by high performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS) have been developed to analyse these compounds in wastewater and sewage sludge. Effluent water of nine sewage treatment plants (STPs) has been analysed to assess the impact of the phosphodiesterase type V inhibitors on the environment. One municipal STP (Tarragona, Spain) has been thoroughly studied over the year 2008 (i) with respect to the distribution of these compounds among influent and sewage sludge and (ii) the elimination efficiency. The developed methods allowed quantification at trace concentrations. Sildenafil was present in all investigated samples at the low ng/L and ng/g range, respectively. Tadalafil was not detected or below the limit of detection (LOQ) in effluent water taken in Spain but in sewage sludge (12 ng/g - < LOQ). Vardenafil was present only in one sludge sample and between 5 ng/g and < LOQ in effluent water. The overall removal efficiency of the STP in Tarragona (Spain) is 68%, 69% and 80% for sildenafil, tadalafil and vardenafil, respectively. This study shows for the first time the determination of these compounds in wastewater and sewage sludge.
9 pages, 2 figures, 1 table.-- Printed version published Dec 2007.-- Issue title: Emerging contaminants in wastewaters. Many classes of pharmaceuticals have been detected in wastewaters and surface waters around Europe, but little is known about their occurrence, fate and potential harmful effects on the environment, and that makes them an important group among those compounds considered to be new emerging contaminants. To understand the cycling of pharmaceuticals and their metabolites, it is essential to possess qualitative and quantitative information on their presence in the environment. This review covers the current status and future prospects of advanced hyphenated mass spectrometric (MS) techniques (gas chromatography-MS (GC-MS) and liquid chromatography-MS (LC-MS)) in elucidating the structures of trace contaminants, namely pharmaceutical biodegradation products in complex environmental matrices. The article is oriented towards technique and method and discusses capabilities, potential and limitations of different GC and LC mass analyzers (quadrupole, ion trap, time-of-flight and hybrid techniques) in dealing with analytical challenges of complex matrices and trace contaminants. We also give practical examples of their applications. The main scope of this article is to support and to facilitate the on-going research on pharmaceutical biodegradation products in environmental samples. This work was performed with the financial support of Ad futura fellowship (Science and Education Foundation of the Republic of Slovenia, Public Fund) and was supported by the European Commission Project NORMAN, Network of reference laboratories for monitoring of emerging environmental pollutants (FP6, Global Change and Ecosystems, Contract Nº 018486). Peer reviewed
Transformation products (TPs) of organic contaminants in aquatic environments are still rarely considered in water quality and chemical risk assessment, although they have been found in concentrations that are of concern. Since many different TPs can potentially be formed in the environment and analytical standards are typically lacking for these compounds, knowledge on the prevalence of TPs in aquatic environments is fragmentary. In this study, an efficient procedure was therefore developed to comprehensively screen for large numbers of potential TPs in environmental samples. It is based on a target list of plausible TPs that has been assembled using the University of Minnesota Pathway Prediction System (UM-PPS) for the computer-aided prediction of products of microbial metabolism and an extensive search for TPs reported in the scientific literature. The analytical procedure for screening of the compounds on the target list has been developed to allow for the detection of a broad range of compounds in complex environmental samples in the absence of commercially available reference standards. It includes solid phase extraction with broad enrichment efficiency, followed by liquid chromatography and tandem mass spectrometry with high mass resolution and accuracy. The identification of target TPs consisted of extracting the exact mass from the chromatogram, selecting peaks of sufficient intensity, checking the plausibility of the retention time, and interpreting mass spectra. The procedure was used to screen for TPs of 52 pesticides, biocides, and pharmaceuticals in seven representative surface water samples from different regions in Switzerland. Altogether, 19 TPs were identified, including both some well-known and commonly detected TPs, and some rarely reported ones (e.g., biotransformation products of the pharmaceuticals venlafaxine and verapamil, or of the pesticide azoxystrobin). Overall, the rather low number of TPs detected suggests that TPs may not pose a problem of unexpected magnitude for aquatic resources.
Scientists from academia, industry, and government reviewed current international regulations for the screening of commercial chemicals for bioaccumulation in the context of the current state of bioaccumulation science. On the basis of this review, several recommendations were proposed, including a scientific definition for "bioaccumulative substances," improved criteria for the characterization of bioaccumulative substances (including the trophic magnification factor and the biomagnification factor), novel methods for measuring and calculating bioaccumulation properties, and a framework for screening commercial chemicals for bioaccumulative substances. The proposed framework for bioaccumulation screening improves current practices by reducing miscategorization, making more effective use of available bioaccumulation data that currently cannot be considered, reducing the need for animal testing, providing simpler and cheaper test protocols for animal studies in case animal studies are necessary, making use of alternative testing strategies, including in vitro and in silico metabolic transformation assays, and providing a scientific foundation for bioaccumulation screening that can act to harmonize bioaccumulation screening among various jurisdictions.
The environmental prevalence of a new class of perfluorinated acids, the perfluorinated phosphonic acids (PFPAs), was determined in Canadian surface waters and wastewater treatment plant (WWTP) effluent. For quality control and comparison, the C8- to C11-perfluorinated carboxylic acids and perfluorooctane sulfonic acid were included in the analysis. Water samples were extracted using weak anion-exchange solid-phase extraction cartridges. Perfluorinated phosphonic acids were observed in 80% of surface water samples and in six of the seven WWTP effluent samples. The C8-PFPA was observed at concentrations ranging from 88 +/- 33 to 3400 +/- 900 pg/L in surface waters and from 760 +/- 270 to 2500 +/- 320 pg/L in WWTP effluent. To our knowledge, this is the first observation of PFPAs in the environment. Given their structural similarities with perfluorinated carboxylic and sulfonic acids, PFPAs are expected to be persistent. The observation of PFPAs in the majority of samples analyzed here suggests they are prevalent environmental contaminants and should be considered in future environmental monitoring campaigns to better understand the total burden of fluorinated materials in the environment.
The combined excretion of active pharmaceutical ingredients (APIs) via urine and feces is considered the primary route by which APIs from human pharmaceuticals enter the environment. Disposal of unwanted, leftover medications by flushing into sewers has been considered a secondary route-one that does not contribute substantially to overall environmental loadings. The present study presents the first comprehensive examination of secondary routes of API release to the environment and for direct but unintentional human exposure. These include bathing, washing, and laundering, all of which release APIs remaining on the skin from the use of high-content dermal applications or from excretion to the skin via sweating, and disposal of unused and partially used high-content devices. Also discussed are the health hazards associated with: partially used devices, medication disposal practices of consumers, and interpersonal dermal transfer of API residues. Understanding these secondary routes is important from the perspective of pollution prevention, because actions can be designed more easily for reducing the environmental impact of APIs compared with the route of direct excretion (via urine and feces), for reducing the incidence of unintentional and purposeful poisonings of humans and pets, and for improving the quality and cost-effectiveness of health care. Overall, unintentional exposure to APIs for humans via these routes is possibly more important than exposure to trace residues recycled from the environment in drinking water or foods.
The production and use of nonpolybrominated diphenyl ether (non-PBDE), brominated flame retardant (BFR) alternatives have been on the rise, although their assessment in environmental samples is largely understudied. In the present study, several non-PBDE BFRs were found in the egg pools of herring gulls (Larus argentatus) from seven colonies in the five Laurentian Great Lakes (collected in 1982 to 2006). Of the 19 BFRs monitored, hexabromobenzene (HBB), 1,2-bis(2,4,6-tribromophe-noxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and alpha-, beta-, gamma-, and delta-isomers of 1,2-dibromo-4-(1,2-dibromoeth-yl)cyclohexane (TBECH) were present in eggs from all the colonies with the highest detection frequencies of 100%, 54%, 9% and 97%, respectively. In 2005 and 2006 eggs, the concentrations of DBDPE were highest at three of the seven colonies (1.3 to 288 ng/g wet weight (ww)) and surpassed decabromodiphenyl ether (BDE-209). HBB (0.10 to 3.92 ng/g ww), BTBPE (1.82 to 0.06 ng/g ww), and Sigma-TBECH (0.04 to 3.44 ng/g ww; mainly the beta-isomer 52 to 100% of Sigma-TBECH) were detected at lower concentrations (and generally <SigmaPBDE concentrations). Spatial trends were observed, although temporal trends were not obvious in most cases. Regardless, over the past 25 years non-PBDE BFRs have accumulated variably in female herring gulls and have been transferred during ovogenesis to their eggs, indicating that there has been continual exposure and bioaccumulation of several BFRs in the Great Lakes.
A purge and trap method was used to study the release of brominated organic compounds from polymeric brominated flame retardants (BFRs), a relatively unknown class of flame retardant materials. Among the volatile brominated organics released, pentabromotoluene (PBTo), pentabromoethylbenzene (PBEB), and hexabromobenzene (HBB) were of particular interest because of their high potential to persist in the environment The impact of a thermal stress on the release of these compounds was assessed by applying different constant temperatures for one hour to a polymeric BFR sample. Release rates ranged between 22 +/- 2.1 ng g(-1) h(-1) for PBEB to 2480 +/- 500 ng g(-1) h(-1) for PBTo at room temperature. These rates of release reached 65 +/- 11 ng g(-1) h(-1) for PBEB and 42400 +/- 4700 ng g(-1) h(-1) for PBTo at 100 degrees C. This suggests that the compounding of thermoplastic polyesters done at high temperatures, up to 290 degrees C, could lead to the release of significant amounts of volatile brominated compounds in the environment when crude polymeric BFRs are used as flame retardants. To assess if this unsuspected source of volatile brominated compounds to the environment was relevant to support air concentrations in the Great Lakes area, air samples collected at Egbert (ON, Canada) were analyzed and PBTo, PBEB, and HBB were detected at low levels in some air samples (<0.01 to 0.09 pg/m3). As a second step, a Level III fugacity model was run using release rates of PBTo, PBEB, and HBB determined in this study. Results of the model indicated that prevailing PBEB and HBB air concentrations were not supported by their release from polymeric BFRs but by the use of these compounds as additive BFRs. However, these model predictions suffered from a lack of information on the actual use of polymeric BFRs. Hence, further work is needed to assess the release of potentially persistent brominated aromatic compounds from polymeric BFRs.
Due to the voluntary withdrawals and/or bans on the use of two polybrominated diphenyl ether (PBDE) commercial mixtures, an increasing number of alternate flame retardant chemicals are being introduced in commercial applications. To determine if these alternate BFRs are present in indoor environments, we analyzed dust samples collected from 19 homes in the greater Boston, MA area during 2006. Using pure and commercial standards we quantified the following brominated flame retardant chemicals using GC/ECNI-MS methods: hexabromocyclododecane (sigma HBCD), bis(2,4,6,-tribromphenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and the brominated components found in Firemaster 550 (FM 550): 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) and (2-ethylhexyl)tetrabromophthalate (TBPH), the latter compound being a brominated analogue of di(2-ethylhexyl)phthalate (DEHP). The concentrations of all compounds were log-normally distributed and the largest range in concentrations was observed for HBCD (sum of all isomers), with concentrations ranging from <4.5 ng/g to a maximum of 130,200 ng/g with a median value of 230 ng/g. BTBPE ranged from 1.6 to 789 ng/g with a median value of 30 ng/g and DBDPE ranged from <10.0 to 11,070 ng/g with a median value of 201 ng/g. Of the FM 550 components, TBB ranged from <6.6 to 15,030 ng/g with a median value of 133 ng/g; whereas TBPH ranged from 1.5 to 10,630 ng/g with a median value of 142 ng/g. Furthermore, the ratio of TBB/TBPH present in the dust samples ranged from 0.05 to 50 (average 4.4), varying considerably from the ratio observed in the FM 550 commercial mixture (4:1 by mass), suggesting different sources with different chemical compositions, and/or differential fate and transport within the home. Analysis of paired dust samples collected from different rooms in the same home suggests HBCD, TBB, and TBPH are higher in dust from the main living area compared to dust collected in bedrooms; however, BTBPE and DBDPE levels were comparable between rooms. This study highlights the fact that numerous types of brominated flame retardants are present in indoor environments, raising questions about exposure to mixtures of these contaminants.
A large and ever-increasing number of chemicals are used in commerce, and researchers and regulators have struggled to ascertain that these chemicals do not threaten human health or cause environmental or ecological damage. The presence of persistent organic pollutants (POPs) in remote environments such as the Arctic is of special concern and has international regulatory implications. Responding to the need for a way to identify chemicals of high concern, a methodology has been developed which compares experimentally measured properties, or values predicted from chemical structure alone, to a set of screening criteria. These criteria include partitioning properties that allow for accumulation in the physical Arctic environment and in the Arctic human food chain, and resistance to atmospheric oxidation. Atthe same time we quantify the extent of structural resemblance to a group of known Arctic contaminants. Comparison of the substances that are identified by a mechanistic description of the processes that lead to Arctic contamination with those substances that are structurally similar to known Arctic contaminants reveals the strengths and limitations of either approach. Within a data set of more than 100,000 distinct industrial chemicals, the methodology identifies 120 high production volume chemicals which are structurally similarto known Arctic contaminants and/or have partitioning properties that suggest they are potential Arctic contaminants.
As part of the Integrated Atmospheric Deposition Network (IADN), air samples were collected at five sites around the Great Lakes (two urban, two rural, and one remote) every 12 days during 2005-2006, and the concentrations of polybrominated diphenylethers (PBDEs), 1,2-bis(2,4,6-tribromophenoxy)-ethane (TBE), Dechlorane Plus (DP), and decabromodiphenyl ethane (DBD PE) were measured. The highest mean concentrations of total PBDEs were found at the urban sites in Chicago and Cleveland (65 +/- 4 and 87 +/- 8 pg/m3, respectively), and the lowest at the remote site in Eagle Harbor (5.8 +/- 0.4 pg/m3). With the exception of Chicago, the atmospheric concentrations of BDE-47 and 99 (summed over the gas and particle phases) are decreasing rapidly with half-lives of approximately 2 years, but the concentrations of BDE-209 are not decreasing at any of the five sites. The atmospheric partial pressures of BDE-47 and 99 showed a strong Clausius-Clapeyron relationship with reciprocal atmospheric temperature. TBE, DBDPE and DP were detected at all sites, but with the exception of Chicago, there were insufficient data to determine temporal trends for these compounds. The influence of human population density and synoptic atmospheric transport patterns was explored to explain the relatively high concentrations of BDE-209 in Cleveland.
Since the early 1980s, there has been a steady increase in the use of nonvolatile fluorinated organic compounds for a variety of industrial and commercial applications. The industrial use of these relatively stable compounds has initiated debate over the fate of fluorochemicals in the environment and, ultimately, the bioavailability of these compounds. In this manuscript, we present quantitative results from a study of 65 human sera samples purchased from biological supply companies that provide characterization of specific organic fluorochemicals present in the sera of nonindustrially exposed humans. Summed together, the compound-specific characterization data reported here agree closely with levels of nonspeciated organic fluorine that were originally reported to be present in sera in 1970. The compound-specific method for the extraction of extremely low levels of several commercial organic fluorochemicals from sera and liver with quantitative detection by negative ion electrospray tandem mass spectrometry described represents a robust, previously undescribed approach to quantifying specific organic fluorochemicals in biological matrices.
Recently, low levels of veterinary medicines have been detected worldwide in soils, surface waters, and groundwaters (1,2). Although the impacts of selected compounds – most notably anthelmintics and selected antibacterial compounds – have been extensively investigated (3,4), many other substances found int the environment are less publicly well understood. As a result, researches have raised questions about the impact of veterinary medicines on organisms in the environment and on human health. Several key questions will be addressed in this article. What other veterinary medicines might be in the environment, and should we be concerned about these? How do these substances behave in the environment, and do they differ from other chemical classes (e.g., pesticides)? What are the effects of long-term, low-level exposure to these medicines? Do their degradation products present environmental risks? What subtle human and environmental effects may be elicited by these drugs? Do medicines in the environment play a role in antibacterial resistance? How do these substances interact in the environment with other veterinary medicines and other contaminants?
Pharmaceuticals have been reported in surface waters, prompting legitimate public concern, as pharmaceuticals are biologically active compounds used daily by the public. Currently there are ecotoxicological data available for <1%, thus, the European Union Commission's Scientific committee on Toxicity, Ecotoxicity, and Environment (CSTEE) recommended use of (Q)SAR models and precaution to prioritize further risk assessment of approximately 4500 compounds and their adjuvants. We ranked 2986 different pharmaceutical compounds in 51 classes relative to hazard toward algae, daphnids, and fish using the EPIWIN program. This ranking cannot be used to acquit a compound based on predicted relative ranking. Modifying additives were the most toxic classes. Cardiovascular, gastrointestinal, antiviral, anxiolytic sedatives hypnotics and antipsychotics, corticosteroid, and thyroid pharmaceuticals were the predicted most hazardous therapeutic classes. The overall relative order of susceptibility was estimated to be daphnids > fish > algae. Expert judgment is needed to assess specific hazards for classes like microbial resistance and antibiotics, sex hormones, and endocrine disruptors. As human health and the function of ecological systems are interconnected and subject to the precautionary principle, harmonization of evidence for correlation and causality of adverse effects seems sensible in an ethical and cost-effective context to facilitate substitution of hazardous compounds. Data available: http://www.uoguelph.ca/~hsander/.
Bis(4-chlorophenyl) sulfone (BCPS) is a high production volume chemical (HPVC) applied in thermostable polymers. BCPS has been detected as an environmental contaminant both in Europe and in North America but it is still not a commonly studied pollutant. In this study, three Baltic Sea fish species; herring (Clupea harengus), salmon (Salmo salar) and perch (Perca fluviatilis) from the Swedish coast, and one inland fish species, arctic char (Salvelinus alpinus), were analysed to screen for the occurrence and distribution of BCPS. Salmon and arctic char, were sampled in the early 1970s as well as the late 1990s. Fish eating grey seal (Halichoerus gryphus) and guillemot (Uria aalge) from the Baltic Sea were included to screen for whether BCPS biomagnify or not. The representativeness of the analysed samples for studying bioaccumulation of environmental pollutants was compared through analysis of two well known persistent and bioaccumulating compounds, 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), and 4,4'-DDE. Pooled muscle and blubber samples based on 4-10 individuals were used for analysis, as well as individual samples of grey seal blubber. 2,4,4'-Trichlorodiphenyl sulfone, was synthesised and applied as an internal standard. BCPS was detected in all marine samples but in only one of the fresh water fish samples. The highest BCPS concentrations detected, 1600 and 1900 ng/g lipid weighet (l.w.), were found in muscle from Baltic guillemot. The results indicate that BCPS is bioaccumulated in both grey seal and guillemot, and that the guillemot has higher concentrations of BCPS than the grey seal (50-500 ng/g l.w.). The concentrations found in different species of fish from the Baltic Sea ranged between 15-37 ng/g l.w. and lower concentrations were found in freshwater species (n.d.-1.8 ng/g l.w.). The present study shows that BCPS is found in all investigated species of wildlife but, in most species, still at low concentrations. However, the guillemot has levels in the low ppm range indicating a considerable biomagnification of BCPS in this species.
During 2001, 76 water samples were collected upstream and downstream of select towns and cities in Iowa during high-, normal- and low-flow conditions to determine the contribution of urban centers to concentrations of pharmaceuticals and other organic wastewater contaminants (OWCs) in streams under varying flow conditions. The towns ranged in population from approximately 2000 to 200,000. Overall, one or more OWCs were detected in 98.7% of the samples collected, with 62 of the 105 compounds being found. The most frequently detected compounds were metolachlor (pesticide), cholesterol (plant and animal sterol), caffeine (stimulant), beta-sitosterol (plant sterol) and 1,7-dimethylxanthine (caffeine degradate). The number of OWCs detected decreased as streamflow increased from low- (51 compounds detected) to normal- (28) to high-flow (24) conditions. Antibiotics and other prescription drugs were only frequently detected during low-flow conditions. During low-flow conditions, 15 compounds (out of the 23) and ten compound groups (out of 11) detected in more than 10% of the streams sampled had significantly greater concentrations in samples collected downstream than in those collected upstream of the urban centers. Conversely, no significant differences in the concentrations were found during high-flow conditions. Thus, the urban contribution of OWCs to streams became progressively muted as streamflow increased.
The widespread detection of environmentally persistent perfluorinated acids (PFCAs) such as perfluorooctanoic acid (PFOA) and its longer chained homologues (C9>C15) in biota has instigated a need to identify potential sources. It has recently been suggested that fluorinated telomer alcohols (FTOHs) are probable precursor compounds that may undergo transformation reactions in the environment leading to the formation of these potentially toxic and bioaccumulative PFCAs. This study examined the aerobic biodegradation of the 8:2 telomer alcohol (8:2 FTOH, CF3(CF2)7CH2CH2OH) using a mixed microbial system. The initial measured half-life of the 8:2 FTOH was approximately 0.2 days mg(-1) of initial biomass protein. The degradation of the telomer alcohol was monitored using a gas chromatograph equipped with an electron capture detector (GC/ECD). Volatile metabolites were identified using gas chromatography/ mass spectrometry (GC/MS), and nonvolatile metabolites were identified and quantified using liquid chromatography/ tandem mass spectrometry (LC/MS/MS). Telomer acids (CF3(CF2)7CH2COOH; CF3(CF2)6CFCHCOOH) and PFOA were identified as metabolites during the degradation, the unsaturated telomer acid being the predominant metabolite measured. The overall mechanism involves the oxidation of the 8:2 FTOH to the telomer acid via the transient telomer aldehyde. The telomer acid via a beta-oxidation mechanism was furthertransformed, leading to the unsaturated acid and ultimately producing the highly stable PFOA. Telomer alcohols were demonstrated to be potential sources of PFCAs as a consequence of biotic degradation. Biological transformation may be a major degradation pathway for fluorinated telomer alcohols in aquatic systems.
Human and animal tissues collected in urban and remote global locations contain persistent and bioaccumulative perfluorinated carboxylic acids (PFCAs). The source of PFCAs was previously unknown. Here we present smog chamber studies that indicate fluorotelomer alcohols (FTOHs) can degrade in the atmosphere to yield a homologous series of PFCAs. Atmospheric degradation of FTOHs is likely to contribute to the widespread dissemination of PFCAs. After their bioaccumulation potential is accounted for, the pattern of PFCAs yielded from FTOHs could account for the distinct contamination profile of PFCAs observed in arctic animals. Furthermore, polar bear liver was shown to contain predominately linear isomers (>99%) of perfluorononanoic acid (PFNA), while both branched and linear isomers were observed for perfluorooctanoic acid, strongly suggesting a sole input of PFNA from "telomer"-based products. The significance of the gas-phase peroxy radical cross reactions that produce PFCAs has not been recognized previously. Such reactions are expected to occur during the atmospheric degradation of all polyfluorinated materials, necessitating a reexamination of the environmental fate and impact of this important class of industrial chemicals.
The dynamics of organohalogen contaminants and their metabolites are best studied over time by analysis of biota at high trophic levels. In this study, time trends, 1971-2001, of bis(4-chlorophenyl) sulfone (BCPS) and of methylsulfonyl-substituted metabolites of PCBs and 4,4'-DDE, were investigated in eggs of guillemot (Uria aalge) hatching in the Baltic Proper. Temporal trends of PCBs, trans-nonachlor, beta-HCH, 4,4'-DDT, and 4,4'-DDE were also assessed. Tris(4-chlorophenyl) methane (TCPMe), a 4,4'-DDT by-product, was detected in the eggs. The concentration of BCPS ranged between 2.6-0.76 microg/g on a lipid weight basis over the three decades and showed a significant 1.6% annual decrease. Three metabolites of PCBs, i.e. 3'-MeSO2-CB101, 4'-MeSO2-CB101 and 4-MeSO2-CB149, were quantified in all samples over time and showed an annual decrease of approximately 3% compared to MeSO2-DDE with a decrease of 8.9%. The methylsulfonyl-PCB and -DDE metabolites are eliminated more slowly than the persistent PCB congeners and 4,4'-DDE. Trans-nonachlor decreases by 16% compared to 19% and 9% for 4,4'-DDT and beta-HCH, respectively. The concentration of TCPMe in guillemot decreased by 8.2% per year. A linear relationship was found between TCPMe and 4,4'-DDE concentrations which supports the theory that TCPMe has an origin as a contaminant in commercial 4,4'-DDT products. The very slow decrease in BCPS concentrations is notable and remains to be explained. BCPS is still present at rather high concentrations in the guillemot eggs. The enantiomeric fraction varied between 0.27 and 0.67 which indicates less of a specific retention of the chiral MeSO2-PCBs in guillemot eggs than in grey seal tissues, for example. Independent of meta- or para-substitution of the sulfone group, the most accumulative atropisomer of each of four MeSO2-PCB pairs has been assigned an absolute R structure.
There is increasing scientific interest to understand the environmental fate of fluorotelomer alcohols (FTOHs) and fluorotelomer-based products which may break down to FTOHs. Both are expected to enter aqueous waste streams, which would be processed in a wastewater treatment plant and therein subject to microbial biodegradation. We investigated the biodegradation of 3-14C, 1H,1H,2H,2H-perfluorodecanol [CF3(CF2)6(14)CF2CH2CH2OH, 14C-8-2 FTOH] in mixed bacterial culture and activated sludge. 14CO2 and 14C-organic volatiles in the headspace of the sealed bottles and bottles with continuous air flow were analyzed up to 4 months. After sample extraction with acetonitrile, 14C-labeled biotransformation products (metabolites) were quantified by LC/ARC (on-line liquid chromatography/ accurate radioisotope counting) and identified by quadrupole time-of-flight (Q-TOF) mass spectrometry and GC/MSD (mass selective detector). Three metabolites not yet reported in the literature have been identified as CF3(CF2)6(14)CHOHCH3 (7-2 sFTOH), CF3(CF2)6(14)CH=CHCOOH (7-3 unsaturated acid or 7-3 u acid), and CF3(CF2)6(14)CH=CHCONH2 (7-3 u amide) along with five previously reported metabolites [CF3(CF2)6(14)CF2CH2CHO (8-2 FTAL), CF3(CF2)6 (14)CF2CH2COOH (8-2 acid), CF3(CF2)6(14)CF=CHCOOH (8-2 u acid), CF3(CF2)6(14)CH2CH2COOH (7-3 acid), and CF3(CF2)6(14)COOH (PFOA)]. No CF3(CF2)6(14)CF2COOH (14C-PFNA) was observed, indicating that alpha-oxidation does not take place. It was found that strong adsorption to the activated sludge and subsequent transformation, even under continuous air flow, greatly reduced partitioning of 8-2 FTOH or any transformation products to air. CF3(CF2)4COOH (PFHA; perfluorohexanoic acid) was observed and increased in mixed bacterial culture over 28 days and accounted for about 1% of the initial 14C-8-2 FTOH concentration from day 28 to day 90. 14CO2 accounted for 1% of initial 14C in activated sludge with continuous air flow at day 1 and increased over time. In closed bottles, 14CO2 in the headspace of activated sludge medium increased to 12% of the available 14C over 135 days with periodic addition of ethanol, as compared to 3% when no additional ethanol was added. These results show that replenishment of organic carbon enhanced microbial mineralization of multiple--CF2--groups in the fluorocarbon chain of 14C-8-2 FTOH. At day 90 the net increase of fluoride ion in the mixed bacterial culture was 93 microg L(-1), equivalent to 12% of total mineralization (destruction) of the 14C-8-2 FTOH. These results demonstrate that perfluorinated carbon bonds of 14C-8-2 FTOH are defluorinated and mineralized by microorganisms under conditions which may occur in a wastewater treatment plant, forming shorter fluorinated carbon metabolites.
Low levels of human medicines (pharmaceuticals) have been detected in many countries in sewage treatment plant (STP) effluents, surface waters, seawaters, groundwater and some drinking waters. For some pharmaceuticals effects on aquatic organisms have been investigated in acute toxicity assays. The chronic toxicity and potential subtle effects are only marginally known, however. Here, we critically review the current knowledge about human pharmaceuticals in the environment and address several key questions. What kind of pharmaceuticals and what concentrations occur in the aquatic environment? What is the fate in surface water and in STP? What are the modes of action of these compounds in humans and are there similar targets in lower animals? What acute and chronic ecotoxicological effects may be elicited by pharmaceuticals and by mixtures? What are the effect concentrations and how do they relate to environmental levels? Our review shows that only very little is known about long-term effects of pharmaceuticals to aquatic organisms, in particular with respect to biological targets. For most human medicines analyzed, acute effects to aquatic organisms are unlikely, except for spills. For investigated pharmaceuticals chronic lowest observed effect concentrations (LOEC) in standard laboratory organisms are about two orders of magnitude higher than maximal concentrations in STP effluents. For diclofenac, the LOEC for fish toxicity was in the range of wastewater concentrations, whereas the LOEC of propranolol and fluoxetine for zooplankton and benthic organisms were near to maximal measured STP effluent concentrations. In surface water, concentrations are lower and so are the environmental risks. However, targeted ecotoxicological studies are lacking almost entirely and such investigations are needed focusing on subtle environmental effects. This will allow better and comprehensive risk assessments of pharmaceuticals in the future.
Relative rate methods were used to measure the gas-phase reaction of N-methyl perfluorobutane sulfonamidoethanol (NMeFBSE) with OH radicals, giving k(OH + NMeFBSE) = (5.8 +/- 0.8) x 10(-12) cm3 molecule(-1) s(-1) in 750 Torr of air diluent at 296 K. The atmospheric lifetime of NMeFBSE is determined by reaction with OH radicals and is approximately 2 days. Degradation products were identified by in situ FTIR spectroscopy and offline GC-MS and LC-MS/MS analysis. The primary carbonyl product C4F9SO2N(CH3)CH2CHO, N-methyl perfluorobutane sulfonamide (C4F9SO2NH(CH3)), perfluorobutanoic acid (C3F7C(O)OH), perfluoropropanoic acid (C2F5C(O)OH), trifluoroacetic acid (CF3C(O)OH), carbonyl fluoride (COF2), and perfluorobutane sulfonic acid (C4F9SO3H) were identified as products. A mechanism involving the addition of OH to the sulfone double bond was proposed to explain the production of perfluorobutane sulfonic acid and perfluorinated carboxylic acids in yields of 1 and 10%, respectively. The gas-phase N-dealkylation product, N-methyl perfluorobutane sulfonamide (NMeFBSA), has an atmospheric lifetime (>20 days) which is much longer than that of the parent compound, NMeFBSE. Accordingly,the production of NMeFBSA exposes a mechanism by which NMeFBSE may contribute to the burden of perfluorinated contamination in remote locations despite its relatively short atmospheric lifetime. Using the atmospheric fate of NMeFBSE as a guide, it appears that anthropogenic production of N-methyl perfluorooctane sulfonamidoethanol (NMeFOSE) contributes to the ubiquity of perfluoroalkyl sulfonate and carboxylate compounds in the environment.
A highly chlorinated flame retardant, Dechlorane Plus (DP), was detected and identified in ambient air, fish, and sediment samples from the Great Lakes region. The identity of this compound was confirmed by comparing its gas chromatographic retention times and mass spectra with those of authentic material. This compound exists as two gas chromatographically separable stereoisomers (syn and anti), the structures of which were characterized by one- and two-dimensional proton nuclear magnetic resonance. DP was detected in most air samples, even at remote sites. The atmospheric DP concentrations were higher at the eastern Great Lakes sites (Sturgeon Point, NY, and Cleveland, OH) than those at the western Great Lakes sites (Eagle Harbor, MI, Chicago, IL, and Sleeping Bear Dunes, MI). Atthe Sturgeon Point site, DP concentrations once reached 490 pg/m3. DP atmospheric concentrations were comparable to those of BDE-209 at the eastern Great Lakes sites. DP was also found in sediment cores from Lakes Michigan and Erie. The peak DP concentrations were comparable to BDE-209 concentrations in the sediment core from Lake Erie butwere about 30 times lower than BDE-209 concentrations in the core from Lake Michigan. In the sediment cores, the DP concentrations peaked around 1975-1980, and the surficial concentrations were 10-80% of peak concentrations. Higher DP concentrations in air samples from Sturgeon Point, NY, and in the sediment core from Lake Erie suggest that DP's manufacturing facility in Niagara Falls, NY, may be a source. DP was also detected in archived fish (walleye) from Lake Erie, suggesting that this compound is, at least partially, bioavailable.
Two sediment cores collected from Lake Ontario and Lake Erie were sectioned, dated, and analyzed for five polycyclic musk fragrances and two nitro musk fragrances. The polycyclic musk fragrances were HHCB (Galaxolide), AHTN (Tonalide), ATII (Traseolide), ADBI (Celestolide), and AHMI (Phantolide). The nitro musk fragrances were musk ketone and musk xylene. Chemical analysis was performed by gas chromatography/mass spectrometry (GC/MS), and results from Lake Erie were confirmed using gas chromatography/triple-quadrupole mass spectrometry (GC/MS/MS). The chemical signals observed at the two sampling locations were different from each other primarily because of large differences in the sedimentation rates at the two sampling locations. HHCB was detected in the Lake Erie core whereas six compounds were detected in the Lake Ontario core. Using measured fragrance and 210Pb activity, the burden of synthetic musk fragrances estimated from these sediment cores is 1900 kg in Lake Erie and 18 000 kg in Lake Ontario. The input of these compounds to the lakes is increasing. The HHCB accumulation rates in Lake Erie for 1979-2003 and 1990-2003 correspond to doubling times of 16 +/- 4 and 8 +/- 2 years, respectively. The results reflect current U.S. production trends for the sum of all fragrance compounds.
The past 5 years have seen some major successes in terms of global measurement and regulation of persistent, bioaccumulative, and toxic (PB&T) chemicals and persistent organic pollutants (POPs). The Stockholm Convention, a global agreement on POPs, came into force in 2004. There has been a major expansion of measurements and risk assessments of new chemical contaminants in the global environment, particularly brominated diphenyl ethers and perfluorinated alkyl acids. However, the list of chemicals measured represents only a small fraction of the approximately 30,000 chemicals widely used in commerce (>1 t/y). The vast majority of existing and new chemical substances in commerce are not monitored in environmental media. Assessment and screening of thousands of existing chemicals in commerce in the United States, Europe, and Canada have yielded lists of potentially persistent and bioaccumulative chemicals. Here we review recent screening and categorization studies of chemicals in commerce and address the question of whether there is now sufficient information to permit a broader array of chemicals to be determined in environmental matrices. For example, Environment Canada's recent categorization of the Domestic (existing) Substances list, using a wide array of quantitative structure activity relationships for PB&T characteristics, has identified about 5.5% of 11,317 substances as meeting P & B criteria. Using data from the Environment Canada categorization, we have listed, for discussion purposes, 30 chemicals with high predicted bioconcentration and low rate of biodegradation and 28 with long range atmospheric transport potential based on predicted atmospheric oxidation half-lives >2 days and log air-water partition coefficients > or =5 and < or =1. These chemicals are a diverse group including halogenated organics, cyclic siloxanes, and substituted aromatics. Some of these chemicals and their transformation products may be candidates for future environmental monitoring. However, to improve these predictions data on emissions from end use are needed to refine environmental fate predictions, and analytical methods may need to be developed.
Many screening-level models exist for predicting aerobic biodegradation potential from chemical structure, but anaerobic biodegradation generally has been ignored by modelers. We used a fragment contribution approach to develop a model for predicting biodegradation potential under methanogenic anaerobic conditions. The new model has 37 fragments (substructures) and classifies a substance as either fast or slow, relative to the potential to be biodegraded in the "serum bottle" anaerobic biodegradation screening test (Organization for Economic Cooperation and Development Guideline 311). The model correctly classified 90, 77, and 91% of the chemicals in the training set (n = 169) and two independent validation sets (n = 35 and 23), respectively. Accuracy of predictions of fast and slow degradation was equal for training-set chemicals, but fast-degradation predictions were less accurate than slow-degradation predictions for the validation sets. Analysis of the signs of the fragment coefficients for this and the other (aerobic) Biowin models suggests that in the context of simple group contribution models, the majority of positive and negative structural influences on ultimate degradation are the same for aerobic and methanogenic anaerobic biodegradation.
1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH) is used primarily as an additive flame retardant. Technical grade TBECH consists of near equimolar amounts of two (of a possible four) diastereoisomers: rac-(1R,2R)-1,2-dibromo-(4S)-4-((1S)-1,2-dibromoethyl)cyclohexane ((alpha-TBECH) and rac-(1R,2R)-1,2-dibromo-(4S)-4-((1R)-1,2-dibromoethyl)cyclohexane (beta-TBECH). The two other possible isomers, gamma- and delta-TBECH, appear in the technical mixture when heated at temperatures above 120 degrees C. Careful selection of GC-capillary column length was critical in resolution of the two main diastereoisomers. Column lengths of 60 or 30 m (0.25 microm film thickness) resulted in incomplete separation of the alpha- and beta-isomers, while on a 10 m column, the isomers were baseline separated. The gamma- and delta-isomers could not be resolved on any column length in this study. Increased injector port temperature induced thermal conversion of the alpha- and beta-isomers to gamma- and delta-TBECH. Electron impact ionization (EI) was used to provide specificity because no characteristic ions in the electron capture negative ionization (ECNI) mass spectrum of TBECH were evident. In EI, the dominant ions in the mass spectrum corresponded to a concomitant loss of HBr and Br from the molecular ion; the biggest peak in this ion cluster (m/z 266.9208) was used for quantitation and the second biggest peak (m/z 264.9227) was used for confirmation. Beluga (Delphinapterus leucas) blubber extracts of animals from the Canadian Arctic (n=29) were analyzed using low resolution (LR) MS and high resolution (HR) MS run at a resolving power of 10,000. beta-TBECH was the only isomer observed in the samples and was detected in 17 samples. The LRMS technique appeared to overestimate beta-TBECH concentrations compared to HRMS, suggesting a small interference arose at the nominal mass monitored. This potential interference also led to some false positive and negative values (n=7) based on the expected ion ratio of the quantitation and confirmation ions. Observed concentrations of the beta-isomer as measured by HRMS ranged from 1.1 to 9.3 ng/g (lipid weight).
DecaBDE is a current-use, commercial formulation of an additive, polybrominated diphenyl ether (PBDE) flame retardant composed of > 97% 2,2',3,3',4,4',5,5',6,6'-decabromoDE (BDE-209). Of the 43 PBDE congeners monitored, we report on the temporal trends (1982-2006) of quantifiable PBDEs, and specifically BDE-209, in pooled samples of herring gull (Larus argentatus) eggs from seven colonies spanning the Laurentian Great Lakes. BDE-209 concentrations in 2006 egg pools ranged from 4.5 to 20 ng/g wet weight (ww) and constituted 0.6-4.5% of sigma39PBDE concentrations among colonies, whereas sigma(octa)BDE and sigma(nona)BDE concentrations constituted from 0.5 to 2.2% and 0.3 to 1.1%, respectively. From 1982 to 2006, the BDE-209 doubling times ranged from 2.1 to 3.0 years, whereas for sigma(octa)BDEs and sigma(nona)BDEs, the mean doubling times ranged from 3.0 to 11 years and 2.4 to 5.3 years, respectively. The source of the octa- and nona-BDE congeners, e.g., BDE-207 and BDE-197, are the result of BDE-209 debromination, and they are either formed metabolically in Great Lakes herring gulls and/or bioaccumulated from the diet and subsequently transferred to their eggs. In contrast to BDE-209 and the octa- and nona-BDEs, congeners derived mainly from PentaBDE and OctaBDE mixtures, e.g., BDE-47, -99, and -100, showed rapid increases up until 2000; however, there was no increasing trend post-2000. The data illustrates that PBDE concentrations and congener pattern trends in the Great Lakes herring gull eggs have dramatically changed between 1995 and 2006. Regardless of BDE-209 not fitting the pervasive criteria as a persistent and bioaccumulative substance, it is clearly of increasing concern in Great Lake herring gulls, and provides evidence that regulation of DecaBDE formulations is warranted.
The identification of potential Arctic contaminants requires an assessment of both the long-range transport and the bioaccumulation of the chemicals, most particularly in the indigenous inhabitants of the Arctic. For this purpose, a nonsteady state, zonally averaged global distribution model was linked to a nonsteady state bioaccumulation model describing Inuit exposure from a marine diet. The potential of hypothetical, perfectly persistent chemicals with varying combinations of partitioning properties to enrich in the Arctic environment following emission in the lower latitudes and, additionally, to bioaccumulate in the Arctic food chains was evaluated using the Arctic contamination and bioaccumulation potential (AC-BAP). The AC-BAP is defined as the quotient of the human body burden of the chemical and the quantity of chemical cumulatively emitted to the global environment. The highest AC-BAP values (up to 3.7 x 10(-11) person(-1)) were obtained for hypothetical multimedia chemicals with intermediate volatility and hydrophobicity. Perfectly persistent chemicals with 3.5 < log K(OW) < 8.5 and log K(OA) > 6 had AC-BAP values of at least 10% of the maximum value, indicating that a broad range of chemicals are potential Arctic contaminants if they are persistent. Moreover, the simulation results suggest that a chemical's potential to bioaccumulate has a stronger impact on the overall potential to become an Arctic contaminant in humans than its potential for long-range transport. This modeling exercise demonstrates how linking nonsteady state models of chemical bioaccumulation and of global chemical fate can provide a valuable tool for assessing a chemical's potential to be a contaminant in remote regions.