Endocrine disruption and health effects of caged mussels, Elliptio complanata, placed downstream from a primary-treated municipal effluent plume for 1 year

The influence of rainfall events on the toxicity of urban wastewaters to freshwater mussels Elliptio complanata

The cumulative impacts of rainfall frequency and intensity towards the ecotoxicity of urban pollution is gaining more and more attention in these times of climate change. The purpose of this study was to examine the ecotoxicological impacts of combined sewers overflows and municipal effluent discharge sites during 3 periods (years) of varying intensity precipitations to freshwater mussels Elliptio complanata. Mussels were placed in benthic cages for 3 months during the summer at 2 overflow discharge and 8 km downstream sites including an upstream site for three consecutive years with low (164 mm), medium (182 mm) and high (248 mm) amounts of rain. The results revealed that the effects were mainly influenced by suspended matter loadings and to the dissolved components to a lesser extent. Impacts at the downstream and overflow sites were noticeable at the reproduction (vitellogenin), genotoxicity, neurotoxicity (dopamine and serotonin changes) levels in addition to xenobiotic biotransformation revealed by glutathione S-transferase activity and metallothioneins for organic and heavy metals respectively. The site downstream the effluent produced most of the effects compared to the overflow sites in the Saint-Lawrence River. However, the impacts of combined sewers overflows could become problematic in low dilution systems such as small river and lakes.

The Comet Assay, a Sensitive Biomarker of Water Quality Improvement Following Adoption of Beneficial Agricultural Practices?

Numerous actions have been undertaken by farmers to attenuate the impact of agricultural activities on aquatic ecosystems. The identification of biomarkers that respond quickly to water quality improvement could facilitate the assessment of adopted alternative practices and help maintain mobilization among stakeholders. We evaluated the potential of the comet assay, a biomarker of genotoxic effects, using a freshwater mussel, Elliptio complanata, as a model animal. The frequency of DNA damage was assessed in hemocytes of mussels collected from a pristine habitat and caged for 8 weeks in the Pot au Beurre River, a tributary of the fluvial Lake St.-Pierre (Quebec, Canada) impacted by agricultural activities. We found that the level of DNA damage naturally induced in mussel hemocytes was low and showed very limited variations over time. Compared with these baseline levels and to laboratory controls, we observed a doubling in DNA alterations in mussels exposed to agricultural runoff in the third branch of the Pot au Beurre River. The genotoxic response was significantly lower in mussels caged in the first branch of the Pot au Beurre River, where longer stretches of shoreline have been restored as buffer strips. Glyphosate, mesotrione, imazethapyr, and metolachlor were the main discriminant pesticides between these two branches. Metolachlor was found in sufficient concentrations to induce DNA damage, but it is more likely that the observed genotoxicity was the result of a "cocktail effect," that is, the cumulative contribution of coexisting genotoxicants including the above-mentioned herbicides and ingredients in their formulation. Our findings suggest that the comet assay is a sensitive tool for the early detection of changes in water toxicity following the adoption of agricultural beneficial practices. Environ Toxicol Chem 2023;42:2201-2214. © 2023 Crown copyright and The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article is published with the permission of the Controller of HMSO and the King's Printer for Scotland.

Comparative toxicity of urban wastewater and rainfall overflow in caged freshwater mussel Elliptio complanata

Municipal effluents are well-recognized as disrupting sexual differentiation and reproduction in mussels. However, the contribution to this problem made by rainfall combined with sewer overflow (increased by rain due to climate change) is not well understood. The purpose of this study was to compare the neuroendocrine effects of municipal discharge and rainfall overflow on caged endemic mussel Elliptio complanata. To this end, mussels were experimentally caged and placed for 3 months at a municipal effluent dispersion plume site and at overflow sites. Data revealed that downstream surface water contained some pharmaceuticals (caffeine and carbamazepine) and accumulated significant levels of heterotrophic bacteria, but these effects were not observed at the overflow sites. The principal effects observed at the downstream site were increased soft tissue mass (and gonad index), inflammation, and Vtg proteins in male mussels as determined by a novel immunostaining methodology. The rainfall overflow sites had no effects on these markers, but were specifically associated with reduced Vtg proteins in females, dopamine (Dop), gonad lipids, and DNA strand breaks, with increased metallothioneins. In conclusion, the observed feminizing effects of municipal effluent were not additionally observed in mussels caged at rainfall overflow sites, although the latter exhibited a different pattern of toxicity.

Potamopyrgus antipodarum has the potential to detect effects from various land use activities on a freshwater ecosystem

Identifying risks to ecosystems from contaminants needs a diversity of bioindicators, to understand the effects of these contaminants on a range of taxa. Molluscs are an ideal bioindicator because they are one of the largest phyla with extremely high ecological and economic importance. The aim of this study was to evaluate if laboratory bred Potamopyrgus antipodarum has the potential to show the impact of contaminants from various land use activities and degree of pollution on a freshwater ecosystem. We assessed the impact of contaminants arising from runoff and direct discharges in Merri Creek by measuring organism level responses (survival, growth, and reproduction), and sub-organism level responses (glutathione S-transferase (GST) activity, lipid peroxidation (LPO) activity and catalase (CAT) activity) in snails after 28-d of deployment at nine sites in Merri Creek and one site in Cardinia Creek. In Merri Creek, the top two sites were reference sites (with low impact from human activities), while the rest were impact sites (impacted by various anthropogenic land uses). Cardinia Creek (an additional reference site) had lower human activity. High concentrations of heavy metals, nutrients, and/or synthetic pyrethroids (bifenthrin) dominated these sites, which are likely to have contributed towards the negative responses observed in the snails. There was little influence from environmental conditions and site location on the endpoints because we found a similar response at an additional reference site compared to the reference sites in Merri Creek. At the organism level, reproduction increased and/or reduced, while CAT was affected at the sub-organism level. Potamopyrgus antipodarum has the potential to be a sensitive bioindicator for Australian conditions because the snails responded to varying concentrations of contaminants across different land use activities and showed similar sensitivity to P. antipodarum found in other regions of the globe and other bioindicators.

A multibiomarker approach to assess toxic effects of wastewater treatment plant effluents and activated defence mechanisms in marine (Ruditapes philippinarum) and fresh water (Corbicula fluminea) bivalve species

Since it has been demonstrated that urban effluents can have adverse effects on aquatic organisms, a multibiomarker study was used to evaluate the effects of wastewater treatment plant (WWTP) effluents discharged into the marine and freshwater environments on clams in Cádiz, Spain. One bioassay was performed in the Bay of Cádiz, exposing Ruditapes philippinarum (marine) to a reference site as well as two sites close to WWTP discharges for 14 days. A second bioassay was performed in the Guadalete River, exposing Corbicula fluminea (fresh water) to three sites for 21 days. The biomarkers analysed included defence mechanisms and various toxic effects. Results indicated that WWTP effluents activated defence mechanisms and induced toxic effects in clams exposed to both environments, thus indicating bioavailability of contaminants present in water. Elevated enzymatic activity was found in clams deployed in La Puntilla and El Trocadero compared to control clams and those exposed to the reference site, and 96% of clams deployed at G2 in the Guadalete River died before day 7. Clams exposed to G1 and G3 indicated significant differences in all biomarkers analysed with respect to control clams (p < 0.05). Both species were sensitive to contaminants present in studied sites. This is the first time that these species were used in cages to assess the environmental risk of wastewater effluent discharges in freshwater and marine column environments. The multibiomarker approach provided important ecotoxicological information and is useful for the assessment of the bioavailability and effect of contaminants from WWTP effluents on marine and fresh water invertebrates.

Metabolomics approach reveals disruption of metabolic pathways in the marine bivalve Mytilus galloprovincialis exposed to a WWTP effluent extract

Conventional wastewater treatment plants (WWTPs) discharge a highly diverse range of organic contaminants in aquatic environments, including marine waters. The health of marine ecosystems could be threatened by contaminants release. Environmental metabolomics can be helpful to assess the effects of multi-contamination on marine organisms without any a priori information since it is able to provide meaningful information on the biochemical response of organisms to a stress. The aim of the present study was to evaluate the potential of metabolomics to highlight key metabolites disrupted by a WWTP effluent extract exposure and then elucidate the biological effects of such exposure on Mediterranean mussels (Mytilus galloprovincialis). Exposed male mussels showed numerous metabolites altered in response to WWTP effluent exposure. The highlighted metabolites belong mainly to amino acids metabolism (e.g. tyrosine, phenylalanine, leucine, proline, etc.), neurohormones (dopamine and a serotonin metabolite), purine and pyrimidine metabolism (e.g. adenosine, adenine, guanine, uracil etc.), citric acid cycle intermediates (e.g. malate, fumarate), and a component involved in oxidative stress defense (oxidized glutathione). Modulation of these metabolites could reflect the alteration of several biological processes such as energy metabolism, DNA and RNA synthesis, immune system, osmoregulation, byssus formation and reproduction, which may lead to a negative impact of organism fitness. Our study provided further insight into the effects of WWTP effluents on marine organisms.

Sensitivity to cadmium of the endangered freshwater pearl mussel Margaritifera margaritifera from the Dronne River (France): experimental exposure

Margaritifera margaritifera is a critically endangered species in Europe. Among the causes explaining its decline, metal pollution had never been deeply studied. Thus, an ecotoxicological investigation was developed on this species which comes from the Dronne River (South-West of France). Cadmium (Cd) exposure of mussels at 2 and 5 μg/L for 7 days was conducted to test their vulnerability to this metal, and also the potential endocrine disruption power of Cd. Morphometric analyses, gonad histological observations, metal bioaccumulation, metallothionein (MTs) production, measures of malondialdehyde (MDA), and finally quantitative relative expression analysis of genes involved in various metabolic functions were performed.The main results showed Cd accumulation increasing in a dose-dependent manner, especially in the gills. The same trend was observed for gene expression relative to oxidative stress. Histological analysis of the gonads highlighted a predominance of hermaphrodite individuals, but after 7 days of exposure to Cd, the percentage of female was largely increased compared with controls, from 17 to 33%. These results demonstrate the endocrine disruption effect of Cd on freshwater pearl mussels.The pearl mussel Margaritifera margaritifera is sensitive to cadmium since the metallothioneins are poorly induced, gene expression reveals oxidative stress, and gonads tend to be feminized.

Populations Collapses in Marine Invertebrates Due to Endocrine Disruption: A Cause for Concern?

In the beginning of the twenty first century, the International Program on Chemical Safety published a document entitled Global Assessment of the State-Of-The-Science of Endocrine Disruptors. The work indicated only weak evidence of endocrine-related effects in human populations, and in wild animal populations. This document was revised in 2012 (State of the Science of Endocrine Disrupting Chemicals-2012) (1). The new document and the extensive scientific evidence it provided showed clearly that ED effects could be a risk to human and wildlife health. These works, however, were focused in human health and related animal models, mainly vertebrates and particularly mammals. It can be argued that invertebrates and many other taxa are important parts of all ecosystems, and, in many instances, have been shown to be also vulnerable to endocrine disruption. Thus, this work is aimed to show some observations on important marine invertebrate taxa, from an ecological point of view. The most important example of endocrine disruption in marine wild populations is the imposex response of marine gastropods, known for more than 40 years, and worldwide used to evaluate marine antifouling pollution. Among the mollusks, other important natural resources are bivalve species, used as human food sources and cephalopods, free-living, highly specialized mollusks, and also human food sources. Effects derived from endocrine disruptors in these species indicate that consumption could bring these compounds to human populations in an almost direct way, sometimes without any form of cooking or preparation. While discussing these questions, this work is also aimed to stimulate research on endocrine disruption among the invertebrate taxa that inhabited our oceans, and on which these effects are poorly known today.

The utility of vitellogenin as a biomarker of estrogenic endocrine disrupting chemicals in molluscs

Estrogenic endocrine disrupting chemicals (EDCs) are natural hormones, synthetic compounds or industrial chemicals that mimic estrogens due to their structural similarity with estrogen's functional moieties. They typically enter aquatic environments through wastewater treatment plant effluents or runoff from intensive livestock operations. Globally, most natural and synthetic estrogens in receiving aquatic environments are in the low ng/L range, while industrial chemicals (such as bisphenol A, nonylphenol and octylphenol) are present in the μg to low mg/L range. These environmental concentrations often exceed laboratory-based predicted no effect concentrations (PNECs) and have been evidenced to cause negative reproductive impacts on resident aquatic biota. In vertebrates, such as fish, a well-established indicator of estrogen-mediated endocrine disruption is overexpression of the egg yolk protein precursor vitellogenin (Vtg) in males. Although the vertebrate Vtg has high sensitivity and specificity to estrogens, and the molecular basis of its estrogen inducibility has been well studied, there is growing ethical concern over the use of vertebrate animals for contaminant monitoring. The potential utility of the invertebrate Vtg as a biomonitor for environmental estrogens has therefore gained increasing attention. Here we review evidence providing support that the molluscan Vtg holds promise as an invertebrate biomarker for exposure to estrogens. Unlike vertebrates, estrogen signalling in invertebrates remains largely unclarified and the classical genomic pathway only partially explains estrogen-mediated activation of Vtg. In light of this, in the latter part of this review, we summarise recent progress towards understanding the molecular mechanisms underlying the activation of the molluscan Vtg gene by estrogens and present a hypothetical model of the interplay between genomic and non-genomic pathways in the transcriptional regulation of the gene.

The effects of human drugs in Corbicula fluminea. Assessment of neurotoxicity, inflammation, gametogenic activity, and energy status

The constant release of pharmaceuticals products to aquatic environment even at low concentrations (ng L^-1 to µg L^-1) could lead to unknown chronic effects to non-target organisms. The aim of this study was to evaluate neurotoxic responses, inflammation, gametogenic activity and energy status on the fresh water clam C. fluminea after exposure to different concentrations of caffeine (CAF), ibuprofen (IBU), carbamazepine (CBZ), novobiocin (NOV) and tamoxifen (TMX) for 21 days under laboratory conditions. During the assay, water was spiked every two days with CAF (0; 0.1; 5; 15; 50µgL^-1), IBU (0; 0.1; 5; 10; 50µgL^-1), CBZ, NOV, and TMX (0.1, 1, 10, 50µgL^-1). After the exposure period, dopamine levels (DOP), monoamine oxidase activity (MAO), arachidonic acid cyclooxygenase activity (COX), vitellogenin-like proteins (VTG), mitochondrial electron transport (MET), total lipids (TLP), and energy expenditure (MET/TLP) were determined in gonad tissues, and acetyl cholinesterase activity (AChE) was determined in digestive gland tissues. Results showed a concentration-dependence response on biomarkers tested, except for MAO. Environmental concentrations of pharmaceuticals induced significant changes (p < 0.05) in the neurotoxic responses analyzed (CAF, CBZ and NOV increased DOP levels and CBZ inhibited AChE activity), inflammation (CAF induced COX), and energy status (MET and TLP increased after exposure to CBZ, NOV and TMX). Responses of clams were related to the mechanism of action (MoA) of pharmaceuticals. Biomarkers applied and the model organism C. fluminea constituted a suitable tool for environmental risk assessment of pharmaceutical in aquatic environment.

Trace element and metal sequestration in vitellaria and sclerites, and reactive oxygen intermediates in a freshwater monogenean, Paradiplozoon ichthyoxanthon

Exposure to metals and other trace elements negatively affects infection dynamics of monogeneans, including diplozoids, but, physiological mechanisms linked to exposure have yet to be documented. In this study sequestration of trace elements and reactive oxygen intermediate production in the monogenean, Paradiplozoon ichthyoxanthon, was demonstrated. During dissection of host fish, Labeobarbus aeneus, the gills were excised and assessed for P. ichthyoxanthon, which were removed and frozen for fluorescence microscopy or fixed for transmission electron microscopy. Trace elements were sequestered in the vitellaria and sclerites in P. ichthyoxanthon, and the presence of reactive oxygen intermediates was observed predominantly in the tegument of the parasite. Trace elements and metals identified and ranked according to weight percentages (wt%) in the vitellaria were Cu > C > Au > O > Cr > Fe > Si while for the sclerites C > Cu > O > Au > Fe > Cr > Si were identified. For most element detected, readings were higher in the vitellaria than the sclerites, except for C and O which were higher in sclerites. Specifically for metals, all levels detected in the vitellaria were greater than in sclerites. Based on the proportion of trace elements present in the vitellaria and sclerites it appears that most trace elements including metals were sequestered in the vitellaria. The results of reactive oxygen intermediate production in the tegument of the parasite suggests either trace element accumulation takes place across the tegument or results from the action of the host's immune response on the parasite. The results serve as the first demonstration of trace element sequestration and reactive oxygen intermediates in a freshwater monogenean parasite.

Extending the toxicity-testing paradigm for freshwater mussels: Assessing chronic reproductive effects of the synthetic estrogen 17α-ethinylestradiol on the unionid mussel Elliptio complanata

Surface water concentrations of the synthetic estrogen 17α-ethinylestradiol (EE2) as low as 1ng/L can cause adverse reproductive effects in fish under acute and chronic exposure conditions, whereas higher concentrations (> 5ng/L) in acute studies are necessary to elicit adverse effects in freshwater mussels. Prolonged chronic exposures of freshwater mussels to EE2 remain un-evaluated. An extended duration testing paradigm was used to examine reproductive and biochemical (carbohydrate, lipid, protein) effects of EE2 on the unionid mussel, Elliptio complanata, throughout its reproductive cycle. Mussels were exposed to a control and EE2 concentrations (5 and 50ng/L) in six discrete and sequential 28 d tests, and in one discrete and simultaneous 180 d test, from February through August. Foot protrusion and siphoning behavior were recorded daily, along with conglutinate releases and larval (glochidia) mortality. Gonad, hemolymph, and gonad fluid samples were taken for biochemical and vitellogenin-like protein (Vtg) analysis post-exposure. Female mussels released eggs and conglutinates during the months of April to June, indicating sexual maturation during this time. Conglutinates released in the 5ng/L treatment in 28 d exposures contained fewer glochidia and more eggs, and increased concentrations of Vtg in hemolymph were observed from April to August in the 5ng/L treatment during the 180 d exposure. Results indicate that the 180 d test approach, concurrent with the sequence of 28 d tests, enabled a more robust evaluation of mussel behavior and physiology than would have been possible with a single short-term (28 d) test.

Bioaccumulation of pharmaceuticals and personal care products in the unionid mussel Lasmigona costata in a river receiving wastewater effluent

Freshwater mussels are frequently found in rivers receiving effluent from wastewater treatment plants (WWTP), and there is strong evidence that poor water quality is deleterious to freshwater mussel populations. WWTPs are among the main sources of pharmaceuticals and personal care products (PPCPs) in surface waters. We monitored 145 PPCPs in wild and caged mussels both upstream and downstream of the Kitchener WWTP in the Grand River, Ontario, as well as 118 PPCPs in water samples. Our objectives were to characterize the seasonal changes in PPCP concentrations in water, to calculate bioaccumulation factors (BAFs) of PPCPs in mussels, and to determine the chemical and physical properties of PPCPs driving the bioaccumulation. Seventy PPCPs were detected in water, and concentrations were highest in the summer or early fall, which corresponded to low river flow. Forty-three PPCPs from many pharmaceutical classes were detected in mussel tissues, including stimulants, a contrasting agent, anti-inflammatory drugs, anti-bacterial agents, antibiotics, antidepressants, antihistamines, progestins, and illicit drugs such as cocaine and amphetamines. The BAFs ranged from 0.66 for metformin to 32,022 for sertraline. Using partial least squares to predict BAFs based upon chemical properties, log KOC, Log KOW, and fugacity ratio (sediment) all had similar and positive loadings with BAFs (R(2)X = 0.70; caged mussels). BAFs of PPCPs in mussels were predictable from fugacity models that estimate bioconcentration factors using log KOW. Our study demonstrated that mussels readily bioaccumulate PPCPs, in a manner consistent with expectations based upon BCF models and the chemical characteristics of each compound.

Sublethal effects induced by morphine to the freshwater biological model Dreissena polymorpha

Opioids are considered as emerging contaminants in aquatic ecosystems, mainly due to their large illicit consume worldwide. Morphine (MOR) is the main opiate and it was commonly found at measurable concentrations in freshwaters. Even though its occurrence is well documented, just limited information is available regarding its hazard to nontarget organisms. The aim of this study was of the evaluation of sublethal effects induced by MOR to the freshwater bivalve Dreissena polymorpha. We exposed mussels to two MOR concentrations (0.05 µg/L and 0.5 µg/L) for 14 days and we investigated the sublethal effects by a suite of biomarkers. The Neutral Red Retention Assay (NRRA) was used as a test of cytotoxicity, while the oxidative stress was evaluated by the activity of antioxidant and detoxifying enzymes, namely catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), and by measuring the levels of lipid peroxidation (LPO) and protein carbonylation (PCC). The genetic damage was assessed by the Single Cell Gel Electrophoresis (SCGE) assay, the DNA diffusion assay and the micronucleus test (MN test). Finally, the filtration rate of D. polymorpha was evaluated in order to investigate possible physiological effects. Both tested concentrations reduced the lysosome membrane stability of bivalves, but only the highest MOR concentration induced significant changes in the activity of antioxidant enzymes (SOD, CAT, and GPx) and increase in lipid peroxidation levels. Slight increase in primary DNA fragmentation was noticed, while no fixed genetic damage and alterations of the filtering rate were found.

Assessment of biomarkers for contaminants of emerging concern on aquatic organisms downstream of a municipal wastewater discharge

Contaminants of emerging concern (CECs), including pharmaceuticals, personal care products and estrogens, are detected in wastewater treatment plant (WWTP) discharges. However, analytical monitoring of wastewater and surface water does not indicate whether CECs are affecting the organisms downstream. In this study, fathead minnows (Pimephales promelas) and freshwater mussels Pyganodon grandis Say, 1829 (synonym: Anodonta grandis Say, 1829) were caged for 4 weeks in the North Saskatchewan River, upstream and downstream of the discharge from the WWTP that serves the Edmonton, AB, Canada. Passive samplers deployed indicated that concentrations of pharmaceuticals, personal care products, an estrogen (estrone) and an androgen (androstenedione) were elevated at sites downstream of the WWTP discharge. Several biomarkers of exposure were significantly altered in the tissues of caged fathead minnows and freshwater mussels relative to the upstream reference sites. Biomarkers altered in fish included induction of CYP3A metabolism, an increase in vitellogenin (Vtg) gene expression in male minnows, elevated ratios of oxidized to total glutathione (i.e. GSSG/TGSH), and an increase in the activity of antioxidant enzymes (i.e. glutathione reductase, glutathione-S-transferase). In mussels, there were no significant changes in biomarkers of oxidative stress and the levels of Vtg-like proteins were reduced, not elevated, indicating a generalized stress response. Immune function was altered in mussels, as indicated by elevated lysosomal activity per hemocyte in P. grandis caged closest to the wastewater discharge. This immune response may be due to exposure to bacterial pathogens in the wastewater. Multivariate analysis indicated a response to the CECs Carbamazepine (CBZ) and Trimethoprim (TPM). Overall, these data indicate that there is a 1 km zone of impact for aquatic organisms downstream of WWTP discharge. However, multiple stressors in municipal wastewater make measurement and interpretation of impact of CECs difficult since water temperature, conductivity and bacteria are also inducing biomarker responses in both fish and mussels.

Effects of cadmium and 17β-estradiol on Mytilus galloprovincialis redox status. Prooxidant-antioxidant balance (PAB) as a novel approach in biomonitoring of marine environments

Cadmium and 17β-estradiol are rapidly accumulated in mussel tissues, making mussels excellent pollution sentinel organisms. The aim of the present study was to compare the oxidative responses of the mussels after 1, 3 and 7 days of exposure to cadmium with those to 17β-estradiol and subsequently, to suggest a multi-parametric approach for biomonitoring studies. Our results showed that environmentally relevant concentrations of either cadmium or 17β-estradiol for 1, 3 and 7 days induced oxidative stress in hemocytes of exposed mussels. The latter was determined by significantly increased ROS levels and apoptosis, by suppression of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferase (GST) expression levels and subsequent increased prooxidant levels, as measured by prooxidant-antioxidant balance (PAB) assay. To our knowledge this is the first time that prooxidant-antioxidant balance is evaluated in invertebrates as an index of oxidative stress. The simultaneous use of the parameters of prooxidant-antioxidant balance and antioxidant enzymes expression patterns, in combination with ROS production levels and apoptosis, in mussel hemocytes is suggested as an approach that may help to better evaluate the impact of environmental pollution on marine organisms and thereupon ecosystems.

Occurrence of contaminants of emerging concern along the California coast (2009-10) using passive sampling devices

Three passive sampling devices (PSDs), polar organic chemical integrative samplers (POCIS), polyethylene devices (PEDs), and solid-phase microextraction (SPME) samplers were used to sample a diverse set of chemicals in the coastal waters of San Francisco Bay and the Southern California Bight. Seventy one chemicals (including fragrances, phosphate flame retardants, pharmaceuticals, PAHs, PCBs, PBDEs, and pesticides) were measured in at least 50% of the sites. The chemical profile from the San Francisco Bay sites was distinct from profiles from the sites in the Southern California Bight. This distinction was not due to a single compound or class, but by the relative abundances/concentrations of the chemicals. Comparing the PSDs to mussel (Mytilus spp.) tissues, a positive correlation exists for the 25 and 26 chemicals in common for the PEDs and SPME, respectively. Diphenhydramine was the only common chemical out of 40 analyzed in both POCIS and tissues detected at a common site.

The involvement of metallothionein in the development of aquatic invertebrate

The many documents on metallothioneins (MTs) in aquatic organisms focus especially on their use as biomarkers in environmental monitoring programs, but there are a few papers that summarize the physiological role of MTs in aquatic organisms especially in their development. The multifaceted role of MTs include involvement in homeostasis, protection against heavy metals and oxidant damage, metabolic regulation, sequestration and/or redox control. MTs could be induced by heavy metals which are able to hinder gametogenesis, suppress embryogenesis, and hamper development. Here we pay more attention on the non-essential metal cadmium, which is the most studied heavy metal regarding MTs, and its effects on the development of aquatic invertebrates. In this paper, we have collected published information on MTs in aquatic organisms - mollusks, crustaceans, etc., and summarize its functions in aquatic invertebrates, especially those related to their development.

Neurochemical effects of benzodiazepine and morphine on freshwater mussels

The purpose of this study was to examine the neurochemical effects of morphine, diazepam, a common benzodiazepine, and an effluent concentrate on the endemic freshwater mussel Elliptio complanata. Mussels were exposed to the drugs and to the solid-phase concentrate of a municipal effluent and left to stand at 15 degrees C for 48h. Neurochemical effects were determined by monitoring changes in dopamine, serotonin, glutamate and gamma-aminobutyric acid (GABA) levels in the visceral mass (containing the nerve ganglia) of mussels. The activities of acetylcholinesterase (AChE), dopamine and serotonin-dependent adenylyl cyclase (ADC) were also determined in the mussels. Oxidative stress was determined by tracking changes in lipid peroxidation (LPO) in the mitochondrial and post-mitochondrial fractions. The results revealed that the drugs and the effluent extract were biologically active in mussels. Morphine reduced serotonin and increased dopamine in mussel tissues while reducing AChE activity and increasing GABA levels. This suggests the induction of a relaxation state in mussels. Diazepam also reduced serotonin levels but produced no change in dopamine levels. However, dopamine-sensitive ADC activity was readily activated, indicating the potential effect on opiate signaling. Diazepam increased glutamate levels slightly, but AChE remained stable. The increase in both dopamine ADC activity and glutamate concentrations was also associated with greater oxidative stress on the mitochondrial and post-mitochondrial fractions in cells. A comparison of the global response pattern of these drugs with those of the effluent extract revealed only a relative proximity to morphine. In conclusion, the data warrant more studies on the analysis of opiates and benzodiazepines in municipal effluents to better address the potential environmental hazard of these neuroactive drug classes to aquatic organisms.

Are endocrine disrupting compounds a health risk in drinking water?

There has been a great deal of international discussion on the nature and relevance of endocrine disrupting compounds in the environment. Changes in reproductive organs of fish and mollusks have been demonstrated in rivers downstream of sewage discharges in Europe and in North America, which have been attributed to estrogenic compounds in the effluent. The anatomical and physiological changes in the fauna are illustrated by feminization of male gonads. The compounds of greatest hormonal activity in sewage effluent are the natural estrogens 17Beta-estradiol, estrone, estriol and the synthetic estrogen ethinylestradiol. Androgens are also widely present in wastewaters. Investigations of anthropogenic chemical contaminants in freshwaters and wastewaters have shown a wide variety of organic compounds, many of which have low levels of estrogenic activity. In many highly populated countries the drinking water is sourced from the same rivers and lakes that are the recipients of sewage and industrial discharge. The River Thames which flows through London, England, has overall passed through drinking water and sewage discharge 5 times from source to mouth of the river. Under these types of circumstance, any accumulation of endocrine disrupting compounds from sewage or industry potentially affects the quality of drinking water. Neither basic wastewater treatment nor basic drinking water treatment will eliminate the estrogens, androgens or detergent breakdown products from water, due to the chemical stability of the structures. Hence a potential risk to health exists; however present data indicate that estrogenic contamination of drinking water is very unlikely to result in physiologically detectable effects in consumers. Pesticide, detergent and industrial contamination remain issues of concern. As a result of this concern, increased attention is being given to enhanced wastewater treatment in locations where the effluent is directly or indirectly in use for drinking water. In some places at which heavy anthropogenic contamination of drinking water sources occurs, advanced drinking water treatment is increasingly being implemented. This treatment employs particle removal, ozone oxidation of organic material and activated charcoal adsorption of the oxidation products. Such processes will remove industrial organic chemicals, pesticides, detergents, pharmaceutical products and hormones. Populations for which only basic wastewater and drinking water treatment are available remain vulnerable.