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Due to their great environmental hazards, the widely used legacy perfluoroalkyl acids (PFAAs) are gradually restricted, and novel alternatives are being developed and applied. For efficient control of emerging environmental risks in agricultural production, we systematically studied the source apportionment in field soils and bioaccumulation characteristics in multiple crops of 12 PFAAs and five novel alternatives in an industrial-intensive region of China, followed by human exposure estimation and health risk assessment. Compared with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), shorter-chained PFAAs and novel alternatives have become the dominant components in local soils and crops, indicating their wide application. A positive matrix factorization (PMF) model coupled with multivariate analysis identified fluoropolymer manufacturing and textile treatment as the principal sources. The bioaccumulation factors (BAFs) of individual PFAAs and alternatives in crops decreased with increasing carbon chain lengths. As a novel alternative of PFOA, hexafluoropropylene oxide dimer acid (GenX) exhibited much higher BAFs; for the alternative of PFOS, 6:2 chlorinated polyfluorinated ether sulfonic acid (6:2 Cl-PFESA) showed lower BAFs. The bioaccumulation capacities of PFAAs and alternatives were also associated with soil organic matter and crop species. Through crop consumption, short-chained PFAAs and novel alternatives might pose emerging human health threats. [Display omitted] • Legacy PFAAs are being replaced by novel alternatives in China. • A PMF model and multivariate analysis demonstrate multiple sources of local PFASs. • BAFs of PFASs depends on their carbon chain structures, crop species and SOM. • Compared to PFOA, its alternative GenX shows higher crop accumulation potential. • PFBA, PFPeA, GenX, 6:2 Cl-PFESA and 6:2 FTS may pose new health threats via diet. [ABSTRACT FROM AUTHOR]

• Microplastics were examined at water treatment works, service reservoirs & customer tap outlets. • µFTIR analysis identified 19 polymer types, with PA, PET, PP, and PS as the most abundant. • Polymer types and concentrations varied by sampling round, location, and water company. • The highest concentrations of PA, PP, and PS were observed in customer tap outlets. • Average microplastics concentrations (∼0.025 MP/L) were similar across locations. Water treatment works have previously shown high efficiency in removing microplastics > 25 µm from raw source water. However, what is less well known is the extent to which microplastics of this size class are generated or lost within the water distribution network, particularly whether there is a greater presence in the customer tap than in the water treatment works outlet. This study focused on the presence of 21 different types of synthetic polymer particles with sizes larger than 25 µm examined through multiple rounds of sampling at outlets of water treatment works (WTW), service reservoirs (SR), and customer taps (CT) managed by seven different water companies in Britain. Nineteen different types of polymers were detected; their signature and concentration varied based on the round of sampling, the location within the water supply network, and the water company responsible for managing the supply. Among the polymers examined, polyamide (PA), polyethene terephthalate (PET), polypropylene (PP), and polystyrene (PS) were the most commonly found. Apart from PET having its highest concentration of 0.0189 microplastic per litre (MP/L) in the SR, the concentrations of the other three most frequent polymers (PS = 0.017 MP/L, PA = 0.0752 MP/L, PP= 0.1513 MP/L) were highest in the CT. The overall prevalence of this size of microplastics in the network is low, but there was a high variability of polymer types and occurrences. These spatial and temporal variations suggested that the MP in the distribution network may exist as a series of pulses. Given the presence and polymer types, the potential for some of the microplastics to originate from materials used in the water network and domestic plumbing systems cannot be ruled out. As found before, the absolute number of microplastics in the water distribution network remained extremely low. [Display omitted] [ABSTRACT FROM AUTHOR]

Perfluoroalkyl substances (PFASs) have become a recognized concern due to their mobility, persistence, ubiquity and health hazards in the environment. In this study, ten types of vegetables and three types of grain crops were collected in two open-air fields with different distances (0.3 km, 10 km) from a mega fluorochemical industrial park (FIP), China. Bioaccumulation characteristics of PFASs in light of crop types and organs were explored, followed by analyzing human exposure and risks to local residents with different age groups and dietary habits. Elevated levels of ∑PFASs were found nearby the FIP ranging from 79.9 ng/g to 200 ng/g in soils and from 58.8 ng/g to 8085 ng/g in crops. Perfluorooctanoic acid (PFOA) was the predominant PFAS component in soil; while shorter-chain perfluoroalkyl carboxylic acids (PFCAs), especially perfluorobutanoic acid (PFBA), were the major PFAS contaminants in multiple crops, resulting from their bioaccumulation preference. Depending on the crop types, the bioaccumulation factors (BAFs) of ∑PFASs for edible parts varied from 0.36 to 48.0, and the highest values were found in shoot vegetables compared with those in fruit vegetables, flower vegetables, root vegetables and grain crops. For typical grains, the BAFs of ∑PFASs decreased in the order of soybean (Glycine max (Linn.) Merr.), wheat (Triticum aestivum L.) and corn (Zea mays L.), possibly related to their protein and lipid content. Among specific organs in the whole plants, leaves exhibited the highest BAFs of ∑PFASs compared with corresponding roots, stems, husks or grains. With increasing carbon chain lengths of individual PFCAs (C4-C8), the logarithm of their BAFs for edible parts of various crops showed a linear decrease (0.1–1.16 log decrease per CF 2 unit), and the largest decrease was observed in grains. Human exposure to PFOA via the consumption of contaminated crops represents a health risk for local residents, especially for low-age consumers or urban consumers with higher vegetable diet. Implications for planting optimization and food safety were provided aiming to reduce health hazards of PFASs. Unlabelled Image • Industrial emission caused serious PFASs pollution to nearby agricultural system. • Vegetables and grains have bioaccumulation preference to shorter-chain PFASs. • For edible parts, shoot vegetables showed highest BAFs of ∑PFASs in multiple crops. • The logarithm of BAFs exhibited linear decrease with carbon chain lengths of PFCAs. • Health risk of PFASs via crop consumption varied for different ages or diet habits. [ABSTRACT FROM AUTHOR]

[Display omitted] Perfluoroalkyl acids (PFAAs) are contaminants of global concern, and the inadvertent consumption of PFAA-contaminated crops may pose a threat to public health. Therefore, systematically studying their source tracing, bioaccumulation prediction and risk assessments in crops is an urgent priority. This study investigated the source apportionment and transport of PFAAs and novel fluorinated alternatives (collectively as per- and polyfluoroalkyl substances, PFASs) from factories to agricultural fields in a fluorochemical industrial region of China. Furthermore, bioaccumulation specificities and prediction of these chemicals in different vegetables were explored, followed by a comprehensive risk assessment from agricultural fields to dinner plates which considered precursor degradation. A positive matrix factorization model revealed that approximately 70 % of PFASs in agricultural soils were derived from fluorochemical manufacturing and metal processing. Alarming levels of ∑PFASs ranged 8.28–84.3 ng/g in soils and 163–7176 ng/g in vegetables. PFAS with short carbon chain or carboxylic acid group as well as branched isomers exhibited higher environmental transport potentials and bioaccumulation factors (BAFs) across a range of vegetables. The BAFs of different isomers of perfluorooctanoic acid (PFOA) decreased as the perfluoromethyl group moved further from the acid functional group. Hexafluoropropylene oxide dimer acid (GenX) showed relatively low BAFs, probably related to its ether bond with a high affinity to soil. Vegetables with fewer Casparian strips (e.g., carrot and radish), or more protein, possessed larger BAFs of PFASs. A bioaccumulation equation integrating critical parameters of PFASs, vegetables and soils, was built and corroborated with a good contamination prediction. After a total oxidizable precursors (TOP) assay, incremental perfluoroalkyl carboxylic acids (PFCAs) were massively found (325–5940 ng/g) in edible vegetable parts. Besides, precursor degradation and volatilization loss of PFASs was firstly confirmed during vegetable cooking. A risk assessment based on the TOP assay was developed to assist the protection of vegetable consumers. [ABSTRACT FROM AUTHOR]

Coastal ecosystem health is of vital importance to human well-being. Field investigations of major pollutants along the whole coast of China were carried out to explore associations between coastal development activities and pollutant inputs. Measurements of target pollutants such as PFAAs and PAHs uncovered notable levels in small estuary rivers. The Yangtze River was identified to deliver the highest loads of these pollutants to the seas as a divide for the spatial distribution of pollutant compositions. Soil concentrations of the volatile and semi-volatile pollutants showed a cold-trapping effect in pace with increasing latitudinal gradient. The coastal ecosystem is facing high ecological risks from metal pollution, especially copper (Cu) and zinc (Zn), while priority pollutants of high risks vary for different kinds of protected species, and the ecological risks were influenced by both climate and physicochemical properties of environmental matrices, which should be emphasized to protect and restore coastal ecosystem functioning. [Display omitted] • Field investigations of major pollutants along the coast of China were carried out. • The distributions of pollutants are correlated with specific industry sectors. • The distribution characteristics of pollutants varied in different climatic zones. • The ecological risks are affected by both climate and physicochemical properties. [ABSTRACT FROM AUTHOR]

Declines in invertebrate biodiversity 1,2 pose a significant threat to key ecosystem services. 3–5 Current analyses of biodiversity often focus on taxonomic diversity (e.g., species richness), 6,7 which does not account for the functional role of a species. Functional diversity of species' morphological or behavioral traits is likely more relevant to ecosystem service delivery than taxonomic diversity, as functional diversity has been found to be a key driver of a number of ecosystem services including decomposition and pollination. 8–12 At present, we lack a good understanding of long-term and large-scale changes in functional diversity, which limits our capacity to determine the vulnerability of key ecosystem services with ongoing biodiversity change. Here we derive trends in functional diversity and taxonomic diversity over a 45-year period across Great Britain for species supporting freshwater aquatic functions, pollination, natural pest control, and agricultural pests (a disservice). Species supporting aquatic functions showed a synchronous collapse and recovery in functional and taxonomic diversity. In contrast, pollinators showed an increase in taxonomic diversity, but a decline and recovery in functional diversity. Pest control agents and pests showed greater stability in functional diversity over the assessment period. We also found that functional diversity could appear stable or show patterns of recovery, despite ongoing changes in the composition of traits among species. Our results suggest that invertebrate assemblages can show considerable variability in their functional structure over time at a national scale, which provides an important step in determining the long-term vulnerability of key ecosystem services with ongoing biodiversity change. • Caddisflies showed a decline and recovery in functional diversity • Pollinator taxonomic diversity and functional diversity showed opposite patterns • Pest control agents and pests showed greater stability in functional diversity Greenop et al. show patterns ranging from collapse and recovery to stable trends in functional diversity for invertebrate species supporting key ecosystem services across Great Britain over a 45-year period. These results highlight variability in the long-term vulnerability of key ecosystem services with ongoing biodiversity change. [ABSTRACT FROM AUTHOR]

• Concentration of 94 pharmaceuticals investigated in fish plasma at 9 locations in EU. • "Read-Across Hypothesis" used to assess the risk of pharmacological effects in fish. • Risperidone and flupentixol in fish plasma > human therapeutic plasma concentrations. • No target pharmaceuticals were found in fish plasma at 7 of 9 investigated sites. To gain a better understanding of which pharmaceuticals could pose a risk to fish, 94 pharmaceuticals representing 23 classes were analyzed in blood plasma from wild bream, chub, and roach captured at 18 sites in Germany, the Czech Republic and the UK, respectively. Based on read across from humans, we evaluated the risks of pharmacological effects occurring in the fish for each measured pharmaceutical. Twenty-three compounds were found in fish plasma, with the highest levels measured in chub from the Czech Republic. None of the German bream had detectable levels of pharmaceuticals, whereas roach from the Thames had mostly low concentrations. For two pharmaceuticals, four individual Czech fish had plasma concentrations higher than the concentrations reached in the blood of human patients taking the corresponding medication. For nine additional compounds, determined concentrations exceeded 10% of the corresponding human therapeutic plasma concentration in 12 fish. The majority of the pharmaceuticals where a clear risk for pharmacological effects was identified targets the central nervous system. These include e.g. flupentixol, haloperidol, and risperidone, all of which have the potential to affect fish behavior. In addition to identifying pharmaceuticals of environmental concern, the results emphasize the value of environmental monitoring of internal drug levels in aquatic wildlife, as well as the need for more research to establish concentration-response relationships. [ABSTRACT FROM AUTHOR]

• Industrial fluorochemical waste contaminates the river-estuary-sea environment. • PFOA contamination is dominant in aquatic animals with a >90% overall contribution. • The freshwater winkle has the highest PFOA concentration of 2161 ng/g (ww) • Trophic levels and carbon sources vary widely within some aquatic species. • Aquatic food consumption screening values of PFOA are provided. Substantial perfluoroalkyl acids (PFAAs) production still occurs in China, and the consumption of aquatic products is a critical exposure pathway of PFAAs in humans. In this study, specimens of 16 freshwater and 40 marine species were collected in the river-estuary-sea environment affected by a mega fluorochemical industry park in China in 2015, and the edible tissues of these organisms were analyzed for PFAA levels. Perfluorooctanoic acid (PFOA) was the dominating contaminant with an overall contribution of more than 90%, and concentrations as high as 2161 ng/g wet weight (measured in the freshwater winkle). All species with the greatest PFOA levels were benthic. The trophic magnification factor (TMF) of PFOA was 1.10 for freshwater species and 1.28 for marine species, indicating that PFOA was slightly magnifying. Analysis of carbon source indicated that freshwater species were more benthic feeding, while marine species were more pelagic feeding. Aquatic food consumption screening values of PFOA were modified according to estimated daily intake (EDI) values, which generated recommendations for limited meal categories and the do-not-eat category. Thus, this study provides recommendations for mitigating the health risks of PFAA-contaminated aquatic food, ranging from food selection to consumption frequency and proper food processing. [ABSTRACT FROM AUTHOR]

• A multiple-level system was proposed for risk rank of PPCPs in waters. • 12 PPCPs showed environmental risks in Chinese surface waters. • Detected frequency, exposure and effect distribution were important to risk ranking. Interest in the risks posed by trace concentrations of pharmaceuticals and personal care products (PPCPs) in surface waters is increasing, particularly with regard to potential effects of long-term, low-dose exposures of aquatic organisms. In most cases, the actual studies on PPCPs were risk assessments at screening-level, and accurate estimates were scarce. In this study, exposure and ecotoxicity data of 50 PPCPs were collected based on our previous studies, and a multiple-level environmental risk assessment was performed. The 50 selected PPCPs are likely to be frequently detected in surface waters of China, with concentrations ranging from the ng L−1 to the low-g L−1, and the risk quotients based on median concentrations ranged from 2046 for nonylphenol to 0 for phantolide. A semi-probabilistic approach screened 33 PPCPs that posed potential risks to aquatic organisms, among which 15 chemicals (nonylphenol, sulfamethoxazole, di (2-ethylhexyl) phthalate, 17β-ethynyl estradiol, caffeine, tetracycline, 17β-estradiol, estrone, dibutyl phthalate, ibuprofen, carbamazepine, tonalide, galaxolide, triclosan, and bisphenol A) were categorized as priority compounds according to an optimized risk assessment, and then the refined probabilistic risk assessment indicated 12 of them posed low to high risk to aquatic ecosystem, with the maximum risk products ranged from 1.54% to 17.38%. Based on these results, we propose that the optimized risk assessment was appropriate for screening priority contaminants at national scale, and when a more accurate estimation is required, the refined probability risk assessment is useful. The methodology and process might provide reference for other research of chemical evaluation and management for rivers, lakes, and sea waters. [ABSTRACT FROM AUTHOR]

The presence of pharmaceuticals in the environment, especially the aquatic environment, has received a lot of attention in the last 20 plus years. Despite that attention, the two most important questions regarding pharmaceuticals in the environment still cannot be answered. It is not possible to put the threat posed by pharmaceuticals into perspective with the many other threats (stressors) facing aquatic organisms, such as low flows due to over-abstraction of water, inhibited passage of migratory species due to dams and weirs, diseases, algal blooms causing low oxygen levels and releasing toxins, eutrophication, climate change, and so on. Nor is it possible to identify which pharmaceuticals are of concern and which are not. Not only can these key questions not be answered presently, they have received extremely little attention, despite being identified 10 years ago as the two most important questions to answer. That situation must change if resources and expertise are to be effectively used to protect the environment. Environ Toxicol Chem 2024;43:589-594. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Importance: We describe the importance of Type IV pilus retraction to colonization and persistence by a mouse commensal Neisseria, N. musculi, in its native host. Our findings have implications for the role of Tfp retraction in mediating interactions of human-adapted pathogenic and commensal Neisseria with their human host due to the relatedness of these species., Competing Interests: The authors declare no conflict of interest.

Antidepressants are one of the most commonly prescribed pharmaceuticals. Although they have been frequently detected in aquatic environments around the globe, little is known regarding their adverse effects on humans and aquatic organisms. Recently, an in vitro monoamine transporter inhibition assay was developed to detect transporter-inhibitory activities of antidepressants in wastewater in Japan. However, it was unclear which antidepressants were responsible for transporter-inhibitory activities in wastewater. Herein, the per capita consumption of 32 antidepressants, their excretion of unchanged parent compounds, per capita water consumption, removal rate during wastewater treatment processes, and potency values from the monoamine transporter inhibition assay were used to prioritize antidepressants of concern in effluent wastewater in England and Japan. In both countries, sertraline and O -desmethylvenlafaxine had the highest contribution to inhibitory activities against the human serotonin transporter (hSERT) and zebrafish SERT (zSERT), respectively. It was found that the antidepressants inhibited the zSERT more strongly than the hSERT. The inhibitory activities found against the zSERT in wastewater in England and Japan were higher than thresholds for abnormal behavior in fish. The antidepressants prioritized in this study provide insight into launching environmental monitoring and ecotoxicological studies of antidepressants.

Diabetes mellitus is a complex metabolic disorder that is associated with an increased risk of breast cancer. Despite this correlation, the interplay between tumor progression and diabetes, particularly with regard to stiffening of the extracellular matrix, is still mechanistically unclear. Here, we established a murine model where hyperglycemia was induced before breast tumor development. Using the murine model, in vitro systems, and patient samples, we show that hyperglycemia increases tumor growth, extracellular matrix stiffness, glycation, and epithelial-mesenchymal transition of tumor cells. Upon inhibition of glycation or mechanotransduction in diabetic mice, these same metrics are reduced to levels comparable with nondiabetic tumors. Together, our study describes a novel biomechanical mechanism by which diabetic hyperglycemia promotes breast tumor progression via glycating the extracellular matrix. In addition, our work provides evidence that glycation inhibition is a potential adjuvant therapy for diabetic cancer patients due to the key role of matrix stiffening in both diseases.

As we attempt to manage chemicals in the environment we need to be sure that our research efforts are being directed at the substances of greatest threat. All too often we focus on a chemical of concern and then cast around for evidence of its effects in an unstructured way. Risk assessment based on laboratory ecotoxicity studies, combined with field chemical measurements, can only take us so far. Uncertainty about the range and sufficiency of evidence required to take restorative action often puts policymakers in a difficult situation. We review this conundrum and reflect on how the "Hill criteria," used widely by epidemiologists, have been applied to a weight-of-evidence approach (a term sometimes used interchangeably with ecoepidemiology) to build a case for causation. While using a set of such criteria to address sites of local environmental distress has been embraced by the US Environmental Protection Agency, we urge a wider adoption of weight-of-evidence approaches by policymakers, regulators, and scientists worldwide. A simplified series of criteria is offered. Progress will require a sustained commitment to long-term wildlife and chemical monitoring over a sufficient geographic spread. Development of a comprehensive monitoring network, coupled with assembling evidence of harm in a structured manner, should be the foundation for protecting our ecosystems and human health. This will enable us to not only judge the success or failure of our efforts but also diagnose underlying causes. Environ Toxicol Chem 2021;40:2968-2977. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC., (© 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.)

Microplastics were characterized in eight water treatment works (WTWs) in England and Wales (UK). Sources included river water, groundwater, and an upland reservoir. Water treatment varied from disinfection, filtration, sedimentation, and activated carbon techniques. At each WTW, five repeat samples of raw and potable water and two repeat sludge samples were taken over 5 months. Microplastics in water were captured on 10 μm filters and nonplastic materials digested in the laboratory. Microplastics ≥25 μm were analyzed using Fourier-transform infrared microscopy. Blanks revealed consistent polyethylene (PE), poly(ethylene terephthalate) (PET), and polypropylene (PP) contamination. Spike recoveries for 63-90 μm polyamide microplastics demonstrated 101% (standard deviation, SD 27%) and 113% (SD 15%) recovery for raw and potable waters and 52% (SD 13%) for sludge. Only four of the six WTWs sampled for raw water and only two of eight WTWs in their potable water had microplastics above the limit of quantification. Considering only the WTWs with quantifiable microplastics, then on average, 4.9 microplastic particles/L were present in raw water and only 0.00011 microplastic particles/L were present in potable water (99.99% removal). Values in waste sludge were highly variable. PE, PET, and PP were the most common polymers quantified in raw water and sludge, and polystyrene and acrylonitrile butadiene styrene were the most common polymers quantified in potable water.

Knowledge of the hazards and associated risks from chemicals discharged to the environment has grown considerably over the past 40 years. This improving awareness stems from advances in our ability to measure chemicals at low environmental concentrations, recognition of a range of effects on organisms, and a worldwide growth in expertise. Environmental scientists and companies have learned from the experiences of the past; in theory, the next generation of chemicals will cause less acute toxicity and be less environmentally persistent and bioaccumulative. However, researchers still struggle to establish whether the nonlethal effects associated with some modern chemicals and substances will have serious consequences for wildlife. Obtaining the resources to address issues associated with chemicals in the environment remains a challenge., (Copyright © 2020, American Association for the Advancement of Science.)

The potential persistence and migration of 14 antibiotics comprising sulfonamides, fluoroquinolones, macrolides and tetracyclines were conducted using a 50-d recirculating flume study supported by batch attenuation experiments with spiked concentrations. The study demonstrated that photodegradation was the dominant attenuation process for these antibiotics in the water environment. The half-lives of 2-26 d were in order of sulfadiazine > sulfadimethoxine > sulfamerazine > sulfamethoxazole > sulfamethazine > sulfathiazole > ofloxacin > enrofloxacin > norfloxacin > ciprofloxacin > erythromycin > tetracycline > roxithromycin > oxytetracycline. These modest half-lives meant that the antibiotics were predicted to travel 30-400 km down a typical river before half the concentration would be lost. All antibiotics were detected on the surface sediment in the flume study. Under hyporheic exchange, some of them continually migrated into the deeper sediment and also the sediment pore water. All fluoroquinolones were detected in the sediments. The sulfonamides were detected in the pore water with relatively high concentrations and frequencies. Sulfadiazine, sulfamethazine and sulfathiazole in the upper layer pore water were found to be approaching equilibrium with the surface water. The high presence of sulfonamides in the pore water indicated that their high mobility and persistence potentially pose a risk to hyporheic zone., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The present study reviewed the impacts of wastewater on macroinvertebrates over 4 decades in a United Kingdom lowland river. This involved examining changes in chemicals, temperature, flow, and macroinvertebrate diversity from the 1970s until 2017 for a wastewater-dominated river downstream of Swindon in the United Kingdom (population ~ 220 000). When the wastewater treatment process changed from trickling filter to activated sludge in 1991, biological oxygen demand was nearly halved (90th percentile from 8.1 to 4.6 mg/L), ammonia peaks dropped more than 7-fold (90th percentile from 3.9 to 0.53 mg/L), whereas dissolved oxygen climbed consistently above 60% saturation (10th percentile from 49 to 64%) at a sampling point 2 km downstream of the wastewater treatment plant. A sustained increase in the number of macroinvertebrate species was evident from that point. River flow did not change, temperature rose slightly, and the major metal concentrations declined steadily over most of the monitoring period. Neither the introduction of phosphate stripping in 1999 nor the use of tertiary granular activated charcoal from 2008 to 2014 had strong positive effects on subsequent macroinvertebrate diversity. That the diversity still had not reached the ideal status by 2016 may be related to the modest habitat quality, agricultural pesticides, and limited recolonization potential in the catchment. The results indicate that urban wastewaters, with their chemical pollutants, are today probably not the biggest threat to the macroinvertebrate diversity of multiply stressed lowland rivers in the United Kingdom. Environ Toxicol Chem 2019;38:1820-1832. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC., (© 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.)

Endocrine disrupting chemicals (EDCs) are substances that alter the function of the endocrine system and consequently cause adverse effects to humans or wildlife. The release of particular EDCs into the environment has been shown to negatively affect certain wildlife populations and has led to restrictions on the use of some EDCs. Current chemical regulations aim to balance the industrial, agricultural and/or pharmaceutical benefits of using these substances with their demonstrated or potential harm to human health or the environment. A summary is provided of the natural science evidence base informing the regulation of chemicals released into the environment that may have endocrine disrupting effects on wildlife. This summary is in a format (a 'restatement') intended to be policy-neutral and accessible to informed, but not expert, policy-makers and stakeholders.

Little is known about the mechanisms influencing the differences in attenuation of antibiotics between rivers. In this study, the natural attenuation of four antibiotics (azithromycin, clarithromycin, sulfapyridine, and sulfamethoxazole) during transport along the Thames River, UK, over a distance of 8.3 km, and the Katsura River, Japan, over a distance of 7.6 km was compared. To assist interpretation of the field data, the individual degradation and sorption characteristics of the antibiotics were estimated by laboratory experiments using surface water or sediment taken from the same rivers. Azithromycin, clarithromycin, and sulfapyridine were attenuated by 92, 48, and 11% in the Thames River stretch. The first-order decay constants of azithromycin and sulfapyridine were similar to those in the Katsura River, while that of clarithromycin was 4.4 times higher. For sulfamethoxazole, the attenuation was limited in both rivers. Loss of sulfapyridine was attributed to both direct and indirect photolysis in the Thames River, but to only direct photolysis in the Katsura River. Loss of azithromycin and clarithromycin was attributed to sorption to sediment in both rivers. The probable explanation behind the difference in loss rates of clarithromycin between the two rivers was considered to be sediment sorption capacity.

The predicted aquatic estrogen concentrations for the whole of England and Japan were determined and compared using population and flow data. The overall value for English surface waters was 0.9 ng/L estradiol equivalents (EEQ) compared to 0.1 ng/L overall for Japan. Available dilution of sewage effluent was considered to be more important than contraceptive pill usage in this relative risk. A national survey of Japanese rivers using the yeast estrogen assay (YES) gave a median value of 0.27 ng/L EEQ which, while higher than that predicted, confirmed an overall low endocrine disruption risk. Using local population and flow data for 27 separate catchments, the predicted EEQ and measured EEQ (YES) values compared well, confirming the national picture that endocrine disruption would not be a widespread phenomena in Japan. Simple predictions based on population and flow can give an appropriate "ball park" value for catchments and even nations for concentrations of polar organic contaminants which have a majority human origin.

The occurrence of free and conjugated estrogens was examined in a survey of eleven sewage treatment plants (STPs) and their discharge water in the United Kingdom using grab sampling. The STPs included trickling filter with and without tertiary treatment, and activated sludge with tertiary treatment. For three activated sludge plants both influent and effluent samples were compared. For a further 8STPs only the effluent was examined. The estrone-3-sulphate, estradiol-3-sulphate and estriol-3-sulphate concentrations (up to 20 ng L(-1)) were typically 5-fold that of the respective free estrogen concentration in the effluents. This represents a substantial additional 'potential' estrogen load arriving in the receiving waters. Estrone-3-glucuronide was found at 9 ng L(-1), estradiol-3-glucuronide at 7 ng L(-1), and estriol-3-glucuronide at 32 ng L(-1) in sewage influent. Except on one occasion, no glucuronide conjugates could be found in the effluent. The results suggest in most cases glucuronide conjugates will be completely transformed in sewage treatment whilst sulphate conjugates will only be partially removed., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Daily steroid estrogen concentrations as 17β-estradiol equivalents (E2 equiv.) were modeled from 1992 to 2008 for single locations on the well populated Thames and Soar rivers in England. The historic daily mean flow values which were the basis of this exercise came from a selected gauging site on each river. The natural variation in flow from winter to summer typically produced a 20- to 30-fold difference in predicted estrogen concentration over the course of a year. Based on all the predicted values from minimum to maximum over the 1992 to 2008 period there was a 98-fold difference in estrogen concentrations on the basis of flow alone for the Thames (0.1-12.7 ng/L E2 equiv.) and 67-fold for the Soar (0.2-13.3 ng/L E2 equiv.). This compares to a predicted 0.5-fold difference that could arise from differences in sewage treatment and 0.1-fold difference due to differences in in-stream biodegradation. The seasonal variation in flow generated a repeating "roller coaster" in predicted estrogen concentrations. Regularly measured phosphate data for the river Avon over the period 1993 to 1996, where point sources also dominate, was compared against flow and predicted estrogen concentrations. The pattern of predicted estrogen and measured total phosphate concentration were very closely related. This dramatic variation in contaminant concentration over the year due to flow poses questions over what we mean by environmental relevance and the representation of the real environment in aquatic ecotoxicity tests.

Effluent discharges at Rodbourne sewage treatment works (STWs) were assessed using chemical and in vitro biological analysis as well as modelling predictions. Results showed that Rodbourne STW discharged less estrone (E1) than expected, but similar 17beta-estradiol (E2) and 17alpha-ethinyl estradiol (EE2) to those predicted by a widely cited effluent prediction model. The Exposure Analysis Modelling System (EXAMS) model was set up using measured effluent concentrations as its starting point to predict estrogen concentrations along a 10 km length of the receiving water of the River Ray. The model adequately simulated estrogen concentrations along the river when compared to July 2007 measured data. The model predicted combined estrogen equivalents in reasonable agreement with estrogenicity as measured by passive sampler (POCIS) extracts using the yeast estrogen screen. Using gauged mean flow values for 2007 the model indicated that the most important determinand for estrogen exposure in the Ray was not season, but proximity to the Rodbourne effluent. Thus, fish in the first 3 km downstream of Rodbourne were typically exposed to two or even three times more estrogens than those living 7-10 km further downstream. The modelling indicated that, assuming the effluent estrogen concentrations measured in February 2008 were typical, throughout the year the whole length of the Ray downstream of Rodbourne would be estrogenic, i.e. exceeding the 1 ng/L E2 equivalent threshold for endocrine disruption., (Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.)

Fish can be exposed to a complex mixture of chemical contaminants arising from the exposure to wastewater treatment works (WwTWs) effluents. Some of these contaminants are estrogenic and have been associated with feminisation of male fish and the presence of populations containing intersex individuals. However the detection of trace levels (ng/L) of estrogenic chemicals surface waters can be difficult and does not give information on the exposure of aquatic organisms to these contaminants. In this study we assessed whether the analysis of estrogenic substances that bioconcentrate in fish bile can be used to detect the exposure of fish to feminising contaminants in receiving waters and effluents, and thus facilitate their monitoring of these substances in aquatic environments. Estrogenic metabolites in bile were deconjugated using enzymatic hydrolysis and partially purified by solid phase extraction. Steroidal and xenoestrogens were derivatized to their trimethylsilyl ethers and quantified by gas-liquid chromatography-mass spectrometry (GC-MS/MS) using multiple reaction monitoring. The method was validated using spiked bile samples from immature female rainbow trout (Oncorhynchus mykiss) as well as bile from sexually mature roach (Rutilus rutilus) that had been exposed to either tap water or an undiluted estrogenic effluent for 10 days or captured from a river site downstream of a WwTWs effluent discharge. The mean recovery of target analytes from spiked bile was between 86 and 99% and the limit of detection was between 0.1 and 0.7ng/mL bile for bisphenol A (BPA), 17beta-estradiol (E2), estrone (E1) and 17alpha-ethinylestradiol (EE2), and 11, 60 and 327ng/mL bile for branched nonyl chain isomeric mixtures of 4-nonylphenolethoxylate (NP1EO), 4-nonylphenol (NP) and 4-nonylphenoldiethoxylate (NP2EO), respectively. All target analytes were detected in bile from roach exposed directly to a WwTWs effluent, with concentrations between 6-13microg/mL bile for NP, 18-21microg/mL for NP1EO, 75-135microg/mL for NP2EO, 0.7-2.5microg/mL for BPA, E2 and E1 and 17-29ng/mL for EE2. With the exception of NP2EO, all analytes were detected in at least 2 out of the 5 fish sampled from the River Thames. BPA and NP1EO were detected in all three reference fish held in tap water indicating possible contamination from laboratory plastics. The work shows that analysis of 20-100microL quantities of bile could be a useful approach in detecting exposure to mixtures of estrogenic contaminants taken up by fish from WwTW effluents and has the potential for monitoring the efficacy of remediation strategies that may be adopted for reduction of these endocrine disrupting chemicals in the aquatic environment., (Copyright 2009 Elsevier B.V. All rights reserved.)

Cytotoxic, also known as antineoplastic, drugs remain an important weapon in the fight against cancer. This study considers the water quality implications for the Thames catchment (United Kingdom) arising from the routine discharge of these drugs after use, down the drain and into the river. The review focuses on 13 different cytotoxic drugs from the alkylating agent, antimetabolite, and anthracycline antibiotic families. A geographic-information-system-based water quality model was used in the present study. The model was informed by literature values on consumption, excretion, and fate data to predict raw drinking water concentrations at the River Thames abstraction points at Farmoor, near Oxford, and Walton, in West London. To discover the highest plausible values, upper boundary values for consumption and excretion together with lower removal values for sewage treatment were used. The raw drinking water cytotoxic drug maximum concentrations at Walton (the higher of the two) representative of mean and low flow conditions were predicted to be 11 and 20 ng/L for the five combined alkylating agents, 2 and 4 ng/L for the three combined antimetabolites, and 0.05 and 0.10 ng/L the for two combined anthracycline antibiotics, respectively. If they were to escape into tap water, then the highest predicted concentrations would still be a factor of between 25 and 40 below the current recommended daily doses of concern. Although the risks may be negligible for healthy adults, more concern may be associated with special subgroup populations, such as pregnant women, their fetuses, and breast-feeding infants, due to their developmental vulnerability.

An evaluation of measured and predicted concentrations of 17-ethinylestradiol in surface waters of the United States and Europe was conducted to develop expected long-term exposure concentrations for this compound. Measured environmental concentrations (MECs) in surface waters were identified from the literature. Predicted environmental concentrations (PECs) were generated for European and U.S. watersheds using the GREAT-ER and PhATE models, respectively. The majority of MECs are nondetect and generally consistent with model PECs and conservative mass balance calculations. However, the highest MECs are not consistent with concentrations derived from conservative (worst-case) mass balance estimates or model PECs. A review of analytical methods suggests that tandem or high-resolution mass spectrometry methods with extract cleanup result in lower detection limits and lower reported concentrations consistent with model predictions and bounding estimates. Based on model results using PhATE and GREAT-ER, the 90th-percentile low-flow PECs in surface water are approximately 0.2 and 0.3 ng/L for the United States and Europe, respectively. These levels represent conservative estimates of long-term exposure that can be used for risk assessment purposes. Our analysis also indicates that average concentrations are one to two orders of magnitude lower than these 90th-percentile estimates. Higher reported concentrations (e.g., greater than the 99th-percentile PEC of approximately 1 ng/L) could result from methodological problems or unusual environmental circumstances; however, such concentrations are not representative of levels generally found in the environment, warrant special scrutiny, and are not appropriate for use in risk assessments of long-term exposures.

The effect of concentration on the biodegradation rate of the steroid estrogens, estrone (E1) and 17-alpha-ethinylestradiol (EE2), was studied in batch and continuous-flow reactor systems using fresh activated sludge from two sewage treatment plants. Between the concentrations of 0.03 to 10 μg/L in the batch system no consistent difference was found in the biodegradation rates for either estrogen. The biodegradation half-life was 0.3 to 0.7 h for E1, and 1.5 to 4.4 h for EE2 at 15 to 20°C. However, at 100 μg/L, biodegradation rates for both estrogens decreased, with the half-life prolonged to around 2.5 h for E1 and 12 to 18 h for EE2. In continuous-flow experiments, over a 2 h residence time, 95% of E1 and 48% of EE2 were removed on average at 0.1 μg/L, whilst 52% of E1 and 20% of EE2 were removed at 100 μg/L. In general, spiking concentration of estrogens did not appear to affect biodegradation rates between the ng/L to low μg/L levels in activated sludge; however, the rates greatly slowed down when the concentration increased up to 100 μg/L. The results suggest activated sludge biodegradation studies with estrogens in the high μg/L levels could give misleading results and should be avoided.

This article describes the development of a short pre-treatment method that allows the simultaneous analysis of free estrogens (estrone, 17beta-estradiol, estriol and 17 alpha-ethynylestradiol) and their sulphate and glucuronide conjugated forms. For a range of matrices, from sewage effluent to river water, the developed methodology based on solid-phase extraction and fractionation technique with ultra-performance liquid chromatography system showed effective separation of the targeted estrogens. The detection limits of this method ranged from 0.2 to 0.8 ng L(-1) for river water. The recoveries for river water and sewage effluent varied from 63% to 127%. The problems of matrix effects and ion suppression or enhancement were allowed quantitatively for in the analysis using standard addition. The developed method was used successfully to detect estrogens and their conjugates in both raw and treated wastewater, and river water at a location in Japan. High concentrations of the free estrogens estrone, 17beta-estradiol and estriol were found in the influent (22.6, 77.2, 64.6 ng L(-1), respectively) but only E1 was still present at a high concentration in the effluent which was reflected in the downstream river concentration. Estrone-3-sulphate was detected up to 18.0 ng L(-1) in influent water sample and 1.1 ng L(-1) in downstream water. For the sulphate conjugates, removal efficiencies varied from 35 to 88%. Glucuronide conjugates were detected only once in the sewage influent.

The possible effects of changing climate on a southern and a north-eastern English river (the Thames and the Yorkshire Ouse, respectively) were examined in relation to water and ecological quality throughout the food web. The CLASSIC hydrological model, driven by output from the Hadley Centre climate model (HadCM3), based on IPCC low and high CO(2) emission scenarios for 2080 were used as the basis for the analysis. Compared to current conditions, the CLASSIC model predicted lower flows for both rivers, in all seasons except winter. Such an outcome would lead to longer residence times (by up to a month in the Thames), with nutrient, organic and biological contaminant concentrations elevated by 70-100% pro-rata, assuming sewage treatment effectiveness remains unchanged. Greater opportunities for phytoplankton growth will arise, and this may be significant in the Thames. Warmer winters and milder springs will favour riverine birds and increase the recruitment of many coarse fish species. However, warm, slow-flowing, shallower water would increase the incidence of fish diseases. These changing conditions would make southern UK rivers in general a less favourable habitat for some species of fish, such as the Atlantic salmon (Salmo salar). Accidental or deliberate, introductions of alien macrophytes and fish may change the range of species in the rivers. In some areas, it is possible that a concurrence of different pressures may give rise to the temporary loss of ecosystem services, such as providing acceptable quality water for humans and industry. An increasing demand for water in southern England due to an expanding population, a possibly reduced flow due to climate change, together with the Water Framework Directive obligation to maintain water quality, will put extreme pressure on river ecosystems, such as the Thames.

A system was devised which allows particles to remain in suspension in a conventional 60 L aquarium without undue disturbance to resident fish. Using this system, juvenile rainbow trout were exposed for one week to 4-tert-octylphenol (OP, 10-1000 microg/L) with or without the presence of suspended sediments (10-20mg/L of natural suspended sediments from the River Calder, UK). About 8% of the added OP partitioned to the solid phase. Vitellogenin levels were determined in the plasma of the exposed rainbow trout and showed a dose-dependent increase with regards to OP exposure concentration. Considerable variation in the vitellogenin response was observed between separate runs with the same OP concentration. There was no statistically significant (at P < 0.05) difference in plasma VTG levels between the OP treatments with or without suspended sediments. This suggests that the dissolved concentration is the key factor and natural suspended sediment neither protects against, nor exacerbates, the endocrine disrupting effect of OP on fish.

The occurrence of intersex fish is widespread in the rivers of England and Wales. The extent of intersex in fish populations is believed to be strongly linked to their exposure to steroid estrogens. The present study presents, to our knowledge, the first national, catchment-based risk assessment for steroid estrogens in the world. A graphical information system-based model predicted the concentrations of estradiol (E2), estrone, and ethinylestradiol, which were combined and compared with known biological effect levels to predict the risk of endocrine disruption for 10,313 individual river reaches (21,452 km) receiving effluent from more than 2000 sewage treatment plants serving more than 29 million people. The large scale of this assessment underlines the usefulness of computer-based risk assessment methods. Overall, 61% [corrected] of the modeled reaches (all percentages are in terms of the total river length modeled) in England and Wales were predicted to be not at risk from endocrine disruption (mean concentrations, <1 ng/L E2 equivalents). A large range existed in the percentage of river reaches at risk in the various regions, from 5% in Wales to 67% in the Thames catchment. Important factors influencing this proportion are the population density, particularly their location, and the available dilution. A very small proportion of reaches (approximately 1-3%) were predicted to be at high risk (>10 ng/L E2 equivalents). Many of these high-risk reaches, however, were ditches, which were composed almost entirely of sewage effluent. The model could be applied equally well to any other chemical of concern emanating from the human population that would be impractical to assess by measurement.

Endocrine disruption in the aquatic environment has been a much-researched topic worldwide for the last fifteen years. We have not attempted to write a traditional review of the topic with this paper. Instead, based on unpublished reports and our own personal memories, we provide a history of the development of endocrine disruption research in the last 30 years, since the initial, accidental discovery of intersex fish in an English river in 1978. We focus on how the key questions were tackled, and the often surprising answers to some of these questions. We cover what we now know, and what we still do not know. Based on our current understanding, we emphasize the crucial role played by interdisciplinary research in moving the issue forward. The paper concludes with a selection of general messages about chemicals in the environment which have emerged from endocrine disruption research, and how these have changed our understanding of chemicals in the environment. If lessons have been learnt, and are acted upon when the next chemical 'scare' emerges (as it inevitably will), then it should be possible to act more efficiently and effectively to better protect the environment than was achieved during the "oestrogens in the environment" era.

To carry out meaningful ecotoxicity studies on novel polar organic microcontaminants, it is essential to know what concentrations wildlife may be exposed to. Traditionally these values were obtained by analytical chemistry, but in recent years GIS water quality models have been developed which may offer a quick and reliable way of getting the same information. Thus, two ways of obtaining basically the same information now exist, and an issue, therefore, arises as to which method is the most appropriate to use in which situation. To address this issue we have critically reviewed and compared measuring and modeling approaches for the determination of sewage effluent and river water concentrations of organic microcontaminants. Where model predictions and chemical measurements can be directly compared in sewage effluents, receiving waters, and across catchments, reported model mean values have all been within 1 order of magnitude of the measured values, with typically no more than a 3- or 4-fold difference. Interlaboratory chemical analysis of some organic microcontaminants in effluents in the challenging ng/L range have provided results which have varied from one another by a similar margin. No such comparison has been carried out yet for GIS water quality models to determine variation in predicted concentrations. As the level of ecotoxicological effects of many chemicals is often considerably higher than the reported measured or modeled values, such errors that might occur will often be of no consequence. But due to their extraordinary potency, much more accuracy is required with some natural and synthetic hormones. Significantly, modeling is no more complex to conduct when dealing with contaminants at ng/L compared with mg/L concentrations, but the same cannot be said for chemical analysis. A combination of modeling and measuring techniques will give the greatest confidence in risk assessment.

An assessment of the steroid estrogen removing performance of 23 different sewage treatment plants (STPs) was performed. The assessment relied on a model to estimate influent concentrations, and completed questionnaires on the STP treatment details from the relevant water companies. This information was compared with observed effluent 17beta-estradiol (E2) and estrone (E1) concentrations. The 10 biological filter plants (BFP) in the study performed poorly with only 30% (SD 31) removal on average for E1. This reduced E1 removal performance of the BFPs compared to all the other STP types in the survey was statistically significant (p<0.001). Scenarios of all the STPs as activated sludge types, and one as all BFP types were modelled using the GREAT-ER model set up for the Aire/Calder catchment in the UK. This difference was shown to have an important effect on predicted river E1 concentrations and consequent risk classifications.

Background: The threat of pandemic influenza has focused attention and resources on virus surveillance, prevention, and containment. The World Health Organization has strongly recommended the use of the antiviral drug Tamiflu both to treat and prevent pandemic influenza infection. A major concern for the long-term efficacy of this strategy is to limit the development of Tamiflu-resistant influenza strains. However, in the event of a pandemic, hundreds of millions of courses of Tamiflu, stockpiled globally, will be rapidly deployed. Given its apparent resistance to biodegradation and hydrophilicity, oseltamivir carboxylate (OC), the active antiviral and metabolite of Tamiflu, is predicted to enter receiving riverwater from sewage treatment works in its active form., Objective: Our objective in this study was to determine the likely concentrations of OC released into U.S. and U.K. river catchments using hydrologic modeling and current assumptions about the course and management of an influenza pandemic., Discussion: We predict that high concentrations of OC (micrograms per liter) capable of inhibiting influenza virus replication would be sustained for periods of several weeks, presenting an increased risk for the generation of antiviral resistance and genetic exchange between influenza viruses in wildfowl. Owing to the apparent recalcitrance of OC in sewage treatment works, widespread use of Tamiflu during an influenza pandemic also poses a potentially significant, uncharacterized, ecotoxicologic risk in each affected nation's waterways., Conclusion: To gauge the hazard presented by Tamiflu use during a pandemic, we recommend a) direct measurement of Tamiflu persistence, biodegradation, and transformation in the environment; b) further modeling of likely drug concentrations in the catchments of countries where humans and waterfowl come into frequent dose contact, and where significant Tamiflu deployment is envisaged; and c) further characterization of the risks of generating Tamiflu-resistant viruses in OC-exposed wildfowl.

For endocrine disrupting chemicals in the environment, concerns arise primarily from the effects that may be induced in wildlife. A well studied example is estrogenic chemicals in the aquatic environment and their effects on fish. Directly measuring effects, in fieldwork studies, is an expensive and time-consuming approach that is fraught with many difficulties, ranging from study design right through to data analysis and interpretation. An alternative approach would be to predict the scale of effect(s) using suitable modeling techniques. We have attempted to do this using estrogenic chemicals as an example. We chose this group of aquatic pollutants because of the current considerable interest in them and the wealth of biological data available on them. Using the established GREAT-ER hydrological model,we have first predicted the concentrations and then the estrogenic effects on fish, of estrone, estradiol, ethinyl estradiol, and nonylphenol individually throughout an entire river catchment. We then show that knowledge of the biological responses of fish to mixtures of these chemicals can be used to predict the effect of environmentally realistic mixtures of them. To determine the degree of risk posed by this group of chemicals, it was necessary to take into account mixture effects: assessment on a chemical by chemical basis led to underestimations of the risk. Finally, we show that the approach can be used to predict how the risk will be affected by changes in the concentration of one chemical in the mixture. Although we have used only one endpoint (vitellogenin induction as an estrogenic response) and one group of similarly acting chemicals, we suggest that this general approach could prove extremely useful to regulatory authorities and other parties charged with protecting aquatic wildlife from adverse effects caused by chemicals in their environment.

In the past 10 years, many thousands of research papers covering the many different aspects of endocrine disruption in the environment have been published. What has been learned from all this research? We have tried to reduce this very large volume of research into a relatively small number of "lessons". Hence, this paper is not a typical review, but instead it summarizes our personal opinions on what we consider are the major messages to have come from all this research. We realize that what has been a lesson to us may have been obvious from the outset to someone more knowledgeable on that particular aspect of the burgeoning field of endocrine disruption. In addition, it is inevitable that others will consider that we have "missed" some lessons that they would have expected to find included in our list. If so, we encourage them to submit them as responses to our paper. Our own lessons range widely, from the design and interpretation of data from fieldwork studies, through some key messages to come out of the very many laboratory studies that have been conducted, to issues around the sources and fates in the environment of endocrine-disrupting chemicals, and finally to the key role of sewage treatment in controlling the concentrations of these chemicals in the aquatic environment. Having (hopefully) learned our lessons, we have then applied them to the difficult issue of how best to approach future concerns about the potential impacts of other new and emerging contaminants (e.g., pharmaceuticals) on wildlife.

To predict sewage influent and effluent concentrations of the steroid estrogens 17beta-estradiol, estrone, and 17alpha-ethinylestradiol, a review of human excretion was carried out. This included conjugation and metabolism of the natural and synthetic steroid estrogens within the body, together with quantities excreted in the urine and feces by different members of the population. This has been combined with fate and behavior information for conjugated and unconjugated estrogens in the sewage treatment system to enable sewage works influent and effluent concentration predictions to be made. The model has proved to be reasonably accurate when tested against recent measurements of these steroid estrogens in the influent and effluent of sewage treatment works. The model may be used with river dilution ratios to predict which sewage treatment works are most likely to cause the greatest endocrine disruption due to steroid estrogens.

The potential for the herbicides isoproturon, atrazine and mecoprop to degrade in the major UK aquifers of chalk, sandstone and limestone was studied using laboratory microcosms spiked at 100 microg litre(-1). Significant mecoprop degradation was only observed in sandstone groundwater samples. Atrazine transformation, based on the formation of metabolites, did occur in most groundwater samples, but only at a rate of 1-3% per year. A potential to degrade isoproturon was observed in groundwater samples from each of the aquifer types, with the most rapid and consistent degradation occurring at the sandstone field site. Biodegradation was confirmed by the formation of monodesmethyl- and didesmethyl-isoproturon. Isoproturon degradation potential rates obtained from the groundwater microcosms could not be correlated with either dissolved organic carbon or numbers of bacteria in the groundwater. It was noted that the ability of the groundwater at a field site to degrade a pesticide was not related to performance of the soil above.

Concentrations of estradiol, estrone, and ethinylestradiol were measured in the water column (daily for 28 or 14 days) and in the bed sediment (weekly over the same period) of the River Nene and the River Lea, U.K., upstream and downstream of sewage treatment works (STW). The concentrations of the three steroids in the STW effluents were also measured. Estrone was detected at the highest concentration and in almost all samples from the three STW effluents, concentrations ranging from <0.4 to 12.2 ng/L. Estradiol was also detected frequently (<0.4-4.3 ng/L), but ethinylestradiol was detected infrequently (<0.4-3.4 ng/L). Positive detections were only found for estrone in the sediment, and these seemed to be unrelated to the water column concentrations. Levels of estrone were clearly raised above background levels in the rivers as a result of the STW discharges. Levels of estradiol and ethinylestradiol were too close to their detection limits to assess the STW impact. River water estrone concentration declined downstream at a rate that was in excess of that due to dilution. The most likely cause of this decline is a combination of sorption and biodegradation equivalent to a first-order decay half-life of 2.5 days for the River Nene and 0.5 days for the River Lea.