Steroid hormonal bioactivities, culprit natural and synthetic hormones and other emerging contaminants in waste water measured using bioassays and UPLC-tQ-MS

Perfluorooctane sulfonate (PFOS) and benzo[a]pyrene (BaP) synergistically induce neurotoxicity in C6 rat glioma cells via the activation of neurotransmitter and Cyp1a1-mediated steroid hormone synthesis pathways

Humans are often exposed to complex mixtures of multiple pollutants rather than a single pollutant. However, the combined toxic effects and the molecular mechanism of PFOS and BaP remain poorly understood. In this study, two typical environmental pollutants, perfluorooctane sulfonate acid (PFOS) and benzo [a]pyrene (BaP), were selected to investigate their combined neurotoxic effects on rat C6 glioma cells at environmentally relevant concentrations. The results showed that coexposure to low-dose PFOS and BaP induced greater toxicity (synergistic effect) than did single exposure. PFOS-BaP coexposure had stronger toxic effects on inducing oxidative stress and promoting early apoptosis. Targeted metabolomics confirmed that increased levels of the neurotransmitters 5-hydroxytryptophan, dopamine, tryptophan and serotonin disturb the phenylalanine, tyrosine and tryptophan biosynthesis pathways. Mechanistically, exposure to a low-dose PFOS-BaP binary mixture induces steroid hormone synthesis disorder through the activation of Cyp1a1 and Hsd17b8 (steroid hormone synthesis genes) and Dhcr24 and Dhcr7 (cholesterol synthesis genes). These findings are useful for comprehensively and systematically elucidating the biological safety of PFOS-BaP and its potential threats to human health.

Beyond the Drinking Water Directive: The use of reporter gene assays as an added tool for effect-based monitoring of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in drinking water sources

Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are legacy organic micropollutants (OMPs) that are sporadically detected in drinking water (DW) sources. The European Drinking Water Directive requires EU member states to monitor 5 PAHs in DW and its sources. The Dutch national regulations require 6 additional PAHs to be monitored and 7 polychlorinated biphenyls (PCBs). These indicator compounds act as representatives for large compound classes. PCBs alone comprise 209 congeners, it is evident that conventional chemical target analysis (GC-tQ-MS) alone is not sufficient to monitor these entire compound classes. This study investigated the application of reporter gene assays as effect-based methods (EBMs) to monitor PAHs and PCBs in DW sources. Herein, it was assessed what added value the bioassays can bring compared to the current approach of chemical target analysis for PCBs and PAHs. Regulated and non-regulated PAHs and PCBs were tested in four bioassays to determine the relative potency factors (RPFs) for these compounds. Non-regulated congeners were found to be active in the PAH-CALUX and anti-AR CALUX. An assessment of surface water (SW) spiked with standard mixtures containing PAHs and PCBs confirmed the predictable behavior of the PAH-CALUX. Moreover, the bioassay was able to detect AhR-mediated activity caused by non-regulated PAHs and PCBs, whereas this would have been missed by conventional chemical target analysis. Last, a field study was conducted in Dutch DW sources at six sampling moments. The PAH-CALUX detected AhR-mediated activity at all sampling moments and an ecological effect-based trigger (EBT) value was exceeded on multiple accounts. Combined application of GC-tQ-MS and the PAH-CALUX ensures compliancy with monitoring legislation and provides additional insights into potential hazards to humans and the environment.

Effect-directed analysis of androgenic compounds from sewage sludges in China

The safety of municipal sewage sludge has raised great concerns because of the accumulation of large-scale endocrine disrupting chemicals in the sludge during wastewater treatment. The presence of contaminants in sludge can cause secondary pollution owing to inappropriate disposal mechanisms, posing potential risks to the environment and human health. Effect-directed analysis (EDA), involving an androgen receptor (AR) reporter gene bioassay, fractionation, and suspect and nontarget chemical analysis, were applied to identify causal AR agonists in sludge; 20 of the 30 sludge extracts exhibited significant androgenic activity. Among these, the extracts from Yinchuan, Kunming, and Shijiazhuang, which held the most polluted AR agonistic activities were prepared for extensive EDA, with the dihydrotestosterone (DHT)-equivalency of 2.5 - 4.5 ng DHT/g of sludge. Seven androgens, namely boldione, androstenedione, testosterone, megestrol, progesterone, and testosterone isocaproate, were identified in these strongest sludges together, along with testosterone cypionate, first reported in sludge media. These identified androgens together accounted for 55 %, 87 %, and 52 % of the effects on the sludge from Yinchuan, Shijiazhuang, and Kunming, respectively. This study elucidates the causative androgenic compounds in sewage sludge and provides a valuable reference for monitoring and managing androgens in wastewater treatment.

Microalgae: A potential bioagent for treatment of emerging contaminants from domestic wastewater

Water crisis around the world leads to a growing interest in emerging contaminants (ECs) that can affect human health and the environment. Research showed that thousands of compounds from domestic consumers, such as endocrine disrupting chemicals (EDCs), personal care products (PCPs), and pharmaceuticals active compounds (PhAcs), could be found in wastewater in concentration mostly from ng L-1 to μg L-1. However, generally, wastewater treatment plants (WWTPs) are not designed to remove these ECs from wastewater to their discharge levels. Scientists are looking for economically feasible biotreatment options enabling the complete removal of ECs before discharge. Microalgae cultivation in domestic wastewater is likely a feasible approach for removing emerging contaminants and simultaneously removing any residual organic nutrients. Microalgal growth rate and contaminants removal efficiency could be affected by various factors, including light intensity, CO2 addition, presence of different nutrients, etc., and these parameters could greatly help make microalgae treatment more efficient. Furthermore, the algal biomass harvests could be repurposed to produce various bulk chemicals such as sustainable aviation fuel, biofuel, bioplastic, and biochar; this could significantly enhance the economic viability. Therefore, this review summarizes the microalgae-based bioprocess and their mechanisms for removing different ECs from different wastewaters and highlights the different strategies to improve the ECs removal efficiency. Furthermore, this review shows the role of different ECs in biomass profile and the relevance of using ECs-treated microalgae biomass to produce green products, as well as highlights the challenges and future research recommendations.

Identification of antimicrobial and glucocorticoid compounds in wastewater effluents with effect-directed analysis

Pharmaceuticals, such as glucocorticoids and antibiotics, are inadequately removed from wastewater and may cause unwanted toxic effects in the receiving environment. This study aimed to identify contaminants of emerging concern in wastewater effluent with antimicrobial or glucocorticoid activity by applying effect-directed analysis (EDA). Effluent samples from six wastewater treatment plants (WWTPs) in the Netherlands were collected and analyzed with unfractionated and fractionated bioassay testing. Per sample, 80 fractions were collected and in parallel high-resolution mass spectrometry (HRMS) data were recorded for suspect and nontarget screening. The antimicrobial activity of the effluents was determined with an antibiotics assay and ranged from 298 to 711 ng azithromycin equivalents·L^-1. Macrolide antibiotics were identified in each effluent and found to significantly contribute to the antimicrobial activity of each sample. Agonistic glucocorticoid activity determined with the GR-CALUX assay ranged from 98.1 to 286 ng dexamethasone equivalents·L^-1. Bioassay testing of several tentatively identified compounds to confirm their activity revealed inactivity in the assay or the incorrect identification of a feature. Effluent concentrations of glucocorticoid active compounds were estimated from the fractionated GR-CALUX bioassay response. Subsequently, the biological and chemical detection limits were compared and a sensitivity gap between the two monitoring approaches was identified. Overall, these results emphasize that combining sensitive effect-based testing with chemical analysis can more accurately reflect environmental exposure and risk than chemical analysis alone.

Photochemical reaction of glucocorticoids in aqueous solution: Influencing factors and photolysis products

Glucocorticoids (GCs), as endocrine disruptors, have attracted widespread attention due to their impacts on organisms' growth, development, and reproduction. In the current study, the photodegradation of budesonide (BD) and clobetasol propionate (CP), as targeted GCs, was investigated including the effects of initial concentrations and typical environmental factors (Cl^-, NO₂^-, Fe³⁺, and fulvic acid (FA)). The results showed that the degradation rate constants (k) were 0.0060 and 0.0039 min^-1 for BD and CP at concentration of 50 μg·L^-1, and increased with the initial concentrations. Under the addition of Cl^-, NO₂^-, and Fe³⁺ to the GCs/water system, the photodegradation rate was decreased with increasing Cl^-, NO₂^-, and Fe³⁺ concentrations, which were in contrast to the addition of FA. Electron resonance spectroscopy (EPR) analysis and the radical quenching experiments verified that GCs could transition to the triplet excited states of GCs (³GCs*) for direct photolysis under irradiation to undergo, while NO₂^-, Fe³⁺, and FA could generate ·OH to induce indirect photolysis. According to HPLC-Q-TOF MS analysis, the structures of the three photodegradation products of BD and CP were elucidated, respectively, and the phototransformation pathways were inferred based on the product structures. These findings help to grasp the fate of synthetic GCs in the environment and contribute to the understanding of their ecological risks.

Identifying antimicrobials and their metabolites in wastewater and surface water with effect-directed analysis

This study aimed to identify antimicrobial contaminants in the aquatic environment with effect-directed analysis. Wastewater influent, effluent, and surface water (up- and downstream of the discharge location) were sampled at two study sites. The samples were enriched, subjected to high-resolution fractionation, and the resulting 80 fractions were tested in an antibiotics bioassay. The resulting bioactive fractions guided the suspect and nontargeted identification strategy in the high-resolution mass spectrometry data that was recorded in parallel. Chemical features were annotated with reference databases, assessed on annotation quality, and assigned identification confidence levels. To identify antibiotic metabolites, Phase I metabolites were predicted in silico for over 500 antibiotics and included as a suspect list. Predicted retention times and fragmentation patterns reduced the number of annotations to consider for confirmation testing. Overall, the bioactivity of three fractions could be explained by the identified antibiotics (clarithromycin and azithromycin) and an antibiotic metabolite (14-OH(R) clarithromycin), explaining 78% of the bioactivity measured at one study site. The applied identification strategy successfully identified antibiotic metabolites in the aquatic environment, emphasizing the need to include the toxic effects of bioactive metabolites in environmental risk assessments.

Effect-Based Trigger Values Are Essential for the Uptake of Effect-Based Methods in Water Safety Planning

Effect-based methods (EBMs) using in vitro bioassays and well plate-based in vivo assays are recommended for water quality monitoring because they can capture the mixture effects of the many chemicals present in water. Many in vitro bioassays are highly sensitive, so an effect in a bioassay does not necessarily indicate poor chemical water quality. Consequently, effect-based trigger values (EBTs) have been introduced to differentiate between acceptable and unacceptable chemical water quality and are required for the wider acceptance of EBMs by the water sector and regulatory bodies. These EBTs have been derived for both drinking water and surface water to protect human and ecological health, respectively, and are available for assays indicative of specific receptor-mediated effects, as well as assays indicative of adaptive stress responses, apical effects, and receptor-mediated effects triggered by many chemicals. An overview of currently available EBTs is provided, and a simple approach is proposed to predict interim EBTs for assays currently without an EBT based on the effect concentration of the assay reference compound. There was good agreement between EBTs predicted using this simplistic approach and EBTs from the literature derived using more robust methods. Finally, an interpretation framework that outlines the steps to take if the effect of a sample exceeds the EBT was developed to help facilitate the uptake of EBMs in routine water quality monitoring and water safety planning for drinking water production. Environ Toxicol Chem 2023;42:714-726. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Endocrine disrupting chemicals entering European rivers: Occurrence and adverse mixture effects in treated wastewater

In the present study on endocrine disrupting chemicals (EDCs) in treated wastewater, we used chemical and effect-based tools to analyse 56 wastewater treatment plant (WWTP) effluents from 15 European countries. The main objectives were (i) to compare three different receptor-based estrogenicity assays (ERα-GeneBLAzer, p-YES, ERα-CALUX®), and (ii) to investigate a combined approach of chemical target analysis and receptor-based testing for estrogenicity, glucocorticogenic activity, androgenicity and progestagenic activity (ERα-, GR-, AR- and PR-GeneBLAzer assays, respectively) in treated wastewater. A total of 56 steroids and phenols were detected at concentrations ranging from 25 pg/L (estriol, E3) up to 2.4 μg/L (cortisone). WWTP effluents, which passed an advanced treatment via ozonation or via activated carbon, were found to be less contaminated, in terms of lower or no detection of steroids and phenols, as well as hormone receptor-mediated effects. This result was confirmed by the effect screening, including the three ERα-bioassays. In the GeneBLAzer assays, ERα-activity was detected in 82 %, and GR-activity in 73 % of the samples, while AR- and PR-activity were only measured in 14 % and 21 % of the samples, respectively. 17β-estradiol was confirmed as the estrogen dominating the observed estrogenic mixture effect and triamcinolone acetonide was the dominant driver of glucocorticogenic activity. The comparison of bioanalytical equivalent concentrations (BEQ) predicted from the detected concentrations and the relative effect potency (BEQ_chem) with measured BEQ (BEQ_bio) demonstrated good correlations of chemical target analysis and receptor-based testing results with deviations mostly within a factor of 10. Bioassay-specific effect-based trigger values (EBTs) from the literature, but also newly calculated EBTs based on previously proposed derivation options, were applied and allowed a preliminary assessment of the water quality of the tested WWTP effluent samples. Overall, this study demonstrates the high potential of linking chemical with effect-based analysis in water quality assessment with regard to EDC contamination.

Evaluation of Three ISO Estrogen Receptor Transactivation Assays Applied to 52 Domestic Effluent Samples

Estrogens are released to the aquatic environment by wastewater treatment plant (WWTP) effluents and can affect wildlife. In the last three decades, many in vitro assay platforms have been developed to detect and quantify estrogenicity in water. In 2018, the International Organization for Standardization (ISO) standardized protocols became available for three types of in vitro estrogen receptor transactivation assays (ERTAs) detecting estrogenicity in 96-well plates (ISO19040 1-3). Two ERTAs-lyticase Yeast Estrogen Screen (L-YES) and Arxula YES (A-YES)-use genetically modified yeast strains, whereas the third utilizes stably transfected human cells. One human cell based assay is ERα-CALUX, which is based on a genetically modified human bone osteosarcoma cell line. In the present study, we characterized the performance, comparability, and effectiveness of these three ERTAs, including an evaluation involving proposed water quality thresholds (effect-based trigger values [EBTs]). For a robust evaluation, we collected 52 effluent samples over three sampling campaigns at 15 different WWTPs in Switzerland. Estrogen receptor transactivation assay results were correlated and compared with results from chemical analysis targeting known estrogens. The three ERTAs showed comparable data over all campaigns. However, the selection of EBTs plays a significant role in the interpretation and comparison of bioassay results to distinguish between acceptable and unacceptable water quality. Applying a fixed cross-assay EBT for effluent of 4 ng L^-1 resulted in varying numbers of threshold exceedances ranging between zero and four samples depending on the ERTA used. Using assay-specific EBTs showed exceedances in eight samples (ERα-CALUX) and in one sample (A-YES), respectively. Thus, proposed EBTs do not produce similar risk profiles across samples and further refinement of assay-specific EBTs is needed to account for assay-specific differences and to enable the application of ERTAs as effect-based methods in environmental monitoring. Environ Toxicol Chem 2022;41:2512-2526. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Characterisation of (anti-)progestogenic and (anti-)androgenic activities in surface and wastewater using high resolution effectdirected analysis

The quality of surface waters is threatened by pollution with low concentrations of bioactive chemicals, among which those interfering with steroid hormone systems. Induced by reports of anti-progestogenic activity in surface waters, a two-year four-weekly survey of (anti-)progestogenic activity was performed at three surface water locations in the Netherlands that serve as abstraction points for the production of drinking water. As certain endogenous and synthetic progestogenic compounds are also potent (anti-)androgens, these activities were also investigated. Anti-progestogenic and anti-androgenic activities were detected in the majority of the monitoring samples, sometimes in concentrations exceeding effect-based trigger values, indicating the need for further research. To characterize the compounds responsible for the activities, a high resolution Effect-Directed Analysis (hr-EDA) panel was combined with PR and AR CALUX bioassays, performed in agonistic and antagonistic modes. The influent and effluent of a domestic wastewater treatment plant (WWTP) were included as effluent is a possible emission source of active compounds. As drivers for androgenic and progestogenic activities several native and synthetic steroid hormones were identified in the WWTP samples, namely androstenedione, testosterone, DHT, levonorgestrel and cyproterone acetate. The pesticides metolachlor and cyazofamid were identified as contributors to both the anti-progestogenic and anti-androgenic activities in surface water. In addition, epiconazole contributed to the anti-progestogenic activities in the rivers Rhine and Enclosed Meuse. This study showed the strength of hr-EDA for the identification of bioactive compounds in environmental samples and shed light on the drivers of (anti-)progestogenic and (anti-)androgenic activities in the aquatic environment.

Development and implementation of an analytical procedure for the quantification of natural and synthetic steroid hormones in whole surface waters

Natural and synthetic steroid hormones are chronically released into aquatic spheres. Whereas knowledge on their combined mode of action and the cocktail effect are needed, only few multi-class methods address the challenge of their trace quantification in surface waters. The current study describes a sensitive multi-residue analytical strategy aiming to quantify 23 steroid hormones belonging to androgens, estrogens, glucocorticoids and progestogens in whole surface waters. The procedure relies on a two-step solid-phase extraction followed by an ultra-performance liquid chromatography separation coupled to tandem mass spectrometry detection (UPLC-MS/MS). Isotope dilution was implemented when possible in order to ensure the reliability of the measurement. The procedure was optimized toward the reliable quantification of the 23 target compounds at the predicted no-effect concentrations when existing or below the ng L^-1 level. Satisfactory absolute global recoveries ≥ 77% were obtained for almost all compounds (21 out of 23) in intermediate precision conditions. Measurement errors were comprised between -27% and +17% for the great majority of compounds (21 out of 23) with standard deviations < 20% in intermediate precision conditions. Despite signal suppression was observed in water samples, satisfactory limits of quantification were achieved, ranging from 0.035 ng L^-1 for 17alpha-ethinylestradiol to 1 ng L^-1 for 6beta-hydroxycortisol and 6beta-hydroxydexamethasone. Abiotic stability was demonstrated for the great majority of target compounds (22 out of 23) in reference water samples stored at 4 ± 3 °C during 48 h, driving our sampling strategy. To demonstrate its fitness for purpose, the procedure was implemented in a preliminary monitoring survey of Belgian surface waters. As a result, 6 out of 23 target compounds were detected or quantified, showing a contamination by some estrogens and glucocorticoids at levels ranging from 0.1 to 0.9 ng L^-1.

Coupling high-performance thin-layer chromatography with a battery of cell-based assays reveals bioactive components in wastewater and landfill leachates

Over the last two decades, effect-directed analysis (EDA) gained importance as a seminal screening tool for tracking biological effects of environmental organic micro-pollutants (MPs). As EDA using high-performance liquid chromatography and bioassays is costly and time consuming, recent implementations of this approach have combined high-performance thin-layer chromatography (HPTLC) with effect-based methods (EBMs) using cell-based bioassays, enabling the detection of estrogenic, androgenic, genotoxic, photosystem II (PSII)- inhibiting, and dioxin-like sample components on a HPTLC plate. In the present study, the developed methodologies were applied as a HPTLC-based bioassay battery, to investigate toxicant elimination efficiency of wastewater treatment plants (WWTPs), and to characterize the toxic potential of landfill leachates. Activity levels detected in untreated landfill leachates, expressed as reference compound equivalence (EQ) concentration, were up to 16.8 µg β-naphthoflavone-EQ L^-1 (indicating the degree of dioxin-like activity), 1.9 µg estradiol-EQ L^-1 (estrogenicity) and 8.3 µg diuron-EQ L^‑1 (PSII-inhibition), dropping to maximal concentrations of 47 ng β-naphthoflavone-EQ L^-1, 0.7 µg estradiol-EQ L^-1 and 53.1 ng diuron-EQ L^-1 following treatment. Bisphenol A (BPA) is suggested to be the main contributor to estrogenic activity, with concentrations determined by the planar yeast estrogen screen corresponding well to results from chemical analysis. In the investigated WWTP samples, a decrease of estrogenic activity of 6-100% was observed following treatment for most of the active fractions, except of a 20% increase in one fraction (Rf = 0.568). In contrast, androgenicity with concentrations up to 640 ng dihydrotestosterone-EQ L^-1 was completely removed by treatment. Interestingly, genotoxic activity increased over the WWTP processes, releasing genotoxic fractions into receiving waters. We propose this combined HPTLC and EBM battery to contribute to an efficient, cheap, fast and robust screening of environmental samples; such an assay panel would allow to gain an estimate of potential biological effects for prioritization prior to substance identification, and its routine application will support an inexpensive identification of the toxicity drivers as a first tier in an EDA strategy.

Development of a framework to derive effect-based trigger values to interpret CALUX data for drinking water quality

Bioassays are increasingly being implemented for water quality monitoring as targeted chemical analyses are not always sufficient for the detection of all emerging chemicals or transformation products. However, the interpretation of bioassay results remains challenging, in particular because a positive response does not necessarily indicate that there may be an increased risk. For this purpose, effect-based trigger (EBT) values have been introduced as thresholds above which action needs to be undertaken to determine the cause of the response. The goals of this study were to (i) evaluate various approaches used to determine EBT values and (ii) based on the findings, derive human health EBT values for Chemical Activated LUciferase gene eXpression (CALUX) in vitro bioassays used for routine monitoring of water quality in the Netherlands. Finally, (iii) an uncertainty analysis was carried out to determine the protective power of the derived EBT values and the chance that potentially harmful substances might not be detected. EBT values that can be implemented in routine monitoring could be determined for four of eight selected bioassays. These EBT were compared to bioassay results from routine water quality monitoring carried out in the Netherlands. Furthermore, a framework for the calculation and evaluation of derived EBT values for routine application to monitor drinking water and its sources is proposed.

Using bioanalytical tools to detect and track organic micropollutants in the Ganga River near two major cities

Major rivers in India are subject to ongoing impacts from urban drain discharges, most of which contain high levels of domestic and industrial wastewater and stormwater. The aim of the present study was to determine the levels of bioactive organic micropollutants at the discharge points of major urban drains in comparison to upstream and downstream sites. To achieve this, we employed a panel of in vitro bioanalytical tools to quantify estrogenic, androgenic, progestogenic, glucocorticoid and peroxisome proliferator-like activity in water extracts collected from two Indian cities in the Ganga Basin. Cytotoxicity of the water extracts in a human-derived cell line and the potential to cause oxidative stress in a fish cell line were also investigated. We found high levels of activity for all endpoints in samples directly receiving urban drain discharge and low levels at sites upstream from drain discharges. Estrogenicity was detected at levels equivalent to 10 ng/L 17β-estradiol, representing a high likelihood of biomarker effects in fish. Sites located downstream from drain discharges exhibited low to intermediate activity in all assays. This study demonstrates the importance of managing urban drain discharges and the utility of applying bioanalytical tools to assess water quality.

Fate and behavior of progestogens in activated sludge treatment: Kinetics and transformation products

Previous studies have shown the high ecotoxicological potential of progestogens (PGs) on the reproductive system of aquatic organisms. Yet the ubiquitous presence of several PGs in wastewater treatment plant (WWTP) effluents indicates an incomplete removal during treatment. To investigate the fate and behavior of PGs during biological wastewater treatment, nine commonly used PGs were incubated in aerobic lab-scale degradation experiments with activated sludge taken from a municipal WWTP. The degradation kinetics revealed a fast removal after 48 h for most of the compounds. Cyproterone acetate and dienogest were the most recalcitrant of the analyzed steroids with half-lives of 8.65 h and 4.55 h, respectively. Thus, only moderate removals of these PGs can be predicted in full-scale WWTPs. Moreover, numerous transformation products (TPs) were detected via high-resolution mass spectrometry. Hydrogenation or dehydrogenation of ring A and non-selective hydroxylations of 17α-hydroxyprogesterone derivatives (medroxyprogesterone acetate, chlormadinone acetate, cyproterone acetate) as well as for 19-nortestosterone derivatives (dienogest, norethisterone acetate, etonogestrel) were observed as major transformation reactions. Seven of the identified TPs were confirmed by reference standards. The biodegradation of cyproterone acetate revealed an almost quantitative transformation to 3α‑hydroxy cyproterone acetate which is reported to be genotoxic. In a comparative evaluation of the TPs formed and the steroid structure, it was observed that molecular structure played a role in the inhibition of several transformation reactions, explaining the increased recalcitrance of these compounds. In addition, aromatization of the steroid ring A was identified for the 19-nortestosterone derivatives leading to the formation of estrogen-like TPs. For instance, the degradation of norethisterone acetate led to the formation of 17α-ethinylestradiol, a well-known and very potent synthetic estrogen. The evidence of the conversion of progestogenic to estrogenic compounds and the formation of potentially hazardous TPs indicates the need of a more comprehensive environmental risk assessment for synthetic steroids. Two of the newly identified TPs (3α-hydroxy cyproterone acetate and ∆9,11-dehydro-17α-cyanomethyl estradiol) were detected in WWTP effluents for the first time.

Wastewater treatment efficacy evaluated with in vitro bioassays

Bioassays show promise as a complementary approach to chemical analysis to assess the efficacy of wastewater treatment processes as they can detect the mixture effects of all bioactive chemicals in a sample. We investigated the treatment efficacy of ten Australian wastewater treatment plants (WWTPs) covering 42% of the national population over seven consecutive days. Solid-phase extracts of influent and effluent were subjected to an in vitro test battery with six bioassays covering nine endpoints that captured the major modes of action detected in receiving surface waters. WWTP influents and effluents were compared on the basis of population- and flow-normalised effect loads, which provided insights into the biological effects exhibited by the mixture of chemicals before and after treatment. Effect removal efficacy varied between effect endpoints and depended on the treatment process. An ozonation treatment step had the best treatment efficacy, while WWTPs with only primary treatment resulted in poor removal of effects. Effect removal was generally better for estrogenic effects and the peroxisome proliferator-activated receptor than for inhibition of photosynthesis, which is consistent with the persistence of herbicides causing this effect. Cytotoxicity and oxidative stress response provided a sum parameter of all bioactive chemicals including transformation products and removal was poorer than for specific endpoints except for photosynthesis inhibition. Although more than 500 chemicals were analysed, the detected chemicals explained typically less than 10% of the measured biological effect, apart from algal toxicity, where the majority of the effect could be explained by one dominant herbicide, diuron. Overall, the current study demonstrated the utility of applying bioassays alongside chemical analysis to evaluate loads of chemical pollution reaching WWTPs and treatment efficacy.

High resolution effect-directed analysis of steroid hormone (ant)agonists in surface and wastewater quality monitoring

Monitoring of chemical water quality is extremely challenging due to the large variety of compounds and the presence of biologically active compounds with unknown chemical identity. Previously, we developed a high resolution Effect-Directed Analysis (EDA) platform that combines liquid chromatography with high resolution mass spectrometry and parallel bioassay detection. In this study, the platform is combined with CALUX bioassays for (anti)androgenic, estrogenic and glucocorticoid activities, and the performance of the platform is evaluated. It appeared to render very repeatable results, with high recoveries of spiked compounds and high consistency between the mass spectrometric and bioassay results. Application of the platform to wastewater treatment plant effluent and surface water samples led to the identification of several compounds contributing to the measured activities. Eventually, a workflow is proposed for the application of the platform in a routine monitoring context. The workflow divides the platform into four phases, of which one to all can be performed depending on the research question and the results obtained. This allows one to make a balance between the effort put into the platform and the certainty and depth by which active compounds will be identified. The EDA platform is a valuable tool to identify unknown bioactive compounds, both in an academic setting as in the context of legislative, governmental or routine monitoring.

Assessing species-specific differences for nuclear receptor activation for environmental water extracts

In vitro bioassays are increasingly applied to detect endocrine disrupting chemicals (EDCs) in environmental waters. Most studies use human nuclear receptor assays, but this raises questions about their relevance for evaluating ecosystem health. The current study aimed to assess species-specific differences in the activation or inhibition of a range of human and zebrafish nuclear receptors by different water extracts. Wastewater and surface water extracts were run in transactivation assays indicative of the estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR), progesterone receptor (PR), mineralocorticoid receptor (MR), pregnane X receptor (PXR) and peroxisome proliferator-activated receptor gamma (PPARγ). The transactivation assays were complemented with competitive binding assays for human AR, GR, PR and MR. In most cases, both human and zebrafish nuclear receptor activity were detected in the water extracts. Only some species-specific differences in potency and activity were observed. Water extracts were more active in zebrafish PXR compared to human PXR whereas the opposite was observed for PPARγ. Further, all water extracts inhibited zebrafish PR, while only one extract showed weak anti-progestagenic activity for human PR. Due to these observed differences, zebrafish nuclear receptor assays may be preferable over human nuclear receptor assays to assess the potential risks of EDCs to aquatic organisms. However, recognizing issues with availability of zebrafish nuclear receptor assays and the relatively small differences in responsiveness for many of the human and zebrafish nuclear receptors, including the widely studied ER, the current study supports the continued use of human nuclear receptor assays for water quality monitoring.

Analysis of the aerobic biodegradation of glucocorticoids: Elucidation of the kinetics and transformation reactions

Glucocorticoids (GCs) are one of the most prescribed pharmaceutical classes worldwide. They have reached the focus as environmental pollutants in the current scientific research, due to their potential risks to aquatic organisms even in the lower ng L^-1 range. The objective of this study was to determine the kinetic behavior of selected GCs and to identify their main transformation products (TPs) in lab scaled biodegradation experiments. Therefore, we analyzed the removal of 13 GCs in aerated incubation experiments with activated sludge taken from a German municipal wastewater treatment plant (WWTP) as inoculum. For all steroids, an exponential decrease of the concentrations was observed, which was modelled by pseudo-first order kinetics. Overall, the rate constants k_biol. ranged from 0.07 L g_ss^-1 d^-1 (triamcinolone acetonide) to 250 L g_ss^-1 d^-1 (prednisolone). These results emphasize the broad variation in the biodegradability and recalcitrance of certain GCs. The selection of the studied GCs enabled a deduction of microbiological stability related to functional groups. Based on the identified TPs, a variety of enzymatically mediated reactions were postulated. Moreover, the identified TPs are characterized by an intact steroid core structure. Thus residual endocrine activity cannot be ruled out. The main observed reactions were regioselective hydrogenation of carbon double-bonds, degradation of the steroid C17 side-chain, ester hydrolysis and oxidative hydroxylation. In total, 41 TPs were tentatively identified and 22 of them were unambiguously confirmed via reference standards. Additionally, 12 TPs were detected in the effluents of municipal WWTPs and, to the best of our knowledge, the occurrence of eight of these TPs has been shown for the first time. These TPs might significantly contribute to the detected residual endocrine activities in the aquatic environments. Therefore, there is a strong need for efficient removal strategies, in particular for persistent steroid hormones with elevated potencies.

Statistical analysis of a large set of semi-quantitative GC-MS screening data to evaluate and prioritize organic contaminants in surface and drinking water of the Netherlands

Due to anthropogenic activities in the catchments, surface waters are contaminated with a large variety of chemical compounds. Drinking water companies in the Netherlands use surface water from the rivers Rhine, and Meuse, Lake IJssel and water from a reclaimed land area as sources for the production of drinking water. Samples from the abstraction points and the produced drinking waters were investigated using chemical screening with gas chromatography coupled to mass spectrometry to detect an as wide as possible range of organic contaminants, generating enormous data sets. This study aimed to evaluate and interpret five and a half years of screening data to get insight in the variety of known and new less polar compounds in surface and drinking waters, and to investigate if there were spatial patterns in the detection of compounds. Compounds from a wide variety of applications were detected. The vast majority of detected compounds was found only in a few samples. Certain compounds, however, e.g. organophosphate flame retardants, were detected with prevalences up to 100% per location. Most compounds were detected in samples from the rivers Rhine and Meuse, less in those from Lake IJssel and the reclaimed land area and only few in drinking water. Principal component and Hierarchical Cluster Analyses helped to detect patterns in the presence of contaminants on particular locations and to prioritize compounds for further investigation of their emission sources, and -in case of unknown compounds - their identification.

Emerging pollutants in water environment: Occurrence, monitoring, fate, and risk assessment

The occurrence of emerging pollutants (EPs) is continuously reported worldwide. Nevertheless, only few of these compounds are toxicologically evaluated due to their vast numbers. Reliable analytical methods and toxicity assessment methods are the basis of either the management or the elimination of EPs. In this paper, literature published in 2018 on EPs were reviewed with special regard to their occurrence, detection methods, fate in the environment, and ecological toxicity assessment. Particular focus was placed on practical considerations, novel processes, and new solution strategies. PRACTITIONER POINTS: Literature published in 2018 on emerging pollutants were reviewed. This review article is with special regard to the occurrence, detection methods, fate and toxicity assessment of emerging pollutants. Particular focus was placed on practical considerations, novel processes and new solution strategies.

Synthetic progestin etonogestrel negatively affects mating behavior and reproduction in Endler's guppies (Poecilia wingei)

High rates of progestins consumption in the form of active ingredients in women's oral contraceptives and other hormonal preparations may lead to their increased concentrations in aquatic environments and subsequent harmful effect on fish reproduction. The objective of the present study was to assess the effect of etonogestrel, a third-generation synthetic progestin, on the reproductive behavior, fertility, gonads histology, and secondary sexual characteristics of male and female Endler's guppies (Poecilia wingei). Fish were subjected for 34 days to two concentrations of etonogestrel, including one possibly environmentally relevant (3.2 ng L^-1) and one sublethal (320 ng L^-1) concentration. A mating behavior study was subsequently conducted and revealed that the treatment with etonogestrel significantly reduced mating frequency in the exposed fish compared to controls. All the exposed females were unable to reproduce. In addition, female fish exposed to the highest level of etonogestrel were masculinized, as their anal fins and body coloration showed patterns similar to those of male fish. Etonogestrel-exposed females also had fewer developed oocytes. In conclusion, the low etonogestrel concentration (3.2 ng L^-1) led to a reduction of mating activity in males without effect on their reproductive success, but it completely inhibited reproduction in females. Exposure to etonogestrel clearly has more severe consequences for females than males.

Do progestins contribute to (anti-)androgenic activities in aquatic environments?

Unknown compounds with (anti-)androgenic activities enter the aquatic environment via municipal wastewater treatment plants (WWTPs). Progestins are well-known environmental contaminants capable of interfering with androgen receptor (AR) signaling pathway. The aim of the present study was to determine if 15 selected progestins have potential to contribute to (anti-)androgenic activities in municipal wastewaters and the respective recipient surface waters. AR-specific Chemically Activated LUciferase gene eXpression bioassay in agonistic (AR-CALUX) and antagonistic (anti-AR-CALUX) modes and liquid chromatography tandem atmospheric pressure chemical ionization/atmospheric photoionization with hybrid quadrupole/orbital trap mass spectrometry operated in high resolution product scan mode (LC-APCI/APPI-HRPS) methods were used to assess (anti-)androgenic activity and to detect the target compounds, respectively. The contribution of progestins to (anti-)androgenic activities was evaluated by means of a biologically and chemically derived toxicity equivalent approach. Androgenic (0.08-59 ng/L dihydrotestosterone equivalents - DHT EQs) and anti-androgenic (2.4-26 μg/L flutamide equivalents - FLU EQs) activities and progestins (0.19-75 ng/L) were detected in selected aquatic environments. Progestins displayed androgenic potencies (0.01-0.22 fold of dihydrotestosterone) and strong anti-androgenic potencies (9-62 fold of flutamide). Although they accounted to some extent for androgenic (0.3-29%) and anti-androgenic (4.6-27%) activities in influents, the progestins' contribution to (anti-)androgenic activities was negligible (≤2.1%) in effluents and surface waters. We also tested joint effect of equimolar mixtures of target compounds and the results indicate that compounds interact in an additive manner. Even if progestins possess relatively strong (anti-)androgenic activities, when considering their low concentrations (sub-ng/L to ng/L) it seems unlikely that they would be the drivers of (anti-)androgenic effects in Czech aquatic environments.