Endocrine-disrupting compounds in the Xiangjiang River of China: Spatio-temporal distribution, source apportionment, and risk assessment

Occurrence, partitioning behavior, and ecological risk assessment of octylphenol and nonylphenol in surface waters and sediments of Terengganu Rivers, Malaysia

The occurrence, partitioning behavior, and ecological risk assessment of octylphenol (OP) and nonylphenol (NP) were investigated in the surface water and sediment of three rivers in Terengganu, Malaysia, to understand the fate and ecological risk of these chemicals in aquatic ecosystems. Target chemicals were extracted using solvent extractant and cleaned up via solid-phase extraction. This is followed by analysis via high-performance liquid chromatography (HPLC), and verification by liquid chromatography-tandem mass spectrometry (LC-MS/MS). OP was consistently higher in both surface water and sediment, while NP was predominantly found in sediment with minimal detection in surface water. Concentrations in sediment (OP, 0.19-30.88 ng/g dw; NP, 0.38-84.42 ng/g dw) and in surface water (OP, 0.0019-0.0077 ng/mL; NP, 0.0007-0.0023 ng/mL) suggest strong adsorption from water to sediment due to the hydrophobic effects of these compounds. The partitioning behavior of OP was evaluated using two indicators: (1) the sediment-water partition coefficient (Kd) and (2) the carbon-normalized partition coefficient (K'oc). The results indicated that OP is readily adsorbed and released from sediment, with log Kd values ranging from 3.06 to 3.57 and log K'oc values from 3.00 to 3.97. A significant positive correlation was observed between physical water parameters (temperature, salinity, and pH), whereas a significant negative correlation was found between these parameters and the concentrations of OP and NP in sediment. The ecological risk assessment showed that OP in water posed a low risk, while OP and NP in sediment presented varying risks, ranging from low to high risk between 2018 and 2019. This baseline information on the partitioning behavior is invaluable for predicting the environmental fate of these compounds in sediment-water interactions in Malaysia and for assessing the ecological risks they may pose to aquatic organisms.

Early brain gene network alterations and growth disruptions in juvenile Chinese longsnout catfish (Leiocassis longirostris) induced by 17β-estradiol and 17α-methyltestosterone

Endocrine-disrupting chemicals (EDCs) 17β-estradiol (E2β) and 17α-methyltestosterone (MT) have been detected in aquatic environments at concentrations capable of perturbing neuroendocrine systems, yet their molecular mechanisms of action remain incompletely characterized. This study investigated the effects of chronic exposure to E2β and MT on brain development and neuroendocrine regulation in Leiocassis longirostris, a commercially important catfish species endemic to the Yangtze River Basin. Juvenile fish were exposed to three nominal dietary doses (100-300 ng) of each hormone for 30 days, corresponding to waterborne concentrations (556-1667 ng/L) within the upper range of environmental detections. Histopathological analysis revealed dose-dependent plasma accumulation in cerebral microvasculature, indicative of compromised blood-brain barrier integrity. Transcriptomic profiling identified significant suppression of immediate early genes (IEGs) critical for synaptic plasticity, including FOS, JUN, EGR1, NR4A1, CEBP-A/D, and ETS1, with E2β exerting stronger inhibitory effects (maximal at 200 ng-dose). Concomitant upregulation of neuroendocrine genes cga (gonadotropin α-subunit) and pomcb (pro-opiomelanocortin) suggested compensatory endocrine feedback mechanisms. Growth inhibition was observed in both treatment groups, with E2β-induced reductions in body weight exceeding those of MT. Functional enrichment analysis linked these transcriptional changes to disrupted pathways in synaptic signaling, chromatin remodeling, and endocrine regulation. Collectively, these findings demonstrate that estrogenic and androgenic EDCs impair neurodevelopmental processes via suppression of IEGs, leading to growth retardation and endocrine dysregulation. This study underscores the sublethal risks posed by sex steroid EDCs to wild fish populations and highlights the need for targeted regulatory measures to mitigate aquatic endocrine disruption.

Ten-month comprehensive assessment of steroid hormones in the tributaries of Baiyun District, Guangzhou City, China: Spatiotemporal dynamics, source attribution, and environmental implications

The occurrence of steroid hormones in small river ecosystems raises environmental alarms due to their limited dilution capacity, heightened susceptibility to diverse pollution sources, and their substantial contribution to the contamination of larger river systems. Here, we investigated the occurrence of 40 steroid hormones over 10 months in 10 first-order tributaries (n = 250) of Guangzhou City, China. The observed concentrations of Σsteroid hormones ranged from 30.5 to 450 ng/L (mean: 55.6 ± 35.4 ng/L). No substantial variation in steroid hormone concentrations was observed between the flood and dry seasons, reflecting an intricate balance of dilution dynamics, agricultural runoff, and wastewater releases. Further correlation analysis underscored wastewater discharge as a consistent source of steroid hormone occurrence, with spikes coinciding with concurrent fertilizer application and rainfall intervals. Steroid hormone concentrations displayed significant spatial variations. Correlation analyses connected steroid hormone levels to nutrients in tributaries and agricultural ditch water and land usage, highlighting the joint effect of runoff and various wastewater types on steroid hormone distribution. Interestingly, steroid hormone levels displayed minimal variation along the tributaries, suggesting uniform and continuous pollution sources. Source attribution analysis revealed that 51.7 % of steroid hormones originated from untreated domestic wastewater, followed by treated wastewater, livestock wastewater, and runoff. Notably, 92.0 % of the sampling sites registered at least one steroid hormone level exceeding the risk quotient threshold of 1, indicating widespread ecological hazards. Our research emphasizes the persistent and stable nature of steroid hormone-related risks across seasons and along the tributaries, highlighting the imperative for vigilant monitoring. We further advocate for intensified surveillance efforts during pivotal periods (e.g., fertilization periods and low rainfall intervals), to better address these environmental challenges.

Occurrence and risks of pharmaceuticals, personal care products, and endocrine-disrupting compounds in Chinese surface waters

The continuous and rapid increase of chemical pollution in surface waters has become a pressing and widely recognized global concern. As emerging contaminants (ECs) in surface waters, pharmaceutical and personal care products (PPCPs), and endocrine-disrupting compounds (EDCs) have attracted considerable attention due to their wide occurrence and potential threat to human health. Therefore, a comprehensive understanding of the occurrence and risks of ECs in Chinese surface waters is urgently required. This study summarizes and assesses the environmental occurrence concentrations and ecological risks of 42 pharmaceuticals, 15 personal care products (PCPs), and 20 EDCs frequently detected in Chinese surface waters. The ECs were primarily detected in China's densely populated and highly industrialized regions. Most detected PPCPs and EDCs had concentrations between ng/L to µg/L, whereas norfloxacin, caffeine, and erythromycin had relatively high contamination levels, even exceeding 2000 ng/L. Risk evaluation based on the risk quotient method revealed that 34 PPCPs and EDCs in Chinese surface waters did not pose a significant risk, whereas 4-nonylphenol, 4-tert-octylphenol, 17α-ethinyl estradiol, 17β-estradiol, and triclocarban did. This review provides a comprehensive summary of the occurrence and associated hazards of typical PPCPs and EDCs in Chinese surface waters over the past decade, and will aid in the regulation and control of these ECs in Chinese surface waters.

Pollution characteristics and risk assessment of endocrine-disrupting chemicals in surface water of national (freshwater) aquatic germplasm resource reserves in Guangdong Province

The distribution, composition, and risk assessment of 8 EDCs in the surface water of 14 national aquatic germplasm resource reserves (freshwater) were investigated during dry and wet seasons. Bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) were the main contributors of the 8 EDCs. The concentrations of phenolic pollutants in surface water during the dry season were higher than those in the wet season. However, no significant seasonal differences were found among the steroid hormones. According to the evaluation of estrogenic activity (EEQ > 1.0), E2 and EE2 were the main contributors to estrogenic activity. EDC mixtures posed a higher risk to crustaceans and fish (RQ > 1.0) and a moderate to high risk to algae (RQ > 0.1). Fish were the most sensitive aquatic organisms. In the study areas, EE2, E1, BPA, NP, and E2 had a higher risk than the other three compounds and should be controlled as a priority.

Pharmaceuticals and personal care products contamination in the rivers of Chennai city during the COVID-19 pandemic

Pharmaceuticals and personal care products (PPCPs) monitoring in surface water is crucial to address the escalating threat of antimicrobial resistance and safeguard public health. This study aimed to investigate the occurrence of 21 different PPCPs, including wastewater chemical markers, antibiotics, and parabens in the surface water of Chennai city using Ultra Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry (UPLC-MS/MS) analysis. It is noteworthy that chemical markers viz., carbamazepine (CBZ) and caffeine (CAF) were detected in all the sites and contributed to more than 95% of the total PPCPs load indicating a significant intrusion of wastewater. Among the antibiotics, fluoroquinolones were dominant in this study. Interestingly, a significant and strong correlation was seen between fluoroquinolones, CBZ and CAF (R2 = 0.880-0.928, p < 0.05), suggesting similarities in their sources. More than 50% of the sites exhibited a risk for antimicrobial resistance (RQAMR) with RQAMR > 1 for ciprofloxacin, indicating a significant public health concern. The ecotoxicological risk assessment of PPCPs showed no risk to any organisms, except for triclosan, which posed a risk to fish and daphnids at one site near an open drain in Buckingham canal.

New insight into the spatiotemporal distribution and ecological risk assessment of endocrine-disrupting chemicals in the Minjiang and Tuojiang rivers: perspective of watershed landscape patterns

This study evaluated the pollution characteristics, spatiotemporal distribution, and ecological risks of eight endocrine-disrupting chemicals (EDCs) in the Minjiang and Tuojiang rivers. Utilizing 3S technology (ArcGIS, remote sensing, GPS) and Fragstats, the research calculated eight landscape pattern indices related to land use types along the Minjiang river and established correlations between landscape factors and EDC distribution through stepwise multiple regression. The results indicated that bisphenol A (BPA) and nonylphenol (NP) were the most concerning EDCs, with detection frequencies of 97-100% and peak concentrations up to 63.35 ng L-1, primarily located in the middle and lower reaches of the Minjiang river and the upper reaches of the Tuojiang river. There was a significant correlation between the spatial distribution of pollutants and landscape patterns, where increased fragmentation, a higher number of patches, and complex patch shapes within a 10-kilometer buffer zone were associated with elevated levels of river pollution. By integrating four classical mathematical models to fit curves for acute and chronic toxicity data of BPA and NP, the findings suggested that BPA posed a higher ecological risk. This interdisciplinary research provided essential theoretical insights for investigating river pollution and its influencing factors, offering a new perspective on simultaneous river pollution control, urban functional zoning, and adjustment of watershed landscape spatial patterns from an urban planning standpoint.

Concentration of steroid hormones in sediment of surface water resources in China: systematic review and meta-analysis with ecological risk assessment

The risk quotient (RQ) related to Estrone (E1), 17β-E2 (E2), Estriol (E3) and 17α-ethynylestradiol (EE2) in sediment of water resources in China was calculated using Monte Carlo Simulation (MCS) method. Fifty-four papers with 64 data-reports included in our study. The rank order of steroid hormones in sediment based on log-normal distribution in MCS was E1 (3.75 ng/g dw) > E3 (1.53 ng/g dw) > EE2 (1.38 ng/g dw) > E2 (1.17 ng/g dw). According to results, concentration of steroid hormones including E1, E2 and E3 in sediment of Erhai lake, northern Taihu lake and Dianchi river was higher than other locations. The rank order of steroid hormones based on percentage high risk (RQ > 1) was EE2 (87.00%) > E1 (70.00%) > E2 (62.99%) > E3 (11.11%). Hence, contamination control plans for steroid hormones in sediment of water resources in China should be conducted continuously.

Distribution, migration patterns, and food chain human health risks of endocrine-disrupting chemicals in water, sediments, and fish in the Xiangjiang River

Exposure to endocrine-disrupting chemicals (EDCs) in freshwater systems has garnered increasing attention. A comprehensive analysis of the migration patterns, bioaccumulation, and consumer health risk of EDCs along the Xiangjiang River due to fish consumption from the river ecosystem was provided. Twenty natural and synthetic target EDCs were detected and analyzed from the water, sediments, and fish samples collected along the Xiangjiang River. There were significant correlations between the EDC concentrations in fish and the sediments. This revealed that EDCs in sediments play a dominant role in the uptake of EDCs by fish. The bioaccumulation factor and biota-sediment accumulation factor were calculated, with the highest values observed for nonylphenol. Pearson's correlation analysis showed that bisphenol A is the most reliable biological indicator of EDC contamination in fish. Furthermore, based on the threshold of toxicological concerns and the health risk with dietary intake, crucian carp and catfish from the Xiangjiang River pose a certain risk for children and pregnant women compared to grass carp. The Monte Carlo simulation results indicated a certain risk of cumulative ∑EDC exposure for local residents due to fish consumption.

Occurrence of organophosphorus flame retardants in Xiangjiang River: Spatiotemporal variations, potential affecting factors, and source apportionment

The environmental occurrence of organophosphorus flame retardants (OPFRs) is receiving increasing attention. However, their distribution in the Xiangjiang River, an important tributary in the middle reaches of the Yangtze River, is still uncharacterized, and the potential factors influencing their distribution have not been adequately surveyed. In this study, the occurrence of OPFRs in the Xiangjiang River was comprehensively investigated from upstream to downstream seasonally. Fourteen OPFRs were detected in the sampling area, with a total concentration (∑OPFRs) ranging from 3.16 to 462 ng/L, among which tris(1-chloro-2-propyl) phosphate was identified as the primary pollutant (ND - 379 ng/L). Specifically, ∑OPFRs were significantly lower in the wet season than in the dry season, which may be due to the dilution effect of river flow and enhanced volatilization caused by higher water temperatures. Additionally, Changsha (during the dry season) and Zhuzhou (during the wet season) exhibited higher pollution levels than other cities. According to the Redundancy analysis, water quality parameters accounted for 35.7% of the variation in the occurrence of OPFRs, in which temperature, ammonia nitrogen content, dissolved oxygen, and chemical oxygen demand were identified as the potential influencing factors, accounting for 28.1%, 27.2%, 24.1%, and 11.5% of the total variation, respectively. The results of the Positive Matrix Factorization analysis revealed that transport and industrial emissions were the major sources of OPFRs in Xiangjiang River. In addition, there were no high-ecological risk cases for any individual OPFRs, although tris(2-ethylhexyl) phosphate and tributoxyethyl phosphate presented a low-to-medium risk level. And the results of mixture risk quotients indicated that medium-risk sites were concentrated in the Chang-Zhu-Tan region. This study enriches the global data of OPFRs pollution and contributes to the scientific management and control of pollution.

Assessment of occurrence, partitioning and ecological risk for 144 steroid hormones in Taihu Lake using UPLC-MS/MS with machine learning model

Steroid hormones (SHs) have attracted mounting attention due to their endocrine-disrupting effects on humans and aquatic organisms. However, the lack of analytical methods and toxicity data for a large number of SHs has limited the effective management of SH contamination in the water-sediment systems. In this study, we developed a highly sensitive analytical method for the simultaneous quantification of 144 SHs to investigate their occurrence, spatial distribution and partitioning in the water and sediment in Taihu Lake. The results showed that the total concentrations of SHs in water and sediment were 366.88-998.23 ng/L (mean: 612.84 ng/L) and 17.46-150.20 ng/g (mean: 63.41 ng/g), respectively. The spatial distribution of SHs in Taihu Lake might be simultaneously influenced by the pollution sources, lake hydrodynamics, and sediment properties. The sediment-water partitioning result implied that 28 SHs were in dynamic equilibrium at the water-water interface. In addition, 22 and 12 SHs tended to spread to water and settle into sediment, respectively. To assess the ecological risk of all SHs, a robust random forest model (R2 = 0.801) was developed to predict the acute toxicity of SHs for which toxicity data were not available from publications. Risk assessment showed that SHs posed a high ecological risk throughout Taihu Lake, with the highest risk in the northwestern areas. Estrone, 17β-estradiol and 17α-ethynylestradiol were the dominant risk contributors and were therefore recommended as the priority SHs in Taihu Lake. This work provided a valuable dataset for Taihu Lake, which would help to provide guidance and suggestions for future studies and be useful for the government to develop the mitigation and management measures.

Novel biosensor for high-throughput detection of progesterone receptor-interacting endocrine disruptors

Progesterone receptor (PR)-interacting compounds in the environment are associated with serious health hazards. However, methods for their detection in environmental samples are cumbersome. We report a sensitive activity-based biosensor for rapid and reliable screening of progesterone receptor (PR)-interacting endocrine disrupting chemicals (EDCs). The biosensor is a cell line which expresses nuclear mCherry-NF1 and a green fluorescent protein (GFP)-tagged chimera of glucocorticoid receptor (GR) N terminus fused to the ligand binding domain (LBD) of PR (GFP-GR-PR). As this LBD is shared by the PRA and PRB, the biosensor reports on the activation of both PR isoforms. This GFP-GR-PR chimera is cytoplasmic in the absence of hormone and translocates rapidly to the nucleus in response to PR agonists or antagonists in concentration- and time-dependent manner. In live cells, presence of nuclear NF1 label eliminates cell fixation and nuclear staining resulting in efficient screening. The assay can be used in screens for novel PR ligands and PR-interacting contaminants in environmental samples. A limited screen of river water samples indicated a widespread, low-level contamination with PR-interacting contaminants in all tested samples.

Water, Water Everywhere, but Every Drop Unique: Challenges in the Science to Understand the Role of Contaminants of Emerging Concern in the Management of Drinking Water Supplies

The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.

Bisphenol A contamination in aquatic environments: a review of sources, environmental concerns, and microbial remediation

The production of polycarbonate, a high-performance transparent plastic, employs bisphenol A, which is a prominent endocrine-disrupting compound. Polycarbonates are frequently used in the manufacturing of food, bottles, storage containers for newborns, and beverage packaging materials. Global production of BPA in 2022 was estimated to be in the region of 10 million tonnes. About 65-70% of all bisphenol A is used to make polycarbonate plastics. Bisphenol A leaches from improperly disposed plastic items and enters the environment through wastewater from plastic-producing industries, contaminating, sediments, surface water, and ground water. The concentration BPA in industrial and domestic wastewater ranges from 16 to 1465 ng/L while in surface water it has been detected 170-3113 ng/L. Wastewater treatment can be highly effective at removing BPA, giving reductions of 91-98%. Regardless, the remaining 2-9% of BPA will continue through to the environment, with low levels of BPA commonly observed in surface water and sediment in the USA and Europe. The health effects of BPA have been the subject of prolonged public and scientific debate, with PubMed listing more than 17,000 scientific papers as of 2023. Bisphenol A poses environmental and health hazards in aquatic systems, affecting ecosystems and human health. While several studies have revealed its presence in aqueous streams, environmentally sound technologies should be explored for its removal from the contaminated environment. Concern is mostly related to its estrogen-like activity, although it can interact with other receptor systems as an endocrine-disrupting chemical. Present review article encompasses the updated information on sources, environmental concerns, and sustainable remediation techniques for bisphenol A removal from aquatic ecosystems, discussing gaps, constraints, and future research requirements.

Review of Endocrine Disrupting Compounds (EDCs) in China's water environments: Implications for environmental fate, transport and health risks

Endocrine Disrupting Compounds (EDCs) are ubiquitous in soil and water system and have become a great issue of environmental and public health concern since the 1990s. However, the occurrence and mechanism(s) of EDCs' migration and transformation at the watershed scale are poorly understood. A review of EDCs pollution in China's major watersheds (and comparison to other countries) has been carried out to better assess these issues and associated ecological risks, compiling a large amount of data. Comparing the distribution characteristics of EDCs in water environments around the world and analyzing various measures and systems for managing EDCs internationally, the significant insights of the review are: 1) There are significant spatial differences and concentration variations of EDCs in surface water and groundwater in China, yet all regions present non-negligible ecological risks. 2) The hyporheic zone, as a transitional zone of surface water and groundwater interaction, can effectively adsorb and degrade EDCs and prevent the migration of high concentrations of EDCs from surface water to groundwater. This suggests that more attention needs to be paid to the role played by critical zones in water environments, when considering the removal of EDCs in water environments. 3) In China, there is a lack of comprehensive and effective regulations to limit and reduce EDCs generated during human activities and their discharge into the water environment. 4) To prevent the deterioration of surface water and groundwater quality, the monitoring and management of EDCs in water environments should be strengthened in China. This review provides a thorough survey of scientifically valid data and recommendations for the development of policies for the management of EDCs in China's water environment.

Socioeconomic and seasonal effects on spatiotemporal trends in estrogen occurrence and ecological risk within a river across low-urbanized and high-husbandry landscapes

Estrogen pollution is a persistent issue in rivers. This study investigated the occurrence, spatiotemporal variation mechanisms, sources, and ecological risks of estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), diethylstilbestrol (DES), and bisphenol-A (BPA) in the waters of the Zijiang River, a tributary of the middle Yangtze River. The results revealed elevated detection frequencies and estrogen concentrations in the dry season compared to the wet season, mainly due to the precipitation dilution effect. Total estrogen concentration ranged from 21.2 to 97.5 ng/L in the dry season, which was significantly correlated to spatial distributions of animal husbandry and population. Among the estrogens studied in the river, E2, BPA, and EE2 were predominant. The collective sources of E1, E2, E3, and EE2 were traced back to human and husbandry excrement, whereas BPA emitted from daily life products, contributing to 55.5% and 42.7% of the total estrogen concentration, respectively. Particularly, the average and median E1, E2, and EE2 concentrations in the river exceeded the environmental quality standards of the European Union. The total estrogenic activity dominated by EE2 exceeded the 1 ng E2/L threshold, with levels exceeding 10 ng E2/L during the dry season. The risk quotients exhibited a high ecological risk of E1 and EE2 to fish and a moderate to high ecological risk of E1 to crustaceans, EE2 to mollusks, and E2 to fish. Therefore, E1, E2, and EE2 pollution of the river may lead to both high estrogenic potency and moderate or high ecological risk; thus, they should be considered priority pollutants in the river. These results yield valuable insights into the spatiotemporal change mechanisms, sources, and ecological risks of estrogens in river water of low-urbanization and rural watersheds.

Occurrence, tissue distribution, and risk assessment of progestins, androgens, estrogens, and phenols in wild freshwater fish species

The presence of endocrine-disrupting chemicals (EDCs) in aquatic environments such as water, sediment, and sludge received more and more attention. However, the bioaccumulate properties of EDCs, particularly progestins and androgens, in various tissues of different wild freshwater fish species, as well as their effects on human health, have not been fully studied. The muscle, liver, and gills of three wild fish species obtained from the East Dongting Lake in southern China were examined for the presence of 19 EDCs (4 progestins, 5 androgens, 6 estrogens, and 4 phenols). Seventeen analytes were detected in all fish samples, and the concentrations of progestins, androgens, estrogens, and phenols ranged from ND-78.80 ng/g (wet weight, ww), ND-50.40 ng/g ww, ND-3573.82 ng/g ww, and ND-88.17 ng/g ww, respectively. The bioaccumulation of some EDCs in wild fish from East Dongting Lake was species-specific. Additionally, AND, EES, P4, and E2 were discovered in the liver at higher levels than in the muscle, suggesting that livers had a larger ability for enriching these EDCs than the muscle. Furthermore, the relationships between the fish sizes and the EDC concentrations indicated that total weight and length had a negligible impact on the bioaccumulation of EDCs in various fish species. Most importantly, the effects of EDCs on human health as a result of fish consumption were assessed. Although the estimated daily intakes (EDIs) of most EDCs were much lower compared with the corresponding acceptable daily intakes (ADIs) via consuming fish collected in this study, the EDI of EE2 in Silurus asotus was higher than the ADI of E2, indicating that Silurus asotus from East Dongting Lake should be eaten in moderation by local residents.

Insights into environmental caffeine contamination in ecotoxicological biomarkers and potential health effects of Danio rerio

Caffeine (CAF) exposures have been shown to cause several pharmacological and biological effects in target and non-target organisms. Although there are already several ecotoxicological studies with CAF in non-target organisms, they are focused on marine organisms, with relevant concentrations in these ecosystems, therefore, less ecologically relevant to freshwater ecosystems (the main ecoreceptor of this type of anthropogenic contaminant). The present study aimed to assess the chronic effects (28 days) of sub-lethal and environmentally relevant concentrations of CAF (0.16, 0.42, 1.09, 2.84, 7.40, 19.23, and 50 μg/L) in Danio rerio. Biochemical endpoints as biomarkers of antioxidant defense, biotransformation, lipid peroxidation, energy sources, and neurotransmission were assessed. CAF exposure induced alterations in antioxidant defenses (superoxide dismutase and glutathione reductase activities, and glutathione content) preventing lipid peroxidation. Lactate dehydrogenase activity decreased in all the concentrations tested, while acetylcholinesterase activity was only affected by the highest concentrations tested (19.23 and 50 μg/L). We also utilized a multi-biomarker approach (Integrated Biomarker Response version 2, IBRv2) to investigate the effects of CAF in the dispersion scope of individual biochemical responses of D. rerio. IBRv2 showed that the concentration of 50 μg/L promotes the highest stress. However, the results showed that CAF induced disturbances in the metabolic pathways studied in D. rerio. These results demonstrated the toxic effects of CAF on freshwater fish, compromising their physiological functions and evidencing the need for monitoring the residues of CAF released into the inland aquatic environments. Furthermore, this research evidence that phylogenetically and physiologically different species may present different biological responses with concern for ecologically relevant environmental conditions. In this sense, the present study generated ecotoxicologically relevant data, that can be considered by environment regulators, since the here-endpoints evaluated showed sensitivity and consistency in the evaluation of caffeine risks in freshwater environments.

An effective tool for tracking steroids and their metabolites at the watershed level: Combining fugacity modeling and a chemical indicator

Steroids have attracted concern worldwide because of their potential carcinogenicity and severe adverse effects on aquatic organisms. However, the contamination status of various steroids, particularly their metabolites, at the watershed level remains unknown. This was the first study to employ field investigations to elucidate the spatiotemporal patterns, riverine fluxes, and mass inventories, and conduct a risk assessment of 22 steroids and their metabolites. This study also developed an effective tool for predicting the target steroids and their metabolites in a typical watershed based on the fugacity model combined with a chemical indicator. Thirteen steroids in the river water and seven steroids in sediments were identified with total concentrations of 1.0-76 ng/L and <LOQ-121 ng/g, respectively. In water, the levels of steroids were higher in the dry season, but the opposite trend was observed in sediments. Approximately 89 kg/a flux of steroids were transported from the river to the estuary. Mass inventories indicated that sediments acted as crucial sinks for steroids. Steroids in rivers might pose low to medium risks to aquatic organisms. Importantly, the fugacity model combined with a chemical indicator effectively simulated the steroid monitoring results within an order of magnitude at the watershed level, and various key sensitivity parameter settings provided reliable steroid concentration predictions under different circumstances. Our results should benefit environmental management and pollution control of steroids and their metabolites at the watershed level.

A robust multi-residue method for the monitoring of 25 endocrine disruptors at ultra-trace levels in surface waters by SPE-LC-MS/MS

Estrogenic endocrine disruptors are one of the biggest ecotoxicological threats in water that pose a significant ecological burden and health-risk for humans due to their high biological activity and proven additive effects. Therefore, we have developed and validated the most comprehensive and ultra-sensitive analytical method published to date, for reliable quantification of 25 high-risk endocrine disruptors at their ecologically relevant concentrations: naturally excreted hormones (estradiol, estrone, estriol, testosterone, corticosterone, and progesterone), synthetic hormones used for contraception and menopausal symptoms (ethinylestradiol, drospirenone, chlormadinone acetate, norgestrel, gestodene, tibolone, norethindrone, dienogest, and cyproterone) and bisphenols (BPS, BPA, BPF, BPE, BPAF, BPB, BPC, and BPZ). It is based on a solid-phase extraction of water samples, followed by a robust dansyl chloride derivatization with detection by liquid chromatography-tandem mass spectrometry with a single sample preparation and two analytical methods using the same analytical column and mobile phases. The achieved limits of quantitation are in the sub-ng L^-1 range, and detection limits as low as 0.02 ng L^-1, meeting the newest proposal for environmental quality standards (EQS) by the EU water framework directive for estradiol and ethinylestradiol. The method was extensively validated and applied to seven representative Slovenian water samples, where we detected 21 out of 25 analytes; 13 were quantified in at least one sample. Estrone and progesterone were quantified in all samples, reaching levels up to 50 ng L^-1; ethinylestradiol was higher than the current EQS (0.035 ng L^-1) in three samples, and estradiol was above its EQS (0.4 ng L^-1) in one sample, proving the method's applicability and the necessity for monitoring these pollutants.

Distribution and source apportionment of phenolic EDCs in rivers in the Pearl River Delta, South China

The sources and distribution characteristics of three phenolic endocrine-disrupting compounds (EDCs), e.g., alkylphenols (APs) (including nonylphenols (NPs) and 4-t-octylphenol (OP)) and Bisphenol A (BPA), were investigated in the rivers of the Pearl River Delta Region (PRDR) with complex land-use types. The mean concentrations of NPs, OP, and BPA in river water including wet and dry seasons were 87, 6, and 74 ng/L in the agricultural regions (n = 10), 135, 7, and 61 ng/L in the transitional regions (n = 8), and 249, 15, and 152 ng/L in the urban regions (n = 28). Contents of NPs and BPA were high in the river sediments (ranged from 7 to 3048 ng/g and 2 to 271 ng/g, respectively). Equilibrium analysis results suggested that sediment release was not the main source of the river EDCs. Principal component analysis (PCA) showed that sewage was the major source of EDCs in the dry season, while the leaching effect of rainfall on the agricultural soils, urban roads, and commercial products was an important source in the wet season. Furthermore, the ratio of APs and total concentration of phenolic EDCs (ΣEDCs) was used to characterize the agricultural regions and urban regions in the PRDR. The ratio was less than 0.6 in the agricultural regions while the ratio was large than 0.6 in the dry season and less than 0.6 in the wet season in urban regions. BPA and NPs in transitional region and urban region had small/medium potential risk to aquatic organisms.

Occurrence, distribution, and ecological risk assessment of pharmaceuticals and personal care products in the surface water of the middle and lower reaches of the Yellow River (Henan section)

Pharmaceuticals and personal care products (PPCPs) are commonly seen emerging organic contaminants in aquatic environments. The transects for the occurrence and distribution of 24 PPCPs along the middle and lower reaches of the Yellow River (Henan section) were investigated in this study. All 24 targeted compounds were detected in surface water, with concentrations in the range from not detected (ND) to 527.4 ng/L. Among these PPCPs, caffeine is found to have the highest concentration and its detection frequency is 100%. The total PPCP concentration ranged from 136 ng/L to 916 ng/L (median, 319.5 ng/L). Spatial analysis showed that the pollution level of PPCPs in the trunk stream was lower than that in most tributaries in the middle and lower reaches of the Yellow River (Henan section). The ecotoxicological risk assessment indicated that norfloxacin, azithromycin, estrone, and triclosan posed high risks to aquatic organisms (RQ > 1), roxithromycin and oxytetracycline imposed moderate risks (0.1 ≤ RQ < 1), and the tributary Jindi River had the highest mixed risk (MRQ = 222).

Environmental fate and toxicity of androgens: A critical review

Androgens are released by humans and livestock into the environment and which cause potent endocrine disruptions even at nanogram per liter levels. In this article, we reviewed updated research results on the structure, source, distribution characteristics and the fate of androgens in ecological systems; and emphasized the potential risk of androgens in aquatic organism. Androgens have moderately solubility in water (23.6-58.4 mg/L) and moderately hydrophobic (log Kow 2.75-4.40). The concentration of androgens in surface waters were mostly in ng/L ranges. The removal efficiencies of main wastewater treatment processes were about 70-100%, except oxidation ditch and stabilization ponds. Sludge adsorption and microbial degradation play important role in the androgens remove. The conjugated androgens were transformed into free androgens in environmental matrices. Global efforts to provide more toxicity data and establish standard monitoring methods need a revisit. Of the day available, there is an urgent need for comprehensive consideration of the impact of androgens on the environment and ecology.

A New Method for Environmental Risk Assessment of Pollutants Based on Multi-Dimensional Risk Factors

Pollutant discharge causing the deterioration of the watershed environment has seriously threatened human health and ecosystem function. The importance of improving the risk warning system is becoming more and more prominent. Traditional chemical risk assessment methods focused on toxicity and the exposure of pollutants without considering the impact of persistent pollutants in different environmental media. In this study, a new approach was proposed to reflect multi-dimensional evaluation with a synthetic risk factor (SRF) of pollutants. The integrating parameters of SRF include toxicity endpoint values, environmental exposure level, persistent properties, and compartment features. Selected pesticides, perfluorinated compounds, organophosphate esters and endocrine disruptors were analyzed by the proposed and traditional methods. The results showed a higher risk outcome using SRF analysis for PFOS, imazalil, testosterone, androstenedione and bisphenol A, which were different from those obtained by the traditional method, which were consistent with existing risk management. The study demonstrated that the SRF method improved the risk assessment of various pollutants in different environmental media in a more robust fashion, and also provided a more accurate decision basis for ecological environment protection.

Sexual hormones in a coastal river adjacent to the Bohai Sea: Characteristic pollutants and dominantly influencing factors

Characteristic sexual hormones (SHs) and the factors that dominantly influence their occurrence in coastal ecosystems are less understood. This study verified the relationships between SHs and environmental factors and further inferred the possible controlling mechanisms of SH distribution. A characteristic pollutant of SHs was first proposed by determining the contamination level and ecological risks of SHs (seven species) in a coastal river adjacent to the Bohai Sea. The results showed that the 17β-oestradiol (17β-E2), estriol (E3), and 17α-ethynylestradiol (EE2) had high mean concentrations of 11.20 (±1.31), 10.17 (±4.91), and 16.71 (±0.88) ng L^-1, respectively, in the river water. The concentration of estrone (E1) was positively related to microbial substances of DOMs (p < 0.05). The humification index (HIX) had a negative relationship with E3 (p < 0.05). In water, the distribution of total SHs was regulated by the HIX and fluorescence index (FI), which might be related to photodegradation reactions. The 17α-oestradiol (17α-E2) and EE2 were related to humified organic matter, while E3 and androstenedione (ADD) were influenced by sewage input. The 17β-E2, E1, and 17α-E2 may be derived from animal sources, while E3, ADD, EE2, and progesterone were from human activities. Oestrogens, including E1, 17α-E2, 17β-E2, and EE2, displayed higher ecological risks than androgens and progesterone, with medium to high risk in most sites. The 17β-E2 was regarded as a characteristic pollutant of SHs throughout the river system, which displayed the highest risk. This paper may provide a reference for SH risk management and control.

Dealing with complex contamination scenarios: using a multi-geochemical approach to assess environmental quality and identify pollution sources in a semi-arid estuary from Brazil

The Jundiaí-Potengi Estuary (EJP) is located on the semi-arid coast of northeastern Brazil and is influenced by multiple sources of contamination. The sediment quality of EJP was assessed by using a multi-geochemical approach during the dry and wet seasons. Sediments were analyzed for concentrations of nutrients, metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, hormones (natural and synthetic), and sterols. The results were integrated by multivariate methods. The sediment was altered by the presence of contaminants from anthropogenic and natural sources. The middle and lower estuarine areas were considered more degraded in both seasons. In these regions, metals, hormones, sterols, and PAHs were found, indicating that these regions are severely affected by industrial, sanitary and aquaculture effluents, combustion of fossil fuels, and oil spills. The upstream region was contaminated by pesticides. The contamination pattern along the EJP shows the prevalence of local sources which continuously release the chemicals into the estuary. Worse conditions occurred during the rainy season, when the runoff from urban and rural areas is more intense and carries a greater load of contaminants to the EJP.

Cyp17a effected by endocrine disruptors and its function in gonadal development of Hyriopsis cumingii

Estrogens and androgens that coexist in the aquatic environment could potentially affect shellfish, however, endocrine disrupting effects of them in shellfish are significant. As an important aquaculture shellfish in China, Hyriopsis cumingii has remarkable economic benefits. In this study, the effects of endocrine disrupting chemicals on the steroid synthase Hc-Cyp17a in the male and female gonads of the H. cumingii were assessed by exposing juvenile mussels to cultured waters containing 17β-Estradiol (E2) and 17α-Methyltestosterone (MT) for 28 days. At the same time, the E2 content in the four stages of gonadal development, the expression changes of Hc-Cyp17a in gonadal development and its localization in the mature gonad were measured to explore the relationship between genes and hormones. The results showed that both E2 and MT at 50 ng/L and 200 ng/L could affect the transcription level of Hc-Cyp17a, which was inhibited initially and promoted in post-development. E2 content was positively correlated with gonadal development stage, which was in mussel. By tracing the expression of Hc-Cyp17a, difference was found during different developmental periods. The expression level in ovary was higher than that in testis during gonadal development of 1/ 2/ 3-year-old mussels and showed an increasing trend with age. Furthermore, the expression levels in 6 tissues of mature individuals were measured and it showed that there was a significant difference between male and female in the gonads (p < 0.01). In situ hybridization, it suggested that Hc-Cyp17a was significantly signaled in the follicular wall and oocyte of female and in the follicular membrane of testis, respectively. These results could play a vital role in assessing and understanding the effects of aquatic environment on the endocrine system of H. cumingii.

A review on advances in removal of endocrine disrupting compounds from aquatic matrices: Future perspectives on utilization of agri-waste based adsorbents

In the recent past, a class of emerging contaminants particularly endocrine disrupting compounds (EDCs) in the aquatic environment have gained a lot of attention. This is due to their toxic behaviour, affecting endocrine activities in humans as well as among aquatic animals. Presently, there are no regulations and discharge limits for EDCs to preclude their negative impact. Furthermore, the conventional treatment processes fail to remove EDCs efficiently. This necessitates the need for more research aimed at development of advanced alternative treatment methods which are economical, efficient, and sustainable. This paper focusses on the occurrence, fate, toxicity, and various treatment processes for removal of EDCs. The treatment processes (physical, chemical, biological and hybrid) have been comprehensively studied highlighting their advantages and disadvantages. Additionally, the use of agri-waste based adsorption technologies has been reviewed. The aim of this review article is to understand the prospect of application of agri-waste based adsorbents for efficient removal of EDCs. Interestingly, research findings have indicated that the use of these low-cost and abundantly available agri-waste based adsorbents can efficiently remove the EDCs. Furthermore, the challenges and future perspectives on the use of agri-waste based adsorbents have been discussed.

Comparison of 17β-Estradiol Adsorption on Corn Straw- and Dewatered Sludge-Biochar in Aqueous Solutions

Removal of steroid hormones from aqueous environment is of prevailing concern because of their adverse impact on organisms. Using biochar derived from biomass as adsorbent to remove pollutants has become more popular due to its low cost, effectiveness, and sustainability. This study evaluated the feasibility of applying corn straw biochar (CSB) and dewatered sludge biochar (DSB) to reduce 17β-estradiol (E2) from aquatic solutions by adsorption. The experimental results showed that the adsorption kinetics and isotherm behavior of E2 on the two biochars were well described by the pseudo-second-order (R2 > 0.93) and Langmuir models (R2 > 0.97). CSB has higher E2 adsorption capacity than DSB, and the maximum adsorption capacity was 99.8 mg/g obtained from Langmuir model at 298 K, which can be attributed to the higher surface area, porosity, and hydrophobicity of this adsorbent. Higher pH levels (>10.2) decreased the adsorption capacities of biochar for E2, while the ionic strength did not significantly affect the adsorption process. The regeneration ability of CSB was slightly better than that of DSB. The possible adsorption mechanism for E2 on biochar is suggested as π−π interactions, H−bonding, and micropores filling. These results indicated that CSB has more potential and application value than DSB on reducing E2 from aqueous solutions when considering economy and removal performance.

Estrogen Receptors Mediated Negative Effects of Estrogens and Xenoestrogens in Teleost Fishes-Review

Estrogen receptors (ERs) play a key role in many biochemical and physiological processes, that are involved in maintaining organism homeostasis. At the most basic level, they can be divided into nuclear estrogen receptors and membrane estrogen receptors that imply their effect in two ways: slower genomic, and faster non-genomic. In these ways, estrogens and xenoestrogens can negatively affect animal health and welfare. Most of the available literature focuses on human and mammalian physiology, and clearly, we can observe a need for further research focusing on complex mutual interactions between different estrogens and xenoestrogens in aquatic animals, primarily fishes. Understanding the mechanisms of action of estrogenic compounds on the ERs in fishes and their negative consequences, may improve efforts in environmental protection of these animals and their environment and benefit society in return. In this review, we have summarized the ER-mediated effects of xenoestrogens and estrogens on teleost fishes metabolism, their carcinogenic potential, immune, circulatory, and reproductive systems.

Pollution Characteristics and Risk Prediction of Endocrine Disruptors in Lakes of Wuhan

As a new and ubiquitous trace organic pollutant, endocrine-disrupting compounds (EDCs) can cause endocrine-disrupting effects on organisms even at low levels. However, little information is available on the resource and assessment of EDC risks in the water environment. The study area was selected based on the paucity of information on the pollution status of inland lakes. Wuhan has numerous and diverse types of lakes which receive micropollutants from different pathways. In this study, the spatial distribution, occurrence, quantity and ecological risks of EDCs in 12 lakes were investigated. Five EDCs, including 17-alpha-ethinylestradiol (17α-EE₂), estrone (E₁), β-estradiol (β-E₂), estriol (E₃) and bisphenol A (BPA) were detected in surface waters. The distribution of EDC content in the lakes was ordered as follows: exurban zone < suburban area < urban areas. The pollution sources in remote lakes mainly included agricultural and aquaculture wastewater, while those in suburban and urban areas included domestic or industrial wastewater. Areas with higher EDC content were frequently related to agricultural activities, aquaculture water or dense populations. Water quality parameters, including dissolved oxygen, pH and water temperature, were significantly related to the occurrence and distribution of EDCs in the lakes. Risk assessment demonstrated that the occurrence of EDCs posed minimum to medium risk to aquatic organisms in the lakes. The results showed that the lakes faced a threat hormone pollution though it was at lower doses and, thus, the ecological risk of EDCs should be considered in future environmental policies and decisions in China.

High microwave responsivity Co-Bi25FeO40 in synergistic activation of peroxydisulfate for high efficiency pollutants degradation and disinfection: Mechanism of enhanced electron transfer

Cobalt doped Bi₂₅FeO₄₀ was used as a heterogeneous catalyst in microwave (MW) co-activation of peroxydisulfate (PDS) system for organic contaminant purification and disinfection simultaneously. Due to low charge-transfer resistance and fast electron migration, Co-Bi₂₅FeO₄₀ showed superior catalytic efficiencies for activation PDS to degrade over 92.0% of bisphenol A (BPA) with the initial concentrations ranging from 40 mg/L to 120 mg/L in 5.0 min. The non-radical oxidation pathway via electron transfer regime on the surface of Co-Bi₂₅FeO₄₀ was the dominant reactive species in the reaction system. Benefit from the energy transfer and cross-coupling reactions of microwave, the Co-Bi₂₅FeO₄₀/MW/PDS system can generate abundant reactive sites to facilitate the formation of more surface-bonding complexes. Microwave energy can be absorbed by Co-Bi₂₅FeO₄₀ catalysts to promote activation of PDS and production of nanobubbles. The generated nanobubbles increase the temperature of the local solution to promote the reaction. The Co-Bi₂₅FeO₄₀/MW/PDS system also exhibited excellent bactericidal capability for Escherichia coli (E.coli). The catalysts, oxidants and microwaves acted on E. coli to form physical, and oxidative pressure simultaneously, causing cell damaged and made bacterial death. This work provides prospects toward high-efficiency integration of contaminant purification and pathogenic microorganisms inactivation.

Single and mixture toxicity evaluation of three phenolic compounds to the terrestrial ecosystem

Endocrine-disrupting chemicals (EDCs) are primarily studied regarding endocrine-mediated effects in mammals and fish. However, EDCs can cause toxicity by mechanisms outside the endocrine system, and, as they are released continuously into soils, they may pose risks to terrestrial organisms. In this work, the plant Allium cepa and the earthworm Eisenia foetida were used as test systems to evaluate the toxicity and cyto-/geno-toxicity of three environmental phenols known as EDCs (Bisphenol A - BPA, Octylphenol - OP, Nonylphenol - NP). The tested phenols were evaluated in environmentally relevant concentrations (μg/L) and in single forms and mixture. BPA, OP, and NP did not inhibit the seed germination and root development in A. cepa in their single forms and mixture. However, all single forms of the tested phenols caused cellular and DNA damages in A. cepa, and although these effects persist in the mixtures, the effects were verified at lower levels. These phenols caused acute toxicity to E. foetida after 48 h of exposure and at both conditions evaluated (single forms and mixture); however, unlike A. cepa, in earthworms, mixtures and single forms presented the same level of effects, indicating that interspecies physiological different might influence the mixture toxicity. In summary, our results suggest that BPA, OP, and NP are toxicants to earthworm and cyto-/geno-toxicants to monocotyledonous plants at low concentrations. However, interaction among these phenols reduces the magnitude of their individual effects (antagonistic effect) in the plant test system. Therefore, this study draws attention to the need to raise knowledge about the ecotoxicity of phenolic compounds to help predict their ecological risks and protect non-target terrestrial species.

A critical review on the distribution and ecological risk assessment of steroid hormones in the environment in China

During past two decades, steroid hormones have raised significant public concerns due to their potential adverse effects on the hormonal functions of aquatic organisms and humans. Considering China being a big producer and consumer of steroid hormones, we summarize the current contamination status of steroid hormones in different environmental compartments in China, and preliminarily assess the associated risks to ecological systems. The results show that steroid hormones are ubiquitously present in Chinese surface waters where estrogens are the most studied steroids compared with androgens, progestogens and glucocorticoids. Estrone (E1), 17β-estradiol (17β-E2) and estriol (E3) are generally the dominant steroid estrogens in Chinese surface waters, whereas for the other steroids, androsterone (ADR), epi-androsterone (EADR), progesterone (PGT), cortisol (CRL) and cortisone (CRN) have relatively large contributions. Meanwhile, the investigations for the other environmental media such as particles, sediments, soils and groundwater have been limited, as well as for steroid conjugates and metabolites. The median risk quotients of most steroid hormones in surface waters and sediments are lower than 1, indicating low to moderate risks to local organisms. This review provides a full picture of steroid distribution and ecological risks in China, which may be useful for future monitoring and risk assessment. More studies may focus on the analysis of steroid conjugates, metabolites, solid phase fractions, analytical method development and acute/chronic toxicities in different matrices to pursue a more precise and holistic risk assessment.

A review of 17α-ethynylestradiol (EE2) in surface water across 32 countries: Sources, concentrations, and potential estrogenic effects

17α-ethynylestradiol (EE2) is a synthetic estrogen with very strong estrogenic potency. Due to its wide usage in human and livestock as well as its high recalcitration to biodegradation, it was ubiquitous in different environment. This review summarized EE2 concentration levels in surface waters among 32 countries across seven continents. EE2 concentrations varied greatly in different surface waters, which ranged from not detected to 17,112 ng/L. The top 10 countries ranked in the order of high to low average EE2 concentration in surface water, were Vietnam, Cambodia, China, Laos, Brazil, Argentina, Kuwait, Thailand, Indonesia and Portugal, with the respective mean concentrations of 27.7, 22.1, 21.5, 21.1, 13.6, 9.6, 9.5, 8.8, 7.6 and 6.6 ng/L. Generally speaking, the EE2 concentration levels in surface waters in developing countries were much higher than those in developed countries. EE2 in effluent of municipal wastewater treatment plant (WWTP) was the dominant source to most countries, which suggested that improving the EE2 removal performance of municipal WWTP is the key to mitigate EE2 contamination to surface water body. Livestock, hospital, pharmacy factory and aquaculture wastewaters were also the important sources, but further work should be performed to elucidate their contribution. Evaluation based on estrogenic effects, the EE2-derived estrogen equivalence in surface waters ranged from 0 to 33 ng E2/L, among which about 65% of surface waters among 32 countries were at risk or high risk, indicating global serious EE2 contamination. MAIN FINDING: EE2 concentration in surface waters across 32 countries were summarized, along which its potential estrogenic effects were evaluated.

Screening priority indicator pollutants in full-scale wastewater treatment plants by non-target analysis

Wastewater treatment plants (WWTPs) are the main sources of emerging contaminants (ECs) in aquatic environment. However, the standards for limiting emerging pollutants in effluent are extremely lacking. We investigated the occurrence and removal of emerging pollutants in 16 WWTPs in China using non-target analysis. 568 substances screened out were divided into 9 kinds including 167 pharmaceuticals, 113 natural substances, 85 pesticides, 86 endogenous substances, 64 chemical raw materials, 14 personal care products, 17 food additives, 6 hormones and 16 others. And they were divided into 5 fates. Pesticides and pharmaceutical compounds seemed to be the most notable categories, the kinds detected in each sample is the largest compared with other compounds. Besides, the average removal rate of pesticides and pharmaceuticals in all WWTPs were the lowest, at 9.54% and 23.77%, respectively. Priority pollutants were screened by considering distribution of pollutants with different fates. Pollutants with the same fate especially "consistent" in different WWTPs had attracted attention. 4 potential priority pollutants including metoprolol, carbamazepine, 10, 11-dihydro-10, 11-dihydroxycarbamazepine and irbesartan were proposed. And it was found that the 4 compounds, "consistent suspects" and "consistent non-targets" had similar rankings of removal rate in 16 WWTPs, which can reflect the performance of different WWTPs.

The anaerobic biodegradation of emerging organic contaminants by horizontal subsurface flow constructed wetlands

The horizontal subsurface flow constructed wetland (HFCW) is widely studied for the treatment of wastewater containing emerging organic contaminants (EOCs): pharmaceuticals, personal care products, and steroidal hormones. This study evaluates the performance of HFCW for the removal of these types of EOCs based on the data collected from peer-reviewed journal publications. In HFCW, anaerobic biodegradation is an important removal mechanism of EOCs besides their removal by the filter media (through sedimentation, adsorption, and precipitation) and plant uptake. The average removal efficiency of 18 selected EOCs ranged from 39% to 98%. The moderate to higher removal efficiency of 12 out of 18 selected EOCs in HFCW indicates the suitability of this type of constructed wetland (CW) for the treatment of wastewater containing these EOCs. The reasonably good removal (>50% in most of the cases) of these EOCs in HFCW might be due to the occurrence of anaerobic biodegradation as one of their major removal mechanisms in CWs. Although the effluent concentration of EOCs was substantially decreased after the treatment, the environmental risk posed by them was not fully reduced in most of the cases. For instance, estimated risk quotient of 11 out of 18 examined EOCs was extremely high for the effluent of HFCW.

Cancer risk landscapes: A framework to study cancer in ecosystems

Cancer is a family of diseases that has been documented in most metazoan species and ecosystems. Human induced environmental changes are increasingly exposing wildlife to carcinogenic risk factors, and negative repercussions on ecosystems and on the conservation of endangered species are already been observed. It is therefore of key importance to understand the spatiotemporal variability of those risk factors and how they interact with the biosphere to mitigate their effects. Here we introduce the concept of cancer risk landscape that can be applied to understand how species are exposed to, interact with, and modify cancer risk factors. With this publication we aim to provide a framework in order to stimulate a discussion on how to mitigate cancer-causing risk factors.

Occurrence and distribution of natural and synthetic progestins, androgens, and estrogens in soils from agricultural production areas in China

The occurrence of biologically potent sex hormones in agricultural soils is of growing concern due to their ability to disrupt the endocrine systems of aquatic organisms after being transported to surface waters via runoff. This study, therefore, examined the large-scale occurrence of 34 natural and synthetic sex hormones (13 progestins, 16 androgens, and 5 estrogens) in soils from 7 provinces and 1 municipality in China. The target sex hormones were detected in 99.3% of the soil samples, indicating their widespread occurrence in most agricultural areas. Additionally, seven synthetic progestins were detected in soils for the first time. The total concentration of the 34 sex hormones (Σsex hormones) in the sampled soils ranged from below the method detection limit to 23.7 ng/g (mean of 4.72 ± 4.07 ng/g), with androgens and progestins being the most dominant hormone groups. Significant correlations were observed among the concentrations of Σestrogens, Σandrogens, and Σprogestins (r = 0.117-0.433, p < 0.001), suggesting similar sources of sex hormones. The mean concentration of Σsex hormones varied considerably across the selected provinces/municipality. Notably, the annual slaughter of poultry and swine (R² = 0.75-0.88), female population (R² = 0.57-0.58), and soil organic carbon content (R² = 0.20-0.55) in each province were significantly correlated with the concentrations or mean concentrations of Σsex hormones, Σestrogens, or Σprogestins. This finding implies that these parameters contributed to the occurrence and distribution of sex hormones in the studied soils. Finally, risk quotients for some sex hormones exceeded 0.01, indicating medium or high risks to agroecosystems. This study highlights the importance of designing an optimal manure fertilization strategy in order to mitigate the risks posed by sex hormones in agroecosystems.

Occurrence and distribution of hormones and bisphenol A in Laguna Lake, Philippines

The occurrence of hormones and hormone-like compounds in water has been regarded as an emerging environmental concern. These water contaminants are known to cause endocrine disruption that may affect aquatic organisms. In this study, hormones and phenolic xenoestrogens were investigated and measured in the surface waters of Laguna Lake, Philippines. Laguna Lake is the largest lake in the country that has many uses including fish cultivation and source for potable water production. The hormones estrone, 17-beta-estradiol, 17-alpha-ethynylestradiol, progesterone and testosterone as well as the plasticizer bisphenol A in the lake water were determined by solid phase extraction and LC-MS/MS. The extraction method exhibited good recoveries (75-90% in spiked lake water) while the instrumental method of analysis has low detection limits (0.01-0.24 μg/L) and good linear response (>99% in the 0-50 μg/L concentration range). In the nine sampling sites across the lake, estrone was found in concentrations between 0.03 and 0.30 ng/L. 17-Beta-estradiol, testosterone and progesterone were detected in some of the sites in concentrations up to 0.36, 0.22, and 2.05 ng/L, respectively. Bisphenol A was detected in all sites in higher concentrations of 0.71-47.40 ng/L. Although there are no local guidelines yet, the determination and monitoring of these emerging water contaminants are important because of their potential environmental impacts. Further to this initial study, investigations on point sources spanning the tributary rivers, long-term determination of locational and temporal variations, and assessment of ecotoxicological risks are needed. These are crucial in the regulation and mitigation of discharges into the lake.

Occurrence, fate, persistence and remediation of caffeine: a review

Pharmaceutical and personal care products (PPCPs) have gained attention in recent years due to their continuous discharge in natural waters. Their persistence in the environment has impacted flora, fauna and human being worldwide. One of the most common PPCPs is caffeine (1, 3, 7-trimethylxanthine) which acts as a stimulant to the central nervous system in humans and is found in nature in about 60 plant species, especially in coffee, tea and cacao plants. Here we discuss the evidence with respect to caffeine occurrence, its persistence and remediation in light of increasing knowledge and the impact of caffeine on the environment. Daily intake of caffeine around the world is found to increase due to the frequent introduction of new caffeinated beverages as well as increased consumption of coffee, tea and carbonated soft drinks, which has led to increase in its concentration in water bodies including agricultural soil. The caffeine concentration in different water system, studied by various authors is also described. Diverse effects of the use of caffeine on several organisms including humans are also briefly presented. Therefore, urgent attention for the removal of caffeine and its derivatives is the need of the hour. Various methods described in literature for caffeine degradation/removal is also presented. Another widely used technique in environmental remediation is molecular imprinting (MIP); however, only few MIPs have been demonstrated for caffeine which is also discussed. Regular monitoring can be useful to control toxic effects of caffeine. Graphical abstract.

Occurrence, distribution, and health risk assessment of 20 personal care products in indoor and outdoor swimming pools

The distribution of 20 personal care products (PCPs), including seven preservatives, six UV filters, five anticorrosion agents, and two antimicrobials, were determined in 40 swimming pools using solid phase extraction followed by liquid chromatography-tandem mass spectrometry. Among 14 targets detected, 1H-benzotriazole and triclocarban were observed in all samples. The detected concentrations of preservatives, UV filters, anticorrosion agents, and antimicrobials were in the ranges of not detected (nd)-179 ng L^-1, nd-289 ng L^-1, nd-58.4 ng L^-1, and nd-56.9 ng L^-1, respectively. The presence of preservatives, UV filters and antimicrobials in pool waters might be mainly brought in by human activities while anticorrosion agents were mainly from the source water. Furthermore, the concentrations of methylparaben, ethylparaben, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5-chloro-1H-benzotriazole, and 5,6-dimethyl-1H-benzotriazole in indoor pools were found higher than those in outdoor pools. The longer opening time and weaker light intensity for indoor pools might cause the difference. The redundancy analysis showed significantly negative correlations between the concentrations of parabens and the contents of residual chlorine in the pool waters. A higher chlorine residue may promote the decomposition of parabens. Health risk assessment showed that skin penetration would be the main approach for the intake of PCPs by swimmers while swimming. Compared with the non-athletic swimmers, the athletic swimmers might be more sensitive, but the health risks for both groups of swimmers could be negligible.

Endocrine disrupting compounds, pharmaceuticals and personal care products in the aquatic environment of China: Which chemicals are the prioritized ones?

Endocrine disrupting compounds (EDCs), pharmaceuticals and personal care products (PPCPs) have been of great concern as emerging contaminants of aquatic environment. Therefore, there is an urgent need to identify top contaminants so as to allocate better management measures. A list of 77 pharmaceuticals, 20 personal care products (PCPs) and 36 EDCs that were frequently detected in Chinese surface waters was examined in this study. The reported chemicals were concentrated in the highly populated and industrialized areas of China (e.g. the Bohai region, Yangtze River Delta and Pearl River Delta). The concentrations of EDCs and PPCPs were closely related to human domestic sewage and industrial wastewater discharge, and they were generally higher than or at least comparable to most of global rivers. Based on the proximity between the medians of reported exposure concentrations and effect concentrations, the risk ranking results showed that EDCs, e.g. estrone (E1), estriol (E3), 17α-ethynylestradiol (EE2), and PCPs, e.g. triclocarban (TCC), triclosan (TCS), were deemed to represent higher risks to aquatic organisms across China, as well as the Northern rivers (including the Bohai region), Yangtze River Basin, and Pearl River Basin. Pharmaceuticals posed relatively lower risks to organisms owing to their higher effect concentrations. By comparison, the Northern rivers were hotspots where many chemicals were identified as posing greater risks than the Yangtze River Basin and Pearl River Basin. Fish was the most sensitive taxa to 17β-estradiol (βE2) and EE2, which was almost 100,000 times higher risk than algae and worms. Atrazine (ATZ) and galaxolide (HHCB), posed comparably higher risks to algae and worms. The results of this work provide a sound guidance for future monitoring and management of chemicals in China.

Inhibition of pancreatic lipase by environmental xenoestrogens

Environmental xenoestrogens are the most accessible endocrine disrupting chemicals that have been reported with harmful effects on human health. Although the influences of xenoestrogens on the endocrine system have been extensively studied, it remains unclear whether these xenoestrogens can affect the digestive system in mammals. This study aimed to investigate the inhibitory effects and the underlying mechanism of six non-steroidal synthetic estrogens (including hexestrol, diethylstilbestrol, dienestrol, bisphenol A, bisphenol AF and bisphenol Z) on pancreatic lipase (PL), a key digestive enzyme responsible for lipid digestion and absorption in mammals. The results clearly demonstrated that hexestrol, diethylstilbestrol and dienestrol exhibited strong inhibition on PL, with the IC₅₀ values of less than 1.0 μM. Further investigations elucidated that these three synthetic estrogens functioned as mixed inhibitors of PL, with the K_i values of less than 1 μM. Moreover, molecular dynamics simulations showed that diethylstilbestrol and its analogues might block the binding of substrate on PL via occupying the portal to the active site of PL and thereby inhibit the hydrolytic activity of this key enzyme. Collectively, these results suggested that diethylstilbestrol and its analogues were potent PL inhibitors, which might play a profound role in lipid absorption and weight gain in mammals.

Assessment of water contamination and health risk of endocrine disrupting chemicals in outdoor and indoor swimming pools

The occurrence of endocrine disrupting chemicals (EDCs) in swimming pool waters has been scarcely investigated. In this study, the concentrations of 20 EDCs (4 phenols, 6 estrogens, 4 progestogens, 5 androgens, and 1 pharmaceutical) in 40 outdoor and indoor swimming pools in Changsha, China were investigated. Out of them, two phenols (bisphenol A and 4-tert-octylphenol), three estrogens (17β-estradiol, 17ɑ-ethinlestradiol (EE2), and hexestrol), one pharmaceutical (caffeine), and two progestogens (progesterone and levonorgestrel) were detected in the collected samples. The androgens were not detected. Bisphenol A and caffeine were the dominant EDCs at concentrations of ND-23.22 ng/L and ND-39.08 ng/L, respectively. The levels of caffeine were significantly higher in indoor swimming pools (11.15 ng/L in average) than those in outdoor pools (1.90 ng/L in average) (p < 0.05), owing to the less sun's UV radiation and less use of sunscreens containing caffeine. The progestogens (progesterone and levonorgestrel) and estrogens (17β-estradiol and hexestrol) were only detected in outdoor swimming pools. The detection frequencies and concentrations of bisphenol A and caffeine in downtown pools were significantly higher than those in outskirt pools. Besides, the correlations between the concentrations of EDCs and water quality parameters evaluated by the Spearman correlation analysis implied that residual chlorine had strong oxidant capable to bisphenol A and suggested that caffeine could be a potential indicator of organic contamination in swimming pool water. Finally, a quantitative risk assessment revealed that non-athletic child and athletic adult female were vulnerable subpopulations. The EDI_total of EE2 for athletic child, non-athletic female, non-athletic male, and non-athletic child were higher than ADI_EE2 adopted by Australia and the EDI_total of EE2 for athletic female and athletic male were higher than ADI_EE2 adopted by the United States.

Degradation of bisphenol A by persulfate coupled with dithionite: Optimization using response surface methodology and pathway

The degradation efficiency of bisphenol A (BPA) was investigated in the process of persulfate (PS) coupled with dithionite (DTN) as a function of concentration of BPA, PS, DTN and solution pH. A simple response surface methodology (RSM) based on central composite design (CCD) was employed to determine the influence of individual and interaction of above variables and the optimum processing parameters. It is satisfactory of a quadratic model with low probabilities (<0.0001) at a confidence level of 95% to predict the BPA degradation efficiency. The model was well fitted to the actual data and the correlation coefficients of R² and R²-adj were 0.9270 and 0.8885, respectively. In addition, the obtained optimum conditions for BPA degradation were 1.79 μM, 131.77 μM, 93.64 μM for BPA, PS, DTN and pH = 3.62, respectively. It achieved a degradation efficiency >90% within 150 min. Moreover, the trapping experiment of active species demonstrated that SO₄^·- and ·OH were the dominant species and natural water matrix showed an obvious inhibition effect on BPA degradation. The BPA degradation pathway was predicted based on GC-MS results in this study.

Function of agricultural waste montmorillonite-biochars for sorptive removal of 17β-estradiol

Agricultural wastes of cow manure and wheat straw were used to prepare montmorillonite (Mt)-biochars (CMt and WMt) for sorptive removal of 17β-estradiol (E2) from aqueous solution. The E2 adsorption performance of the two Mt-biochars was investigated using systematic adsorption kinetics and isotherms. The results exhibited that the maximum E2 adsorption amount of CMt was 41.02 mg/g, while it was 62.89 mg/g for WMt. Meanwhile, intraparticle diffusion model demonstrated that intraparticle diffusion was not the only rate-limiting step, both film diffusion and intraparticle diffusion were involved in the diffusion process. Higher pH levels (>10) decreased the adsorption capacities of Mt-biochars for E2. However, the ionic strength and the background electrolytes did not significantly affect adsorption process. Moreover, the two Mt-biochars both exhibited excellent regeneration and reusability. These results provided a potential solution to the recycling of agricultural wastes and the problem of estrogen contaminant.

The responses of bacterial community and N2O emission to nitrogen input in lake sediment: Estrogen as a co-pollutant

Excessive nitrogen (N) input is one of the most important causative factors of lake eutrophication, which has aroused increasing public attention in past decades. Estrogen contamination is also an increasing environmental problem in aquatic systems around the world. Although both substances usually co-exist in aquatic ecosystems, many researches have only investigated the influences of either N or estrogen individually on sediment bacterial community and nitrous oxide (N₂O) emission. Knowledge regarding the combined effects of N and estrogen is still very limited. In this study, a 30-day laboratory incubation experiment was performed to examine the impacts of different N sources (ammonium and nitrate) combined with 17β-estradiol (E2) on sediment bacterial community. High-throughput 16S rRNA gene sequencing technique was used and N₂O emission was measured. The results revealed that the relative abundances of Proteobacteria and Bacteroidetes were higher in nitrate treatment than ammonium treatment. Compared to N treatments, N and E2 combined treatments showed higher relative abundances of Proteobacteria, Bacteroidetes, and Firmicutes, but lower relative abundances of Chloroflexi, Acidobacteria, and Actinobacteria over entire incubation period. At the genus level, the relative abundances of genera Flavobacterium, Pseudomonas, Arenimonas, Novosphingobium, Massilia, Aquabacterium, and Bacillus were enhanced by N treatments and especially N and E2 combined treatments, compared to sediment without addition of N and E2. However, the relative abundances of Sporacetigenium, Gaiella, Desulfatiglans, Nitrospira, and Haliangium were decreased in N treatments. Apart from the changes in bacterial community structure, N₂O emission was also influenced by different treatments. Nitrate exerted a more significant positive effect on N₂O emission than ammonium, and the cumulative emission of N₂O was highest in nitrate and E2 combined treatment. Very low abundances of ammonia monooxygenase (amoA) gene and hydroxylamine oxidase (hao) gene were observed in sediments compared to other genes involved in N cycles (such as nitrate reductase (narG and napA) genes, nitrite reductase (nirB, nirK, and nrfA) genes, and nitric oxide reductase (norB) gene), implying that denitrification rather than nitrification played an important role in sediments. The abundances of napA, nirK, and norB were higher in N and E2 combined treatments, indicating that E2 might provide a carbon source for denitrifiers. Moreover, decrease in the abundance of nitrous oxide reductase (nosZ) gene during the denitrifying process in N and E2 combined treatment might be an important reason for increases of N₂O emission. These results indicated that alterations of the bacterial community structure due to the co-existence of N and E2 could also change the abundances of genes involved in N cycle.

Utilization of activated carbon for maximizing the efficiency of zirconium oxide for photodegradation of 4-octylphenol

Utilization of AC/zirconium oxide (ZrO₂) for the removal of 4-octylphenol (4-OP) from aqueous solution has been studied under simulated visible-light as a cost effective technique. To draw complete images for the prepared materials, a series of characterization methods was performed. Brunauer-Emmett-Teller (BET) data has proved that AC has high surface area and total pore volumes that are decreased after incorporation of ZrO₂. Morphologically, TEM showed massive quantity of ZrO₂ spherical shape nanoparticles loaded with carbon and EDX showed the uniform distribution of all the prepared materials. The photocatalytic performance has been traced via adopting a matrix effect analysis to correlate the photodegradation of 4-OP in the presence of visible light as a time function, pH, photocatalyst dose and initial concentration of 4-OP. The positive impact of AC content in AC/ZrO₂ composite on the adsorption of 4-OP was strikingly observed with expanding the AC content in AC/ZrO₂ composite up to 33% (wt/wt). Almost 97% of the 4-OP was removed within 180 min under simulated visible light. The optimum reaction conditions for 95% removal of 4-OP were 120 min, 1 g L^-1 catalyst dose at pH 8. The photocatalytic degradation of the 4-OP was well fitted with pseudo first-order L-H kinetic model.