Bernhard Henkelmann

Helmholtz-Zentrum für Umweltforschung, Leipzig, Saxony, Germany

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Publications (107)328.19 Total impact

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    ABSTRACT: This study investigated a wide range of semi-volatile organic compounds (SVOCs), including 28 persistent organochlorine pesticides (OCPs), 18 polychlorinated biphenyls (PCBs), 13 polybrominated diphenyl ethers (PBDEs), and 3 hexabromocyclododecane (HBCD) congeners in lichen, moss and soil collected from the southeastern Tibetan Plateau, China. This allows research provides insight into elevation gradient distributions and possible cold trapping effects of SVOCs in this high mountain area, and compares lichens and mosses as air passive samplers for indicating SVOC occurrences. DDTs, endosulfans, HCHs and hexachlorobenzene predominated in all of the samples. Source analysis indicted that there were fresh inputs of DDTs and HCHs in the sampling region. Lichens and mosses shared commonalities in revealing the profiles and levels of SVOCs based on their lipid-content-normalized concentrations. The concentrations of 12 OCPs and 14 PCBs in lichens were significantly linearly correlated with altitudes, whereas the correlations for mosses and soil with altitudes were insignificant. Both a frequency distribution diagram and the Mountain Contamination Potential Model indicated that SVOCs with specific values of log KOA (8-11) and log KWA (2-4) had relative high mountain contamination potential on the Tibetan Plateau. Copyright © 2015 Elsevier B.V. All rights reserved.
    Science of The Total Environment 06/2015; 518. DOI:10.1016/j.scitotenv.2015.03.024 · 3.16 Impact Factor
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    ABSTRACT: The human body is not a chemically uncontaminated system. Every simple action that humans undertake, such as drinking water, eating, nursing, and even breathing air, puts the system under environmental xenobiotic exposure stress. Environmental chemicals have been shown to produce unwanted effects on health and remove the right to healthy living, starting from the first encounter in utero to geriatrics, throughout the lifespan. Organochlorine pesticides (OCPs) and polychlorinated biphenyl (PCB) levels, important members of the persistent organic pollutants (POPs), have been detected before in human breast milk and also in the adipose tissue of women from different regions of Turkey; however, there was no information about the blood levels of these chemicals. This study generated the first information that evaluates OCP and PCB contamination levels in the blood of the women living in Turkey. The current study measured the blood concentrations of OCPs and PCBs in 58 healthy women (age 20-41 years; mean age 28 years) who were living in Istanbul, Turkey, in the years 2010-2012. Samples were analyzed for 29 OCPs and 18 PCB congeners using high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). PCB 153 was the predominant congener (643.2 pg/g lipid), followed by PCB 138 and PCB 180. 4,4'-DDE (24872.8 pg/g lipid) was the most common organochlorinated pesticide contaminant in studied blood samples. Results for analyzed chlorinated compounds were as follows: ∑PCB 2682 ± 3300 pg/g lipid; ∑DDT 25,938 ± 28,644 pg/g lipid; and ∑HCH 2930 ± 2222 pg/g lipid, respectively. The mean concentration of ∑WHOPCB-TEQ was 0.037 pg/g on a lipid basis. This information will be important base data during the assessment of the general health concerns of women, as well as for studies about how endocrine disruptors affect humans for forthcoming studies.
    Environmental Monitoring and Assessment 03/2015; 187(3):4358. DOI:10.1007/s10661-015-4358-0 · 1.68 Impact Factor
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    ABSTRACT: The levels and patterns of organochlorine pesticides and degradation products in rainwater samples collected in relation to a contaminated site in Kibaha district, Tanzania were investigated. The compounds detected in the samples by GC–MS and isotope dilution methodology included DDT, DDE, DDD, HCHs, dieldrin, heptachlor, chlordane, endrin and hexachlorobenzene. The concentrations of total DDT and total HCH ranged 0.005–3200 μg L−1 and 0.01–170 μg L−1, respectively and they indicated input of significantly non-degraded technical mixtures. The highest concentrations for other compounds ranged 0.001–1.3 μg L−1. The highest concentrations were found in samples collected in the vicinity of the contaminated site and the concentrations at other points showed a general even distribution suggesting repeated volatilization and deposition mechanisms. The strong positive correlations in the concentrations of the compounds indicated a common source. A decrease in concentrations with time was indicated, although the decrease was not significant during the period of sampling. The findings indicate risks and concerns for public and environmental health.
    Chemosphere 01/2015; 118:12–19. DOI:10.1016/j.chemosphere.2014.05.051 · 3.50 Impact Factor
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    ABSTRACT: Triolein-containing semipermeable membrane devices (SPMDs) and butyl rubber (BR) based sorbents were employed as passive samplers in 14 coastal stations of Turkey including shipyards and marinas to characterize time-integrated levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) and their relationship to potential pollution sources. Passive samplers of SPMDs and BR sorbents were deployed for 30 days in the spring of 2012. The maximum concentrations of total PAH and PCB compounds sequestered by SPMDs were 3338 ng g− 1 SPMD and 4247 pg g− 1 SPMD. (END)-I and DDT-related compounds were dominant OCP compounds for most of the sites in passive samplers. Total PAH concentrations in SPMDs were found 1.2 to 8 times higher than the concentrations in BRs. However, BR sorbents were able to sample some PAHs which could not be sampled by SPMDs. The concentrations of PCBs and OCPs in BRs were similar or higher than SPMDs. SPMD-data were used to estimate the average ambient water concentrations of the contaminants. Two existing theoretical approaches have been used to derive the concentrations of hydrophobic pollutants in the ambient waters. The results were found very similar and range from 7318 to 183864 pg L− 1 for PAHs, from 2 to 186 pg L− 1 for PCBs, and from 98 to 848 pg L− 1 for OCPs. Furthermore, a simple numerical model was designed to estimate the boat-related water concentrations in marinas by using the seawater data supplied by SPMDs. The model was mainly built on the water concentration and the capacities of a particular marina and then applied to two sites in the second marina. A good correlation was found between the model outputs and SPMD-water data.
    Environment International 12/2014; 73:85–93. DOI:10.1016/j.envint.2014.07.013 · 5.66 Impact Factor
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    ABSTRACT: For evaluating the brown mussel Perna perna as a sentinel organism regarding environmental concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the present study reports original data on the relationship between the concentrations of these chemicals in bottom surface sediments, suspended solids (SS) and concentrations bioaccumulated by this bivalve. Three P. perna cultivation areas, located at three bays in southeastern Brazil were used in this study. The three estuaries are under different degrees of environmental impact. Variations in the OCP and PCB concentrations bioaccumulated by the bivalves tended to be similar to those observed in the sediment, but differed from those found in SS. This latter difference might suggest that the SS trapping apparatuses should have been left in place for approximately 60days (not only 15days). This longer period would allow the integration of the environmental variability of the OCP and PCB burden adsorbed to this compartment. Authors encourage future studies to evaluate P. perna exposure to OCPs and PCBs through the evaluation of sediment concentrations.
    Chemosphere 11/2014; 114:9–15. DOI:10.1016/j.chemosphere.2014.04.008 · 3.50 Impact Factor
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    ABSTRACT: Bulk deposition samples were collected at three elevated summits in different parts of the Alps from 2005 to 2010. Deposition samples were analyzed for a wide range of organochlorine pesticides (OCPs). HCHs, DDT, DDD, DDE, chlordanes, cis-heptachlor, HCB, dieldrin and endrin were found in all samples, only aldrin was found less frequently.Differences in the mean deposition rates between the three sites reflect the different amounts of precipitation at these sites. At the northern edge of the Alps with the highest annual total precipitations, mean annual deposition rates were at least twice those at the Swiss site for most of the investigated OCP. Average annual deposition of α-HCH amounted to 602, 461 and 216 ng m−2 year−1, the sum of DDT, DDD and DDE to 579, 210 and 144 ng m−2 year−1 and the sum of trans- and cis-chlordane to 35, 47, 16 ng m−2 year−1 at Zugspitze, Sonnblick, and Weissfluhjoch, respectively.A quite distinct seasonal pattern of OPC deposition was observed at all three locations. For most of the HCH isomers, higher deposition rates were observed in summer than in winter at all three sites, which may be caused by enhanced re-volatilization due to higher summer temperatures and the ongoing application of HCH-containing products in some regions as well. For the other investigated OCPs, higher summer deposition rates were found only at Weissfluhjoch. This site is more often affected by air masses crossing the river Po basin than the other two sites, an area exhibiting higher summer temperatures compared to other regions adjacent to the Alps.
    Atmospheric Environment 11/2014; DOI:10.1016/j.atmosenv.2014.10.060 · 3.06 Impact Factor
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    ABSTRACT: Halogenated carbazoles have recently been detected in soil and water samples, but their environmental effects and fate are unknown. Eighty-four soil samples obtained from a site with no recorded history of pollution were used to assess the persistence and dioxin-like toxicity of carbazole and chlorocarbazoles in soil under controlled conditions for 15 months. Soil samples were divided into two temperature conditions, 15 and 20 °C, both under fluctuating soil moisture conditions comprising 19 and 44 drying-rewetting cycles, respectively. This was characterized by natural water loss by evaporation and rewetting to -15 kPa. Accelerated solvent extraction (ASE) and cleanup were performed after incubation. Identification and quantification were done using high-resolution gas chromatogram/mass spectrometer (HRGC/MS), while dioxin-like toxicity was determined by ethoxyresorufin-O-deethylase (EROD) induction in H4IIA rat hepatoma cells assay and multidimensional quantitative structure-activity relationships (mQSAR) modelling. Carbazole, 3-chlorocarbazole and 3,6-dichlorocarbazole were detected including trichlorocarbazole not previously reported in soils. Carbazole and 3-chlorocarbazole showed significant dissipation at 15 °C but not at 20 °C incubating conditions indicating that low temperature could be suitable for dissipation of carbazole and chlorocarbazoles. 3,6-Dichlorocarbazole was resistant at both conditions. Trichlorocarbazole however exhibited a tendency to increase in concentration with time. 3-Chlorocarbazole, 3,6-dibromocarbazole and selected soil extracts exhibited EROD activity. Dioxin-like toxicity did not decrease significantly with time, whereas the sum chlorocarbazole toxic equivalence concentrations (∑TEQ) did not contribute significantly to the soil assay dioxin-like toxicity equivalent concentrations (TCDD-EQ). Carbazole and chlorocarbazoles are persistent with the latter also toxic in natural conditions.
    Environmental Science and Pollution Research 08/2014; 22(2). DOI:10.1007/s11356-014-3386-6 · 2.76 Impact Factor
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    ABSTRACT: The levels, compositions and distributions of organochlorine pesticides and metabolites were determined in soil samples collected 5-14years after clean-up was carried out at seven contaminated sites in Tanzania. Samples were collected from various depths (5-10cm, 30cm, and 50cm for most sites and up to 300cm for one site. Determination of the analytes was performed using a high resolution GC-MS and isotope dilution technology. DDT, DDD, DDE, HCH isomers, aldrin, dieldrin, endrin, endosulfans, chlordanes and heptachlor were the major compounds detected. The concentrations of total DDT and total HCH were up to 250000 and 164000mgkg(-1), respectively, while the highest concentrations for other compounds ranged from 29 to 3300mgkg(-1). The results indicated that there were no significant degradations/transformations of the pesticides for most of the sites. The highest concentrations of the compounds were mostly found in surface soil samples and there were variations in distribution among the sampling depths. The results indicate risks and concerns for public health and the environment.
    Chemosphere 08/2014; 117C:330-337. DOI:10.1016/j.chemosphere.2014.07.052 · 3.50 Impact Factor
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    ABSTRACT: Winam Gulf of Lake Victoria is considered to be contaminated with toxic chemicals emanating from anthropogenic activities, especially near large industrial towns such as Kisumu. This has recently caused concerns about its water quality and impact on aquatic organisms and human beings. This study was justified by the need to generate baseline concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in surface sediment from selected sites in the lake and determine the influence of activities on their concentrations and potential risks to fish-eating birds living near the lake. Surface sediments (<30cm) from three different fish landing beaches, located 200m from the shore of Winam Gulf of Lake Victoria near Kisumu city, Homa Bay and Mbita (control) towns, were analysed. The total mean concentrations (in pgg(-1)drywt) were found to range from 17.4-812 (Σdl-PCBs), 36.6-813 (ΣPCDDs) and 1.45-46.4 (ΣPCDFs). The calculated Toxic Equivalents (TEQWHO(2005)) ranged from 0.001-0.43 (Σdl-PCBs) and 0.09-31 (ΣPCDD/Fs). The fish landing beaches at Kisumu city were found to be contaminated with respect to dl-PCBs and dioxins, followed by Homa Bay and Mbita. The relatively high levels of octachlorodibenzo-p-dioxin (OCDD) and octachlorodibenzofuran (OCDF) influenced the TEQ and the ΣPCDFs/ΣPCDDs ratios indicated chemical processes as partial sources of the dioxins. The levels of contaminants obtained in this study showed potential exposure to aquatic organisms and fish eating birds through food chain transfer.
    Chemosphere 08/2014; 118C:143-147. DOI:10.1016/j.chemosphere.2014.07.062 · 3.50 Impact Factor
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    ABSTRACT: The concentrations of 28 organochlorine pesticides (OCPs) in the urban air of Dalian, China were measured using semipermeable membrane devices (SPMDs) for the first time. Alpha-hexachlorocyclohexane (α-HCH), β-HCH, pentachlorobenzene (PentCB), hexachlorobenzene (HexCB), 4,4′-dichlorodiphenyltrichloroethane (4,4′-DDT), 4,4′-dichlorodiphenyldichloroethene, endosulfan-I and endosulfan-II were the predominant OCPs in the urban air of Dalian. The concentration of OCPs sequestrated by SPMDs (C SPMD) ranged from undetected to 56,772 pg SPMD−1 and had a linear correlation with the reciprocal of the average ambient atmospheric temperature (1/T). The C SPMD of PentCB and HexCB had negative correlations with T, whereas the other detected OCPs had a positive correlation. The source of HCHs, DDTs, HexCB, PentCB, chlordane, and endosulfan in the air were also evaluated. The OCPs in the urban air of Dalian could be attributed to the seasonal usage of pesticides, combustion, volatilization of aged OCPs from soil, water, plants, and long-range atmospheric transport.
    Chinese Science Bulletin 08/2014; 59(24):2957-2965. DOI:10.1007/s11434-014-0437-9 · 1.37 Impact Factor
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    ABSTRACT: Concentrations of PAHs, PCBs and OCPs in sediments and mussels (caged and/or native) were determined at 16 stations in six major sites of coastal Turkey. The biological effects of pollution were evaluated using sediment toxicity tests and enzyme activity assays. EROD, PROD, GST, AChE, CaE, and GR activities were evaluated using the digestive glands of mussels. The total PAH concentrations in the sediments varied between nd and 79,674ngg(-1) dw, while the total OCP concentrations were in the range of nd to 53.7ngg(-1) dw. The total PAH concentrations in mussels varied between 22.3 and 37.4ngg(-1) ww. The average concentrations of total PCBs in mussels were 2795pgg(-1) ww in the shipyard, 797pgg(-1) ww in Marina 2 and 53pgg(-1) ww in Marina 1 stations. The results of whole-sediment toxicity tests showed a strong correlation between toxicity test results and pollutant concentrations. Selected cytosolic enzyme activities in digestive glands differed significantly depending on localities. These differences in enzyme activities were mainly related to the different pollutant levels of the sampling sites. The micro-organic contaminant profile patterns, toxicity tests and biomarker studies showed that shipyards and shipbreaking yards are the major potential sources of organic pollution in coastal areas.
    Science of The Total Environment 07/2014; 496C:165-178. DOI:10.1016/j.scitotenv.2014.07.035 · 3.16 Impact Factor
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    ABSTRACT: Pristine mountains are ideal settings to study transport and behavior of persistent organic pollutants (POPs) along gradients of climate and land cover. The present work investigated the concentrations and patterns of 28 organochlorine pesticides (OCPs), 25 polychlorinated biphenyl (PCBs), 13 polybrominated diphenyl ethers (PBDEs), and 3 hexabromocyclododecane (HBCDs) isomers in the air of the Shergyla Mountain, southeastern Tibetan Plateau. Endosulfan І, hexachlorobenzene, pentachlorobenzene, hexachlorocyclohexanes and dichlorodibenzotrichloroethane and its degradation products (DDTs) were the predominant compounds while PBDEs and HBCDs showed the lowest background concentrations. Most of the target POPs had significantly higher concentrations in summer than those in winter. Increasing trends of the concentrations of DDTs and endosulfan were found with increasing altitude on the western slope in the Shergyla Mountain. Potential forest filter effect was observed based on the lower air concentrations of the target POPs in the forest than the ones out of the forest.
    Environmental Pollution 05/2014; 191C:166-174. DOI:10.1016/j.envpol.2014.04.031 · 3.90 Impact Factor
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    ABSTRACT: Polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) are persistent, toxic, and bioaccumulate in the environment. Due to their high analytical costs, these compounds are hardly regulated and mostly not monitored in the Third World. To overcome this, bioassays have been proposed as low-cost alternative methods. Two of the most established bioanalytical tools, the dioxin antibody-based enzyme-linked immunosorbent assay ELISA and the micro-EROD bioassay are evaluated and compared to high resolution gas chromatography and high resolution mass spectrometry (HRGC/HRMS) analytical methodology. The methods were tested using thirteen soils and sediment samples selected from diverse sites in Montevideo, Uruguay. The WHO2005 total toxic equivalent (WHO2005-TEQ) of soils ranged from 2.4 to 2212 (ng WHO2005-TEQ/Kg dry sample) and from 0.14 to 9.4 (ng WHO2005-TEQ/Kg dry sample) in sediments. This study shows significant contamination related to dioxin-like compounds, particularly in sites where uncontrolled burnings were carried out. ELISA and micro-EROD bioassay correlated well with HRGC/HRMS, R Spearman 0.773 and 0.913, respectively and were highly correlated to each other, R Spearman 0.879. Preliminary threshold values of bioassay toxic equivalents of 330 (ng/Kg dry sample) for the micro-EROD bioassay and 220 (ng/Kg dry sample) for ELISA are proposed.
    Toxicology in Vitro 04/2014; DOI:10.1016/j.tiv.2014.04.009 · 3.21 Impact Factor
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    ABSTRACT: Mass fluxes of polycyclic aromatic hydrocarbons (PAHs) were calculated for the Three Gorges Reservoir (TGR) in China, based on concentration and discharge data from the Yangtze River. Virtual Organisms (VOs) have been applied during four campaigns in 2008, 2009 (twice) and 2011 at sampling sites distributed from Chongqing to Maoping. The total PAH mass fluxes ranged from 110 to 2160mgs(-1). Highest loads were determined at Chongqing with a decreasing trend towards Maoping in all four sampling campaigns. PAH remediation capacity of the TGR was found to be high as the mass flux reduced by more than half from upstream to downstream. Responsible processes are thought to be adsorption of PAH to suspended particles, dilution and degradation. Furthermore, the dependence of PAH concentration upon water depth was investigated at Maoping in front of the Three Gorges Dam. Although considerable differences could be revealed, there was no trend observable. Sampling of water with self-packed filter cartridges confirmed more homogenous PAH depth distribution. Moreover, PAH content of suspended particles was estimated from water concentrations gathered by VOs based on a water-particle separation model and subsequently compared to PAH concentration measured in water and in filter cartridges. It could be shown that the modeled data predicts the concentration caused by particle-bound PAHs to be about 6 times lower than PAHs dissolved in water. Besides, the model estimates the proportions of 5- and 6-ring PAHs being higher than in water phase.
    Science of The Total Environment 04/2014; DOI:10.1016/j.scitotenv.2014.03.076 · 3.16 Impact Factor
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    ABSTRACT: SPMD-based virtual organisms (VOs) were employed for time-integrating, long-term sampling combined biological and chemical analyses for exposure assessment of hydrophobic organic pollutants (HOPs) in a drinking water reservoir, China. The SPMDs were deployed at four and five sites in the Danjiangkou (DJK) reservoir over two periods of 26 and 31d to sequester the hydrophobic contaminants in water. The chosen bioassay response for the extracts of the SPMDs, the induction of 7-ethoxyresorufin-o-deethylase (EROD) was assayed using a rat hepatoma cell line (H4IIE). The known aryl hydrocarbon receptor (AhR) agonists PAHs and PCBs were analyzed by HRGC/HRMS instrument. The cause-effect relationship between the observed AhR activities and chemical concentrations of detected AhR agonists was examined. The results show that the extracts from the SPMD samples could induce AhR activity significantly, whereas the chemically derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQcal) was not correlated with the bioassay-derived TCDD equivalent (TEQbio). The known AhR agonists could only account for 2-10% of the observed AhR responses among which the contribution of PCBs could almost be neglected. Unidentified AhR-active compounds represented a greater proportion of the TCDD equivalent (TCDD-EQ) in SPMD samples from DJK. Based on the first assessment, the VO followed by the combination of chemical and biological analyses emerges as a resource efficient water monitoring device in ecotoxicological assessment for toxicologically relevant compounds which are readily available for uptake by resident aquatic biota in drinking water resources.
    Chemosphere 02/2014; DOI:10.1016/j.chemosphere.2014.01.056 · 3.50 Impact Factor
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    ABSTRACT: Pristine mountains are ideal settings to study transport and behavior of persistent organic pollutants (POPs) along gradients of climate and land cover. The present work investigated the concentrations and patterns of 28 organochlorine pesticides (OCPs), 25 polychlorinated biphenyl (PCBs), 13 polybrominated diphenyl ethers (PBDEs), and 3 hexabromocyclododecane (HBCDs) isomers in the air of the Shergyla Mountain, southeastern Tibetan Plateau. Endosulfan І, hexachlorobenzene, pentachlorobenzene, hexachlorocyclohexanes and dichlorodibenzotrichloroethane and its degradation products (DDTs) were the predominant compounds while PBDEs and HBCDs showed the lowest background concentrations. Most of the target POPs had significantly higher concentrations in summer than those in winter. Increasing trends of the concentrations of DDTs and endosulfan were found with increasing altitude on the western slope in the Shergyla Mountain. Potential forest filter effect was observed based on the lower air concentrations of the target POPs in the forest than the ones out of the forest.
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    ABSTRACT: In this study, Mediterranean mussel species, Mytilus galloprovincialis, were exposed to phenanthrene (PHE) due to its ubiquitousness and bioavailability in the aquatic environment. Kinetic parameters of the PHE bioaccumulation and depuration were calculated for an 11-day uptake and subsequent 11-day depuration periods. Those values of kinetic rate constants for uptake and depuration of PHE were calculated as varying between 93-177 and 0.18-0.25, respectively. Negative correlation was observed between the PHE concentrations and kinetic rate constants. Bioaccumulation Factors (BAFs) for the mussels exposed to different PHE concentrations were calculated from both kinetic rate constants and from the experimental data and found between 509-701 and 441-658, respectively. Experimental quantitative structure activity relationship (QSAR) values for PHE were found comparable to the calculated QSARs reported in literature. Two sub-lethal biomarker methods (filtration rate and lysosomal stability) were applied to observe the responses of the mussels throughout the experimental period. Results of both biomarkers show that PHE negatively affects mussels during the uptake of PHE, and mussels were able to recover physiologically at the end of depuration period according to the filtration rate results.
    Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering 07/2013; 48(9):1037-46. DOI:10.1080/10934529.2013.773799
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    ABSTRACT: 3-Chlorocarbazole, 3,6-dichlorocarbazole, dibromocarbazole, and 1,3,6,8-tetrabromocarbazole are emerging environmental contaminants which have been detected recently in water, sediment, and soil samples. However, their sources and occurrence have not been explained. Here, we report an enzymatic synthesis of bromo- and chlorocarbazoles by chloroperoxidase from Caldariomyces fumago in water. Density functional theory (DFT) method was used to predict the most stable products. Carbazole and chloroperoxidase were assayed in vitro in the presence of hydrogen peroxide, bromide, and chloride ions in different substrate ratio treatments against constant and varying enzyme concentrations. Halogenated carbazoles formed were identified by high-resolution gas chromatography coupled to mass spectrometry. In all treatments, bromination and chlorination took place, but the composition and concentration of compounds formed varied from one treatment to another. Mono-, di-, tri-, and tetra-substituted bromo- and chlorocarbazoles which include the reported environmental contaminants were synthesized. 3-Substituted and 3,6-substituted congeners were relatively higher in concentration. Enzyme concentration did not favor preferential formation of any of the compounds synthesized. However, their synthesis was influenced by halide concentration. Congeners with bromine and chlorine at position of C-3, C-3,6, C-1,3,6, and C-1,3,6,8 were calculated as the stable intermediate sigma complexes by DFT method. Regioselectivity in halogenation is discussed and hypothesis of the likely stable products in the environment explained. This study provides evidence that bromo- and chlorocarbazoles reported previously can be formed enzymatically in the environment, demonstrating the need to consider aromatic pollutants transformation and their potential toxicity enhancements in the management of water pollution and contaminated sites.
    Environmental Science and Pollution Research 06/2013; DOI:10.1007/s11356-013-1823-6 · 2.76 Impact Factor
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    ABSTRACT: The concentration of polycyclic aromatic hydrocarbons (PAHs) in the urban air of Dalian, China was monitored from November 2009 to October 2010 with an active high-volume sampler and a semipermeable membrane device (SPMD) passive sampler. The samples were analyzed for the sixteen US EPA priority monitoring PAHs using GC/MS. The concentrations of ∑PAHs in particle and gas phases ranged from 3.2–90.6 ng m−3 and 40.8–155 ng m−3, respectively. The PAHs of 3–4 rings covered 89.2% of the total concentrations (gas phase + particle phase). Furthermore, the gas-particle partitioning phenomena and the results measured from the field versus those predicted by the Junge-Pankow adsorption model, octanol-air partitioning coefficient (K OA) based absorption model, the absorption into the organic matter plus the adsorption to the soot carbon model using the soot-air partitioning coefficients (K SA) were discussed in this article. The dominant contributors of PAHs in the gas phase of active samples and SPMD passive samples were similar. The SPMD mainly sequestrated gas phase PAHs. The linear correlation coefficients between C SPMD and C air-gas were 0.7316 and 0.7403; C SPMD and C air-total were 0.7397 and 0.7409 at Dalian Jiaotong University sampling site and Dalian Meteorological Observatory sampling site, respectively. The quantitative structure-property relationship (QSPR) of the sampling rate of SPMD for PAHs was studied, which can be predicted by the core–core repulsion energy and the energy of the highest occupied molecular orbital of PAH molecules.
    Polycyclic Aromatic Compounds 05/2013; 33(3):265-288. DOI:10.1080/10406638.2013.777672 · 0.83 Impact Factor
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    ABSTRACT: Two commercially important fish species, Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) belonging to different trophic levels were collected from the Napoleon Gulf and Thurston Bay in Lake Victoria. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were extracted from the fish muscles and livers using the (13)C isotope dilution method, followed by multiple column chromatography clean-up. Analysis was achieved by a high resolution gas chromatography coupled with a high resolution mass spectrometer. The concentrations of analytes ranged from 0.07 to 0.59pgg(-1) fresh weight (fw) and 0.3-19.0pgg(-1) in L. niloticus and 0.06-0.18 and 0.2-15.7pgg(-1) in O. niloticus, for ∑PCDD/Fs and ∑dl-PCBs, respectively. Differences in congener concentrations were observed between the two fish species and study sites, and this was attributed to differences in feeding habits and trophic levels. World Health Organization-toxic equivalents (WHO-TEQs) were in the range 0.01-0.16pgTEQg(-1) for the PCDD/Fs and 0.001-0.74pgTEQg(-1) for the dl-PCBs. The TEQ values in the present study were lower compared to those of most fish samples reported in literature and were within permissible levels recommended by the European Union, implying that the fish was fit for human consumption.
    Chemosphere 05/2013; DOI:10.1016/j.chemosphere.2013.03.033 · 3.50 Impact Factor