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Effects of the antibiotic enrofloxacin on the ecology of tropical eutrophic freshwater microcosms
... In addition, 20% of the water (volume) was exchanged between the cosms every two weeks to promote homogeneity among the systems (Sumon et al., 2018). During the experimental period, nitrogen (1.4 mg/L nitrogen, urea) and phosphorus (0.18 mg/L P, trisodium phosphate) were added every three weeks to the systems (Rico et al., 2014;Sumon et al., 2018). After the establishment time of seven months (30-05-2019), the model ecosystems were weekly dosed for four weeks with three imidacloprid treatment levels (treatment-1 (0.01 μg/L), treatment-2 (0.1 μg/L) and treatment-3 (1 μg/L)) and control (i.e., not dosed with the insecticide) with three replicates each, using freshly prepared stock imidacloprid solutions from the imidacloprid formulation containing 350 g a.i./L. ...
... Afterwards, the glass slides were put back in the cosms in their original position. Chlorophyll-a of periphyton and phytoplankton was quantified using ultraviolet-visible (UV-VIS) spectrophotometric technique (Rico et al., 2014) after extraction of the chlorophyll-a from the GF/C glass-fibre filter using acetone solvent. The periphyton and phytoplankton chlorophyll-a concentrations were expressed in mg/m 2 and μg/L, respectively. ...
... The collected macroinvertebrates were taxonomically identified to family level except for C. dipterum, C. horaria and P. minutissima, and counted. The alive macroinvertebrates were released back to their original cosms (Rico et al., 2014;Sumon et al., 2018). ...
This study aimed to investigate the effect of imidacloprid on structural (invertebrates and primary producers) and functional (organic matter decomposition and physicochemical parameters) characteristics of tropical freshwaters using acute single species and mesocosm studies performed in Ethiopia. The recovery of affected endpoints was also studied by using a mesocosm study period of 21 weeks. Our acute toxicity test showed that Cloeon dipterum (96-h EC50 = 1.5 μg/L) and Caenis horaria (96-h EC50 = 1.9 μg/L) are relatively sensitive arthropods to imidacloprid. The mesocosm experiment evaluated the effects of four applications of imidacloprid with a weekly interval and the results showed that the macroinvertebrate and zooplankton community structure changed significantly due to imidacloprid contamination in mesocosms repeatedly dosed with ≥0.1 and ≥ 0.01 μg/L, respectively (time weighted average concentrations of 112 days (TWA112d) of ≥0.124 and ≥ ≈0.02 μg/L, respectively). The largest responses were found for C. dipterum, C. horaria, Brachionus sp. and Filinia sp. Chlorophyll-a concentrations of periphyton and phytoplankton significantly increased in the ≥0.1 μg/L treatments levels which are indirect effects as a result of the release of grazing pressure. A significant, but quantitatively small, decrease of organic matter decomposition rate was observed in mesocosms treated with repeated doses of 1 μg/L (TWA112d of 2.09 μg/L). No recovery was observed for the macroinvertebrates community during the study period of 21 weeks, but zooplankton recovered after 9 weeks. We observed spatio-temporal related toxicity differences between tropical and temperate aquatic taxa, with tropical taxa generally being more sensitive. This suggests that use of temperate toxicity data for the risk assessment of imidacloprid in tropical region is not recommended.
... During this establishment time (7 months) 20 % of the water (volume) was exchanged between the cosms every two weeks to promote the homogeneity among the systems . During the whole experimental period nitrogen (1.4 mg/L nitrogen, urea) and phosphorus (0.18 mg/L P, trisodium phosphate) were added every three weeks to the systems (Rico et al., 2014;Sumon et al., 2018). After the establishment time of seven months (30-05-2019) the model ecosystems were weekly dosed for four weeks with four treatment levels (0 (control), 0.01, 0.1 and 1 µg/L) with three replicates each, using freshly prepared dosage imidacloprid solutions from imidacloprid formulation containing 350 g a.i./L. ...
... After that the glass slides were put back in the cosms in their original position. Chlorophyll-a of periphyton and phytoplankton was quantified using ultraviolet-visible (UV-VIS) spectrophotometric technique (Rico et al., 2014) after extraction of the chlorophyll-a from the GF/C glass-fibre filter using acetone solvent. The periphyton and phytoplankton chlorophyll-a concentrations were expressed in mg/m 2 and µg/L, respectively. ...
... The collected macroinvertebrates were taxonomically identified to family level except for C. dipterum, C. horaria and P. minutissima, and counted. The alive macroinvertebrates were released back to their original cosms (Rico et al., 2014;Sumon et al., 2018). ...
Ethiopia is a predominantly agrarian country where about 85% of the country’s population is engaged in the agricultural sector. The sector has enjoyed substantial growth during the last two decades. To increasing crop production and productivity to achieve high agricultural growth and alleviate food security problems in the growing population through, for example, intensive use of agricultural inputs such as fertilizers and pesticides are priorities for the Ethiopian government. As a result of this agricultural intensification policy of the Ethiopian government, the use of pesticides and fertilizers has increased year to year and will be expected to further increase in the years to come. The central Ethiopian rift valley region, particularly in the vicinity of Lake Ziway, is amongst the regions where agrochemicals (pesticides and fertilizers) are most intensively used by smallholder farmers producing vegetables and fruits (e.g., tomato, onion, cabbage, green bean and pepper) and by large-scale farms producing horticulture crops (e.g., cut-flowers and grape). Residual concentrations of pesticides and nutrients used by the small- and large-scale farmers may enter Lake Ziway through several routes such as agricultural land runoff, effluent discharge, drift during spraying, and inadequate handling of remnant pesticides and empty pesticide containers. Currently, there is high concern about the pollution of Lake Ziway by residuals of agrochemicals (e.g., pesticide) and their ecological effects. In addition, Lake Ziway is under threat of pollution by urban wastes (solid and liquid wastes) sourced from the fast-growing Batu and Meki towns found at the south-west and north-west side of the lake, respectively. Therefore, a systemic investigation that assesses the ecological impacts of pollutants to Lake Ziway (e.g., pesticides, trace metals and microplastics, and nutrients) due to agricultural and urbanization in the catchment area of the lake is needed to support its conservation and protection. The main objectives of our studies were; 1) to review the status, temporal and spatial variability of water quality and biological resources of Lake Ziway, 2) to assess the goods and services that local communities currently derive from the lake, 3) to investigate the current use and misuse of pesticides by small- and large-scale farmers in the vicinity of Lake Ziway, monitor pesticide concentrations in lake sediment and water compartments, and evaluate the associated ecological risks, 4) to assess the distribution of microplastics in the sediment and some fish species in Lake Ziway, and 5) to assess structural and functional effects of the pesticide imidacloprid to the aquatic ecosystem typical for the Ethiopian tropical climate . The thesis begins with a literature review ( Chapter 2 ) on the biological resources, and spatio-temporal variation of water quality of the lake focusing on nutrients, metals and pesticides, and other stress factors such as sedimentation and water abstraction for irrigation use. The results of this study indicate the deteriorating trends of several water quality and ecological parameters. Several water concentration levels of nutrients and trace metals (e.g., PO43−, NO3−, NH4+, Ca2+, Cu and Ni) of the lake show increasing trends. For some parameters the water quality of the lake exceeded guideline values for safe drinking water (e.g., alkalinity, Fe, and pesticides like diazinon and spiroxamine) and for aquatic life (e.g., NH4+, Fe, Cr, Cu and Se). The literature review also showed that water samples from shoreline locations of the lake proximate to floriculture farms showed increased values for some physicochemical parameters (e.g., NO3−, NH4+, K, Na and electrical conductivity) and residual pesticides of various types (e.g., boscalid, methomyl, carbendazim and spiroxamine). In Chapter 3 , the ecosystem goods and services (ES) that the Lake Ziway provides for the communities of the region were identified and prioritized by local people based on the relevance for their livelihood. Concurrently, the pesticide use and handling practices of the small- and large-scale farmers found in proximate to Lake Ziway was assessed. The potential impacts of pesticides on the ES of the lake was also assessed using a conceptual approach that links the effect of pesticides on organisms of the lake due to contamination to effect on ES provision by the lake ecosystem. The results of the study showed that Lake Ziway supplies a wide array of ES for the local communities including 15 classes of provisioning ES , 3 classes of regulating and maintenance ES, and 6 classes of cultural services. The study also indicated misuse and improper handling of pesticides by smallholder farmers. Malpractices of farmers included improper storage, over-dosage, too high application frequencies (up to 12 times/crop/season) in violation of recommended interval days, mixing pesticides near the water canal and dumping pesticide wastes into their surrounding environment. In addition, the wastewater effluent released from the floriculture farms into Lake Ziway is another concern as no evidence is presented that show its effective treatment before it released into the lake ecosystem. The study found that the pesticide use and handling practices of the farmers in the region were unsustainable and likely expose the Lake Ziway ecosystem to pesticide contamination at such levels potential to pose impact to the ES of the lake. The environmental levels of pesticides and physicochemical parameters, including nutrients in water and sediment compartments of Lake Ziway were investigated in Chapter 4 . Variation in the distribution and composition of biological organisms (macroinvertebrates and fish) were also assessed by correlation with monitored environmental variables (pesticides and physicochemical variables). Ecological risks of the individual pesticide and risks due to the mixture of the pesticides were evaluated using risk quotients (RQ) and mixed-model approaches, respectively. The results showed contamination of water and sediment of Lake Ziway with different types of insecticides and fungicides, where malathion, dimethoate, metalaxyl, diazinon, chlorpyrifos, fenitrothion and endosulfan were detected in more than half of the water samples (> 50%), and diazinon, α-cypermethrin and endosulfan were observed frequently (> 25%) in sediment samples. Effects on physicochemical properties of the water of the lake and higher residual levels of the quantified pesticides were observed at locations proximate to floriculture, smallholder agriculture and urban settlements. The effects on structural and functional endpoints of the lake were also studied in relation to levels of the environmental variables (e.g., nutrients and pesticides). For most of the pesticides quantified in water and sediment the calculated SSD based acute RQ was > 1, indicating possible to very high ecological risks. Arthropods and fish are expected to be highly affected by the measured mixture of pesticides. The effect was high at locations of the lake that are proximate to smallholders’ farms, and receive largescale farms’ wastewater and sites where the inflow rivers join the lake. Spatio-temporal distribution of plastic particles in sediment and in the gastrointestinal tract of fish of Lake Ziway was studied, and discussed in Chapter 5 . The effect of the contaminant, plastic particles, are also discussed by comparing its estimated concentration in the sediment of the lake to the threshold effect concentrations reported in the literature. The results of the study indicated that shoreline sediments of Lake Ziway are contaminated by plastic particles and the highest estimated sediment concentration was in exceedance of effect threshold values reported in the literature, thus it is likely to cause effect on benthic communities. More than one-third of the sampled fish individuals were also found with ingested plastic particles in their gastrointestinal tracts, which may also have human health risk implication. The particle size analysis result also demonstrated the benthopelagic transfer of plastic particles from sediment to fish. Chapter 6 presents and discusses the results of an effect study of imidacloprid pesticide, using a mesocosm experimental setup with tropical freshwater conditions typical for Ethiopia. Structural (e.g., macroinvertebrates, zooplanktons, phytoplankton and periphyton) and functional (e.g., decomposition of organic matter and physicochemical parameters) endpoints were studied. The recovery of the community from the effect of the pesticide was also studied. In addition, acute single species toxicity of imidacloprid to local freshwater arthropods was studied and discussed. Effect concentrations (L(E)C50 and L(E)C10) and no observed effect values (NOEC) were calculated for the experimental water quality parameters and biological endpoints. A direct effect of imidacloprid was observed on aquatic organisms, in which the macroinvertebrates: Cloeon dipterum and Caenis horaria, and the zooplankton: Brachionus sp. and Filinia sp. were the most negatively affected species compared to other species. Treatment-related significant increases in chlorophyll-a concentrations of periphyton and phytoplankton were also found, which are likely indirect effects as the primary producers are released from grazing pressure (e.g., by the grazers Cloeon dipterum, Brachionus sp. and Filinia sp. and scrapers Planorbidae sp. and Physidae sp.) as a direct effect of the imidacloprid insecticide. Higher sensitivity of tropical aquatic species to imidacloprid was also demonstrated relative to their temperate counterparts. Recovery was observed for zooplankton community (9 weeks), but no recovery was found for macroinvertebrates in 21 weeks of the recovery period of the experiment. In conclusion, key findings in our studies are discussed in Chapter 7 . Agricultural and urbanization activities are affecting the ecology and water quality of Lake Ziway by discharging nutrients, trace metals, residual pesticides and plastic particles among others into the lake. Intervention measures and future research outlooks are pointed out, that can help the protection and conservation of Lake Ziway and other Ethiopian aquatic ecosystems experiencing similar anthropogenic pressures in their catchments. Accordingly, the thesis recommends: 1) training on pesticide safe use and handling for smallholder farmers to improve the skill and knowledge, 2) promotion and adoption of IPM technologies to reduce use and misuse of pesticide, 3) strengthening regulatory control on the registration, and purchase and use of pesticides, 4) implementation and improvement of urban waste management, 5) establishment of modern laboratory facilities to enable risk assessment of pesticides and emerging chemicals and 6) wide application of EPT richness index to monitor the water quality of Lake Ziway and other aquatic ecosystem with similar anthropogenic pressures, as it is quick, effective and cheap compared to monitoring of physical and chemical variables.
... Résumées dans le tab. 10, les études évaluant la toxicité de la ciprofloxacine (CIP) et l´enrofloxacine (ENRO) sur la communauté microbienne concordent bien entre elles, avec des effets dès 0,2mg/kg pour le sol (CIP, Girardi et al. 2011), 100µg/L en microcosme d´eau douce tempérée (CIP, Maul et al. 2006), 100µg/L en microcosme d´eau douce tropicale (ENRO, Rico et al. 2014) et 200µg/L en microcosme d´eau salée (CIP, Näslund et al. 2008). Maul (et al. 2006) reportent une diminution des organismes utilisant les carbohydrates comme substrat, cependant cela n´affecte ni la croissance ni la survie des invertébrés présents dans le microcosme (Gammarus sp. ...
... et L. liba). De la même manière, la diminution des bactéries et archées responsables de l´oxydation de l´ammoniaque n´a pas de conséquences sur les macro-invertébrés, ou sur le phyto-et zooplancton contenus dans les microcosmes concernés (Rico et al. 2014). Un changement de faible ampleur dans l´équilibre microbien peut ne pas avoir de répercussions sur les détritivores si l´on considère qu´il y a une redondance fonctionnelle suffisante dans l´écosystème pour pallier le manque de certaines catégories de bactéries. ...
... Les seules concentrations rapportées s´élèvent à 9,2ng/g dans les sédiments au New Jersey, USA (Gibs et al. 2013), s´échelonnent de 9 à 390 ng/g de poids sec des particules sédimentées en Finlande (particules sédimentées collectées à 35cm du fond de la rivière, Lahti et al. 2011) et atteignent 653 ng/g de sédiment dans le nord de la Chine (contamination due principalement aux effluents de grandes villes mais aussi à l´aquaculture, Zhou et al, 2011). Malheureusement, les essais réalisés dans des systèmes eau-sédiment avec exposition initiale aqueuse ne rapportent pas la concentration sédimentaire correspondant à l´effet (ou l´absence d´effet) observé (Maul et al.2006, Rico et al. 2014, de sorte qu´il est difficile d´évaluer la concentration, en mg/kg de sédiment, protectrice pour les invertébrés. ...
To which extend the current environmental risk assessment procedure is able to identify the potential risk of human pharmaceuticals on aquatic species? That is the question this work addresses using two examples: diclofenac and ciprofloxacin.
I defended this work in June 2014 to graduate my Pharmacy Diploma (Pharm. D) from Paris Descartes University.
... System B was identical to A, but did not contain any introduced organisms. As periphyton can develop in the microcosms (Rico et al., 2014;Peng et al., 2018b), the effect of sediment-associated HHCB on periphyton communities was also examined. In each microcosm, five microscopic glass slides (7.5 × 2.5 cm) were hung at a depth of 10 cm using nylon sewing thread and left for the duration of exposure (28 days). ...
... During the experiment, the microcosms were aerated using a glass pipette connected to an aeration system and any evaporated water was replenished with aerated tap water at weekly intervals. Nitrogen (0.7 mg/L as urea) and phosphorus (0.09 mg/L as triple super phosphate) were added biweekly to the systems to provide nutrients for algal growth (Rico et al., 2014). No food was added to microcosms, as all introduced invertebrates can feed on algae, microorganisms, and/or sediment (Table S3). ...
... D. magna and phytoplankton were sampled through collecting overlying water using a Teflon siphon, whereas benthic macroinvertebrates were sampled through gently sieving sediment. Additionally, periphyton were sampled via scraping introduced microscopic glass slides (in 0.5-L de-chlorinated tap water) (Rico et al., 2014). See our previous study for more details on community sampling and analysis (Peng et al., 2018b). ...
... System B was identical to A, but did not contain any introduced organisms. As periphyton can develop in the microcosms (Rico et al., 2014;Peng et al., 2018b), the effect of sediment-associated HHCB on periphyton communities was also examined. In each microcosm, five microscopic glass slides (7.5 × 2.5 cm) were hung at a depth of 10 cm using nylon sewing thread and left for the duration of exposure (28 days). ...
... During the experiment, the microcosms were aerated using a glass pipette connected to an aeration system and any evaporated water was replenished with aerated tap water at weekly intervals. Nitrogen (0.7 mg/L as urea) and phosphorus (0.09 mg/L as triple super phosphate) were added biweekly to the systems to provide nutrients for algal growth (Rico et al., 2014). No food was added to microcosms, as all introduced invertebrates can feed on algae, microorganisms, and/or sediment (Table S3). ...
... D. magna and phytoplankton were sampled through collecting overlying water using a Teflon siphon, whereas benthic macroinvertebrates were sampled through gently sieving sediment. Additionally, periphyton were sampled via scraping introduced microscopic glass slides (in 0.5-L de-chlorinated tap water) (Rico et al., 2014). See our previous study for more details on community sampling and analysis (Peng et al., 2018b). ...
Galaxolide (HHCB) is used as a fragrance ingredient in household and personal care products, and has been ubiquitously detected in the environment. Here we investigated the fate of HHCB in subtropical freshwater microcosms, and evaluated effects of sediment-associated HHCB on a biological community consisting of algae, Daphnia, benthic macroinvertebrates and bacteria. The concentrations of sediment-associated HHCB did not change significantly during a 28 days exposure period, but HHCB accumulated in worms with biota-sediment accumulation-factor (BSAF) values in the range of 0.29-0.66 for Branchiura sowerbyi and 0.94-2.11 for Limnodrilus hoffmeisteri. There was no significant effects of HHCB (30 μg/g dry weight (dw) sediment) on chlorophyll-a content, sediment bacterial community composition, and survival and growth of benthic macro-invertebrates. However, the presence of benthic macroinvertebrates altered the sediment bacterial community structure relative to microcosms without introduced organisms. The findings of this study suggest that a single high-dose of HHCB, over 28 days, at environmentally relevant concentrations would not impose direct toxicological risks to aquatic organisms such as benthic macroinvertebrates.
... During the experiment, evaporated water was replenished with aerated tap water weekly to maintain the original water level. Nitrogen (0.7 mg/L as urea) and phosphorus (0.09 mg/L as triple super phosphate) were added biweekly to the systems to provide nutrients for algal growth (Rico et al., 2014). ...
... D. magna individuals were counted using a binocular microscope at a magnification of 15-25×. Microscopic glass slides were also retrieved and the attached periphyton was collected by scraping them (in 0.5 L of aerated tap water) until the slides were visually clean (Rico et al., 2014). The chlorophyll-a in the water containing the scraped periphyton was then measured as mentioned above. ...
... (Hommen et al., 1994). In order to down-weigh high abundance values and obtain approximately a normal distribution of the data, the abundance values of species were ln (Ax + 1) transformed, where x represents the abundance data and A was set as 2 to avoid false discrepancy between zero abundance values and low abundance values ( Van den Brink et al., 2000;Rico et al., 2014). ...
Triclosan (TCS) is an antibacterial agent that is commonly used in personal care products. Because of its sediment-binding properties, TCS exposure presents a potential threat to sediment-dwelling aquatic organisms. Currently our knowledge of the fate and effects of sediment-associated TCS in aquatic systems is limited. To understand the impact of sediment-associated TCS, we used microcosms to assess effects of TCS exposure on a diverse range of organisms selected to mimic a subtropical community, with an exposure period of 28 days. We included the oligochaete freshwater worm Limnodrilus hoffmeisteri to evaluate the interaction between sediment-associated TCS and sediment-dwelling organisms, including potential loss of TCS from the sediment due to biological activity and bioaccumulation. Benthic macroinvertebrate presence significantly increased the TCS levels from 0.013 ± 0.007 μg/L to 0.613 ± 0.030 μg/L in the overlying water through biological activity, posing a potential additional risk to pelagic species, but it did not result in a significant reduction of the sediment concentration. Furthermore, worms accumulated TCS with estimated Biota-Sediment-Accumulation-Factors (BSAFs) ranging between 0.38-3.55. Other than for algae, TCS at environmental concentrations did not affect the survival of the introduced organisms, including the L. hoffmeisteri. Our results demonstrate that, although TCS at currently detected maximum concentration may not have observable toxic effects on the benthic macroinvertebrates in the short term, it can lead to bioaccumulation in worms.
... Jechalke et al. (2014) found that FQ antibiotics could remain in the soil for years [49]. The water solubility and flow properties of FQ antibiotics play an important role in increasing their concentrations and mobility in water environments, including surface water [24,35,50,51], groundwater [52], sewage [37,42] and sediment samples [7,35,53]. Chee-Sanford et al. (2009) found that the water solubility of ciprofloxacin and enrofloxacin was 30 g/L and 130 g/L, respectively, which were considered hydrophilic (exceeding 1 g/L) [54]. ...
... For example, the good water solubility and long half-life characteristics of FQ antibiotics result in high residue concentrations and long-term existence in the environment [19]. found that enrofloxacin (from 1.4 mg/kg to 2339 mg/kg dry weight) had high binding properties and a long half-life in the river environment [51]. The low biodegradability and absorption characteristics of FQ antibiotics resulted in their residues and metabolites being detected in soil and water sources. ...
Fluoroquinolone antibiotics are widely used in human and veterinary medicine and are ubiquitous in the environment worldwide. This paper recapitulates the occurrence, fate, and ecotoxicity of fluoroquinolone antibiotics in various environmental media. The toxicity effect is reviewed based on in vitro and in vivo experiments referring to many organisms, such as microorganisms, cells, higher plants, and land and aquatic animals. Furthermore, a comparison of the various toxicology mechanisms of fluoroquinolone antibiotic residues on environmental organisms is made. This study identifies gaps in the investigation of the toxic effects of fluoroquinolone antibiotics and mixtures of multiple fluoroquinolone antibiotics on target and nontarget organisms. The study of the process of natural transformation toward drug-resistant bacteria is also recognized as a knowledge gap. This review also details the combined toxicity effect of fluoroquinolone antibiotics and other chemicals on organisms and the adsorption capacity in various environmental matrices, and the scarcity of data on the ecological toxicology evaluation system of fluoroquinolone antibiotics is identified. The present study entails a critical review of the literature providing guidelines for the government to control the discharge of pollutants into the environment and formulate policy coordination. Future study work should focus on developing a standardized research methodology for fluoroquinolone antibiotics to guide enterprises in the design and production of drugs with high environmental biocompatibility.
... Ciprofloxacin (CIP), one of the most widely discovered fluoroquinolone antibiotics in waterbodies, is poorly metabolized and biodegradable, making it ineffectively removed by traditional wastewater treatment [2]. CIP residues in water can harm cyanobacteria and duckweed at concentration of 17-203 µg L − 1 [3], decrease the nitrifying activities of freshwater microbial communities at 100 µg L − 1 [4], and reduce biological removal of nitrogen and phosphorus at high concentration of 2 mg L − 1 [5]. Therefore, it is necessary to use unconventional treatment approaches to effectively remove these antibiotics from aqueous media. ...
... Similarly, the addition of MeOH had a minor inhibitory effect on CIP degradation, reducing efficiency from 99 to 80 %. This shows that neither SO4 •− nor ⋅ OH were likely to be the reactive oxygen species in the N@ZIF-67/PMS system. However, when sodium azide (NaN 3 ) and nitroblue tetrazolium (NBT), unique scavengers for 1 O 2 and O 2 •− with rate constant of 2x10 9 M − 1 s − 1 and 5x104 M − 1 s − 1 ,were added to the reaction mixture, the CIP degradation was significantly suppressed in the system as indicated by the incomplete quenching of the removal process. ...
In this study, N doped ZIF-67 ([email protected]) was prepared via hydrothermal method and applied for heterogeneous catalytic activation of peroxymonosulfate (PMS) in the remediation of pharmaceuticals, exemplified by antibiotic ciprofloxacin (CIP) in aqueous solution. The morphological and physicochemical properties of [email protected] were characterized and the catalytic activity for degradation of organic contaminants was studied. The [email protected] significantly enhanced electron transfer between reacting species with excellent catalytic performance in CIP degradation. CIP degradation in the [email protected]/PMS system took place over a broad pH range of 5 to 9. Moreover, the synergistic effect between nitrogen and ZIF-67 structure not only significantly boosted the CIP removal efficiency but also long-term stability of the composite. The dissolution of cobalt ion was below the allowable drinking water standard. The superoxide radical (O2⋅−) was not only involved in the generation of singlet oxygen (¹O2) but also played a crucial role in CIP degradation. This proof-of-concept study for the development of [email protected] paves the new venue for wastewater remediation through PMS activation.
... Also, the scientists assessed the role that wastewater treatment processes may play in the emergence, transport, and dissemination of the antibiotic resistance in the environment (Ebert et al., 2011;Pleiter et al., 2013;Rico et al., 2014;Szymańska et al., 2019;Kumar et al., 2019). ...
... Ebert et al. (2011) studied the toxicity of enrofloxacin and ciprofloxacin of various photoautotrophic aquatic organisms and discovered that while enrofloxacin presented a higher toxicity to green algae, ciprofloxacin was more toxic to cyanobacteria. Rico et al. (2014) also suggested that the environmentally relevant enrofloxacin concentrations were not likely to result in direct or indirect toxic effects on the tropical eutrophic ecology of freshwater microecosystems. ...
The ecotoxicological guide is elaborated in the frame of the project with eMS code BSB 27, entitled Black Sea Basin interdisciplinary cooperation network for sustainable joint monitoring of environmental toxicants migration, improved evaluation of ecological state and human health impact of harmful substances, and public exposure prevention – MONITOX (Joint Operational Programme Black Sea Basin 2014-2020, financed by the European Union). There are used, also, some of the research results of the finalized international and national projects MIS ETC 1676 (2013-2015), AQUASYS (2015-2019) and of ongoing ones – BSB 165 HydroEcoNex (2018-2021), SOFT1/2/47 (2020-2021), AQUABIO (2020-2023).
The ecotoxicological guide is addressed to researchers, environmentalists, young students (PhD, master undergraduate students) and all those who want to become familiar with the theoretical and applied aspects of ecotoxicological investigations, which include monitoring, deciphering the migration processes of toxic substances in the environment and assessing the ecological status and functioning of aquatic ecosystems.
Editors:
Elena Zubcov, correspondent member of ASM, doctor habilitatus in biological sciences, professor & Antoaneta Ene, professor, doctor habilitatus
... While CIP is readily detectable in many aquatic environments (typically found at ng/L-lg/L levels in surface waters) (Sahlin et al. 2018), it occurs at high levels in the effluents of WWTPs (up to 6.5-31 mg/L) receiving pharmaceutical wastewaters and in rivers (up to 14 mg/L) contaminated with industrial waste (Larsson et al. 2007;Fick et al. 2009). Freshwater primary producers such as cyanobacteria (Microcystis aeruginosa) and duckweed (Lemna minor) are inhibited by CIP at 17-203 lg/L (Robinson et al. 2005); 5-50 mg/kg of CIP reduces the diversity of soil microbial communities (Girardi et al. 2011;Cui et al. 2014); and 100 lg/L of CIP reduces the nitrifying activities of freshwater microbial communities (Rico et al. 2014). Johansson et al. (2014) found that 18-199 lg/L of CIP inhibited the metabolic activities (e.g., substrate utilization) of a periphyton community comprising a variety of autotrophic and heterotrophic organisms. ...
... Therefore, the poor removal of CIP at 50-500 lg/L experimentally observed in our laboratory settings is consistent with the model prediction results based on the sorption and biodegradability parameters. Since a large body of literature reports potential ecological risks by CIP residuals, even at a few micrograms per liter level (Robinson et al. 2005;Johansson et al. 2014;Rico et al. 2014), the unsatisfactory CIP removal obtained in this study strongly suggests the need for alternative technologies to CAS processes in WWTPs and more frequent monitoring campaigns on the occurrence and fate of CIP in receiving water bodies. ...
This study investigated the effects and fate of the antibiotic ciprofloxacin (CIP) at environmentally relevant levels (50–500 µg/L) in activated sludge (AS) microbial communities under aerobic conditions. Exposure to 500 µg/L of CIP decreased species diversity by about 20% and significantly altered the phylogenetic structure of AS communities compared to those of control communities (no CIP exposure), while there were no significant changes upon exposure to 50 µg/L of CIP. Analysis of community composition revealed that exposure to 500 µg/L of CIP significantly reduced the relative abundance of Rhodobacteraceae and Nakamurellaceae by more than tenfold. These species frequently occur in AS communities across many full-scale wastewater treatment plants and are involved in key ecosystem functions (i.e., organic matter and nitrogen removal). Our analyses showed that 50–500 µg/L CIP was poorly removed in AS (about 20% removal), implying that the majority of CIP from AS processes may be released with either their effluents or waste sludge. We therefore strongly recommend further research on CIP residuals and/or post-treatment processes (e.g., anaerobic digestion) for waste streams that may cause ecological risks in receiving water bodies.
... For example, Katipoglu-Yazan et al. (2016) and Gonzalez-Martinez et al. (2014) indicated that nitrification could be inhibited by antibiotics in a sludge reactor where they reduce ammonium oxidation bacteria (AOB). In the freshwater ecosystem, 100 μg L −1 enrofloxacin can potentially impair the nitrification function (Rico et al., 2014). However, few studies have reported no significant effects or even stimulatory effects (Kotzerke et al., 2008;Louvet et al., 2010;Gonzalez-Martinez et al., 2014;Cui et al., 2014). ...
... For the effects of antibiotics on NH 4 + removal, previous reports on water, soil, activated sludge, and enriched nitrifying culture showed different results. Gonzalez-Martinez et al. (2014) reported that 350 ng L −1 ciprofloxacin can reduce nitrification in activated sludge and Rico et al. (2014) reported that b1 mg L −1 enrofloxacin caused the ammonia concentration in the microcosm water to significantly increase. However, Cui et al. (2014) reported that potential nitrification rates were stimulated at low ciprofloxacin concentrations (1 mg kg −1 ), but further indicated that ammonium contents of soil were not altered after ciprofloxacin addition at any time. ...
... Most of the materials and methods used for the microcosm experiment have been described by Rico et al. (2014). ...
... The semi-field microcosm experiment derived safe threshold values for the neonicotinoid insecticide imidacloprid for different structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater ecosystems in sub-tropical Bangladesh (Chapter 4). Those microcosms have been used as a valuable tool for the higher-tier risk assessment of pesticides (Daam et al., 2008(Daam et al., , 2009Hayasaka et al., 2012a;Halstead et al., 2014;Hua and Relyea, 2014; and veterinary medicines (Rico et al., 2014) Kwok et al., 2007;Van den Brink et al., 2016). We recommend further studies to perform the risk assessment of imidacloprid (monitoring or model-based) ...
In Bangladesh, the intensification of agriculture is indispensable due to its ever increasing population, the food security needs, and land scarcity. Severe agro-climatic events (e.g. flash floods, seasonal water scarcity and salinity intrusion in coastal land) pose further difficulties to crop production. To meet the growing demand of food under these harsh conditions, farmers are using a variety of pesticides indiscriminately; a sharp increase of their use was observed during the last decades. Residues of pesticide applied on agricultural land may enter into the aquatic environment through drain, runoff and spray drift, thereby contaminating this environment. Hence, this PhD thesis aimed to investigate the human health issues and ecological risks on aquatic ecosystems posed by the large scale use of pesticides in Bangladesh.
In Chapter 1 the current status of pesticide use in intensive agriculture in Bangladesh is described together with their associated potential risks on the aquatic environments posed by pesticides. The available studies on assessing the fate and effects of pesticides for the (sub-) tropical aquatic ecosystems are reported. Chapter 1 describes the knowledge gap regarding the environmental risks of pesticides in the context of Bangladesh and discusses the tired-based approach to take into account for the risk assessment in Bangladesh.
Chapter 2 outlines the information on the current status of pesticide use in rice-prawn concurrent systems of south-west Bangladesh and human health issues posed by the application of pesticides. The ecological risks of 10 pesticides for the aquatic ecosystems that support the culture of freshwater prawns (Macrobrachium rosenbergii) were assessed using exposure and effect models. The TOXSWA model calculated pesticide exposure (peak and time-weighted average concentrations) in surface waters of rice-prawn systems for different spray drift scenarios. The simple first-tier risk assessment for these 10 pesticides were performed using a risk quotient (RQ) method. The results of RQ method indicated that chlorpyrifos, cypermethrin, alpha-cypermethrin and malathion may pose a high to moderate acute and chronic risks for invertebrates and fish for all spray drift scenarios. The higher-tier PERPEST effect model confirmed the high risks of cypermethrin, alpha-cypermethrin and chlorpyrifos for insects and macro- and micro-crustaceans, which were previously derived by the RQ-based risk assessment approach.
Chapter 3 presents the results of a chemical monitoring in surface water and sediment samples of north-west Bangladesh. The residues of the 10 most commonly used organophosphate insecticides in surface water and sediment samples were measured in that region. Like Chapter 2 of this thesis, the risk assessment of the concentrations of these 10 insecticides for fish, Daphnia and algae was started with a deterministic RQ method based on measured environmental concentrations (MECs) and the threshold concentrations derived from single species toxicity tests. The results showed high acute and/or chronic RQs (RQ > 1) in surface water and sediment for chlorpyrifos, diazinon, quinalphos, malathion and fenitrothion. The higher-tier PERPEST effect model also confirmed the risks of chlorpyrifos, diazinon, quinalphos and fenitrothion for aquatic insects, micro- and macro-crustaceans.
Chapter 4 describes the fate and effects of imidacloprid on several structural and functional endpoints of freshwater ecosystems in Bangladesh as evaluated in freshwater outdoor microcosms. The safe threshold values (i.e. NOECs) of imidacloprid for the individual taxa, community and water quality variables were derived for (sub-)tropical Bangladesh. Single species toxicity tests were also performed using the two most responding species (e.g. Cloeon sp. and Diaptomus sp.) of the microcosm study. The sensitivity of several arthropod species to imidacloprid was much higher in sub-tropical country Bangladesh compared to their temperate counterparts.
Chapter 5 elucidates the acute toxicity of chlorpyrifos on the developmental stages of Banded Gourami (Trichogaster fasciata), which is a local freshwater fish species in Bangladesh. In this chapter, the effects of chlorpyrifos on the incubation period of embryo, hatching success, mortality of embryos and two-day old larvae of Banded Gourami are discussed. Several malformations of larvae including irregular head and eye shape, lordosis, body arcuation, notochordal abnormality and caudal fin damage when exposed to 10 and 100 μg/L chlorpyrifos were also demonstrated.
Chapter 6 investigates the toxicity of chlorpyrifos on the mortality and the reproductive tissues of male and female Banded Gourami (Trichogaster fasciata) over a period of 75 days. The threshold values (NOECs) for male and female mortality, GSI, histopathological alterations of ovary and testis for different time interval were derived in this chapter. The results show that the long-term exposure to chlorpyrifos affect the reproductive tissues of Banded Gourami at exposure concentrations that cause mortality also.
In chapter 7 the major findings of different studies are discussed and after an overview of the conclusions, this thesis recommends: (1) to promote the suitable averting behaviour by farmers during pesticide application, (2) to conduct future experimental, monitoring and model validation studies nationwide, in order to better characterize the risks posed by pesticides for Bangladeshi aquatic ecosystems, (3) to improve the technical facilities (i.e. analytical verification) for future laboratory studies, (4) to reduce the pesticide use based on the recommended dosage by agricultural extension officers, and (5) to seek alternatives of pesticide use through the adoption of integrated pest management (IPM) practices to avoid the risks posed by pesticides.
... Sampled organisms from aquatic environment in north-west Bangladesh will be put in 15 microcosms, considering 5 different concentrations with 3 replications of each. The ecological threshold value i.e. no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) for particular pesticides will be detected through a microcosm study (Daam & Van den Brink, 2010Rico et al., 2014;Wijngaarden et al., 2005). Zooplankton and macroinvertebrate data sets will be analysed by the Principal Response Curve (PRC) method (Rico et al., 2014) using CANOCO software package, version 5. ...
... The ecological threshold value i.e. no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) for particular pesticides will be detected through a microcosm study (Daam & Van den Brink, 2010Rico et al., 2014;Wijngaarden et al., 2005). Zooplankton and macroinvertebrate data sets will be analysed by the Principal Response Curve (PRC) method (Rico et al., 2014) using CANOCO software package, version 5. ...
... Enrofloxacin affects the activity of ammonia-oxidizing bacteria, which increases ammonia quantity in wastewater. It also harms bacterial communities, which are leaf-associated [7]. Amoxicillin forms toxic compounds under the influence of different biotic and abiotic factors and affects aquatic animals like fish by accumulating in muscle tissues [8]. ...
Uncontrolled use of antibiotics on humans, animals, and crops for various reasons pollutes clean water with antibiotic-laden wastewater. This causes a severe effect on the overall health and hygiene of living beings including the expansion of antibiotic resistant microorganisms. Only a fraction of the antibiotic drugs consumed by humans and animals are metabolized. The remainder is excreted and will often find its way into ground and surface waters and of course enters sewerage systems. Wastewater from pharmaceutical industries is another major cause of pollution of water bodies. Using this contaminated water for drinking or domestic use without proper treatment develops antibiotic resistance in the human body, ultimately becoming a severe health issue. Therefore, water treatment should be addressed as an essential and mandatory step to protect the environment and living creatures. Several treatment processes for wastewater are popular; among them, adsorption is one of the most cost-effective and efficient methods, which is also vastly used. This review article briefly discusses different adsorption treatment methods generally used for antibiotic-polluted wastewater. Moreover, this article focuses on different adsorbents available for wastewater treatment and discusses their advantages and disadvantages. Hydrogen bonds, π-π interactions, and hydrophobic interactions are suggested to be the significant probable mechanisms behind the adsorptive removal of antibiotics by respective adsorbents. The temperature and pH of the solution also play essential roles in the adsorption of antibiotics from pharmaceutical wastewater.
... However, the mixture induced a marked increase in NH 4 + concentration. Rico et al. (2014) observed a potential effect on nitrification of the antibiotic enrofloxacin, added to microcosms for 7 days at nominal concentrations of 1, 10, 100, and 1,000 μg/L. The highest concentration of enrofloxacin significantly reduced the number of ammonia-oxidizing bacteria in the sediment, which translated into a higher ammonia concentration in the water and a lower nitrification rate (Table 1). ...
Pharmaceuticals have been identified as a significant threat to the environment. Their constant flow into aquatic ecosystems means that organisms are chronically exposed. To date, there has been a large number of scientific papers assessing the impact of pharmaceuticals on individual organisms from different taxonomic groups. However, the effects of drugs on the environment can be much broader than what can be determined in toxicity tests on individual organisms. These compounds can disrupt entire communities. In this context, special attention should be paid to microbial communities, which regulate many essential processes underpinning aquatic food webs and ecosystem services. This paper reviews current developments related to the effects of pharmaceuticals on microorganisms with a particular focus on whole-community investigations, in both fresh and salt water. We also summarize the opportunities associated with both in situ and laboratory studies, and highlight important knowledge gaps.
... The fractional number of PCR cycles required to generate enough fluorescent signal to reach the threshold (Ct value) is directly proportionate to the amount of starting template (Ginzinger, 2002), allowing accurate quantification of species DNA. The qPCR was successfully used to discriminate the relative abundance of specific microbial groups, Archaea, Bacteria, and Fungi on leaves decomposing in streams (Manerkar et al., 2008) or bacterial and archaeal ammonia oxidizers and nitrogen-fixing bacteria in leaf and sediment samples (Rico et al., 2014). Also, qPCR allowed explaining the putative mechanisms underlying biodiversity effects on leaf decomposition under stress by discriminating the contribution of different aquatic hyphomycete ecotypes to the total fungal biomass produced in multicultures (Fernandes et al., 2011). ...
... In order to improve the ecological reality, the assessment of the environmental effects of nutrients should be carried out at the community and even ecosystem level. Model ecosystems (i.e., microcosms and mesocosms), which take into account species interactions and identify the latent interactions among biotic community structure and ecosystem function [6], can be used to evaluate the long-term impacts of nutrients in the indoor experiment by collecting parts of natural ecosystems [7,8]. ...
The excessive nutrients in freshwater have been proven to promote eutrophication and harmful algae blooms, which have become great threats to water quality and human health. To elucidate the responses of the plankton community structure and function to total phosphorus (TP) at environmental concentrations in the freshwater ecosystem, a microcosm study was implemented. The results showed that plankton communities were significantly affected by the TP concentration ≥ 0.1 mg/L treatments. In terms of community structure, TP promoted the growth of Cyanophyta. This effect was transmitted to the zooplankton community, resulting in the promotion of Cladocera growth from day 42. The community diversities of phytoplankton and zooplankton had been continuously inhibited by TP. The principal response curve (PRC) analysis results demonstrated that the species composition of phytoplankton and zooplankton community in TP enrichment treatments significantly (p ≤ 0.05) deviated from the control. For community function, TP resulted in the decline in phytoplankton photosynthesis. The chlorophyll fluorescence parameters were significantly inhibited when TP concentration reached 0.4 mg/L. In TP ≥ 0.1 mg/L treatments, the reductions in total phytoplankton abundances led to a continuous decrease in pH. This study can directly prove that the plankton community changes significantly when TP concentrations are greater than 0.1 mg/L and can help managers to establish specific nutrient management strategies for surface water.
... For instance, Ciprofloxacin (CIP), a drug of third generation FQs, has been used widely for disease control in curing infections of intestinal and respiratory organs, typical water borne diseases [4,8]. CIP residues in water can harm cyanobacteria and duckweed at concentration of 17-203 µg L -1 [9], decrease the nitrifying activities of freshwater microbial communities at 100 µg L -1 [10], and reduce biological removal of nitrogen and phosphorus at high concentration of 2 mg L -1 [11]. ...
A catalyst, NiCo2O4/MnOOH/GO, was successfully synthesized by immobilizing NiCo2O4 and graphene oxide (GO) on MnOOH for the activation of peroxymonosulfate (PMS) with enhanced catalytic activity in ciprofloxacin (CIP) degradation. Results demonstrated 99% removal of CIP (0.02 mM) in the NiCo/Mn/GO system after 30 min at 0.2 mM of PMS and 0.15 g/L of NiCo/Mn/GO. The effects of solution pH, catalyst dose, PMS concentration, major inorganic ions, and natural organic matter (NOM) on CIP degradation were studied. The NiCo/Mn/GO exhibited good sustainability in catalytic removal efficiency for multiple uses. Furthermore, scavenger tests and electron paramagnetic resonance (EPR) results showed that singlet oxygen (¹O2), superoxide radicals (O2•-), sulfate radicals (SO4•−), and hydroxyl radicals (•OH) were generated in the NiCo/Mn/GO+PMS system and participated in CIP degradation. The NiCo/Mn/GO is a promising catalyst for PMS activation in the degradation of CIP and other emerging contaminants.
... CIP is already noticed in several water sources (typically ng/L-μg/L concentration levels in surface waters) [31], with higher amounts in the effluents of wastewater treatment plants (up to 6.5-31 mg/L) loaded by pharmaceutical wastewaters, as well as in rivers (up to 14 mg/L) polluted with industrial waste [29,30]. It has a large impact on water plants producing freshwater using microbiota, soil and other environmental issues [32][33][34][35][36][37][38]. Since CIP amount in waters can reach the toxicity limit of the majority of aquatic organisms, proper treatment of CIP in wastewater plants is urgent. ...
The pure TiO2 and lanthanum (La³⁺)-doped titanium dioxide (TiO2) nanofibers were synthesized by electrospinning method followed via calcination at different temperatures (from 400 °C to 700 °C). Structures of the nanofibers were characterized by X-ray diffraction, scanning electron microscopy, TEM images and diffuse reflectance spectroscopy. The size of the nanofiber diameters was determined to be 129 and 101 nm, for pure TiO2 and (0.1%)La³⁺:TiO2 materials, respectively. The prepared nanofibers possess a crystalline structure, and wide distribution of the band-gaps, in the 2.867–3.210 eV range. Effects of La³⁺-dopant content, calcination temperature, and different doses of photocatalysts on the photodegradation efficiency were studied. The optimal level of La³⁺ and the optimal temperature of calcination were 0.1% La³⁺ and 600 °C, respectively. The photocatalytic degradation of methylene blue (91%, with a rate constant of 2.179×10⁻² min⁻¹) and ciprofloxacin (CIP) (99.5%, with a rate constant of 1.981×10⁻² min⁻¹) pollutants was highest on the (0.1%)La³⁺:TiO2 annealed at 600 °C, after 300 min irradiation under visible light. This photocatalyst displayed sustainable efficiency for CIP degradation up to five consecutive uses.
... A field study found a reduction of microbial growth and respiration following exposure to a pharmaceutical mixture including antibiotics (Rosi-Marshall et al., 2013). In a tropical mesocosm study, OMD and invertebrate communities were similar between control treatments and those treated with an antibiotic at environmentally relevant concentrations, though the density of certain bacterial groups declined (Rico et al., 2014). Overall, the fact that antibiotics rarely occur in isolation suggests that the cascade effects observed under laboratory conditions are more relevant for mechanistic insight than for prediction of effects in the natural environment. ...
The ecosystem process of organic matter decomposition (OMD) in fresh waters is realised by a complex interaction among different groups of microorganisms (including bacteria and fungi) and detritivorous animals. As a consequence of this multi-level interaction, biotic (e.g., competition, predation) and abiotic (e.g., flow, temperature, toxicants) factors may influence the performance of either (micro)organism group with potential feedback to detritivores, and in turn OMD. In this chapter, we discuss how the abiotic factor toxicants affects OMD. We organised the chapter along a conceptual model that pinpoints groups of organisms and their interactions, which are critical for OMD. We focus on four toxicant classes (i.e., fungicides, antibiotics, insecticides and metals) that specifically affect fungi, bacteria or detritivorous invertebrates or have a broad activity spectrum. We summarize the effects caused by these toxicant classes on relevant groups of organisms, which are often determined by the toxicant mode of action. On this basis, we develop effect pathways leading to alterations in OMD dynamics. Finally, we discuss whether and how these effect pathways may support the interpretation of effect patterns observed under (semi-)field conditions and highlight research gaps we suggest addressing in order to improve understanding and prediction power.
... The fractional number of PCR cycles required to generate enough fluorescent signal to reach the threshold (Ct value) is directly proportionate to the amount of starting template (Ginzinger, 2002), allowing accurate quantification of species DNA. The qPCR was successfully used to discriminate the relative abundance of specific microbial groups, Archaea, Bacteria, and Fungi on leaves decomposing in streams (Manerkar et al., 2008) or bacterial and archaeal ammonia oxidizers and nitrogen-fixing bacteria in leaf and sediment samples (Rico et al., 2014). Also, qPCR allowed explaining the putative mechanisms underlying biodiversity effects on leaf decomposition under stress by discriminating the contribution of different aquatic hyphomycete ecotypes to the total fungal biomass produced in multicultures (Fernandes et al., 2011). ...
The physiology, biochemistry and diversity of aquatic microbial decomposers have been largely investigated in low-order streams. However, some aspects still need further attention to better ascertain how microbial decomposer diversity can ensure ecosystem processes and services, particularly under the challenges posed by global environmental change. Aquatic microbial decomposers play a key role in processing plant litter in streams by degrading the most recalcitrant compounds and facilitating nutrient and energy transfer to higher trophic levels. Among microbial decomposers, fungi, particularly aquatic hyphomycetes, play a fundamental role at the early stages of plant litter decomposition, while the relevance of bacteria increases at the late stage of the decomposition. High-throughput sequencing and metagenomic techniques open new avenues towards a more comprehensive understanding of microbial decomposer ecology. This chapter provides a general overview of aquatic microbial diversity and activity on decomposing plant litter. Attention will be paid to the relationships between microbial diversity and their ecological functions under the major threats posed by the ongoing global environmental change to provide the response patterns of microbial decomposers to maintain nutrient and energy fluxes in streams.
... Over the past decades, model ecosystem studies, such as microcosms and mesocosms are using as important techniques to assess the risk of pesticides [30][31][32][33] and veterinary medicines [34]. There are a number of advantages of using microcosm for toxicity studies, i.e. microcosms allow replications, experimental set-up and ecological realism in a controlled environment [35]. ...
The organophosphate pesticide fenitrothion is widely used as an agricultural pesticide to control tiger bug in larval rearing for aquaculture. The objectives of the present study were to assess the effects of fenitrothion on certain structural (phytoplankton, zooplankton, macro-invertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater microcosms. Fenitrothion 50 EC was applied in 12 microcosms (PVC tanks having 400 L of dechlorinated tap water) providing concentrations of 0, 25, 50 and 100 µg/L at a 4-day interval over a period of 4 weeks. Each of the experimental treatment was executed in three replicates. The results indicated the consistent significant effects for most of the species composition of zooplankton and macro-invertebrates. Univariate analysis showed a significant decrease in abundance (p < 0.05) of all identified insects (i.e. Notonecta sp., Gerris sp., Ranatra linearis and Chironomid larvae), when compared to control in all sampling days throughout the treatment period (no observed effect concentration; NOEC = < 25 µg/L). No consistent significant effects were observed for most of the phytoplankton taxa and organic matter decomposition and water quality variables (dissolved oxygen, free CO2, pH, nitrate etc.). However, several taxa of different endpoints were found sensitive to even the lowest concentration of fenitrothion (25 µg/L). Further studies with acute and chronic conditions are recommended involving more local species exposed to < 25 µg/L of fenitrothion.
... They noticed that enrofloxacin was more toxic to green algae whereas ciprofloxacin was more toxic towards cyanobacteria. Rico et al. (2014) reported that environmental concentration of enrofloxacin was not high enough to cause any direct or indirect toxic effects on water ecology, whereas, Wagil et al. (2014) stated the moderated level of environmental risk due to enrofloxacin, norfloxacin and ciprofloxacin based on the occurrence of these ABs in the rivers in North Poland. Usually toxicity studies considered single ABs whereas in aquatic environment ABs occurred in mixture along with their by-products and other pollutants. ...
Abstract:
The review provides a comprehensive overview of the available state-of-the-art of nanoparticles (NPs) and antibiotics (ABs) occurrence and their fate in the natural aquatic settings by addressing different research questions and the challenges faced while addressing those questions. Firstly, understand the interaction of NPs and ABs with themselves in addition to other matrix components (presence of natural organic matter, bacteria, biofilms, other anthropogenic pollutants and metals from natural sources). Secondly, summarize the bactericidal activity of NP and AB due to reactive oxygen species (ROS) production. The complete information was gathered from database and analysed as per the conjectured questions under laboratory versus environmental-relevant conditions (1. Fate of NPs and ABs, and 2. Will the presence of NPs and ABs alone and their mixtures influence the ROS concentration and antibacterial activity), and proposed six reactions to describe the fate of NP and AB in natural aquatic settings. However, laboratory-based studies revealed that NP and AB fate largely depend on the ionic strength, organic matter content and pH of the matrix whereas field based information is missing about this. The former was performed at sterile conditions using sophisticated instruments and standard protocol as compared to latter and can't be replicated under natural aquatic settings due to lack of: (i) accurate environmental concentration of NPs and ABs, (ii) knowledge of bacterial type and their concentration, (iii) optimized protocol and tracking systems. The author's recommendation is to verify the proposed reactions experimentally by using the frequently found pairs of NPs and ABs in the natural aquatic settings. Further, ranked them on their decreasing order of toxicity and informed regulatory bodies for further action. Overall research is needed in the suggested directions to reduce uncertainty behind the impacts of NPs and ABs on the aquatic settings and their role in bactericidal activity.
... As antibiotics, driven by their mode of action, affect bacteria (Brandt et al., 2015), they can influence leaf-associated microbial communities (Maul et al., 2006; https://doi.org/10.1016/j.aquatox.2020.105461 Received 22 August 2019; Received in revised form 4 February 2020; Accepted 28 February 2020 Rico et al., 2014a). Effects on bacteria, may release aquatic fungi from competitive pressure for the same resources (Bundschuh et al., 2009) potentially altering leaves' nutritious quality and palatability for shredders (i.e., dietary effect pathway; Hahn and Schulz, 2007;Bundschuh et al., 2009). ...
Antibiotics may constitute a risk for aquatic detritivorous macroinvertebrates (i.e., shredders) via waterborne and dietary antibiotic exposure. In addition, antibiotics can alter the food quality for shredders mediated by shifts in leaf-associated decomposer (i.e., aquatic fungi and bacteria) communities. However, little is known about the relative importance of the waterborne and dietary effect pathway. Therefore, we followed a tiered testing approach aimed at assessing the relative importance of these effect pathways. We employed the antibiotic ciprofloxacin (CIP) and the shredder Gammarus fossarum as model stressor and test species, respectively. In a first step, we assessed the short-term waterborne toxicity of CIP using survival and leaf consumption of G. fossarum as response variables. Alterations in the leaf-associated decomposer community, which may be reflected by their palatability, were assessed using food choice assays. Finally, we conducted a 2 × 2-factorial experiment over 24 days assessing the pathways individually and combined using energy processing (i.e., leaf consumption and feces production), growth and energy storage (i.e., neutral lipid fatty acids) as variables. Short term waterborne exposure indicated low toxicity with LC50 and EC50 values of 13.6 and 6.4 mg CIP/L, respectively. At the same time, shredders did not prefer any leaf material during the food choice assay. However, the fungal community was significantly affected in the highest CIP-treatments (0.5 and 2.5 mg/L) suggesting an altered food quality for shredders. This assumption is supported by the results of the long-term assay. At 0.5 mg CIP/L, gammarids’ leaf consumption, growth and energy storage were increased when subjected via the dietary pathway, which was linked to changes in the leaf-associated microbial community. Our data highlight the importance of dietary effect pathways for effects on shredders, potentially impacting energy dynamics in detritus-based stream ecosystems.
... It can be used to treat specific infections and against a broad spectrum of Gram-negative and Gram-positive bacteria in both stationary and growth phases of bacterial replication (Scheer, 1987). Its wide in vivo distribution, unique antimicrobial effect, high bioavailability, less toxicity, and side effects, make it one of the most commonly used antibiotics for treatment of various animal infectious diseases, and a desirable antibiotic choice for difficult-to-treat infections, particularly those that need long-term antibiotic treatment (Divers et al., 2008;Ebert et al., 2011;Reyes-Herrera et al., 2011;Jerjomiceva et al., 2014;Lin et al., 2014;Rico et al., 2014;Andrieu et al., 2015;Nguyen Dang Giang et al., 2015;Phillips et al., 2015;Piras et al., 2015;Carrascosa et al., 2017;Foster et al., 2017;Roth et al., 2017;Strze R pa et al., 2017;Zhu et al., 2017;Rico et al., 2018). The bactericidal activity of enrofloxacin is concentration-dependent, with susceptible bacterial cell death occurring within 20-30 minutes of exposure. ...
Enrofloxacin, a third-generation fluoroquinolone, is a broad-spectrum antimicrobial drug against a lot of veterinary bacterial diseases. However, bactericidal activity of enrofloxacin is concentration-dependent and its poor aqueous solubility and bitter taste limit its development and application. Meanwhile, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), a widely used cyclodextrin analog, is a safe and an effective drug carrier. It forms inclusion complexes with its drug substrates and improves their physiochemical and pharmacokinetic properties. Enrofloxacin was also found to form a stable inclusion complex with HP-β-CD and different research groups have shown improved solubility for enrofloxacin by 32.5%, 9.25 and 165-fold. Our own efforts in this direction resulted in manifold improvement (916-fold) in its solubility compared to the previous studies. It was further shown that pharmaceutical properties, absorption and bioavailability, of enrofloxacin have also been significantly improved by complexation with HP-β-CD.
... Many organisms are intrinsically resistance to antibiotics and culturable antibiotic resistance bacteria are pervasive in water column [16]. There is a highly potential risk of structural change of leaf-associated bacterial communities due to the exposure of Enrofloxacin (an antibiotic) and significantly reduction of ammonia-oxidizing bacteria and ammonia-oxidizing archaea, which affect the aquatic environment and lead to cause eutrophication [17]. Sterile tools would be used to collect the sample from the water column at a depth of about 15cm to isolate antibiotics and antibiotic resistant bacteria and microorganisms. ...
Currently, the micropllutants such as antibiotics
are not included in the environmental effects monitoring
program for municipal wastewater effluent. This paper presents
the importance of the integration of the antibiotics in EEM
program. In addition, various types of the sample collection and
analysis method for antibiotics monitoring are discussed. It is
concluded that antibiotic monitoring program would give an
insight view of the effectiveness of antibiotic removal measure of
the environmental management and would be very crucial tool
for finding the proper remedial actions for the wastewater
treatment authorities.
... 30 More recently, exposure to antibiotics has demonstrated potential to influence key ecosystem functions, such as the findings that 50 μg/kg sulfadimethoxine reduces soil nitrification, 31 and 1 μg/L of enrofloxacin reduces abundance of ammoniaoxidizing Archaea in lake systems. 32 Although the early environmental PPCP literature often focused on antibiotics, a suite of non-prescription and prescription drugs also has been associated with disrupted biological and ecological processes. The mechanisms underlying these associations are often unknown. ...
Pharmaceuticals and personal care products (PPCPs) garner increasing attention globally for both their usefulness as indicators of human waste and their potency as emerging organic toxicants. Three decades of rapid increase in PPCP study combined with an increasing number of PPCPs on the global market have created opportunity (1) to review trends in diversity of compounds, sewage treatment techniques (STTs), and ecosystems investigated as well as (2) to identify knowledge gaps in the literature. We conducted a quantitative evidence synthesis of 6,517 abstracts from primary articles in the environmental PPCP literature by examining relative abundance of specific PPCP classes, STTs, and ecosystem types. Our results demonstrate that non-prescription drugs and antibiotics dominated PPCP abstracts, appearing in 51% and 39% of reviewed abstracts respectively, in comparison to hormones (18%), prescription drugs (18%), fragrances (0.3%), and antioxidants (0.0%), which can all elicit physiological and ecological responses even at low concentrations. References to centralized STTs (e.g., activated sludge - 37%) were more frequent than decentralized STTs (e.g., septic - 2%), despite decentralized STTs being common and frequently high impact sources of sewage pollution worldwide. Freshwater lotic systems (63%) were more prevalent than freshwater lentic (24%) and terrestrial (20%) systems. This discrepancy is notable because the longer residence times of lentic and terrestrial systems may enable PPCPs to concentrate and thus increase risk of biological consequences. These results highlight distinct opportunities to address knowledge gaps in the environmental PPCP literature, including underrepresented compounds (e.g., fragrances), sewage treatment techniques (e.g., septic systems), and ecosystem types (e.g., lakes).
... Conversely, pharmaceuticals are biologically active substances with very specific mode of action, usually designed to interfere with metabolic processes in vertebrates (mainly mammals). Therefore, many of them are not expected to result in adverse effects on aquatic organisms, although some exceptions exist such as structural and functional alterations of microbial communities caused by antibiotics (Rico et al., 2014;Välitalo et al., 2017) or fish behavioral effects caused by physichiatric drugs (Brodin et al., 2013;Brooks, 2014). The knowledge of the effects of complex mixtures of pesticides and pharmaceuticals in freshwater ecosystems is still very limited, and improved monitoring and management policies are still required to assess their combined exposure and to minimize their risks for aquatic ecosystems. ...
Pesticides and point source contaminants (primarily pharmaceuticals) were monitored in 16 sampling sites of the upper Tagus river basin during spring, summer and autumn of 2016. A qualitative screening analysis was performed using a library of 430 compounds. Next, a novel method was implemented for the selection and quantification of contaminants with LC-MS/MS. The method is based on the frequency of detection in the screening, ecotoxicity data and the potential use in the watershed. Moreover, the efficacy of grab samples and passive samples (POCIS) in detecting compound-specific exposure patterns was compared during the summer sampling campaign. The screening method detected the presence of 268 compounds in the study area, out of which 52 were selected for the quantitative analysis (20 pesticides and 32 point source chemicals). Although very helpful in the prioritization exercise, the qualitative screening demonstrated some biases and the need for improvement by using more effective instruments for confirming positive results. Grab samples proved not to be fully suitable for contaminants with discontinuous exposure such as pesticides, which may be underestimated, but offer a sufficient basis for the characterization of contaminants coming from urban wastewaters. All selected chemicals showed a very high concentration variability due to differences among sampling sites, which are related to agricultural intensity and demographic pressure. Some insecticides (chlorpyrifos, dimethoate, imidacloprid), herbicides (diuron, metribuzine, simazine, terbuthylazine), and fungicides (carbendazim) were measured at concentrations exceeding 100 ng/L; while paracetamol, ibuprofen, some antibiotics (azithromycin, sulfamethoxazole, trimethoprim) and life-style compounds (caffeine, paraxanthine, nicotine) were found at very high concentrations (up to several μg/L). The results of this work represent the basis for the development of an ecological risk assessment for the aquatic ecosystem in the upper Tagus river basin and for the identification of basin-specific contaminant mixtures of environmental concern.
... Several studies have been reported on the presence of the antibiotics in the surface water [8,9], ground water [10,11], municipal wastewater [12,13], soil [14] and even in the drinking water [15]. Rico et al. [16] mentioned the occurrence of antibiotics in the aquatic environment relatively low ranges (0.001 μg/L-10 μg/L). The antibiotics are considered as "pseudo-persistent" contaminants, it is due to their continuous entry and presence in the aquatic environment [17]. ...
The present study was envisioned to assess the short (96 h) and long-term (35 days) antioxidant responses of Labeo rohita exposed to different concentrations (10, 50, and 100 μg/L) of commonly used antibiotic, erythromycin. When compared to the control groups, superoxide dismutase (SOD) activity in the gills of the erythromycin treated fingerlings was significantly (P < .05) decreased during short-term, and the activity was increased (except 7th day in 10, and 50 μg/L) during long-term study period. Whereas in the liver, SOD activity of the erythromycin treated fingerlings was significantly (P < .05) elevated throughout the exposure period. In both the study period, catalase (CAT) activity in the gills, and liver of the erythromycin treated fingerlings were significantly (P < .05) decreased, when compared to the control groups. Glutathione peroxidase GPx, and lipid peroxidation (LPO) activities in the gills, and liver of the erythromycin treated fingerlings were found higher than the control groups in the both (short, and long-term) study period. In conclusion, erythromycin induce oxidative stress in aquatic organism (L. rohita), and this data could be an effective baseline for molecular toxicology to monitor the impact of antibiotics on non-target organisms.
... In the present study, lower richness and diversity were observed in the cultures supplemented with the target antibiotics, particularly in those fed with ENR. This antibiotic has been shown in other studies to significantly affect the structure and diversity of microbial communities with different environmental origins (Rico et al., 2014;Fernandes et al., 2015;Alexandrino et al., 2017). Regarding microbial community structure, the phylum Proteobacteria was found to dominate the cultures supplemented with the target antibiotics, suggesting that this taxonomical group accommodates bacterial species that may have an important role in the biodegradation of these compounds. ...
This work investigated the potential of microbial communities native to an estuarine environment to biodegrade enrofloxacin (ENR) and oxytetracycline (OXY). Sediments collected from two sites in the Douro river estuary (Porto, Portugal) were used as inocula for the biodegradation experiments. Experiments were carried out for one month, during which ENR and OXY (1 mg L-1) were supplemented individually or in mixture to the cultures at 10-day intervals. Acetate (400 mg L-1) was added to the cultures every 3 days to support microbial growth. A series of experimental controls were established in parallel to determine the influence of abiotic breakdown and adsorption in the removal of the antibiotics. Removal of antibiotics was followed by measuring their concentration in the culture medium. Additionally, next-generation sequencing of the 16S rRNA gene amplicon was employed to understand how microbial communities responded to the presence of the antibiotics. At the end of the biodegradation experiments, microbial cultures derived from the two estuarine sediments were able to remove up to 98% of ENR and over 95% of OXY. The mixture of antibiotics did not affect their removal. ENR was removed mainly by biodegradation, while abiotic mechanisms were found to have a higher influence in the removal of OXY. Both antibiotics adsorbed at different extents to the estuarine sediments used as inocula but exhibited a higher affinity to the sediment with finer texture and higher organic matter content. The presence of ENR and OXY in the culture media influenced the dynamics of the microbial communities, resulting in a lower microbial diversity and richness and in the predominance of bacterial species belonging to the phylum Proteobacteria. Therefore, microbial communities native from estuarine environments have potential to respond to the contamination caused by antibiotics and may be considered for the recovering of impacted environments through bioremediation.
... Most of the materials and methods used for the microcosm experiment have been described by Rico et al. (2014). ...
The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones.
... BAC has showed evidence that it initially inhibited the nitrification efficiency at a BAC feed concentration of 5 mg L À1 in a biological nitrogen removal processes (Hajaya and Pavlostathis, 2012). Similar results have been observed for antibiotics, which have been proved to have a significant and rapid negative impact on the presence of amoA in soils (Colloff et al., 2008) and tropical eutrophic freshwater microcosms (Rico et al., 2014). More research is still needed to investigate the effect of BAC on the nitrogen cycle based on the changes of nitrogen removal rate and denitrifer community in the natural water system. ...
Benzylalkyldimethylethyl ammonium compounds are pervasive in natural environments and toxic at high concentrations. The changes in functional genes and microbial diversity in eutrophic lake samples exposed to benzyldimethyldodecyl ammonium chloride (BAC) were assessed. BAC exerted negative effects on bacteria abundance, particularly at concentrations of 100 μg L-1 and higher. A significant increase in the number of the quaternary ammonium compound-resistant gene qacA/B was recorded within the 10 μg L-1 treatment after the first day of exposure. Not all antibiotic resistance genes increased in abundance as the concentrations of BAC increased; rather, gene abundances were dependent on the gene type, concentrations of BAC, and contact time. The nitrogen fixation-related gene nifH and ammonia monooxygenase gene amoA were inhibited by high concentrations of BAC after the first day, whereas an increase of the nitrite reductase gene nirK was stimulated by exposure. Microbial communities within higher treatment levels (1000 and 10 000 μg L-1) exhibited significantly different community composition compared to other treatment levels and the control. Selective enrichment of Rheinheimera, Pseudomonas, and Vogesella were found in the higher treatment levels, suggesting that these bacteria have some resistance or degradation capacity to BAC. Genes related with RNA processing and modification, transcription, lipid transport and metabolism, amino acid transport and metabolism, and cell motility of microbial community function were involved in the process exposed to the BAC stress.
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... In the present study, lower richness and diversity were observed in the cultures supplemented with the target antibiotics, particularly in those fed with ENR. This antibiotic has been shown in other studies to significantly affect the structure and diversity of microbial communities with different environmental origins (Rico et al., 2014;Fernandes et al., 2015;Alexandrino et al., 2017). Regarding microbial community structure, the phylum Proteobacteria was found to dominate the cultures supplemented with the target antibiotics, suggesting that this taxonomical group accommodates bacterial species that may have an important role in the biodegradation of these compounds. ...
In this study, the microbial degradation of two antibiotics, enrofloxacin (ENR) and oxytetracycline (OXY), belonging respectively to fluoroquinolones and tetracyclines classes is reported. Biodegradation of the two antibiotics was tested by supplementing culture medium with ENR and OXY individually and in mixture. Two sediments from Douro estuary (Porto, Portugal) were used as inocula. Biodegradation experiments were conducted along a period of 2 months, during which the antibiotics were supplemented to the cultures every 10 days, at the concentration of 1 mgL⁻¹, using acetate as a co-substrate. Complete removal of OXY from the inoculated culture medium was always observed within the 10 days period, while removal of ENR varied between 70% and 90%. The results presented in this study indicate that biodegradation can be an important mechanism for the environmental removal of the tested compounds.
... For example, a recent study reported significantly higher frequencies of AMR genes in urinary Escherichia coli isolates from Chileans living in aquaculture regions compared to isolates from non-aquaculture localities, suggesting that AM use in the Chilean salmon industry may be contributing to increased risks of AMR genes in humans (Tomova et al. 2015). AM use in animal husbandry, therefore, has repercussions for humans, while many AMs also are directly toxic to non-pathogenic bacteria and primary producers, possibly affecting ecosystem functions and biochemical processes mediated by microorganisms (Christensen et al. 2006;Rico et al. 2014a;Guo et al. 2015). ...
Global seafood provides almost 20% of all animal protein in diets, and aquaculture is, despite weakening trends, the fastest growing food sector worldwide. Recent increases in production have largely been achieved through intensification of existing farming systems, resulting in higher risks of disease outbreaks. This has led to increased use of antimicrobials (AMs) and consequent antimicrobial resistance (AMR) in many farming sectors, which may compromise the treatment of bacterial infections in the aquaculture species itself and increase the risks of AMR in humans through zoonotic diseases or through the transfer of AMR genes to human bacteria. Multiple stakeholders have, as a result, criticized the aquaculture industry, resulting in consequent regulations in some countries. AM use in aquaculture differs from that in livestock farming due to aquaculture’s greater diversity of species and farming systems, alternative means of AM application, and less consolidated farming practices in many regions. This, together with less research on AM use in aquaculture in general, suggests that large data gaps persist with regards to its overall use, breakdowns by species and system, and how AMs become distributed in, and impact on, the overall social-ecological systems in which they are embedded. This paper identifies the main factors (and challenges) behind application rates, which enables discussion of mitigation pathways. From a set of identified key mechanisms for AM usage, six proximate factors are identified: vulnerability to bacterial disease, AM access, disease diagnostic capacity, AMR, target markets and food safety regulations, and certification. Building upon these can enable local governments to reduce AM use through farmer training, spatial planning, assistance with disease identification, and stricter regulations. National governments and international organizations could, in turn, assist with disease-free juveniles and vaccines, enforce rigid monitoring of the quantity and quality of AMs used by farmers and the AM residues in the farmed species and in the environment, and promote measures to reduce potential human health risks associated with AMR.
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... The influence of interspecific competition on the vulnerability of microalgae communities to antibiotic stress has been investigated in a very limited number of studies. In a previous study we assessed the fate and effects of ENR in tropical eutrophic freshwater microcosms but found no consistent effects on primary producers at concentrations up to 1 mg/L (Rico et al., 2014a). In that study, however, the number of cyanobacteria taxa was low and their occurrence very erratic, which impeded the identification of clear dose-response relationships. ...
Primary producers are amongst the most sensitive organisms to antibiotic pollution in aquatic ecosystems. To date, there is little information on how different environmental conditions may affect their sensitivity to antibiotics. In this study we assessed how temperature, genetic variation and species competition may affect the sensitivity of the cyanobacterium Microcystis aeruginosa and the green-algae Scenedesmus obliquus to the antibiotic enrofloxacin. First, we performed single-species tests to assess the toxicity of enrofloxacin under different temperature conditions (20°C and 30°C) and to assess the sensitivity of different species strains using a standard temperature (20°C). Next, we investigated how enrofloxacin contamination may affect the competition between M. aeruginosa and S. obliquus. A competition experiment was performed following a full factorial design with different competition treatments, defined as density ratios (i.e. initial bio-volume of 25/75%, 10/90% and 1/99% of S. obliquus/M. aeruginosa, respectively), one 100% S. obliquus treatment and one 100% M. aeruginosa treatment, and four different enrofloxacin concentrations (i.e. control, 0.01, 0.05 and 0.10mg/L). Growth inhibition based on cell number, bio-volume, chlorophyll-a concentration as well as photosynthetic activity were used as evaluation endpoints in the single-species tests, while growth inhibition based on measured chlorophyll-a was primarily used in the competition experiment. M. aeruginosa photosynthetic activity was found to be the most sensitive endpoint to enrofloxacin (EC50-72h =0.02mg/L), followed by growth inhibition based on cell number. S. obliquus was found to be slightly more sensitive at 20°C than at 30°C (EC50-72h cell number growth inhibition of 38 and 41mg/L, respectively), whereas an opposite trend was observed for M. aeruginosa (0.047 and 0.037mg/L, respectively). Differences in EC50-72h values between algal strains of the same species were within a factor of two. The competition experiment showed that M. aeruginosa growth can be significantly reduced in the presence of S. obliquus at a density ratio of 75/25% M. aeruginosa/S. obliquus, showing a higher susceptibility to enrofloxacin than in the single-species test. The results of this study confirm the high sensitivity of cyanobacteria to antibiotics and show that temperature and inter-strain genetic variation may have a limited influence on their response to them. The results of the competition experiment suggest that the structure of primary producer communities can be affected, at least temporarily, at antibiotic concentrations close to those that have been measured in the environment.
... Besides their applications to livestock, poultry or swine feedlots, pharmaceuticals are widely used in aquaculture (Rico et al., 2014a). The continuous entry of pharmaceuticals into the aquatic environment from wastewater effluents or leaching and runoff of agricultural soils amended with manure, even at low concentrations, may pose long-term risks to aquatic and terrestrial organisms (Klavarioti et al., 2009;Martini et al., 2012;Rico et al., 2014b). In surface waters, pharmaceuticals and their metabolites generally include several pharmaco-therapeutic classes, such as antibiotics, antipyretics, anti-inflammatory drugs, -blockers, lipid regulators, hormones, antidepressants, and anesthetics (Kümmerer, 2009). ...
The ecological risks posed by two β-diketone antibiotics (DKAs, enrofloxacin, ENR and ciprofloxacin, CPX), characterized by their long persistence in aqueous environments and known deleterious effect on model organisms such as zebrafish were analysed using Rhinella arenarum larvae. Sublethal tests were conducted using environmentally relevant concentrations of both ENR and CPX (1-1000 μg L⁻¹) under standard laboratory conditions for 96 h. Biological endpoints and biomarkers evaluated were body size, shape, development and growth rates, and antioxidant enzymes (Glutathione-S-transferase, GST; Catalase, CAT). Risk assessment was analysed based on ration quotients (RQ). The size and shape measurements of the larvae exposed to concentrations greater than 10 μg L⁻¹ of CPX were lower compared to controls (Dunnett post-hoc p < 0.05) and presented signs of emaciation. Concentrations of 1000 μg L⁻¹of CPX induced GST activity, in contrast with inhibited GST and CAT of larvae exposed to ENR. Risk assessments indicated that concentrations greater than or equal to10 μg L⁻¹ of CPX and ENR are ecotoxic for development, growth, detoxifying, and oxidative stress enzymes. It is suggested that additional risk assessments may provide evidence of bioaccumulation of CPX and ENR in tissues or organs of amphibian larvae by mesocosm sediment test conditions. Finally, intestinal microbiome studies should be considered to establish the mechanisms of action of both antibiotics.
... Besides their applications to livestock, poultry or swine feedlots, pharmaceuticals are widely used in aquaculture (Rico et al., 2014a). The continuous entry of pharmaceuticals into the aquatic environment from wastewater effluents or leaching and runoff of agricultural soils amended with manure, even at low concentrations, may pose long-term risks to aquatic and terrestrial organisms (Klavarioti et al., 2009;Martini et al., 2012;Rico et al., 2014b). In surface waters, pharmaceuticals and their metabolites generally include several pharmaco-therapeutic classes, such as antibiotics, antipyretics, anti-inflammatory drugs, -blockers, lipid regulators, hormones, antidepressants, and anesthetics (Kümmerer, 2009). ...
The ecological risks posed by two β-diketone antibiotics (DKAs, enrofloxacin, ENR and ciprofloxacin, CPX), characterized by their long persistence in aqueous environments and known deleterious effect on model organisms such as zebrafish were analysed using Rhinella arenarum larvae. Sublethal tests were conducted using environmentally relevant concentrations of both ENR and CPX (1-1000 μg L−1) under standard laboratory conditions for 96 h. Biological endpoints and biomarkers evaluated were body size, shape, development and growth rates, and antioxidant enzymes (Glutathione-S-transferase, GST; Catalase, CAT). Risk assessment was analysed based on ration quotients (RQ). The size and shape measurements of the larvae exposed to concentrations greater than 10 μg L−1 of CPX were lower compared to controls (Dunnett post-hoc p < 0.05) and presented signs of emaciation. Concentrations of 1000 μg L−1of CPX induced GST activity, in contrast with inhibited GST and CAT of larvae exposed to ENR. Risk assessments indicated that concentrations greater than or equal to10 μg L−1 of CPX and ENR are ecotoxic for development, growth, detoxifying, and oxidative stress enzymes. It is suggested that additional risk assessments may provide evidence of bioaccumulation of CPX and ENR in tissues or organs of amphibian larvae by mesocosm sediment test conditions. Finally, intestinal microbiome studies should be considered to establish the mechanisms of action of both antibiotics.
... The effect of chronic antibiotic exposure on aquatic plants has been poorly characterized, but there is evidence to suggest that antibiotic exposed aquatic plants demonstrate significant changes in the phyllosphere microflora -a change that has unknown ecological consequences (Rico et al., 2014). ...
The environment is increasingly being recognized for the role it might play in the global spread of clinically relevant antibiotic resistance. Environmental regulators monitor and control many of the pathways responsible for the release of resistance-driving chemicals into the environment (e.g., antimicrobials, metals, and biocides). Hence, environmental regulators should be contributing significantly to the development of global and national antimicrobial resistance (AMR) action plans. It is argued that the lack of environment-facing mitigation actions included in existing AMR action plans is likely a function of our poor fundamental understanding of many of the key issues. Here, we aim to present the problem with AMR in the environment through the lens of an environmental regulator, using the Environment Agency (England’s regulator) as an example from which parallels can be drawn globally. The issues that are pertinent to environmental regulators are drawn out to answer: What are the drivers and pathways of AMR? How do these relate to the normal work, powers and duties of environmental regulators? What are the knowledge gaps that hinder the delivery of environmental protection from AMR? We offer several thought experiments for how different mitigation strategies might proceed. We conclude that: (1) AMR Action Plans do not tackle all the potentially relevant pathways and drivers of AMR in the environment; and (2) AMR Action Plans are deficient partly because the science to inform policy is lacking and this needs to be addressed.
... Although several researchers infer that the invertebrate risks posed by some pharmaceuticals (e.g. antimicrobials, anti-inflammatory drugs) are negligible at environmentally relevant concentrations (Cleuvers, 2004;Pascoe et al., 2003;Rico et al., 2014), some have identified possible long-term risks when evaluating antidepressant or antiepileptic drugs (Oetken et al., 2005;Nentwig, 2007). For instance, Nentwig (2007) found that the antidepressant fluoxetine affects the reproduction of the freshwater snail Potamopyrgus antipodarum at concentrations below 1 μg/L. ...
A key challenge for the ecological risk assessment of chemicals has been to evaluate the relative contribution of chemical pollution to the variability observed in biological communities, as well as to identify multiple stressor groups. In this study we evaluated the toxic pressure exerted by > 200 contaminants to benthic macroinvertebrates in the Danube River using the Toxic Unit approach. Furthermore, we evaluated correlations between several stressors (chemical and non-chemical) and biological indices commonly used for the ecological status assessment of aquatic ecosystems. We also performed several variation partitioning analyses to evaluate the relative contribution of contaminants and other abiotic parameters (i.e. habitat characteristics, hydromorphological alterations, water quality parameters) to the structural and biological trait variation of the invertebrate community. The results of this study show that most biological indices significantly correlate to parameters related to habitat and physico-chemical conditions, but showed limited correlation with the calculated toxic pressure. The calculated toxic pressure, however, showed little variation between sampling sites, which complicates the identification of pollution-induced effects. The results of this study show that the variation in the structure and trait composition of the invertebrate community are mainly explained by habitat and water quality parameters, whereas hydromorphological alterations play a less important role. Among the water quality parameters, physico-chemical parameters such as suspended solids, nutrients or dissolved oxygen explained a larger part of the variation in the invertebrate community as compared to metals or organic contaminants. Significant correlations exist between some physico-chemical measurements (e.g. nutrients) and some chemical classes (i.e. pharmaceuticals, chemicals related to human presence) which constitute important multiple stressor groups. This study demonstrates that, in large rivers like the Danube, the variation in the invertebrate community seems to be more related to varying habitat and physico-chemical conditions than to chemical pollution.
... In contrast to enrofloxacin, ciprofloxacin was found to pose a risk to the photoautotrophic organisms (cyanobacterium Anabaena flos-aquae and monocotyledonous macrophyte L. minor) at the predicted environmental concentration. The results of the study performed by Rico et al. (2014) also suggest that environmentally relevant concentrations of enrofloxacin are not likely to result in direct or indirect toxic effects on the ecology of tropical eutrophic freshwater microcosms. In turn, Wagil et al. (2014) reported moderate environmental risk for enrofloxacin, norfloxacin, and ciprofloxacin, based on their occurrence concentration in two rivers in northern Poland and their acute toxicity on L. minor. ...
The discovery of antibiotics is considered one of the most significant scientific achievements of the 20th century, revolutionizing both human and veterinary medicine. However, antibiotics have been recently recognized as an emerging class of environmental contaminants since they have been massively administrated in humans and animals and persist in the environment through a complex vicious cycle of transformation and bioaccumulation. The diffusion of antibiotics in the environment, particularly in natural water systems, contributes to the development and global dissemination of antibiotic resistance. This phenomenon is one of the most important challenges to the health care sector in the 21st century. As a result, studies on the occurrence, fate, and effects of antibiotics in European aqueous environments have increased in the last years. Nevertheless, their potential aquatic ecotoxicity and human toxicity via environmental exposure routes remain unknown. Consequently, antibiotics are not regulated through the current European environmental water quality standards, which requires evidence concerning their widespread environmental contamination and intrinsic hazard. In this context, this literature review summarizes the state of knowledge on the occurrence of antibiotics in the different aqueous environmental systems across the Europe, as reported since 2000. Relating this subject to antibiotic consumption and their dynamic behavior in the environment, the acquired insights provide an improved understanding on aquatic pollution by antibiotics to outline the European scenario. Moreover, it addresses challenges, prospects for future research, and typical topics to stimulate discussion.
Fluoroquinolone antibioticsare widely used in pharmaceuticals and personal care products due to their disease treatment, growth promotion, and prophylaxis, which lead to increasing biological exposure to fluoroquinolones in the global environment. This paper recapitulates the occurrence, fate, and ecotoxicity of fluoroquinolone antibiotics in various environmental media. The toxicity effect and mechanism are also reviewed based on in vitro and in vivo experiments, referring to many organisms, such as microorganisms, cells, higher plants, land and aquatic animals. The combined toxicity effect and coexisting characteristics of fluoroquinolone antibiotics absorbed with other chemicals to organisms in various environmental matrices are also summarized. The current knowledge gaps, further research interests and toxicity mechanisms of fluoroquinolone antibiotics in the environment have been discussed in this research.
The article considers antibiotics of the quinolone series, their using and mechanism of action. Based on the literature data, their application, distribution mechanisms, accumulation and behavior in environmental objects are considered. It is noted that the role of aquatic plants in the processes of biochemical degradation has not been sufficiently studied. Under the conditions of a laboratory model experiment, we studied the patterns of ciprofloxacin elimination by hydatophytes, i.e., aquatic plants completely submerged in water (Canadian pondweed, rigid hornwort, Eurasian watermilfoil). The spectral characteristics of ciprofloxacin were studied and quantitative estimates of the absorption of the antibiotic from solutions with submerged aquatic plants were made. We calculated elimination rate constants and phytoremediation potential. It was found that the rate of elimination of ciprofloxacin and phytoremediation potential depended on the type of aquatic plant and the initial concentration of the antibiotic. The highest elimination rate was found in models containing hornwort. Based on the data obtained, a conclusion was made about the prospects for the using of hydatophytes in phytopurification systems for post-treatment of wastewater from ciprofloxacin.
Metal pollution is a worldwide concern and may pose risks to aquatic organisms, communities, and ecosystems. The toxic effects of metals at the organism level are relatively clear. However, their impacts at the community level are still poorly understood, especially with concurred eutrophication in surface water. In the present study, the effects of Cd on the plankton community structure and function under varying nutrient conditions were evaluated using a microcosm study. The employed concentrations of Cd and nutrient were based on the values currently measured in the freshwater ecosystem. For the plankton structure, our results showed that the Chl a concentration, the abundances of total phytoplankton, Cyanophyta, and Chlorophyta, and the abundance of Copepoda decreased by Cd consistently. The Cyanophyta Oscillatoria tenuis and Copepoda nauplius were the most sensitive species to Cd in the phytoplankton and zooplankton community, respectively. For the community effects, we found the inhibitory effects of Cd on the photosystem II (PSII) activity of phytoplankton community because of the consistent decrease in the chlorophyll fluorescence parameters (Fv/Fm, Y(Ⅱ), and ETR). Furthermore, the reductions of DOC and pH by Cd were only found in the high nutrient condition, which indicated that the toxic effects of Cd on the community structure and community metabolites were aggravated by the increased nutrient. This study emphasizes the importance of considering nutrient conditions when assessing the metal ecotoxicological effects at environmentally relevant concentrations.
This study aimed to investigate the effects of dietary tea tree oil (TTO) on the performance, intestinal antioxidant capacity, and non-specific immunity after ammonia nitrogen stress in Macrobrachium rosenbergii. Six experimental diets were formulated with 0, 25, 50, 100, 200, 400 mg/kg TTO, respectively. A total of 900 prawns (average initial weight, 0.39 ± 0.01 g) were randomly assigned to 6 groups in triplicate in 18 tanks. After an 8-week feeding trial, 20 prawns from each tank were changed with 20 mg/L ammonia stress for 24 h. The results showed that 100 mg/kg TTO significantly increased prawns performance and survival rate compared with the control group. Moreover, 100 and 200 mg/kg TTO significantly improved intestinal antioxidant capabilities by increasing SOD enzyme activities and decreasing MDA levels. In addition, the prawns fed with 100 mg/kg TTO diet showed the highest survival rate under ammonia stress. After ammonia stress, the group of 100 mg/kg TTO significantly improved antioxidant capacity by increasing hemolymph respiratory burst activity, as well as intestinal anti-superoxide anion activity and SOD. Coincidentally, 100 mg/kg TTO significantly upregulated the intestinal relative expression of antioxidant-related genes (peroxiredoxin-5). Further, it was found that 100 mg/kg TTO activated the toll-dorsal pathway in prawns, which performed the similar function as the classic NF-κB pathway by upregulating the TNF-α and IL-1. Finally, 100 mg/kg TTO increased the levels of iNOS activities and NO contents after ammonia stress and enhanced non-specific immunity. The results indicated that 100 mg/kg TTO could significantly improve the M. rosenbergii performance, antioxidant capacity and ammonia stress resistance. We suggested that the mechanisms may be attributed to that TTO enhanced the antioxidant capacity and non-specific immunity of M. rosenbergii via the NF-κB signal pathway.
Response of nitrogen removal efficiency and microbial interactions to organic pollution has been a major issue in wastewater treatment system. However, the nitrogen removal efficiency and interactions among microbial community under antibiotics press is still unclear. Thus, the effect of sulfamethoxazole (SMX) on nitrogen removal and microbial responses of IVCWs was investigated through recorded the nitrogen removal efficiency before and after adding SMX and random matrix theory (RMT)-based network analysis. Results showed that better NH4⁺-N removal (> 90%) after a long period of operation were achieved in IVCWs, but NO3⁻-N was accumulated. However, nitrate removal rates were significantly increased after long-term exposure (60 d) to 100 μg L⁻¹ SMX (from 27.35% to 35.57%) with relatively high SMX removal (53.50%). Surprisingly, the ammonia nitrogen removal rate (90.07−92.70%) were not significantly affected by SMX in IVCWs. Moreover, the bacterial richness was decreased and the bacterial community structures were altered by the presence of SMX, especially those of nitrogen-transforming microorganisms. Molecular ecological network analysis suggested that SMX had positive influences on denitrifying bacteria interactions but reduced the network complexity and microbial interactions on whole molecular network, and among-module connections were weakened obviously at SMX.
In the rhizosphere, plant root exudates can mediate the toxicity of antibiotics on microorganisms, yet the mechanisms are poorly understood. To simulate the antibiotic contamination of global rivers and lakes,...
The growth of the aquaculture industry is becoming more important in the food production sector. Presently, the biggest problem in aquaculture is bacterial diseases that infect the host thus causing outbreaks and economic losses. Vibriosis is a potentially lethal threat in commercial fish farming. Based on previous researches, various infections of the Vibrio genus have been reported hence their virulence is not fully understood. This review aims to provide enlightenment through research findings on Vibriosis-infected fish. Besides, some guidelines regarding control measures of Vibrio in aquaculture, such as the application of immunostimulant, antibiotics, probiotics and quorum sensing molecules, will be also reviewed.
Once released into the environment antibiotics can kill or inhibit the growth of bacteria, and in turn potentially have effects on bacterial community structure and ecosystem function. Environmental risk assessment (ERA) seeks to establish protection limits to minimise chemical impacts on the environment, but recent evidence suggests that the current regulatory approaches for ERA for antibiotics may not be adequate for protecting bacteria that have fundamental roles in ecosystem function. In this study we assess the differences in interspecies sensitivity of eight species of cyanobacteria to seven antibiotics (cefazolin, cefotaxime, ampicillin, sufamethazine, sulfadiazine, azithromycin and erythromycin) with three different modes of action. We found that variability in the sensitivity to these antibiotics between species was dependent on the mode of action and varied by up to 70 times for β-lactams. Probabilistic analysis using species sensitivity distributions suggest that the current predicted no effect concentration PNEC for the antibiotics may be either over or under protective of cyanobacteria dependent on the species on which it is based and the mode of action of the antibiotic; the PNECs derived for the macrolide antibiotics were over protective but PNECs for β-lactams were generally under protective. For some geographical locations we identify a significant risk to cyanobacteria populations based upon measured environmental concentrations of selected antibiotics. We conclude that protection limits, as determined according to current regulatory guidance, may not always be protective and might be better derived using SSDs and that including toxicity data for a wider range of (cyano-) bacteria would improve confidence for the ERA of antibiotics.
It is well known that – mainly, three processes govern the photocatalytic activity – the first one being the exciton formation after absorption of light, the second one is the charge separation and migration and the third one is the surface redox potential. In this study, an effective charge transfer and migration of photo generated electrons and holes from Zinc Selenide (ZnSe) to Reduced Graphene Oxide (RGO) have been reported. Further, these photocatalysts are evaluated by tetracycline (TC) photodegradation under simulated solar light irradiation. The ZnSe decorated RGO photocatalysts have been successfully synthesized using a one‐step solvothermal reaction. X‐ray diffraction, Scanning electron microscopy, Transmission electron microscopy, High‐resolution transmission electron microscopy, Raman and Fourier‐transform infrared spectroscopy are used to characterize the RGO‐ZnSe composite. Ultraviolet–visible spectroscopy and scavenger experiments are used to explore the photocatalysis mechanism of the water pollutant antibiotic TC. The main active species in TC photodegradation was found to be hole (h⁺). Furthermore, this work initiated a promising and effective photocatalyst, the RGO–ZnSe nanocomposites. Hence these nanocomposites could be potentially used for the degradation of organic pollutants.
In this paper a novel multivariate method is proposed for the analysis of community response data from designed experiments repeatedly sampled in time. The long-term effects of the insecticide chlorpyrifos on the invertebrate community and the dissolved oxygen (DO)–pH–alkalinity–conductivity syndrome, in outdoor experimental ditches, are used as example data. The new method, which we have named the principal response curve method (PRC), is based on redundancy analysis (RDA), adjusted for overall changes in community response over time, as observed in control test systems. This allows the method to focus on the time-dependent treatment effects. The principal component is plotted against time, yielding a principal response curve of the community for each treatment. The PRC method distills the complexity of time-dependent, community-level effects of pollutants into a graphic form that can be appreciated more readily than the results of other currently available multivariate techniques. The PRC method also enables a quantitative interpretation of effects towards the species level.
This article describes the long-term effects on the macro invertebrate and zooplankton community in outdoor experimental ditches after a single application of the insecticide chlorpyrifos. Nominal concentrations of 0.1, 0.9, 6, and 44 μg/L of chlorpyrifos were applied to two mesocosms each, while four served as controls. Both macroinvertebrates and zooplankton were sampled from 4 weeks before to 55 weeks after treatment. The macroinvertebrate and zooplankton data sets were combined into one data set and analyzed using the multivariate ordination technique “redundancy analysis.” The method provided a clear description of the effects on the invertebrate community in time while still showing the effects at the species level. Crustacea and Insecta showed a rapid, concentration-dependent decrease in numbers after insecticide application (direct effects). An increase in gastropods and Oligochaeta was found, suggesting indirect effects. The start of recovery of the invertebrate populations affected was found to depend not only on the susceptibility of the taxa but also on ecological characteristics, such as the length of the life cycle. A no-observed-effect concentration of 0.1 μg/L could be derived both at the species and the community level. Safe concentrations, based on no-observed-short-term-effect levels for some characteristic indigenous taxa susceptible to chlorpyrifos, also appeared to protect the total invertebrate community in the long term. The invertebrate community at all treatment levels was considered to have recovered after 24 weeks posttreatment.
Current models and observations indicate that bacterial respiration should increase and growth efficiency (BGE) should decrease with increasing temperatures. However, these models and observations are mostly derived from data collected in temperate regions, and the tropics are under-represented. The aim of this work was to compare bacterial metabolism, namely bacterial production (BP) and respiration (BR), bacterial growth efficiency (BGE) and bacterial carbon demand (BCD) between tropical and temperate ecosystems via a literature review and using unpublished data. We hypothesized that (1) tropical ecosystems have higher metabolism than temperate ones and, (2) that BGE is lower in tropical relative to temperate ecosystems. We collected a total of 498 coupled BP and BR observations (N total = 498; N temperate = 301; N tropical = 197), calculated BGE (BP/(BP+BR)) and BCD (BP+BR) for each case and examined patterns using a model II regression analysis and compared each parameter between the two regions using non-parametric Mann-Whitney U test. We observed a significant positive linear regression between BR and BP for the whole dataset, and also for tropical and temperate data separately. We found that BP, BR and BCD were higher in the tropics, but BGE was lower compared to temperate regions. Also, BR rates per BP unit were at least two fold higher in the tropics than in temperate ecosystems. We argue that higher temperature, nutrient limitation, and light exposure all contribute to lower BGE in the tropics, mediated through effects on thermodynamics, substrate stoichiometry, nutrient availability and interactions with photochemically produced compounds. More efforts are needed in this study area in the tropics, but our work indicates that bottom-up (nutrient availability and resource stoichiometry) and top-down (grazer pressure) processes, coupled with thermodynamic constraints, might contribute to the lower BGE in the tropics relative to temperate regions.
The ecological impact of the dithiocarbamate fungicide metiram was studied in outdoor freshwater microcosms, consisting of 14 enclosures placed in an experimental ditch. The microcosms were treated three times (interval 7 days) with the formulated product BAS 222 28F (Polyram®). Intended metiram concentrations in the overlying water were 0, 4, 12, 36, 108 and 324 μg a.i./L. Responses of zooplankton, macroinvertebrates, phytoplankton, macrophytes, microbes and community metabolism endpoints were investigated. Dissipation half-life (DT50) of metiram was approximately 1–6 h in the water column of the microcosm test system and the metabolites formed were not persistent. Multivariate analysis indicated treatment-related effects on the zooplankton (NOECcommunity = 36 μg a.i./L). Consistent treatment-related effects on the phytoplankton and macroinvertebrate communities and on the sediment microbial community could not be demonstrated or were minor. There was no evidence that metiram affected the biomass, abundance or functioning of aquatic hyphomycetes on decomposing alder leaves. The most sensitive populations in the microcosms comprised representatives of Rotifera with a NOEC of 12 μg a.i./L on isolated sampling days and a NOEC of 36 μg a.i./L on consecutive samplings. At the highest treatment-level populations of Copepoda (zooplankton) and the blue-green alga Anabaena (phytoplankton) also showed a short-term decline on consecutive sampling days (NOEC = 108 μg a.i./L). Indirect effects in the form of short-term increases in the abundance of a few macroinvertebrate and several phytoplankton taxa were also observed. The overall community and population level no-observed-effect concentration (NOECmicrocosm) was 12–36 μg a.i./L. At higher treatment levels, including the test systems that received the highest dose, ecological recovery of affected measurement endpoints was fast (effect period < 8 weeks).
Electronic supplementary material
The online version of this article (doi:10.1007/s10646-012-0909-0) contains supplementary material, which is available to authorized users.
Although antibiotics have been increasingly used and detected in natural samples, their ecotoxicological effects on aquatic wildlife are not yet extensively studied. Considering the environmental threat posed by the biological activity of antibiotics it is quite relevant to assess the resulting impact, especially on sub-lethal endpoints. As such, this study evaluated the effects of ciprofloxacin on Pseudokirchneriella subcapitata and Lemna minor growth, on the survival and reproduction of Daphnia magna and on Gambusia holbrooki survival. The risks associated with ciprofloxacin effects on non-target organisms were quantified through the calculation of the PEC/PNEC ratio. Overall, the toxicity values obtained (at the mg L(-1) level) were higher than the environmental concentrations. P. subcapitata and L. minor were more sensitive under short-term exposures than D. magna and G. holbrooki. No acute toxicity was observed for fish. The chronic assay with D. magna evidenced that long term exposures to lower concentrations of this antibiotic induced impairments on its life-history parameters. Such outcome may pre-empt potential damages on the long-term maintenance of natural populations continuously exposed to the input of antibiotics. Indeed, the PEC/PNEC ratios showed that ciprofloxacin represents a risk for the most sensitive aquatic organisms, since the defined threshold of an acceptable risk was considerably surpassed.
Southeast Asia has become the center of rapid industrial development and economic growth. However, this growth has far outpaced investment in public infrastructure, leading to the unregulated release of many pollutants, including wastewater-related contaminants such as antibiotics. Antibiotics are of major concern because they can easily be released into the environment from numerous sources, and can subsequently induce development of antibiotic-resistant bacteria. Recent studies have shown that for some categories of drugs this source-to-environment antibiotic resistance relationship is more complex. This review summarizes current understanding regarding the presence of quinolones, sulfonamides, and tetracyclines in aquatic environments of Indochina and the prevalence of bacteria resistant to them. Several noteworthy findings are discussed: (1) quinolone contamination and the occurrence of quinolone resistance are not correlated; (2) occurrence of the sul sulfonamide resistance gene varies geographically; and (3) microbial diversity might be related to the rate of oxytetracycline resistance.
Ciprofloxacin (cipro) is a broad-spectrum antibiotic used in human and veterinary medicine that is readily transported into the environment via domestic wastewaters and through direct runoff. Although factors governing cipro fate are becoming understood, an integrated evaluation of disappearance mechanisms in aquatic systems has not been performed. Here we examined cipro disappearance rate in surface waters using both laboratory and field systems under different light, and dissolved (DOC) and particulate organic carbon (POC) conditions to determine when photodegradation versus adsorption dominates cipro fate. Initial laboratory experiments showed that cipro rapidly photodegraded (t(1/2) &SIM; 1.5 h) with numerous photodegradation products being noted when POC levels were low. However, even moderate water column POC levels resulted in reduced photodegradation ( no breakdown products detected) and soluble cipro disappearance rates were accelerated. C-14-ciprofloxacin studies confirmed significant adsorption onto aquatic POC (KOC values of 13,900 to 20,500 L/kg at neutral pH). In contrast, a follow-up mesocosm-scale field study using low POC water showed that photodegradation could also dominate cipro fate. In conclusion, both adsorption and photodegradation strongly influence cipro fate in aquatic systems, although the dominant mechanism appears to depend upon the ambient POC level.
Global environmental change poses emerging environmental health challenges throughout the world. One of such threats could be found in chemical safety in aquatic ecosystem. In the present study, we evaluated the effect of several environmental factors, such as water pH, temperature and ultraviolet light on the toxicity of pharmaceutical compounds in water, using freshwater invertebrate Daphnia magna. Seven pharmaceuticals including ibuprofen, acetaminophen, lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline and sulfathiazole were chosen as test compounds based on their frequent detection in water. The experimental conditions of environmental parameters were selected within the ranges that could be encountered in temperate environment, i.e., water temperature (15, 21, and 25 degrees C), pH (7.4, 8.3, and 9.2), and UV-B light intensity (continuous irradiation of 15.0 microW/cm(2)). For acetaminophen, enrofloxacin and sulfathiazole, decrease in water pH generally led to increase of acute lethal toxicity, which could be explained by the unionized fraction of pharmaceuticals. Increase of water temperature enhanced the acute toxicity of the acetaminophen, enrofloxacin and chlortetracycline, potentially due to alteration in toxicokinetics of chemicals as well as impact on physiological mechanisms of the test organism. The presence of UV-B light significantly increased the toxicity of sulfathiazole, which could be explained by photo-modification of this chemical that lead to oxidative stress. Under the UV light, however, acute toxicity of enrofloxacin decreased, which might be due to photo-degradation. Since changing environmental conditions could affect exposure and concentration-response profile of environmental contaminants, such conditions should be identified and evaluated in order to better manage ecosystem health under changing global environment.
We studied the effects of protist predation on the composition and morphological structure of a marine bacterioplankton assemblage. A mixed bacterial assemblage (0.6 mum filtered North Sea inoculum) was cultivated with unamended seawater as medium in four 1-stage chemostats. After the establishment of a bacterial community, 2 of the chemostats received a 2 mum filtered seawater inoculum. which enabled the development of heterotrophic nanoflagellates (HNF). The dynamics of bacterial and protist community composition in the chemostat cultures was followed by terminal-restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE). These fingerprinting techniques revealed that continuous cultivation with unsupplemented seawater altered the bacterial community composition compared to the inoculum. Fluorescent in situ hybridisation (FISH) analysis showed that the bacterial assemblages in the chemostats were dominated by gamma- Proteobacteria, particularly of the genus Alteromonas. Despite this shift, the overall richness of bacteria in the chemostats remained relatively high with up to 30 different operational taxonomic units (OTUs). HNF exerted efficient grazing control on the bacterial communities during 3 wk of cultivation and reduced bacterial biomass to approximately 10% of that in the predator-free chemostats. Only a modest development of grazing- resistant bacteria occurred, which contrasts with previously published chemostat experiments with freshwater microbial communities. T-RFLP and DGGE analyses also revealed that protist grazing did not result in significant changes in bacterial community composition. However, both fingerprinting techniques showed a relatively high richness (up to 15 different OTUs) and an ongoing succession within the protist assemblage, which might be one explanation for only low feed- back effects and low appearance of grazing-resistance in the predation-controlled bacterial community.
We describe a new molecular approach to analyzing the genetic diversity of complex microbial populations. This technique is based on the separation of polymerase chain reaction-amplified fragments of genes coding for 16S rRNA, all the same length, by denaturing gradient gel electrophoresis (DGGE). DGGE analysis of different microbial communities demonstrated the presence of up to 10 distinguishable bands in the separation pattern, which were most likely derived from as many different species constituting these populations, and thereby generated a DGGE profile of the populations. We showed that it is possible to identify constituents which represent only 1% of the total population. With an oligonucleotide probe specific for the V3 region of 16S rRNA of sulfate-reducing bacteria, particular DNA fragments from some of the microbial populations could be identified by hybridization analysis. Analysis of the genomic DNA from a bacterial biofilm grown under aerobic conditions suggests that sulfate-reducing bacteria, despite their anaerobicity, were present in this environment. The results we obtained demonstrate that this technique will contribute to our understanding of the genetic diversity of uncharacterized microbial populations.
A rapid silver-staining procedure for DNA fragments in polyacrylamide gels is described. The time required for band detection is 15 min and the limit of sensitivity 3 pg/mm2. PCR products subjected to this rapid staining protocol are readily recovered from the gel by excision and elution by incubation at 95 degrees C for 20 min. Bands of up to 3 kb have been recovered and reamplified from either recently prepared or dried gels. The rapid staining protocol significantly decreases the processing time required for silver-stained polyacrylamide gels, which is of particular importance in diagnostic situations. The recovery protocol allows individual bands from complex mixtures to be easily recovered for sequencing or probe preparation.
Few techniques are currently available for quantifying specific prokaryotic taxa in environmental samples. Quantification
of specific genotypes has relied mainly on oligonucleotide hybridization to extracted rRNA or intact rRNA in whole cells.
However, low abundance and cellular rRNA content limit the application of these techniques in aquatic environments. In this
study, we applied a newly developed quantitative PCR assay (5′-nuclease assay, also known as TaqMan) to quantify specific
small-subunit (SSU) rRNA genes (rDNAs) from uncultivated planktonic prokaryotes in Monterey Bay. Primer and probe combinations
for quantification of SSU rDNAs at the domain and group levels were developed and tested for specificity and quantitative
reliability. We examined the spatial and temporal variations of SSU rDNAs from Synechococcus plusProchlorococcus and marine Archaea and compared the results of the quantitative PCR assays to those obtained by alternative methods. The 5′-nuclease assays
reliably quantified rDNAs over at least 4 orders of magnitude and accurately measured the proportions of genes in artificial
mixtures. The spatial and temporal distributions of planktonic microbial groups measured by the 5′-nuclease assays were similar
to the distributions estimated by quantitative oligonucleotide probe hybridization, whole-cell hybridization assays, and flow
cytometry.
Isolated soil DNA from an oak-hornbeam forest close to Cologne, Germany, was suitable for PCR amplification of gene segments
coding for the 16S rRNA and nitrogenase reductase (NifH), nitrous oxide reductase (NosZ), cytochrome cd1-containing nitrite reductase (NirS), and Cu-containing nitrite reductase (NirK) of denitrification. For each gene segment,
diverse PCR products were characterized by cloning and sequencing. None of the 16S rRNA gene sequences was identical to any
deposited in the data banks, and therefore each of them belonged to a noncharacterized bacterium. In contrast, the analyzed
clones of nifH gave only a few different sequences, which occurred many times, indicating a low level of species richness in the N2-fixing bacterial population in this soil. Identical nifH sequences were also detected in PCR amplification products of DNA of a soil approximately 600 km distant from the Cologne
area. Whereas biodiversity was high in the case of nosZ, only a few different sequences were obtained with nirK. With respect to nirS, cloning and sequencing of the PCR products revealed that many false gene segments had been amplified with DNA from soil
but not from cultured bacteria. With the 16S rRNA gene data, many sequences of uncultured bacteria belonging to the Acidobacterium phylum and actinomycetes showed up in the PCR products when isolated DNA was used as the template, whereas sequences obtained
for nifH and for the denitrification genes were closely related to those of the proteobacteria. Although in such an experimental approach
one has to cope with the enormous biodiversity in soils and only a few PCR products can be selected at random, the data suggest
that denitrification and N2 fixation are not genetic traits of most of the uncultured bacteria.
Nitrification, the microbial oxidation of ammonia to nitrite and nitrate, occurs in a wide variety of environments and plays a central role in the global nitrogen cycle. Catalyzed by the enzyme ammonia monooxygenase, the ability to oxidize ammonia was previously thought to be restricted to a few groups within the β- and γ-Proteobacteria. However, recent metagenomic studies have revealed the existence of unique ammonia monooxygenase α-subunit (amoA) genes derived from uncultivated, nonextremophilic Crenarchaeota. Here, we report molecular evidence for the widespread presence of ammonia-oxidizing archaea (AOA) in marine water columns and sediments. Using PCR primers designed to specifically target archaeal amoA, we find AOA to be pervasive in areas of the ocean that are critical for the global nitrogen cycle, including the base of the euphotic zone, suboxic water columns, and estuarine and coastal sediments. Diverse and distinct AOA communities are associated with each of these habitats, with little overlap between water columns and sediments. Within marine sediments, most AOA sequences are unique to individual sampling locations, whereas a small number of sequences are evidently cosmopolitan in distribution. Considering the abundance of nonextremophilic archaea in the ocean, our results suggest that AOA may play a significant, but previously unrecognized, role in the global nitrogen cycle.
• Crenarchaeota
• nitrification
• ammonia monooxygenase
Salinispora is the first obligate marine genus within the order Actinomycetales and a productive source of biologically active secondary metabolites. Despite a worldwide, tropical or subtropical distribution
in marine sediments, only two Salinispora species have thus far been cultivated, suggesting limited species-level diversity. To further explore Salinispora diversity and distributions, the phylogenetic diversity of more than 350 strains isolated from sediments collected around
the Bahamas was examined, including strains cultured using new enrichment methods. A culture-independent method, using a Salinispora-specific seminested PCR technique, was used to detect Salinispora from environmental DNA and estimate diversity. Overall, the 16S rRNA gene sequence diversity of cultured strains agreed well
with that detected in the environmental clone libraries. Despite extensive effort, no new species level diversity was detected,
and 97% of the 105 strains examined by restriction fragment length polymorphism belonged to one phylotype (S. arenicola). New intraspecific diversity was detected in the libraries, including an abundant new phylotype that has yet to be cultured,
and a new depth record of 1,100 m was established for the genus. PCR-introduced error, primarily from Taq polymerase, significantly increased clone library sequence diversity and, if not masked from the analyses, would have led
to an overestimation of total diversity. An environmental DNA extraction method specific for vegetative cells provided evidence
for active actinomycete growth in marine sediments while indicating that a majority of sediment samples contained predominantly
Salinispora spores at concentrations that could not be detected in environmental clone libraries. Challenges involved with the direct
sequence-based detection of spore-forming microorganisms in environmental samples are discussed.
In this paper a novel multivariate method is proposed for the analysis of community response data from designed experiments repeatedly sampled in time. The long-term effects of the insecticide chlorpyrifos on the invertebrate community and the dissolved oxygen (DO)-pH-alkalinity-conductivity syndrome, in outdoor experimental ditches, are used as example data. The new method, which we have named the principal response curve method (PRC), is based on redundancy analysis (RDA), adjusted for overall changes in community response over time, as observed in control test systems. This allows the method to focus on the time-dependent treatment effects. The principal component is plotted against time, yielding a principal response curve of the community for each treatment. The PRC method distills the complexity of time-dependent, community-level effects of pollutants into a graphic form that can be appreciated more readily than the results of other currently available multivariate techniques. The PRC method also enables a quantitative interpretation of effects towards the species level.
During the treatment of fish diseases, drugs which inhibit the nitrification process can cause acute ammonia toxicity. The same phenomenon can occur when fish are put into a tank without active cultures of nitrifying bacteria. The purpose of this study was to quantify the inhibitory effects of 15 pharmacological agents, which are often used as therapeutic agents in ichthyopathology, on ammonia removal and nitrate production in a simple closed aquatic system. The experiments were conducted in polyethylene bags containing activated biofilters and synthetic water solutions, held in a water bath. Ammonia was added to initiate the nitrification process, and graded concentrations of various pharmacological agents were added. The effects of the pharmacological agents on in vitro nitrification were assessed by monitoring ammonia and nitrate concentrations compared to controls with no added agents, for 24 hours. Graded concentrations of ampicillin (Albipen®), chloramine T, enrofloxacin (Baytril®), erythromycin, levamisole, methylene blue and polymyxin B induced dose-dependent inhibitions of ammonia removal and nitrate production. The corresponding linear regression curves showed high correlation coefficients and were highly significant (p < 0.05). The addition of chloramphenicol, copper (II ) sulphate, kanamycin disulphate, malachite green, neomycin sulphate, potassium penicillin G, tetracycline and a mixture of trimethoprim and sulphadoxin (Duoprim™) had no significant effects on the nitrification process. A significant dose-related inhibition of nitrate production, but not of ammonia oxidation, was observed with enrofloxacin. The significant correlation (r = 0.940; p < 0.001) between the degrees of inhibition of ammonia oxidation and nitrate production for the various inhibitory pharmacological agents has also been calculated, with a view to validating this method. The data presented suggest that separate tank facilities for hospitalisation or quarantine are necessary when treating diseased fish with ampicillin, enrofloxacin, chloramine T, erythromycin, levamisole, methylene blue or polymyxin B, in order to avoid ammonia poisoning.
1999 FRAME.
