Modeling of steroid estrogen contamination in UK and South Australian rivers predicts modest increases in concentrations in the future

Distribution, ecological fate, and risks of steroid estrogens in environmental matrices

Over the past two decades, steroidal estrogens (SEs) such as 17α-ethylestradiol (EE2), 17β-estradiol (E2),17α-estradiol (17α-E2), estriol (E3) and estrone (E1) have elicited worldwide attention due to their potentially harmful effects on human health and aquatic organisms even at low concentration ng/L. Natural steroidal estrogens exhibit greater endocrine disruption potency due to their high binding effect on nuclear estrogen receptors (ER). However, less has been explored regarding their associated environmental risks and fate. A comprehensive bibliometric study of the current research status of SEs was conducted using the Web of Science to assess the development trends and current knowledge of SEs in the last two decades, from 2001 to 2021 October. The number of publications has tremendously increased from 2003 to 2021. We summarized the contamination status and the associated ecological risks of SEs in different environmental compartments. The results revealed that SEs are ubiquitous in surface waters and natural SEs are most studied. We further carried out an in-depth evaluation and synthesis of major research hotspots and the dominant SEs in the matrices were E1, 17β-E2, 17α-E2, E3 and EE2. Nonetheless, investigations of SEs in soils, groundwater, and sediments remain scarce. This study elucidates SEs distribution, toxicological risks, ecological fate and mitigation measures, which will be beneficial for future monitoring, management, and risk assessment. Further studies are recommended to assess the toxicological risks of different SEs in complex environmental matrices to pursue a more precise and holistic quantitative estimation of estrogenic risk.

Nongenomic effects of estradiol vs. the birth control estrogen ethinyl estradiol on signaling and cell proliferation in pituitary tumor cells, and differences in the ability of R-equol to neutralize or enhance these effects

Ethinyl estradiol (EE₂, the active component of many birth control formulations) persists in treated waste waters and it has become a concerning endocrine-disrupting contaminant throughout the world. Previous studies have not examined the behavior of EE₂ in nongenomic signaling pathways and the subsequent functional responses (either alone or in mixtures) or conducted comparisons with the physiological estrogen estradiol (E₂). In this study, mitogen-activated protein kinases (MAPKs), ERK, and JNK were activated in pituitary tumor cells by fM EE₂, but p38 activation was insensitive to <nM doses. Both E₂ and EE₂ (10 fM to 10 nM) caused cell proliferation as well as triggering intracellular calcium increases and GTP charging of Gαi. E₂ was more effective at causing prolactin release. Previously, we reported that the soy-based diadzein synthetic metabolite R-equol (R-eq) activated nongenomic responses in pituitary cells and impaired the actions of E₂, thereby affecting both prolactin release and cell proliferation. In the present study, as expected, R-eq activated all MAPKs in a dose-dependent manner at concentrations ranging from fM to 100 nm, and it also modified the effects of environmentally and therapeutically relevant levels of EE₂. The physiological/therapeutic doses of E₂/EE₂ that activated p38 were most effectively challenged by R-eq at ≥fM concentrations. R-eq did not alter the proliferative response to E₂ but it elevated the cell numbers induced by EE₂ at all concentrations of added R-eq. The more pronounced ability of R-eq to inhibit the cell-killing mechanisms associated with p38-induced inflammatory responses may explain its capacity to increase the numbers of EE₂-stimulated pituitary tumor cells. Thus, widespread exposure to persistent pharmaceutical estrogens that imperfectly mimic endogenous estrogens may exacerbate cell proliferation in these responsive cells.

MnO2 nanozyme-driven polymerization and decomposition mechanisms of 17β-estradiol: Influence of humic acid

Nanozymes, which display the bifunctional properties of nanomaterials and natural enzymes, are useful tools for environmental remediation. In this research, nano-MnO₂ was selected for its intrinsic enzyme-like activity to remove 17β-estradiol (E2). Results indicated that nano-MnO₂ exhibited laccase-like activity (7.22 U·mg^-1) and removed 97.3 % of E2 at pH 6. Humic acid (HA) impeded E2 removal (only 72.4 %) by competing with E2 for the catalytic sites of the MnO₂ nanozyme surface, and there was a good linear correlation between the kinetic constants and HA concentrations (R² = 0.9489). Notably, the phenolic -OH of E2 interacted with HA to yield various polymeric products via radical-driven covalent coupling, resulting in ablation of phenolic -OH but increase of ether groups in the polymeric structure. Intermediate products, including estrone, E2 homo-/hetero-oligomers, E2 hydroxylated and quinone-like products, as well as aromatic ring-opening species, were identified. Interestingly, HA hindered the extent of E2 oxidation, homo-coupling, and decomposition but accelerated E2 and HA hetero-coupling. A reasonable catalytic pathway of E2 and HA involving MnO₂ nanozyme was proposed. These findings provide novel insights into the influence of HA on MnO₂ nanozyme-driven E2 radical polymerization and decomposition, consequently favoring the ecological water restoration and the global carbon cycle.

Estrogens in municipal wastewater and receiving waters in the Beijing-Tianjin-Hebei region, China: Occurrence and risk assessment of mixtures

The potentially high release of estrogens to surface waters due to high population density and local livestock production in the Beijing-Tianjin-Hebei region may pose adverse effects on reproductive systems of aquatic organisms. This study found that total measured concentrations of estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2) and diethylstilbestrol (DES) were 468 ± 27 ng/L in treated wastewater and 219 ± 23 ng/L in river waters in this region. E2, E3 and EE2 were the predominant estrogens in river waters. The restriction of DES for human use should have been enforced, however concentrations of DES were relatively high compared to other studies. Haihe and Yongdingxin Rivers delivered approximately 1.8 tonnes of estrogens to the Bohai Bay annually. Concentrations of individual estrogens were significantly higher in river waters in the dry season, however, mass loadings were significantly higher in the wet season. The average E2-equivalent concentrations reached 1.2 ± 0.2 and 0.64 ± 0.08 μg-E2/L following long-term and short-term exposure estimates, respectively, in river waters with an EE2 contribution of over 90 %. This could give rise to high risks to fish. Estrogens in river waters largely derived from human excretion. Field studies on estrogenic effects on fish reproductive systems are required locally considering high estrogen contamination levels.

Enhanced estrogen removal in activated sludge processes through the optimization of the hydraulic flow pattern

The removal of β-estradiol (E2) and α-ethinylestradiol (EE2) in biological wastewater treatment plants (WWTP) would need to be improved in order to comply with prospective Environmental Quality Standards (EQS) of 0.4 and 0.035 ng.L^-1 respectively. The effluent concentration of a micropollutant in an activated sludge process is a function of the removal rate, the hydraulic retention time (HRT) and the flow pattern, which is usually overlooked. In order to better understand this aspect, we carried out tracer studies in eight WWTPs in the UK and found that relatively modest changes in aeration tanks would translate into tangible improvements in their flow pattern. We further evaluated the degradation rates for E1 (estrone), E2, E3 (estriol) and EE2 in each WWTP and we estimated that the modification of the flow pattern would be sufficient to place effluent concentrations of E2 (23.2 L∙g_VSS^-1∙d^-1<k_bio<210 L∙g_VSS^-1∙d^-1) far below the prospective EQS, while EE2 (0.3 L∙g_VSS^-1∙d^-1<k_bio<2.9 L∙g_VSS^-1∙d^-1) would have to rely on river dilution for compliance. Regarding E1 and E3, with no prospective legislation, the modifications would place E3 (9.9 L∙g_VSS^-1∙d^-1<k_bio<39.5 L∙g_VSS^-1∙d^-1) effluent concentrations easily below its predicted no-effect concentrations (PNEC = 60 ng.L^-1) while for E1, (2.6 L∙g_VSS^-1∙d^-1<k_bio<19.2 L∙g_VSS^-1∙d^-1) it would very much depend on the degradation rates of the specific WWTP (PNEC = 6 ng.L^-1). Improvement in flow pattern had the additional benefit of improving the effectiveness of other plausible changes in HRT or biological removal rates. Managing the flow pattern of existing WWTPs is a cost-efficient tool for managing the fate of estrogens.

Occurrence, sorption, and transformation of free and conjugated natural steroid estrogens in the environment

Natural steroid estrogens (NSEs), including free estrogens (FEs) and conjugated estrogens (CEs), are of emerging concern globally among public and scientific community due to their recognized adverse effects on human and wildlife endocrine systems in recent years. In this review, the properties, occurrence, sorption process, and transformation pathways of NSEs are clarified in the environment. The work comprehensively summarizes the occurrence of both free and conjugated estrogens in different natural and built environments (e.g., river, WWTPs, CAFOs, soil, and sediment). The sorption process of NSEs can be impacted by organic compounds, colloids, composition of clay minerals, specific surface area (SSA), cation exchange capacity (CEC), and pH value. The degradation and transformation of free and conjugated estrogens in the environment primarily involves oxidation, reduction, deconjugation, and esterification reactions. Elaboration about the major, subordinate, and minor transformation pathways of both biotic and abiotic processes among NSEs is highlighted. The moiety types and binding sites also would affect deconjugation degree and preferential transformation pathways of CEs. Notably, some intermediate products of NSEs still remain estrogenic potency during transformation process; the elimination of total estrogenic activity needs to be addressed in further studies. The in-depth researches regarding the behavior of both free and conjugated estrogens are further required to tackle their contamination problem in the ecosystem. Graphical abstract ᅟ.

Experiments and numerical simulation on the degradation processes of carbamazepine and triclosan in surface water: A case study for the Shahe Stream, South China

We examined the occurrence and fate of pharmaceuticals and personal care products in surface water by combining laboratory experiments with numerical simulations. The degradation processes of two typical PPCPs (triclosan and carbamazepine) collected from the Shahe Stream were studied. Hydrolysis, biodegradation, and photolysis were the three major routes of triclosan (TCS) and carbamazepine (CBZ) degradation. A central composite design method was used to investigate the effects of related natural parameters (including pH, dissolved oxygen, salinity, temperature, light intensity, and humic acid) on the TCS and CBZ degradation processes in the laboratory. Our results showed that the main degradation pathway of CBZ and TCS was direct photolysis during the daytime and that the maximal biodegradation rates of CBZ and TCS occurred at 22 °C when the optimum temperature function was used. Based on our experimental results, the observed degradation of CBZ and TCS followed pseudo-first-order kinetics, and the degradation kinetic equations under the influence of multiple natural parameters were established with estimated average degradation rate constants of 1.2452E-7 s^-1 and 3.1260E-5 s^-1 for CBZ and TCS, respectively. The degradation rate constants were incorporated into a one-dimensional, simply integrated hydrodynamic and water quality model. The proposed numerical model was applied to depict the transportation and transformation of CBZ and TCS in surface water and was validated by observational data from the Shahe Stream. The results showed that our model reproduced the observed patterns of CBZ and TCS concentrations reasonably, with slight overestimations compared to the observed data; the relative errors between the simulated and the observed concentrations were 5.85%-6.82% for CBZ and -156.85%--7.18% for TCS. According to our simulation, the spatial distribution of TCS in surface water was determined by biochemical degradation processes that were most affected by temperature under natural conditions; in contrast, the distribution of CBZ was largely controlled by diffusion.

No evidence of exposure to environmental estrogens in two feral fish species sampled from the Yarra River, Australia: A comparison with Northern Hemisphere studies

Environmental estrogens originate from a variety of sources including sewage treatment plant (STP) effluents and adverse physiological effects (endocrine disruption) have been observed in several fish species sampled downstream of STP discharges. In this study we examined common carp (Cyprinus carpio) and roach (Rutilis rutilis) for signs of exposure to environmental estrogens in the iconic Yarra River, Melbourne, Australia. The Yarra River flows through the city of Melbourne and more than 2 million people live within the catchment. Two STPs discharge water into the Yarra River within the middle reaches, and the areas immediately downstream of these discharge locations were the focus of this study. Carp and roach were chosen as test species since both have been utilised extensively for endocrine disruption research throughout Europe, North America and Asia, and data from various international studies was used for comparison with the results of the present study. Neither species showed evidence of exposure to environmental estrogens, with no elevation of plasma vitellogenin levels in males and no incidence of intersex gonads. Most physiological endpoints in both species from this study were within ranges reported in carp and roach from reference sites in other studies, however some degenerative histological changes in both male and female gonads were observed. Surface water samples showed no estrogenic activity (measured by the yeast-estrogen screen, YES), but did display strong anti-estrogenic and weak androgenic activity (measured by the yeast-androgen screen, YAS). Whilst the results show no evidence of impacts from environmental estrogens in the Yarra River, the presence of both anti-estrogenic and androgenic activity in water samples, as well as some gonadal changes in carp is concerning and indicates that our focus needs to broaden, in order to look for biological impacts in resident fauna that might be due to environmental pollutants other than environmental estrogens.

Developmental Exposure to Ethinylestradiol Affects Reproductive Physiology, the GnRH Neuroendocrine Network and Behaviors in Female Mouse

During development, environmental estrogens are able to induce an estrogen mimetic action that may interfere with endocrine and neuroendocrine systems. The present study investigated the effects on the reproductive function in female mice following developmental exposure to pharmaceutical ethinylestradiol (EE2), the most widespread and potent synthetic steroid present in aquatic environments. EE2 was administrated in drinking water at environmentally relevant (ENVIR) or pharmacological (PHARMACO) doses [0.1 and 1 μg/kg (body weight)/day respectively], from embryonic day 10 until postnatal day 40. Our results show that both groups of EE2-exposed females had advanced vaginal opening and shorter estrus cycles, but a normal fertility rate compared to CONTROL females. The hypothalamic population of GnRH neurons was affected by EE2 exposure with a significant increase in the number of perikarya in the preoptic area of the PHARMACO group and a modification in their distribution in the ENVIR group, both associated with a marked decrease in GnRH fibers immunoreactivity in the median eminence. In EE2-exposed females, behavioral tests highlighted a disturbed maternal behavior, a higher lordosis response, a lack of discrimination between gonad-intact and castrated males in sexually experienced females, and an increased anxiety-related behavior. Altogether, these results put emphasis on the high sensitivity of sexually dimorphic behaviors and neuroendocrine circuits to disruptive effects of EDCs.

Risk of endocrine disruption to fish in the Yellow River catchment in China assessed using a spatially explicit model

The global water availability assessment (GWAVA) model, incorporating regional water abstractions and reservoir information, was used to model the human-sourced steroid estrogens estrone (E1) and estradiol (E2) in the Yellow River catchment (China). The river flows in the main stem were calibrated using gauged flows. Following a review of Chinese data on estrogen discharge from a range of sewage treatment plants, low, median, and high discharge rates were identified and used as best, expected, and worst-case scenarios, respectively. For any given location, the temporal variation of modeled estrogen levels was summarized using the mean and upper 90th percentile, which is where the model predicts 90% of values would be below this concentration. The predicted means and 90th percentiles for E1 were comparable to previous E1 measurements reported in the river. For the whole catchment, only 19% (mean value) of the river system by length was predicted to exceed 1 ng/L E2 equivalents (EEQs) using expected estrogen sewage discharge. Only 3% of the network by length was predicted to exceed the dangerously high 10 ng/L EEQ when considering 90th percentile concentrations. The highest exposures were in the Fen and Wei tributaries. Endocrine disruption risk from estrogens was predicted to be minimal in the main stem. Only in the worst-case discharge scenario and 90th percentile predicted concentrations were the most downstream river reaches of the main stem predicted to be at risk. Reservoirs appeared to be helpful in reducing estrogen concentrations thanks to longer water residence facilitating biodegradation.

Towards spatially smart abatement of human pharmaceuticals in surface waters: Defining impact of sewage treatment plants on susceptible functions

For human pharmaceuticals, sewage treatment plants (STPs) are a major point of entry to surface waters. The receiving waters provide vital functions. Modeling the impact of STPs on susceptible functions of the surface water system allows for a spatially smart implementation of abatement options at, or in the service area of, STPs. This study was performed on a nation-wide scale for the Netherlands. Point source emissions included were 345 Dutch STPs and nine rivers from neighboring countries. The Dutch surface waters were represented by 2511 surface water units. Modeling was performed for two extreme discharge conditions. Monitoring data of 7 locations along the rivers Rhine and Meuse fall mostly within the range of modeled concentrations. Half of the abstracted volumes of raw water for drinking water production, and a quarter of the Natura 2000 areas (European Union nature protection areas) hosted by the surface waters, are influenced by STPs at low discharge. The vast majority of the total impact of all Dutch STPs during both discharge conditions can be attributed to only 19% of the STPs with regard to the drinking water function, and to 39% of the STPs with regard to the Natura 2000 function. Attributing water treatment technologies to STPs as one of the possible measures to improve water quality and protect susceptible functions can be done in a spatially smart and cost-effective way, using consumption-based detailed hydrological and water quality modeling.

Identification of conserved hepatic transcriptomic responses to 17β-estradiol using high-throughput sequencing in brown trout

Estrogenic chemicals are major contaminants of surface waters and can threaten the sustainability of natural fish populations. Characterization of the global molecular mechanisms of toxicity of environmental contaminants has been conducted primarily in model species rather than species with limited existing transcriptomic or genomic sequence information. We aimed to investigate the global mechanisms of toxicity of an endocrine disrupting chemical of environmental concern [17β-estradiol (E2)] using high-throughput RNA sequencing (RNA-Seq) in an environmentally relevant species, brown trout (Salmo trutta). We exposed mature males to measured concentrations of 1.94, 18.06, and 34.38 ng E2/l for 4 days and sequenced three individual liver samples per treatment using an Illumina HiSeq 2500 platform. Exposure to 34.4 ng E2/L resulted in 2,113 differentially regulated transcripts (FDR < 0.05). Functional analysis revealed upregulation of processes associated with vitellogenesis, including lipid metabolism, cellular proliferation, and ribosome biogenesis, together with a downregulation of carbohydrate metabolism. Using real-time quantitative PCR, we validated the expression of eight target genes and identified significant differences in the regulation of several known estrogen-responsive transcripts in fish exposed to the lower treatment concentrations (including esr1 and zp2.5). We successfully used RNA-Seq to identify highly conserved responses to estrogen and also identified some estrogen-responsive transcripts that have been less well characterized, including nots and tgm2l. These results demonstrate the potential application of RNA-Seq as a valuable tool for assessing mechanistic effects of pollutants in ecologically relevant species for which little genomic information is available.

Integrated assessment of wastewater treatment plant effluent estrogenicity in the Upper Murray River, Australia, using the native Murray rainbowfish (Melanotaenia fluviatilis)

The contamination of major continental river systems by endocrine-active chemicals (EACs) derived from the discharge of wastewater treatment plant (WWTP) effluents can affect human and ecosystem health. As part of a long-term effort to develop a native fish model organism for assessment of endocrine disruption in Australia's largest watershed, the Murray-Darling River Basin, the present study evaluated endocrine disruption in adult males of the native Australian Murray rainbowfish (Melanotaenia fluviatilis) exposed to effluent from an activated sludge WWTP and water from the Murray River during a 28-d, continuous-flow, on-site experiment. Analysis of the WWTP effluent and river water detected estrone and 17β-estradiol at concentrations up to approximately 25 ng L(-1) . Anti-estrogenicity of effluent samples was detected in vitro using yeast-based bioassays (yeast estrogen screen) throughout the experiment, but estrogenicity was limited to the first week of the experiment. Histological evaluation of the testes indicated significant suppression of spermatogenesis by WWTP effluent after 28 d of exposure. Plasma vitellogenin concentrations and expression of vitellogenin messenger RNA in liver were not significantly affected by exposure to WWTP effluent. The combination of low contaminant concentrations in the WWTP effluent, limited endocrine disrupting effects in the Murray rainbowfish, and high in-stream dilution factors (>99%) suggest minimal endocrine disruption impacts on native Australian fish in the Murray River downstream from the WWTP outfall.

Environmental concentrations of anti-androgenic pharmaceuticals do not impact sexual disruption in fish alone or in combination with steroid oestrogens

Sexual disruption in wild fish has been linked to the contamination of river systems with steroid oestrogens, including the pharmaceutical 17α-ethinylestradiol, originating from domestic wastewaters. As analytical chemistry has advanced, more compounds derived from the human use of pharmaceuticals have been identified in the environment and questions have arisen as to whether these additional pharmaceuticals may also impact sexual disruption in fish. Indeed, pharmaceutical anti-androgens have been shown to induce such effects under laboratory conditions. These are of particular interest since anti-androgenic biological activity has been identified in the aquatic environment and is potentially implicated in sexual disruption alone and in combination with steroid oestrogens. Consequently, predictive modelling was employed to determine the concentrations of two anti-androgenic human pharmaceuticals, bicalutamide and cyproterone acetate, in UK sewage effluents and river catchments and their combined impacts on sexual disruption were then assessed in two fish models. Crucially, fish were also exposed to the anti-androgens in combination with steroid oestrogens to determine whether they had any additional impact on oestrogen induced feminisation. Modelling predicted that the anti-androgenic pharmaceuticals were likely to be widespread in UK river catchments. However, their concentrations were not sufficient to induce significant responses in plasma vitellogenin concentrations, secondary sexual characteristics or gross indices in male fathead minnow or intersex in Japanese medaka alone or in combination with steroid oestrogens. However, environmentally relevant mixtures of oestrone, 17β-oestradiol and 17α-ethinylestradiol did induce vitellogenin and intersex, supporting their role in sexual disruption in wild fish populations. Unexpectedly, a male dominated sex ratio (100% in controls) was induced in medaka and the potential cause and implications are briefly discussed, highlighting the potential of non-chemical modes of action on this endpoint.

Whole organism responses and intersex severity in rainbow darter (Etheostoma caeruleum) following exposures to municipal wastewater in the Grand River basin, ON, Canada. Part A

Municipal wastewater effluents (MWWEs) contain anthropogenic substances that can exhibit endocrine-disrupting activity. These complex mixtures have been observed to exert adverse effects on fish. Rainbow darter (Etheostoma caeruleum, RBD) is a small benthic fish that is widespread throughout the Grand River, Ontario, Canada, and has been previously shown to be adversely affected by MWWE exposure in this watershed. The objectives of this study were to quantify biological responses in this sentinel species and intersex severity in male fish, in relation to the area of urbanization. It focused on RBD populations adjacent to wastewater outfalls in the Grand River watershed. In May 2011, nine sites across the urban gradient were selected to evaluate the impact of MWWEs. Endpoints for energy storage (i.e. condition factor, k; liversomatic index, LSI) as well as reproductive endpoints (i.e. gonadosomatic index, GSI; gonad development, hormone production), and intersex were assessed in the fish. Rainbow darter showed a high incidence of intersex downstream of the wastewater outfalls, especially below the largest treatment plant outfall at Kitchener (∼85%). We applied an intersex index (score from 0 to 7) that considers the number of eggs within the testis and the stage of maturation of the egg. RBD exposed downstream of the largest wastewater outfall at Kitchener had a score of 3.81±0.37 compared to upstream to the urban areas where there were no intersex males found other than a single individual with a score 1 (average intersex score of site 0.06±0.06). In addition, several fish associated with the Kitchener outfall had macroscopic vitellogenic eggs in the testes (intersex scores 5 and 6). The sub-population of fish located at the wastewater outfall also showed a tendency towards skewed sex ratios (greater proportion of females to male fish) compared to the population at the reference sites. Male fish inhabiting the urbanized area of the Grand River also showed reduced levels of testosterone (T) and 11-ketotestosterone (11KT). Intersex males had the lower levels of 11KT relative to the upstream reference fish but could not be distinguished from normal males collected at the exposed sites. Despite the high levels of intersex at these sites, no relationships were evident among intersex severity and other measured endpoints such as GSI, LSI or in vitro steroid production. The effects observed appear to be associated with urbanization and exposure to treated MWWEs in the watershed. Although intersex incidence and severity was a very good indicator of wastewater exposure, intersex could not be directly linked to other effects in this wild population. The effects of MWWEs on transcriptional changes in adult RBD exposed to the effluents are reported in the corresponding report (Part B).

Impact of climate change and population growth on a risk assessment for endocrine disruption in fish due to steroid estrogens in England and Wales

In England and Wales, steroid estrogens: estrone, estradiol and ethinylestradiol have previously been identified as the main chemicals causing endocrine disruption in male fish. A national risk assessment is already available for intersex in fish arising from estrogens under current flow conditions. This study presents, to our knowledge, the first set of national catchment-based risk assessments for steroid estrogen under future scenarios. The river flows and temperatures were perturbed using three climate change scenarios (ranging from relatively dry to wet). The effects of demographic changes on estrogen consumption and human population served by sewage treatment works were also included. Compared to the current situation, the results indicated increased future risk:the percentage of high risk category sites, where endocrine disruption is more likely to occur, increased. These increases were mainly caused by changes in human population. This study provides regulators with valuable information to prepare for this potential increased risk.

The SOLUTIONS project: challenges and responses for present and future emerging pollutants in land and water resources management

SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7). The project aims to deliver a conceptual framework to support the evidence-based development of environmental policies with regard to water quality. SOLUTIONS will develop the tools for the identification, prioritisation and assessment of those water contaminants that may pose a risk to ecosystems and human health. To this end, a new generation of chemical and effect-based monitoring tools is developed and integrated with a full set of exposure, effect and risk assessment models. SOLUTIONS attempts to address legacy, present and future contamination by integrating monitoring and modelling based approaches with scenarios on future developments in society, economy and technology and thus in contamination. The project follows a solutions-oriented approach by addressing major problems of water and chemicals management and by assessing abatement options. SOLUTIONS takes advantage of the access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and puts major efforts on stakeholder dialogue and support. Particularly, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations are directly supported with consistent guidance for the early detection, identification, prioritisation, and abatement of chemicals in the water cycle. SOLUTIONS will give a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. The SOLUTIONS approach is expected to provide transparent and evidence-based candidates or River Basin Specific Pollutants in the case study basins and to assist future review of priority pollutants under the WFD as well as potential abatement options.

Populations of a cyprinid fish are self-sustaining despite widespread feminization of males

BACKGROUND

Treated effluents from wastewater treatment works can comprise a large proportion of the flow of rivers in the developed world. Exposure to these effluents, or the steroidal estrogens they contain, feminizes wild male fish and can reduce their reproductive fitness. Long-term experimental exposures have resulted in skewed sex ratios, reproductive failures in breeding colonies, and population collapse. This suggests that environmental estrogens could threaten the sustainability of wild fish populations.

RESULTS

Here we tested this hypothesis by examining population genetic structures and effective population sizes (N(e)) of wild roach (Rutilus rutilus L.) living in English rivers contaminated with estrogenic effluents. N(e) was estimated from DNA microsatellite genotypes using approximate Bayesian computation and sibling assignment methods. We found no significant negative correlation between N(e) and the predicted estrogen exposure at 28 sample sites. Furthermore, examination of the population genetic structure of roach in the region showed that some populations have been confined to stretches of river with a high proportion of estrogenic effluent for multiple generations and have survived, apparently without reliance on immigration of fish from less polluted sites.

CONCLUSIONS

These results demonstrate that roach populations living in some effluent-contaminated river stretches, where feminization is widespread, are self-sustaining. Although we found no evidence to suggest that exposure to estrogenic effluents is a significant driving factor in determining the size of roach breeding populations, a reduction in N(e) of up to 65% is still possible for the most contaminated sites because of the wide confidence intervals associated with the statistical model.

Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems

The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict ‘unexpected’ risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems.