Concentration of organic contaminants in fish and their biological effects in a wastewater-dominated urban stream

Neurotoxicity of 4-nonylphenol in adult zebrafish: Evaluation of behaviour, oxidative stress parameters and histopathology of brain

Nonylphenol and its derivatives use as plasticizer or additives in manufacturing industries. Effluents originated from industrial areas are being added to soil, ground water, river and marine water intentionally or unintentionally. Complex mixture of these contaminants enter the food chain and produce sub-lethal deleterious effects mainly on nervous and reproductive systems of aquatic animals and human beings. The information pertaining to oxidative stress-mediated alterations in brain of zebrafish would be helpful to understand the toxicity potential of such compounds in aquatic animals. The aim of the present study was to evaluate the behavioural changes, status of oxidative stress markers; sod, cat, and NF-E2-related factor 2 (nrf2) mRNA gene expression profile; and histopathological changes in the brain of adult zebrafish exposed to 4-nonylphenol (4NP) at concentration of 100 and 200 μg/L of water for 21 days. Zebrafish were divided into four groups viz; control (C1), vehicle (C2, ethanol 10 μg/L of water), treatment 1 (T1, 4-NP, 100 μg/L) and treatment 2 (T2, 4-NP, 200 μg/L). Both exposure levels of 4-NP adversely affected the exploratory behaviour of zebrafish and produced anxiety-like symptom. Concentration-dependent reduction in activity of superoxide dismutase and catalase; and glutathione level, with increased level of malondialdehyde recorded in the brain of exposed zebrafish. Gene expression analysis showed down regulation of sod, cat, nrf2 genes in brain of zebrafish from toxicity groups indicating 4-NP induced oxidative stress in brain. However, noticeable histological alterations were not observed in 4-NP exposed brain of zebrafish.

An In Silico and In Vitro study for Investigating Estrogenic Endocrine Effects of Emerging Persistent Pollutants using Primary Hepatocytes from Grey Mullet (Mugil Cephalus)

There is growing concern about the environmentally relevant concentrations of new emerging persistent organic pollutants, such as perfluorinated compounds and pharmaceuticals, which are found to bioaccumulate in aquatic organisms at concentrations suspected to cause reproductive toxicity due to the activation of estrogen receptor (ER) α and β subtypes. Here, we use a combined in silico and in vitro approach to evaluate the impact of perfluorononanoic acid (PFNA) and Enalapril (ENA) on grey mullet (Mugil cephalus) hepatic estrogen signaling pathway. ENA had weak agonist activity on ERα while PFNA showed moderate to high agonist binding to both ERs. According to these effects, hepatocytes incubation for 48 h to PFNA resulted in a concentration-dependent upregulation of ER and vitellogenin gene expression profiles, whereas only a small increase was observed in ERα mRNA levels for the highest ENA concentration. These data suggest a structure–activity relationship between hepatic ERs and these emerging pollutants.

17α-ethinylestradiol and 4-tert-octylphenol concurrently disrupt the immune response of common carp

The aquatic environment is massively polluted with endocrine-disrupting compounds (EDCs) including synthetic estrogens (e.g. 17α-ethinylestradiol, EE2) and alkylphenols (e.g. 4-tert-octylphenol, 4t-OP). A major mechanism of action for estrogenic EDCs is their interaction with estrogen receptors and consequently their modulation of the action of enzymes involved in steroid conversion e.g. aromatase CYP19. We now studied the effects of EE2 and 4t-OP on the anti-bacterial immune response of common carp. We investigated effects on the number/composition of inflammatory leukocytes and on the gene expression of mediators that regulate inflammation and EDC binding. In vitro we found that high concentrations of both EE2 and 4t-OP down-regulated IFN-γ2 and IFN-γ-dependent immune responses in LPS-stimulated monocytes/macrophages. Similarly, during bacterial infection in fish, in vivo treated with EE2 and 4t-OP, decreased gene expression of il-12p35 and of ifn-γ2 was found in the focus of inflammation. Moreover, during A. salmonicida-induced infection in EE2-treated carp, but not in fish fed with 4t-OP-treated food, we found an enhanced inflammatory reaction manifested by high number of inflammatory peritoneal leukocytes, including phagocytes and higher expression of pro-inflammatory mediators (inos, il-1β, cxcl8_l2). Furthermore, in the liver, EE2 down-regulated the expression of acute phase proteins: CRPs and C3. Importantly, both in vitro and in vivo, EDCs altered the expression of estrogen receptors: nuclear (erα and erβ) and membrane (gpr30). EDCs also induced up-regulation of the cyp19b gene. Our findings reveal that contamination of the aquatic milieu with estrogenic EDCs, may considerably violate the subtle and particular allostatic interactions between the immune response and endogenous estrogens and this may have negative consequences for fish health.

Correlating effluent concentrations and bench-scale experiments to assess the transformation of endocrine active compounds in wastewater by UV or chlorination disinfection

Transformation of endocrine active compounds (EACs) by either chlorination (Cl-D) or UV disinfection (UV-D) was studied by field sampling and bench-scale validation studies. Field testing assessed concentration of 13 EACs in effluent at two Chicago area 250 MGD wastewater reclamation plants (WRP) over two years. One WRP uses chlorination/dechlorination while the other employs UV disinfection. Target compounds included bupropion, carbamazepine, citalopram, duloxetine, estradiol, estrone, fluoxetine, nonylphenol, norfluoxetine, norsertraline, paroxetine, sertraline, and venlafaxine. Concentrations of 9/13 target compounds were partially reduced after disinfection (5-65% reduction). None of the target compounds were fully transformed by either chlorination or UV treatment at the WRP scale. In bench-scale experiments each compound was spiked into deionized water or effluent and treated in a process mimicking plant-scale disinfection to validate transformations. Correlation was observed between compounds that were transformed in bench-testing and those that decreased in concentration in post-disinfection WRP effluent (10/13 compounds). A survey of potential reaction products was made. Chlorination of some amine containing compounds produced chloramine by-products that reverted to the initial form after dechlorination. Transformation products produced upon simulated UV disinfection were more diverse. Laboratory UV-induced transformation was generally more effective under stirred conditions, suggesting that indirect photo-induced reactions may predominate over direct photolysis.

Threshold Responses in the Taxonomic and Functional Structure of Fish Assemblages to Land Use and Water Quality: A Case Study from the Taizi River

Biological functional traits help to understand specific stressors that are ignored intaxonomic data analysis. A combination of biological functional traits and taxonomic data ishelpful in determining specific stressors which are of significance for fish conservation and riverbasin management. In the current study, the Taizi River was used as a case study to understand therelationships between the taxonomic and functional structure of fish and land use and waterquality, in addition to determining the thresholds of these stressors. The results showed thattaxonomic structure was significantly affected by the proportion of urban land and specificconductivity levels, while functional metrics were influenced by the proportions of farmland andforest. Threshold indicator taxa analysis found that Phoxinus lagowskii, Barbatula barbatula nuda,Odontobutis obscura, and Cobitis granoei had negative threshold responses along the gradients ofurban developments and specific conductivity. There was a significant change in fish taxonomiccomposition when the proportion of urban land exceeded a threshold of 2.6–3.1%, or specificconductivity exceeded a threshold of 369.5–484.5 μS/cm. Three functional features—habitatpreference, tolerance to disturbances, and spawning traits—showed threshold responses to theproportion of farmland and forest. The abundance of sensitive species should be monitored as partof watershed management, as sensitive species exhibit an earlier and stronger response to stressorsthan other functional metrics. Sensitive species had a positive threshold response to the proportionof forest at 80.1%. These species exhibited a negative threshold response to the proportion offarmland at 13.3%. The results of the current study suggest that the taxonomic and functionalstructure of fish assemblages are affected by land use and water quality. These parameters shouldbe integrated into routine monitoring for fish conservation and river basin management in the TaiziRiver. In addition, corresponding measures for improving river habitat and water quality shouldbe implemented according to the thresholds of these parameters.

Indicators of exposure to estrogenic compounds at Great Lakes Areas of Concern: species and site comparisons

Adverse effects resulting from potential exposure of wild fishes to estrogenic endocrine disruptors were assessed at seven United States Great Lakes Areas of Concern using biomarkers ranging from organismal (gonadosomatic indices) to tissue/plasma (histology, plasma vitellogenin) and molecular (hepatic gene transcripts) levels. Biomonitoring was conducted on pelagic, top predator species, largemouth Micropterus salmoides and smallmouth M. dolomieu bass and benthic, omnivorous white sucker Catostomus commersonii. Seasonal (spring and fall) comparisons were conducted at select sites. Intersex (testicular oocytes), plasma vitellogenin, and hepatic vitellogenin transcripts were commonly observed in bass species. Testicular oocyte severity was positively, although weakly, correlated with plasma vitellogenin, hepatic transcripts of vitellogenin, estrogen receptor α, and estrogen receptor β2, while negatively correlated with androgen receptor β and phosphoenolpyruvate carboxykinase. No testicular oocytes were observed in white sucker; however, plasma vitellogenin and hepatic vitellogenin transcripts were commonly detected in the males. The results demonstrate the importance of utilizing multiple endpoints to assess exposure to estrogenic compounds as well as the importance of choosing sensitive species.

Water contamination by endocrine disruptors: Impacts, microbiological aspects and trends for environmental protection

Hormone active agents constitute a dangerous class of pollutants. Among them, those agents that mimic the action of estrogens on target cells and are part of the group of endocrine-disruptor compounds (EDCs) are termed estrogenic EDCs, the main focus of this review. Exposure to these compounds causes a number of negative effects, including breast cancer, infertility and animal hermaphroditism. However, especially in underdeveloped countries, limited efforts have been made to warn people about this serious issue, explain the methods of minimizing exposure, and develop feasible and efficient mitigation strategies at different levels and in various environments. For instance, the use of bioremediation processes capable of transforming EDCs into environmentally friendly compounds has been little explored. A wide diversity of estrogen-degrading microorganisms could be used to develop such technologies, which include bioremediation processes for EDCs that could be implemented in biological filters for the post-treatment of wastewater effluent. This review describes problems associated with EDCs, primarily estrogenic EDCs, including exposure as well as the present status of understanding and the effects of natural and synthetic hormones and estrogenic EDCs on living organisms. We also describe potential biotechnological strategies for EDC biodegradation, and suggest novel treatment approaches for minimizing the persistence of EDCs in the environment.

Contaminants of emerging concern in tributaries to the Laurentian Great Lakes: II. Biological consequences of exposure

The Laurentian Great Lakes contain one fifth of the world's surface freshwater and have been impacted by human activity since the Industrial Revolution. In addition to legacy contaminants, nitrification and invasive species, this aquatic ecosystem is also the recipient of Contaminants of Emerging Concern (CECs) with poorly understood biological consequences. In the current study, we documented the presence, concentrations, and biological effects of CECs across 27 field sites in six Great Lakes tributaries by examining over 2250 resident and caged sunfish (Lepomis ssp.) for a variety of morphological and physiological endpoints and related these results to CEC occurrence. CEC were ubiquitous across studies sites and their presence and concentrations in water and sediment were highest in effluent dominated rivers and downstream of municipal wastewater treatment plant discharges. However, even putative upstream reference sites were not free of CEC presence and fish at these sites exhibited biological effects consistent with CEC exposure. Only the Fox River exhibited consistent adverse biological effects, including increased relative liver size, greater prominence of hepatocyte vacuoles and increased plasma glucose concentrations. Canonical Redundancy Analysis revealed consistent patterns of biological consequences of CEC exposure across all six tributaries. Increasing plasma glucose concentrations, likely as a result of pollutant-induced metabolic stress, were associated with increased relative liver size and greater prominence of hepatocyte vacuoles. These indicators of pollutant exposure were inversely correlated with indicators of reproductive potential including smaller gonad size and less mature gametes. The current study highlights the need for greater integration of chemical and biological studies and suggests that CECs in the Laurentian Great Lakes Basin may adversely affect the reproductive potential of exposed fish populations.

Seasonal antioxidant responses in the sea urchin Paracentrotus lividus (Lamarck 1816) used as a bioindicator of the environmental contamination in the South-East Mediterranean

In this study, sea urchin Paracentrotus lividus were sampled seasonally at three stations during 2012 in the coastal areas of the Gulf of Annaba (southeast Mediterranean). For all sea urchins, the gonad index was calculated to determine sea urchin reproductive status. Moreover, a set of biochemical parameters, including biomarkers and oxidative stress parameters, was measured in gonads. The pesticides and physiochemical parameters were measured and dosed in sea water. The results obtained highlighted that the levels of pesticide were generally low and below those commonly applied by environmental quality standards (EQS), indicating that no alarm state is currently present in the Gulf of Annaba. In addition to pollution, seasonal change is an important factor influencing biomarker activity, and the significant increases in biomarker levels in spring are a major observed trend. This activity may also be related to reproductive status. Seasonal variability was confirmed by the significant results of the Kruskal-Wallis test and by the high degree of divergence between seasons in PCA, with a total of 83.83% of variance explained. These results indicate that environmental factors that vary seasonally may affect the antioxidant status of the sea urchin Paracentrotus lividus.

Endocrine active contaminants in aquatic systems and intersex in common sport fishes

Male fish are susceptible to developing intersex, a condition characterized by the presence of testicular oocytes. In the present study, the relationship between intersex and exposure to estrogenic endocrine active contaminants (EACs) was assessed for 2 genera of sport fish, Micropterus and Lepomis, at 20 riverine sites. Seasonal trends and relationships between EACs and intersex (prevalence and severity) were examined at varying putative sources of EACs throughout North Carolina, identified as point sources, nonpoint sources, and reference sites. Intersex was identified in both genera, which was documented for the first time in wild-caught Lepomis. Intersex was more prevalent (59.8%) and more severe (1.6 mean rank) in Micropterus, which was highly correlation to EACs in sediment. In contrast, intersex was less common (9.9%) and less severe (0.2 mean rank) in Lepomis and was highly correlated to EACs in the water column. The authors found that concentrations of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, industrial EACs, and estrogens were highest at point source sites; however, no source type variation was identified in the prevalence or severity of intersex, nor were there seasonal trends in intersex or EAC concentrations. The authors' results associate genus-specific prevalence of intersex with specific EAC classes in common sport fishes having biological, ecological, and conservation implications. Environ Toxicol Chem 2017;36:959-968. © 2016 SETAC.

Sharing the Roles: An Assessment of Japanese Medaka Estrogen Receptors in Vitellogenin Induction

Teleost fish express at least three estrogen receptor (ER) subtypes. To date, however, the individual role of these ER subtypes in regulating expression of estrogen responsive genes remains ambiguous. Here, we investigate putative roles of three ER subtypes in Japanese medaka (Oryzias latipes), using vitellogenin (VTG) I and II as model genes. We identify specific ligand/receptor/promoter dynamics, using transient transactivation assays that incorporate luciferase reporters comprising 3kb promoter/enhancer regions of medaka VTGI and VTGII genes. Four steroidal estrogens (17β-estradiol, estrone, estriol, and 17α-estradiol) were tested in these assays. Results indicate that all three medaka ERs (mERs) are capable of initiating transactivation of both VTG I and II, with ERβ2 exhibiting greatest activity. Promoter deletion analysis suggests that ligand-specific receptor transactivation and utilization of regional-specific estrogen response elements may be associated with differential activities of each medaka ER. Further, cluster analysis of in vivo gene expression and in vitro transactivation suggests that all three ER subtypes putatively play a role in up-regulation of VTG. Results illustrate that preferential ligand/receptor/promoter interactions may have direct implications for VTG gene expression and other ER-mediated regulatory functions that are relevant to the risk assessment of estrogenic compounds.

Impact of treated wastewater reuse and floods on water quality and fish health within a water reservoir in an arid climate

Treated wastewater (TWW) reuse for agricultural irrigation is a well-established approach to coping with water shortages in semi-arid and arid environments. Recently, additional uses of TWW have emerged, including streamflow augmentation and aquatic ecosystem restoration. The purpose of the current study was to evaluate the water quality and fish health, in an artificial reservoir located in an arid climate (the Yeruham Reservoir, Israel), which regularly receives TWW and sporadic winter floods. The temporal distribution of water levels, nutrients and organic micropollutants (OMPs) were measured during the years 2013-2014. OMPs were also measured in sediment and fish tissues. Finally, the status of fish health was evaluated by histopathology. Water levels and quality were mainly influenced by seasonal processes such as floods and evaporation, and not by the discharge of TWW. Out of 16 tested OMPs, estrone, carbamazepine, diclofenac and bezafibrate were found in the reservoir water, but mostly at concentrations below the predicted no-effect concentration (PNEC) for fish. Concentrations of PCBs and dioxins in fish muscle and liver were much lower than the EU maximal permitted concentrations, and similar to concentrations that were found in food fish in Israel and Europe. In the histopathological analysis, there were no evident tissue abnormalities, and low to moderate infection levels of fish parasites were recorded. The results from the Yeruham Reservoir demonstrated a unique model for the mixture effect between TWW reuse and natural floods to support a unique stable and thriving ecosystem in a water reservoir located in an arid region. This type of reservoir can be widely used for recreation, education, and the social and economic development of a rural environment, such as has occurred in the Yeruham region.

ATR-FTIR spectroscopy reveals polycyclic aromatic hydrocarbon contamination despite relatively pristine site characteristics: Results of a field study in the Niger Delta

Fourier-transform infrared (FTIR) spectroscopy is an emerging technique to detect biochemical alterations in biological tissues, particularly changes due to sub-lethal exposures to environmental contaminants. We have previously shown the potential of attenuated total reflection FTIR (ATR-FTIR) spectroscopy to detect real-time exposure to contaminants in sentinel organisms as well as the potential to relate spectral alterations to the presence of specific environmental agents. In this study based in the Niger Delta (Nigeria), changes occurring in fish tissues as a result of polycyclic aromatic hydrocarbon (PAH) exposure at contaminated sites are compared to the infrared (IR) spectra of the tissues obtained from a relatively pristine site. Multivariate analysis revealed that PAH contamination could be occurring at the pristine site, based on the IR spectra and significant (P<0.0001) differences between sites. The study provides evidence of the IR spectroscopy techniques' sensitivity and supports their potential application in environmental biomonitoring.

Endocrine disrupting alkylphenolic chemicals and other contaminants in wastewater treatment plant effluents, urban streams, and fish in the Great Lakes and Upper Mississippi River Regions

Urban streams are an integral part of the municipal water cycle and provide a point of discharge for wastewater treatment plant (WWTP) effluents, allowing additional attenuation through dilution and transformation processes, as well as a conduit for transporting contaminants to downstream water supplies. Domestic and commercial activities dispose of wastes down-the-drain, resulting in wastewater containing complex chemical mixtures that are only partially removed during treatment. A key issue associated with WWTP effluent discharge into streams is the potential to cause endocrine disruption in fish. This study provides a long-term (1999-2009) evaluation of the occurrence of alkylphenolic endocrine disrupting chemicals (EDCs) and other contaminants discharged from WWTPs into streams in the Great Lakes and Upper Mississippi River Regions (Indiana, Illinois, Michigan, Minnesota, and Ohio). The Greater Metropolitan Chicago Area Waterways, Illinois, were evaluated to determine contaminant concentrations in the major WWTP effluents and receiving streams, and assess the behavior of EDCs from their sources within the sewer collection system, through the major treatment unit processes at a WWTP, to their persistence and transport in the receiving stream. Water samples were analyzed for alkylphenolic EDCs and other contaminants, including 4-nonylphenol (NP), 4-nonylphenolpolyethoxylates (NPEO), 4-nonylphenolethoxycarboxylic acids (NPEC), 4-tert-octylphenol (OP), 4-tert-octylphenolpolyethoxylates (OPEO), bisphenol A, triclosan, ethylenediaminetetraacetic acid (EDTA), and trace elements. All of the compounds were detected in all of the WWTP effluents, with EDTA and NPEC having the greatest concentrations. The compounds also were detected in the WWTP effluent dominated rivers. Multiple fish species were collected from river and lake sites and analyzed for NP, NPEO, NPEC, OP, and OPEO. Whole-body fish tissue analysis indicated widespread occurrence of alkylphenolic compounds, with the highest concentrations occurring in streams with the greatest WWTP effluent content. Biomarkers of endocrine disruption in the fish indicated long-term exposure to estrogenic chemicals in the wastewater impacted urban waterways.

Identifying non-point sources of endocrine active compounds and their biological impacts in freshwater lakes

Contaminants of emerging concern, particularly endocrine active compounds (EACs), have been identified as a threat to aquatic wildlife. However, little is known about the impact of EACs on lakes through groundwater from onsite wastewater treatment systems (OWTS). This study aims to identify specific contributions of OWTS to Sullivan Lake, Minnesota, USA. Lake hydrology, water chemistry, caged bluegill sunfish (Lepomis macrochirus), and larval fathead minnow (Pimephales promelas) exposures were used to assess whether EACs entered the lake through OWTS inflow and the resultant biological impact on fish. Study areas included two OWTS-influenced near-shore sites with native bluegill spawning habitats and two in-lake control sites without nearby EAC sources. Caged bluegill sunfish were analyzed for plasma vitellogenin concentrations, organosomatic indices, and histological pathologies. Surface and porewater was collected from each site and analyzed for EACs. Porewater was also collected for laboratory exposure of larval fathead minnow, before analysis of predator escape performance and gene expression profiles. Chemical analysis showed EACs present at low concentrations at each study site, whereas discrete variations were reported between sites and between summer and fall samplings. Body condition index and liver vacuolization of sunfish were found to differ among study sites as did gene expression in exposed larval fathead minnows. Interestingly, biological exposure data and water chemistry did not match. Therefore, although results highlight the potential impacts of seepage from OWTS, further investigation of mixture effects and life history factor as well as chemical fate is warranted.

Caged mudsnail Potamopyrgus antipodarum (Gray) as an integrated field biomonitoring tool: exposure assessment and reprotoxic effects of water column contamination

This study highlights the usefulness of gastropods for water quality monitoring. Gastropods were caged upstream and downstream of an effluent discharge. Exposure was assessed by measurement of organic contaminants in water. Contamination of the Potamopyrgus antipodarum mudsnail was also measured using innovative techniques at the end of the 42 days of exposure. Biological effects were measured at the individual level (growth, reproduction) and subindividual level (energy reserves, vitellin-like proteins, steroid levels, expression of genes involved in estrogen signaling pathways), thus providing a better understanding of reprotoxic effects. The effluent was mainly contaminated by pharmaceutical compounds, as was the mudsnail. The highest concentrations were measured for oxazepam and were higher than 2 mg/kg downstream of the effluent discharge. Alkylphenols, bisphenol A, and vertebrate-like sex-steroid hormones were also bioaccumulated by the mudsnail downstream of the effluent. The combined use of water and snail contamination provided a complete exposure assessment. Exposure was further linked to biological effects. The mudsnail was shown to be a better adapted species for in situ exposures than Valvata piscinalis. Reproduction was sharply decreased after 6 weeks of exposure in the mudsnail. Feeding issues were excluded, confirming the toxic origin. These effects were related to estrogen signaling pathways using genomic analysis. Genes coding for proteins involved in nongenomic signaling pathways were inhibited, and those of genomic pathway repressors were induced. These results suggest that the chemical contamination due to the effluent discharge altered steroid control of reproduction and blocked the transition between oocyte and unshelled embryo, resulting in a drastic decrease of embryo production, while survival was not affected.

Environmental estrogens in an urban aquatic ecosystem: II. Biological effects

Urban aquatic ecosystems are often overlooked in toxicological studies even though they serve many ecosystem functions and sustain fish populations despite large-scale habitat alterations. However, urban fish populations are likely exposed to a broad range of stressors, including environmental estrogens (EEs) that may affect anatomy, physiology and reproduction of exposed fish. Although significant progress has been made in establishing ecological consequences of EE exposure, these studies have focused largely on hydrologically simple systems that lack the complexity of urban aquatic environments. Therefore, the objective of this study was to assess the occurrence and biological effects of EEs across a large urbanized aquatic ecosystem. A multi-pronged study design was employed relying on quantitative determination of select EEs by liquid chromatography tandem mass spectrometry and repeated biological monitoring of wild-caught and caged fish for indications of endocrine disruption. Over three years, EEs were measured in aqueous samples (n=42 samples) and biological effects assessed in >1200 male fish across the 2000km(2) aquatic ecosystems of the Greater Metropolitan Area of Chicago, IL. Our study demonstrated that in addition to water reclamation plant (WRP) effluents, non-WRP sources contribute significant EE loads to the aquatic ecosystem. While resident and caged male fish responded with the induction of the egg-yolk protein vitellogenin, an indicator of EE exposure, neither resident nor caged sunfish exhibited prevalent histopathological changes to their reproductive organs (i.e., intersex) that have been reported in other studies. Vitellogenin induction was greater in spring than the fall and was not correlated with body condition factor, gonadosomatic index or hepatosomatic index. Exposure effects were not correlated with sites downstream of treated effluent discharge further affirming the complexity of sources and effects of EEs in urban aquatic ecosystems.

Environmental estrogens in an urban aquatic ecosystem: I. Spatial and temporal occurrence of estrogenic activity in effluent-dominated systems

The present study investigated occurrence of environmental estrogens (EEs) in waterways managed by the Metropolitan Water Reclamation District of Greater Chicago ('District') - one of the largest and most complex water districts in the United States. The objectives of the study were: (i) to document spatial and temporal occurrence of EEs in the Chicago Area Waterways (CAWs); (ii) to determine whether water reclamation plant (WRP) effluents contribute to estrogenic pollution of the receiving streams; (iii) to determine whether the mandated water quality monitoring data could be used to predict estrogenic pollution in the receiving streams; and (iv) to determine whether snow melt, storm runoff and combined sewer overflows may also be contributors of estrogenic activity to these systems. The estrogenic potency of the waterways was assessed using a cell-based reporter gene assay. The water quality data was readily available as part of the District's regular monitoring program. Our findings indicate that EEs are commonly found in the CAWs, and that WRP effluents are one of, but not the only important contributor to estrogenic activity. Mean estrogenic activities in CAWs (11ng estradiol equivalents (EEQs/L)) are well within the values reported for other urban areas and WRP effluents. The estrogenic activity exhibited significant seasonal variation with highest values noted during the spring and summer months. When comparing the mean estrogenic activity of general use waters, secondary contact waters and WRP effluents, we found that general use waters had significantly lower estrogenic activity (ca 5ng EEQ/L) than the other two matrices (ca 15 and 17ng EEQ/L respectively). Our analyses indicate that estrogenic activity of the waterways was not reliably associated with mandated water quality parameters, and that such measurements may not be useful for predicting estrogenic activity, especially so in the complex urban systems. One of the prominent findings of this study is that EEs do not follow predictable spatial patterns - many of the upstream sites in the heavily urbanized areas had levels of estrogenic activity comparable to those found in the effluents and downstream locations. Our data suggest that surface runoff and snow melt are estrogenic (0-9ng EEQ/L), and given that their estrogenic activities are similar to those of their receiving waterways (0-7ng EEQ/L), we conclude that these non-WRP sources are important contributors to estrogenic activity of the CAWs.

The presence of EU priority substances mercury, hexachlorobenzene, hexachlorobutadiene and PBDEs in wild fish from four English rivers

Since 2007 about 200 to 300 fish per year--generally roach (Rutilus rutilus) also a few bleak (Alburnus alburnus) and eels (Anguilla anguilla)--have been collected from a number of English river sites and stored at -80°C to build up a Fish Tissue Archive as a resource for the monitoring of pollutants. Some of the fish from the Fish Tissue Archive from the years 2007-2011 were analyzed for substances in current and proposed European legislation regarding environmental quality standards (EQS) in biota. It was found that mercury exceeded the EU EQS of 20 μg/kg in 79% of samples with an average and median of 31 and 29 μg/kg. The legacy fungicide hexachlorobenzene (HCB) was below the EQS of 10 μg/kg in all fish analyzed, with a maximum of 6 μg/kg in some eels. The legacy solvent hexachlorobutadiene (HCBD) was below the EQS of 55 μg/kg, being <0.2 μg/kg in all samples where it was measured. The sums of six polybrominated diphenyl ethers (PBDEs) were several orders of magnitude higher than the new proposed 0.0085 μg/kg biota EQS. This study showed that the regular collection and analysis of whole body homogenate samples of relatively small native pelagic fish is suitable for the monitoring of contaminants capable of bioaccumulation. With regard to current or proposed EQS for EU countries, mercury and potentially PBDE in fish are of some concern in these English rivers.