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

Unlocking the roles of wheat root exudates in regulating laccase-catalyzed estrogen humification

While laccase humification has an efficient capacity to convert estrogenic pollutants, the roles of wheat (Triticum aestivum L.) root exudates (W-REs) in the enzymatic humification remain poorly understood. Herein, we presented the research into the effects of W-REs on 17β-estradiol (E2) and bisphenol A (BPA) conversion in vitro laccase humification. W-REs inhibited E2 removal but promoted BPA conversion in the enzymatic humification, and the first-order kinetic constants for E2 and BPA were 0.27-0.69 and 0.28-0.55 h-1, respectively. Specialized small phenols and amino acids in W-REs were susceptible to laccase humification, resulting in increased copolymerization of estrogen and W-REs. In greenhouse hydroponics, the accumulated amounts of E2 (BPA) in the roots and shoots were estimated to be 0.87 (2.15) and 0.43 (0.51) nmol·plant-1 at day 3, respectively. By forming low- and eventually non-toxic copolymeric precipitates between estrogen and W-REs, laccase humification lowered the phytotoxicity and bioavailability of estrogen in the rhizosphere solution, consequently relieving its uptake, accumulation, and distribution in the wheat cells. This work sheds light on the roles of W-REs in regulating laccase-catalyzed estrogen humification, and gives an insight into the path of addressing organic contamination in the rhizosphere and ensuring food safety.

Ecological consequences of antimicrobial residues and bioactive chemicals on antimicrobial resistance in agroecosystems

BACKGROUND

The widespread use of antimicrobials in agriculture, coupled with bioactive chemicals like pesticides and growth-promoting agents, has accelerated the global crisis of antimicrobial resistance (AMR). Agroecosystems provides a platform in the evolution and dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs), which pose significant threats to both environmental and public health.

AIM OF REVIEW

This review explores the ecological consequences of antimicrobial residues and bioactive chemicals in agroecosystems, with a focus on their role in shaping AMR. It delves into the mechanisms by which these substances enter agricultural environments, their interactions with soil microbiomes, and the subsequent impacts on microbial community structure.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Evidence indicates that the accumulation of antimicrobials promotes resistance gene transfer among microorganisms, potentially compromising ecosystem health and agricultural productivity. By synthesizing current research, we identify critical gaps in knowledge and propose strategies for mitigating the ecological risks associated with antimicrobial residues. Moreover, this review highlights the urgent need for integrated management approaches to preserve ecosystem health and combat the spread of AMR in agricultural settings.

Farmland's silent threat: Comprehensive multimedia assessment of micropollutants through non-targeted screening and targeted analysis in agricultural systems

Intricate agricultural ecosystems markedly influence the dynamics of organic micropollutants, posing substantial threats to aquatic organisms and human health. This study examined the occurrence and distribution of organic micropollutants across soils, ditch sediment, and water within highly intensified farming setups. Using a non-targeted screening method, we identified 405 micropollutants across 10 sampling sites, which mainly included pesticides, pharmaceuticals, industrial chemicals, and personal care products. This inventory comprised emerging contaminants, banned pesticides, and controlled pharmaceuticals that had eluded detection via conventional monitoring. Targeted analysis showed concentrations of 3.99-1021 ng/g in soils, 4.67-2488 ng/g in sediment, and 12.5-9373 ng/L in water, respectively, for Σ40pesticides, Σ8pharmaceuticals, and Σ3industrial chemicals, indicating notable spatial variability. Soil organic carbon content and wastewater discharge were likely responsible for their spatial distribution. Principal component analysis and correlation analysis revealed a potential transfer of micropollutants across the three media. Particularly, a heightened correlation was decerned between soil and sediment micropollutant levels, highlighting the role of sorption processes. Risk quotients surpassed the threshold of 1 for 13-23 micropollutants across the three media, indicating high environmental risks. This study highlights the importance of employing non-targeted and targeted screening in assessing and managing environmental risks associated with micropollutants.

The significance of environmentally bioavailable antimicrobials in driving antimicrobial resistance in soils

Antimicrobial resistance (AMR) stands as an escalating public health crisis fueled by antimicrobial residues in the environment, particularly in soil, which acts as a reservoir for antimicrobial resistance genes (ARGs). Merely quantifying the total extractable concentration of antimicrobials, instead of bioavailable fractions, may substantially underestimate their minimal selection concentration for propagating ARGs. To shed light on the role of bioavailability in ARG abundance within soil, a systematic bioavailability assessment method was established for accurately quantifying the partitioning of multi-class antimicrobials in representative Chinese soils. Microcosm studies unveiled that antimicrobials persisting in the bioavailable fraction could potentially prolong their selection pressure duration to trigger AMR. Notably, the co-occurrence of pesticide or steroid hormone influenced the development trends of ARG subtypes, with fluoroquinolone resistance genes (RGs) being particularly susceptible. Partial least squares path model (PLS-PM) analysis uncovered potentially distinct induction mechanisms of antimicrobials: observable results suggested that extractable residual concentration may exert a direct selection pressure on the development of ARGs, while bioavailable concentration could potentially play a stepwise role in affecting the abundance of mobile genetic elements and initiating ARG dissemination. Such unprecedented scrutinization of the interplay between bioavailable antimicrobials in soils and ARG abundance provides valuable insights into strategizing regulatory policy or guidelines for soil remediation.

Spatial distribution, source identification, and potential risks of 14 bisphenol analogues in soil under different land uses in the megacity of Chengdu, China

This study explored the levels, distribution, potential sources, ecological risks and estrogenic activities of 14 bisphenol analogues (BPs) in soil under eight land-use types in the megacity of Chengdu, China. Eleven BPs were detected in the soil samples and the total concentrations ranged from 32.3 to 570 ng/g d.w. Levels of bisphenol BP (BPBP) in the soil (up to 208 ng/g d.w.) only second to the most dominant compound bisphenol A (BPA) were found. Relatively higher Σ14BP accumulation in the soil was observed in the commercial and residential areas (median: 136 ng/g d.w. and 131 ng/g d.w.) compared with agricultural area (median: 67.5 ng/g d.w.). Source identification indicated the role of atmospheric particulate deposition and consecutive anthropogenic activities in BP emission. The ecotoxicity assessment implied that BPA, bisphenol S (BPS), bisphenol F (BPF) and bisphenol PH (BPPH) might pose low to medium risk to the ecosystem due to their extensive use and biological effects. The calculated 17β-estradiol equivalents of BPs were in the range of 0.501-7.74 pg E2/g d.w, and the estrogenic activities were inferior to those contributed by natural estrogens in the soil.

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.

Novel ferrofluid based on hydrophobic deep eutectic solvents for separation and analysis of trace estrogens in environmental water and urine samples

A novel ferrofluid prepared from a hydrophobic deep eutectic solvent (DES) and Fe3O4@graphite composite materials was introduced as a green microextraction medium for the separation and enrichment of trace estrogens in real samples. It was found that the ferrofluid greatly improved the capacity and selectivity of target analytes, benefiting from the enrichment of both DES and Fe3O4@graphite composite materials. Using a combination of high-performance liquid chromatography-fluorescence detection (HPLC-FLD) and vortex-assisted liquid-liquid microextraction (VALLME), a new method was established for simultaneous rapid processing and accurate determination of three estrogens (estradiol [E2], estriol [E3], and ethinyl estradiol [EE2]) in environmental water and urine samples. Key parameters affecting the extraction efficiency were optimized using a single-factor approach and response surface methodology. Under optimal conditions, this method yielded a low limit of detection (1.01 ng L-1, 3.03 ng L-1, and 25.0 ng L-1 for EE2, E2, and E3, respectively), wide linear range (3-200,000 ng L-1), high enrichment factors (9.81-47.2), and satisfactory recovery (73.8-129.0%). Compared with traditional analytical techniques, this method avoids the use of volatile toxic organic extraction solvents and cumbersome phase separation operations.

High enrichment factors in chemical analysis of progestins and in bioassays: insights beyond trace levels

Concerns are growing about adverse effects of progestins on biota, even at ultra-trace concentrations. The enrichment factor (EF) from extraction of analytes in environmental samples that is needed for sample pre-concentration can affect not only performance of the analytical method but also the matrix effect. Therefore, the present study aimed to assess the influence of high sample EF on performance of the high-performance liquid chromatography with atmospheric pressure chemical ionization and photoionization coupled with high-resolution mass spectrometry (HPLC-APCI/APPI-HRMS) method for analysis of progestins in waste water treatment plant (WWTP) effluents and surface waters and analysis of (anti-)progestogenic activities measured by (anti-)PR-CALUX bioassays. The results showed that HPLC-APCI/APPI-HRMS coupled with solid-phase extraction and a high EF (33,333 Lwater/Lextract) enabled the detection of more compounds compared to samples with lower sample EF (10,000 Lwater/Lextract). The matrix effect did not increase proportionally compared to lower EFs (10,000 and 16,666 Lwater/Lextract), and lower limits of quantification were achieved in WWTP effluents and surface waters. The results of bioassays have shown that relative EF of 25 Lwater/Lbioassay appears high enough to detect progestogenic activity in treated waste water. Our study is one of the first to provide insights into sample pre-concentration in analysis of progestins and progestogenicity in aquatic environments.

Occurrence and spatiotemporal distribution of natural and synthetic steroid hormones in soil, water, and sediment systems in suburban agricultural area of Guangzhou City, China

Steroid hormones are highly potent compounds that can disrupt the endocrine systems of aquatic organisms. This study explored the spatiotemporal distribution of 49 steroid hormones in agricultural soils, ditch water, and sediment from suburban areas of Guangzhou City, China. The average concentrations of Σsteroid hormones in the water, soils, and sediment were 97.7 ng/L, 4460 ng/kg, and 9140 ng/kg, respectively. Elevated hormone concentrations were notable in water during the flood season compared to the dry season, whereas an inverse trend was observed in soils and sediment. These observations were attributed to illegal wastewater discharge during the flood season, and sediment partitioning of hormones and manure fertilization during the dry season. Correlation analysis further showed that population, precipitation, and number of slaughtered animals significantly influenced the spatial distribution of steroid hormones across various districts. Moreover, there was substantial mass transfer among the three media, with steroid hormones predominantly distributed in the sediment (60.8 %) and soils (34.4 %). Risk quotients, calculated as the measured concentration and predicted no-effect concentration, exceeded 1 at certain sites for some hormones, indicating high risks. This study reveals that the risk assessment of steroid hormones requires consideration of their spatiotemporal variability and inter-media mass transfer dynamics in agroecosystems.

Occurrence and distribution of trisiloxane ethoxylates in citrus orchard soils in China: Analytical challenges

Trisiloxane ethoxylates (TSEOn) are widely used as agricultural surfactants due to their significant synergism with the active ingredients of pesticides, generally, including three typical end groups which are hydroxyl (TSEOn-H), methoxy (TSEOn-CH3), and acetoxy (TSEOn-COCH3), respectively. However, the potential ecotoxicological and endocrine-disrupting risks of TSEOn congeners have recently attracted ever-growing concern. Above all, there is limited research on the concentration levels of TSEOn in agroecosystems. This study, simultaneous analysis of 39 TSEOn oligomers in citrus orchard soils in China was implemented by the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The method detection limits (MDLs) and the method quantification limits (MQLs) for TSEOn were 0.003-0.07 μg/kg and 0.01-0.20 μg/kg, respectively. The recoveries for TSEOn oligomers in soils ranged from 81 % ∼ 106 % with related standard deviations (RSDs) < 7 %. This newly developed UPLC-MS/MS method with high sensitivity and stability allows us to successfully trace the occurrence of TSEOn congeners in the citrus orchard soils from 3 provinces and 1 municipality in China. The detected concentrations of TSEOn-H oligomers in the sampled soils ranged from 0.02 to 0.288 μg/kg (dry weight). The congener profiles of TSEOn-H were dominated by TSEOn-H (n = 6- 8) in the soils. Additionally, the total concentrations of TSEOn-H congeners (ΣTSEOn-H) in the soils were in the range of 0.03 to 1.49 μg/kg. A comparison of ΣTSEOn-H distribution among the different citrus orchard soils indicated a higher level of ΣTSEOn-H in the soil samples collected from Zhejiang Province. Notably, TSEOn-CH3 or TSEOn-COCH3 oligomers were not detected in the tested soils. To the best of our knowledge, this is the first report on the occurrence and distribution of TSEOn congeners in agricultural soils.

Novel insights into the mechanism of laccase-driven rhizosphere humification for alleviating wheat 17β-estradiol contamination

Global-scale crop contamination with environmental estrogens has posed a huge risk to agri-food safety and human health. Laccase is regarded as an unexceptionable biocatalyst for regulating pollution and expediting humification, but the knowledge of estrogen bioremediation and C storage strengthened by laccase-driven rhizosphere humification (LDRH) remains largely unknown. Herein, a greenhouse microcosm was performed to explore the migration and fate of 17β-estradiol (E2) in water-wheat (Triticum aestivum L.) matrices by LDRH. Compared to the non-added laccase, the pseudo-first-order decay rate constants of E2 in the rhizosphere solution after 10 and 50 μM exposures by LDRH increased from 0.03 and 0.02 h-1 to 0.36 and 0.09 h-1, respectively. Furthermore, LDRH conferred higher yield, polymerizability, O-containing groups, and functional-C signals in the humified precipitates, because it accelerated the formation of highly complex precipitates by radical-controlled continuous polymerization. In particular, not only did LDRH mitigate the phytotoxicity of E2, but it also diminished the metabolic load of E2 in wheat tissues. This was attributed to the rapid attenuation of E2 in the rhizosphere solution during LDRH, which limited E2 uptake and accumulation in each subcellular fraction of the wheat roots and shoots. Although several typical intermediate products such as estrone, estriol, and E2 oligomers were detected in roots, only small-molecule species were found in shoots, evidencing that the polymeric products of E2 were unable to be translocated acropetally due to the vast hydrophobicity and biounavailability. For the first time, our study highlights a novel, eco-friendly, and sustainable candidate for increasing the low-C treatment of organics in rhizosphere microenvironments and alleviating the potential risks of estrogenic contaminants in agroenvironments.

Unveiling the presence of endocrine disrupting chemicals in northern French soils: Land cover variability and implications

Endocrine disrupting chemicals (EDCs) are chemicals that can be found in the environment and have adverse effects on human health by mimicking, perturbing and blocking the function of hormones. They are commonly studied in water surfaces, rarely in soils, although it can be an important source of their presence in the environment. Their detection in soils is analytically challenging to quantify, hence the lack of known background concentrations found in the literature. This scientific research aimed to detect EDCs in soils by analyzing 240 soil samples using an optimized protocol of double extraction and analysis using liquid chromatography coupled to mass spectrometry. The optimized protocol allowed for very sensitive detection of the targeted compounds. The results showed a high concentration of 29.391 ng/g of 17β-estradiol in soils and 47.16 ng/g for 17α-ethinylestradiol. Testosterone and Progesterone were detected at a highest of 1.02 and 6.58 ng/g, respectively. The ∑EDCs which included estrogens, progesterone, testosterone and Bisphenol A was found at an average of 22.72 ± 35.46 ng/g in the study area. The results of this campaign showed a heterogeneous geographic distribution of the EDCs compounds in the different zones of study. Additionally, the study conducted a comparison of the concentration of EDCs in different land covers including urban areas, agricultural lands, grasslands and forests. We observed a significant difference between forests and other land covers (p < 0.0001) for 17α-ethinylestradiol, estriol, and progesterone. This presence of EDCs in forest lands is not yet understood and requires further studies concerning its origins, its fate and its effect on human health. This study is the first large-scale sampling campaign targeting EDCs in soils in Europe and the second in the world. It is also the first to assess the concentrations of these compounds based on different land covers.

Characterization and low-temperature biodegradation mechanism of 17β-estradiol-degrading bacterial strain Rhodococcus sp. RCBS9

Steroidal estrogens residues in the environment can be a serious hazard to humans and animals and has been listed as group 1 carcinogens by World Health Organization (WHO). Microbial degradation is one of the effective strategies for the removal of such contaminants. In this study, a low-temperature degrading bacterial strain (Rhodococcus sp. RCBS9) was isolated from the soil of a dairy farm for 17β-estradiol (E2) degradation. The strain RCBS9 exhibited an efficient degradation potential at low temperatures. To lean how different factors influence E2 degradation, we have found a major role of intracellular enzymes in E2 degradation. Genomic and metabolomic analyses have suggested potential degradation genes and four metabolic pathways. These findings provide valuable strain resources for the low temperature bioremediation of E2 contamination and insights into E2 biodegradation mechanism.

Biotransformation of cyproterone acetate, drospirenone, and megestrol acetate in agricultural soils: Kinetics, microbial community dynamics, transformation products, and mechanisms

The occurrence of biologically active synthetic progestins in agricultural soils is of growing concern due to their potential to disrupt the endocrine function of aquatic fish in nearby surface waters. This study investigated the biotransformation outcomes of cyproterone acetate (CPA), drospirenone (DRO), and megestrol acetate (MGA) in four agricultural soils. The biotransformation data were fitted to a first-order decay model (R2 = 0.93-0.99), with half-lives and first-order decay coefficients ranging from 76.2-217 h and 9.10 × 10-3-3.20 × 10-3 (h-1), respectively. Abundant biotransformation products (TPs) were generated during incubation, with the number and yields varying across the four soils. 1,2-Dehydrogenation was the main transformation pathway of DRO in the four soils (yields of 32.3-214 %). Similarly, 1,2-dehydrogenation was the most relevant transformation pathway of MGA in the four soils (yields of 21.8-417 %). C3 reduction was the major transformation pathway of CPA in soils B, C, and D (yields of 114-245 %). Hydrogenation (yield of 133 %) and hydroxylation (yield of 21.0 %) were the second major transformation pathway of CPA in soil B and C, respectively. In particular, several TPs exhibited progestogenic and antimineralocorticoid activity, as well as genotoxicity. The high-throughput sequencing indicated that interactions between microorganisms and soil properties may affect biotransformation. Spearman correlation and bidirectional network correlation analysis further revealed that soil properties can directly interfere with the soil sorption capacity for the progestins, thus affecting biotransformation. In particular, soil properties can also limit or promote biotransformation and the formation of TPs (i.e., biotransformation pathways) by affecting the relative abundances of relevant microorganisms. The results of this study indicate that the ecotoxicity of synthetic progestins and related TPs can vary across soils and that the assessment of environmental risks associated with these compounds requires special consideration of both soil properties and microbial communities.

Transport of prednisolone, cortisone, and triamcinolone acetonide in agricultural soils: Sorption isotherms, transport dynamics, and field-scale simulation

The occurrence of glucocorticoids (GCs) in agricultural soils has raised concerns due to their high polarity, widespread biological effects in vertebrates, and their potential to disrupt vital processes such as glucose metabolism and immune function. This study investigated the sorption and transport dynamics of three GCs, namely cortisone (COR), prednisolone (PNL), and triamcinolone acetonide (TCA) in five soil-water systems (S1-S5 systems). The sorption data of the GCs were fitted to a linear sorption model (R2 = 0.95-0.99), with organic carbon (OC) normalized sorption coefficients ranging from 2.26 ± 0.02 to 3.36 ± 0.02. The sorption magnitudes (Kd) of the GCs exhibited a nearly linear correlation with their corresponding octanol-water partition coefficients (logKow) in the S1-S3 systems. However, some deviations from linearity were observed in the S4 and S5 systems. Furthermore, a strong correlation was observed between the Kd values of the GCs and the OC% of the soils. These data indicated that specific and hydrophobic partitioning interactions governed the sorption of GCs onto soils. The transport data of the GCs were fitted to a two-site nonequilibrium model using the CXTFIT program (R2 = 0.82-0.98). The retardation factor (R) for each GC exhibited a positive correlation with the OC% and clay contents of soils. Additionally, the relationships between the logR values and logKow values of the GCs deviated slightly from linear correlation in most columns. These results indicated that specific interactions in the columns were more pronounced compared to the batch systems. An initial field-scale simulation demonstrated that frequent precipitation can facilitate the dilution and vertical transport of the GCs through soil profiles. The transport potential of the GCs was affected by the properties and soils and GCs. Overall, these findings provide valuable insights into the transport potential and associated environmental risks of GCs in soil-water systems.

Estrogens and xenoestrogen residues in manure-based fertilizers and their potential ecological risks

Optimal manure treatment aimed at usage as agricultural soil fertilizers is a prerequisite ecological pollution control strategy. In this work, livestock manure-based fertilizers were collected from 71 animal farms across 14 provinces in China. The contamination levels and potential ecotoxicological risks of residual steroid estrogens (SEs): estrone (E1), estriol (E3), 17α-estradiol (17α-E2), 17β-estradiol (17β-E2) and xenoestrogen (XE) bisphenol A (BPA), were investigated. The results showed that the occurrence frequencies for SEs and XE ranged from 66.67% to 100%, and the mean concentration varied considerably across the study locations. The total content of SEs and XE in Hebei province was the highest, and swine manure-based fertilizers concentrations were higher than the levels reported in other animal fertilizers. Compared with farm level manure, manure-based fertilizers are processed by composting, and the micropollutants quantities are significantly reduced (mean: 87.65 - 534.02 μg/kg). The total estradiol equivalent quantity (EEQ) that might migrate to the soil was estimated to be 1.23 μg/kg. Based on the estimated application rate of manure, 38% of the fertilizers risk quotients exceeded 0.1, indicating medium to high risks pressure on terrestrial organisms. Nonetheless, the estrogenic risk was lower in manure-based fertilizers than in manure. This study highlights the significance of proper treatment of livestock manure and designing an optimal manure fertilization strategy to mitigate the risks posed by SEs and XEs to the agroecosystems.

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.

Endocrine Disruption Is Reduced but Still Widespread in Wild Roach (Rutilus rutilus) Living in English Rivers

Endocrine disruption of wild fish, primarily resulting in the feminization of males, has been reported in English river sites for several decades. Estrogenic activity emanating from wastewater treatment works (WwTW) has been conclusively demonstrated to be the main driver of these feminized phenotypes. Here, we revisit 10 English river sites previously surveyed in the late 1990s and early 2000s to assess how the frequency and severity of feminization now compare with the historical surveys. In the contemporary assessment, 60% of the sites revisited still showed endocrine disruption at the tissue organization level (oocytes present in otherwise male gonads; intersex) and 90% of sites had average male plasma vitellogenin concentrations (female-specific yolk protein; a sensitive biomarker of estrogen exposure) above natural baseline levels. In contrast to the historic surveys, none of the males sampled in the contemporary survey had ovarian cavities. At one of the larger WwTW, improvements to treatment technology may have driven a significant reduction in intersex induction, whereas at several of the smaller WwTW sites, the frequencies of feminization did not differ from those observed in the late 1990s. In conclusion, we show that although the severity of feminization is now reduced at many of the revisited sites, endocrine-disrupting chemicals are still impacting wild fish living downstream of WwTW in England.

Abiotic transformation of synthetic progestins in representative soil mineral suspensions

Altrenogest (ALT), drospirenone (DRO), and melengestrol acetate (MLA) are three highly potent synthetic progestins that can be released into agricultural soils, while their fate in soil minerals remains unclear. This study explored the transformation of these progestins in MnO₂, SiO₂, and ferrihydrite suspensions and identified their transformation products (TPs) via high resolution mass spectrometry and density functional theory calculations. Transformations were only observed for DRO and MLA in SiO₂ suspension and ALT in MnO₂ suspension (half-lives = 0.86 min - 9.90 day). ALT transformation was facilitated at higher MnO₂ loadings, while DRO and MLA transformations were inhibited at higher SiO₂ loadings. These data indicated that hydrophobic partitioning interaction was dominant at higher SiO₂ loadings rather than specific interaction, which limited subsequent surface-catalyzed transformation. ALT transformation rate decreased with increasing pH because MnO₂ reduction requires proton participation. In contrast, relatively high pH facilitated MLA and DRO transformation, indicating that base-catalyzed hydrolysis occurred in SiO₂ suspension. The clustermap demonstrated the formation of abundant TPs. Lactone ring and acetoxy group hydrolysis was the major transformation pathway for DRO and MLA, with estimated yields of 57.7% and 173.2% at 6 day, respectively. ALT experienced C12 hydroxylation and formed the major TP 326g (yield of 15.4% at 8 hr). ALT also experienced allyl group oxidation and subsequent C5 hydroxylation, forming the major TP 344a (yield of 14.1% at 8 hr). This study demonstrates that TPs of metastable progestins are likely the main species in soils and that TP identification is a particular priority for risk assessment.

A Novel Estrone Degradation Gene Cluster and Catabolic Mechanism in Microbacterium oxydans ML-6

Global-scale estrone (E1) contamination of soil and aquatic environments results from the widespread use of animal manure as fertilizer, threatening both human health and environmental security. A detailed understanding of the degradation of E1 by microorganisms and the associated catabolic mechanism remains a key challenge for the bioremediation of E1-contaminated soil. Here, Microbacterium oxydans ML-6, isolated from estrogen-contaminated soil, was shown to efficiently degrade E1. A complete catabolic pathway for E1 was proposed via liquid chromatography-tandem mass spectrometry (LC-MS/MS), genome sequencing, transcriptomic analysis, and quantitative reverse transcription-PCR (qRT-PCR). In particular, a novel gene cluster (moc) associated with E1 catabolism was predicted. The combination of heterologous expression, gene knockout, and complementation experiments demonstrated that the 3-hydroxybenzoate 4-monooxygenase (MocA; a single-component flavoprotein monooxygenase) encoded by the mocA gene was responsible for the initial hydroxylation of E1. Furthermore, to demonstrate the detoxification of E1 by strain ML-6, phytotoxicity tests were performed. Overall, our findings provide new insight into the molecular mechanism underlying the diversity of E1 catabolism in microorganisms and suggest that M. oxydans ML-6 and its enzymes have potential applications in E1 bioremediation to reduce or eliminate E1-related environmental pollution. IMPORTANCE Steroidal estrogens (SEs) are mainly produced by animals, while bacteria are major consumers of SEs in the biosphere. However, the understanding of the gene clusters that participate in E1 degradation is still limited, and the enzymes involved in the biodegradation of E1 have not been well characterized. The present study reports that M. oxydans ML-6 has effective SE degradation capacity, which facilitates the development of strain ML-6 as a broad-spectrum biocatalyst for the production of certain desired compounds. A novel gene cluster (moc) associated with E1 catabolism was predicted. The 3-hydroxybenzoate 4-monooxygenase (MocA; a single-component flavoprotein monooxygenase) identified in the moc cluster was found to be necessary and specific for the initial hydroxylation of E1 to generate 4-OHE1, providing new insight into the biological role of flavoprotein monooxygenase.

Biotransformation kinetics and pathways of typical synthetic progestins in soil microcosms

Gestodene (GES), altrenogest (ALT), and medroxyprogesterone acetate (MPA) are three potent synthetic progestins detected in agricultural soils; however, their biotransformation outcomes in soils remain unclear. This study explored the biotransformation of these progestins in five agricultural soils with different physicochemical properties. The biotransformation data were well-described by a first-order decay model (R² = 0.83-0.99), with estimated half-lives ranging between 12.1 and 188 h. Amplicon sequencing indicated that the presence of progestins changed the bacterial richness and community structure in the soils. Linear correlation, canonical correlation, and two-way correlation network analysis revealed that soil properties can affect biotransformation rates by interfering with progestin-soil interactions or with keystone taxa in soils. The clustermap demonstrated the formation of abundant transformation products (TPs). Isomerization and C4(5) hydrogenation were the major transformation pathways for GES (yields of ∼ 13.7 % and ∼ 10.6 %, respectively). Aromatic dehydrogenation was the major transformation pathway for ALT (yield of ∼ 17.4 %). The C17 hydrolysis with subsequent dehydration and hydrogenation was the major transformation pathway for MPA (yield of ∼ 196 %). In particular, some TPs exhibited progestagenic, androgenic, or estrogenic activity. This study highlights the importance of evaluating the ecotoxicity of progestin and TP mixtures for better understanding their risks in the environment.

Occurrence, spatial distribution, and potential risks of organic micropollutants in urban surface waters from qinghai, northwest China

Lack of knowledge on the destiny of organic micropollutants (OMPs) in the Tibetan Plateau region of China prevents the public from being aware of the need for protecting these unique aquatic ecosystems that are precious water resources and source areas of the Yellow River. To address this knowledge gap, this study systematically investigated the multi-residue analysis, distribution, and potential risks of six types of OMPs, namely, neonicotinoid pesticides (NEOs), fungicides, organophosphate esters (OPEs), organophosphorus pesticides (OPPs), psychoactive substances (PSs), and antidepressants (ADs), in surface waters of major cities in Qinghai. A total of 31 compounds, consisting of 8 NEOs, 1 fungicide, 12 OPEs, 2 OPPs, 5 PSs, and 3 ADs, were detected in >50% of the sites, showing their ubiquitous nature in the study area. Results showed that the total OMP concentration in surface water was 28.3-908 ng/L, and OPEs were the dominant composition (48.6%-97.4%). The risk quotient values of the detected diazinon and dursban regularly exceeded 1 for aquatic organisms at all sampling sites, indicating moderate-high chronic ecological risk. The joint probability curves showed that dursban and NEOs have higher risk levels than other OMPs. Although the results of the non-carcinogenic total hazard quotient of the OMPs in the surface water was less than 1 in all age groups and the carcinogenic risk was lower than the negligible risk level, the potential risks to children and infants were considerably greater and should not be underestimated. In addition to pollutant concentration and exposure duration, ingestion rate and body weight (BW) are also important factors affecting health risk, with BW having a negative effect. To the best of the authors' knowledge, this report is the first to describe OMP pollution in Qinghai, and the results provide new insight into the ecological security of the water resources of the Tibetan Plateau.

Activation of persulfate by vanadium oxide modified carbon nanotube for 17β-estradiol degradation in soil: Mechanism, application and ecotoxicity assessment

Steroid hormones in the environment have attracted public attention because of their high endocrine-disrupting activity even at rather low exposure level. Excessive hormones in the soil from the pollutant discharge of intensive farming would pose a potential threat to the ecology and the human health. Vanadium oxide modified carbon nanotube (VO_X-CNT) was synthesized and applied as persulfate (PDS) activator to reduce17β-estrogen (17β-E2) in soil. 86.06 % 17β-E2 could be degraded within 12 h. Process of materials exchange during oxidation was interfered by soil, resulting in insufficient degradation of 17β-E2, but the active species involved in 17β-E2 degradation would also be enriched by it. 17β-E2 was adsorbed on the VO_X-CNT surface and directly degraded mainly by the active species generated on the catalyst surface, and ^•OH dominated the degradation of 17β-E2 in VO_X-CNT/PDS system. CO, defective sites and vanadium oxides on the surface of VO_X-CNT contributed to the generation of activate species. Oxidizer dosage, catalyst dosage, water-soil ratio and soil properties would affect the degradation of 17β-E2. The ecotoxicological impact on soil caused by VO_X-CNT/PDS was acceptable, and would be weakened with time. Additionally, a rapid decrease in the concentration of 17β-E2 and the promotion of maize growth were observed with VO_X-CNT/PDS in situ pilot-scale remediation. Those results reveal that VO_X-CNT/PDS is a potential technology to remove excessive steroid hormone from soil around large-scale livestock and poultry farms.

Mechanism of 17β-estradiol degradation by Rhodococcus equi via the 4,5-seco pathway and its key genes

Steroid estrogens have been detected in oceans, rivers, lakes, groundwaters, soils, and even urban water supply systems, thereby inevitably imposing serious impacts on human health and ecological safety. Indeed, many estrogen-degrading bacterial strains and degradation pathways have been reported, with the 4,5-seco pathway being particularly important. However, few studies have evaluated the use of the 4,5-seco pathway by actinomycetes to degrade 17β-estradiol (E2). In this study, 5 genes involved in E2 degradation were identified in the Rhodococcus equi DSSKP-R-001 (R-001) genome and then heterologously expressed to confirm their functions. The transformation of E2 with hsd17b14 reached 63.7% within 30 h, resulting in transformation into estrone (E1). Furthermore, we found that At1g12200-encoded flavin-binding monooxygenase (FMO_At1g12200) can transform E1 at a rate of 51.6% within 30 h and can transform E1 into 4-hydroxyestrone (4-OH E1). In addition, catA and hsaC genes were identified to further transform 4-OH E1 at a rate of 97-99%, and this reaction was accomplished by C-C cleavage at the C4 position of the A ring of 4-OH E1. This study represents the first report on the roles of these genes in estrogen degradation and provides new insights into the mechanisms of microbial estrogen metabolism and a better understanding of E2 degradation via the 4,5-seco pathway by actinomycetes.

The response of steroid estrogens bioavailability to various sorption mechanisms by soil organic matter extracted with sequential alkaline-extraction method from an agriculture soil

The long-term groundwater contamination risks posed by steroidal estrogens (SEs) in animal-manured agricultural soils are closely associated with the soil organic matter (SOM) content and composition. In this study, the bioavailability of estrone (E1) and 17β-estradiol (17β-E2) under different sorption mechanism in humic acids (HA1 and HA2) and humin (HM) extracted with sequential alkaline-extraction technique (SAET) were examined. These SOMs extracted by SAET showed various properties and sorption characteristics for SEs. The alkyl carbon and condensed SOM increased during SAET, but aromatic carbon decreased and the same trend for polarity. Quick sorption was the major SEs sorption mechanism on HA1 and HA2, which contributed more than 69%; whilst slow sorption rate was about 50% in soil and HM. The logK_oc values were proportional to the TOC of SOM according to Freundlich fitting, and the sorption capacity of sorbent for E1 and 17β-E2 was related to the logK_ow values, indicating that the main mechanism controlling the SEs sorption was hydrophobic interaction. The larger micropore volume of HM and soil was more conducive to the micropore filling of SEs. Meanwhile, the specific sorption of SEs on condensed domain of SOM was the main reason for the strong desorption hysteresis and slow sorption in HM and soil. The SEs degradation rate was positively correlated with the contribution rate of quick adsorption and negatively correlated with the contribution rate of slow adsorption, indicating that the bioavailability of SEs sorbed by hydrophobic interaction was higher than that of micropore filling or specific sorption, which was also the reason for the low bioavailability of SEs in HM and soil. This work confirms the regulation of on-site SOM compositions and their properties on SEs sorption and bioavailability. Characterization of these details is crucial for the improved prediction of long-term risks to groundwater.

Robust strategies to eliminate endocrine disruptive estrogens in water resources

The widespread occurrence and ubiquitous distribution of estrogens, i.e., estrone (E1), estradiol (E2), and estriol (E3) in our water matrices, is an issue of global concern. Public and regulatory authorities are concerned and placing joint efforts to eliminate estrogens and related environmentally hazardous compounds, due to their toxic influences on the environmental matrices, ecology, and human health, even at low concentrations. However, most of the available literature is focused on the occurrence of estrogens in different water environments with limited treatment options. Thus, a detailed review to fully cover the several treatment processes is needed. This review comprehensively and comparatively discusses many physical, chemical, and biological-based treatments to eliminate natural estrogens, i.e., estrone (E1), estradiol (E2), and estriol (E3) and related synthetic estrogens, e.g., 17α-ethinylestradiol (EE2) and other related hazardous compounds. The covered techniques include adsorption, nanofiltration, ultrafiltration, ultrasonication, photocatalysis of estrogenic compounds, Fenton, Fenton-like and photo-Fenton degradation of estrogenic compounds, electro-Fenton degradation of estrogenic compounds, ozonation, and biological methods for the removal of estrogenic compounds are thoroughly discussed with suitable examples. The studies revealed that treatment plants based on chemical and biological approaches are cost-friendly for removing estrogenic pollutants. Further, there is a need to properly monitor and disposal of the usage of estrogenic drugs in humans and animals. Additional studies are required to explore a robust and more advanced oxidation treatment strategy that can contribute effectively to industrial-scale applications. This review may assist future investigations, monitoring, and removing estrogenic compounds from various environmental matrices. In concluding remarks, a way forward and future perspectives focusing on bridging knowledge gaps in estrogenic compounds removal are also proposed.

Weighted gene Co-expression network analysis (WGCNA) reveals a set of hub genes related to chlorophyll metabolism process in chlorella (Chlorella vulgaris) response androstenedione

Androstenedione (ADSD) was the main androgen detected in wastewaters. Chlorella was the most widely used plant in biological wastewater treatment process. In order to understand the toxicological response of chlorella to ADSD contamination, we used the weighted gene co-expression network analysis (WGCNA) method to systematically analyze the gene regulatory networks of chlorella after ADSD treatments. Total of 25 modules was identified from gene co-expression networks, and the turquoise module were selected for GO and KEGG enrichment analysis. Results showed that most hub genes were associated with chloroplast organizations or photosystems processes. Among them, the expressions profiles of hcar, nol, pao and sgr genes were highly correlated to the content fluctuations of chlorophylls after different ADSD treatments. All these results demonstrated that chlorophylls play a key role in preventing cell damage of chlorella caused by ADSD contamination. Besides, we proposed a possible chlorophyll metabolism pathway in chlorella response to ADSD contamination.

Endocrine disrupting effects induced by levonorgestrel linked to altered DNA methylation in rare minnow (Gobiocypris rarus)

Progestins are worldwide environmental contaminants, however, their ecotoxicological risks and underlying molecular mechanisms of effects are not fully understood. In this study, newly hatched rare minnow (Gobiocypris rarus) larvae were exposed to environmentally realistic concentrations (1 and 10 ng/L) of levonorgestrel (LNG) for 6 months. The sex ratios were not affected by LNG at both concentrations, but the growth was significantly inhibited at 10 ng/L while promoted at 1 ng/L. Histological analysis revealed impaired gonadal development. Plasma concentrations of estradiol in females and testosterone in both sexes were significantly induced after exposure to 1 ng/L LNG; plasma concentrations of 11-ketotestosterone were markedly increased in females exposed to 10 ng/L LNG and in males exposed to both concentrations of LNG. The transcription of cyp19a1a was significantly up-regulated in ovaries exposed to LNG at both concentrations, while cyp17a1 was down-regulated in testes exposed to 10 ng/L LNG. The global DNA methylation level was significantly decreased in testes exposed to 10 ng/L LNG, which might be associated with inhibited spermatogenesis. Gender-specific changes in CpG methylation patterns were induced by LNG in the 5' flanking region of cyp19a1a, with hypomethylation in ovaries but hypermethylation in testes, which was linked to the regulation of cyp19a1a transcription. The results suggest that LNG could induce endocrine disrupting effects in fish at environmentally realistic concentrations, which may be linked to altered DNA methylation. This study indicates potentially high ecological risk of LNG to fish populations, and warrants researches on regulatory mechanisms of epigenetic modifications in progestin-induced effects.

Impact of microbial inoculants combined with humic acid on the fate of estrogens during pig manure composting under low-temperature conditions

To investigate the efficiency of psychrotrophic cellulose-degrading fungal strains (PCDFSs) and estrogen-degrading bacteria (EDBs) combined with humic acid (HA) on estrone (E1) and 17-β-estradiol (E2) degradation, five compost groups (T, HA, EDB, PCDFS, and CK) were prepared and composted for 32 days at 11-14°C. The results indicated that inoculation increased the temperature to 62.2°C and promoted E1 degradation to the lowest level of 100.1 ng/kg, while E2 was undetected from day 16. Metagenomic analysis revealed that inoculation altered the microbial community structure by increasing the abundance of cellulose-degrading fungi, especially Meyerozyma (16.7%) (among PCDFSs), and of estrogen-degrading bacteria, particularly Microbacterium (13.4%) (involved in EDBs). Moreover, inoculation increased the levels (>0.500%) of Gene Ontology (GO) associated with estrogen degradation, like 3-β-hydroxy-delta 5-steroid dehydrogenase and monooxygenase. Redundancy analysis demonstrated that temperature and Microbacterium were positively correlated with estrogen degradation. Structural equation model indicated that temperature and estrogen-degrading bacterial genera exhibited positive, significant (p < 0.001) and direct impacts on estrogen degradation. This is the first study to suggest that applying microbial inoculants and HA could accelerate estrogen degradation during composting in cold regions. The research outcomes offer a practical reference for managing compost safety, thereby decreasing its potential environmental and human health impacts.

Spatiotemporal distribution, source apportionment and risk assessment of typical hormones and phenolic endocrine disrupting chemicals in environmental and biological samples from the mariculture areas in the Pearl River Delta, China

The present work studied the levels, distribution, potential sources, ecological and human health risks of typical hormones and phenolic endocrine disrupting chemicals (EDCs) in the mariculture areas of the Pearl River Delta (PRD), China. The environmental levels of 11 hormones (6 estrogens, 4 progestogens, and 1 androgen) and 2 phenolic EDCs were quantified in various matrices including water, sediment, cultured fish and shellfish. Ultrahigh performance liquid chromatography-triple quadrupole tandem mass spectrometry analyses showed that all the 13 target compounds were detected in biotic samples, whereas 10 were detected in water and sediment, respectively. The total concentrations ranged from 35.06-364.53 ng/L in water and 6.31-29.30 ng/g in sediment, respectively. The average contaminant levels in shellfish (Ostrea gigas, Mytilus edulis and Mimachlamys nobilis) were significantly higher than those in fish (Culter alburnus, Ephippus orbis and Ephippus orbis). Source apportionment revealed that the pollution of hormones and phenolic EDCs in PRD mariculture areas was resulted from the combination of coastal anthropogenic discharges and mariculture activities. The hazard quotient values of the contaminants were all less than 1, implying no immediate human health risk. Overall, the present study is of great significance for scientific mariculture management, land-based pollution control, ecosystem protection, and safeguarding human health.

Evaluation of estrogenic and antiestrogenic activity in sludge and explanation of individual compound contributions

Mixture toxicity, including agonistic and antagonistic effects, is an unrevealed environmental problem. Estrogenic endocrine disruptors are known to cause adverse effects for aquatic biota, but causative chemicals and their contributions to the total activity in sewage sludge remain unknown. Therefore, advanced analytical methods, a yeast bioassay and mixture toxicity models were concurrently applied for the characterization of 8 selected sludges with delectable estrogenic activity (and 3 sludges with no activity as blanks) out of 25 samples from wastewater treatment plants (WWTPs). The first applied full logistic model adequately explained total activity by considering the concentrations of the monitored compounds. The results showed that the activity was primarily caused by natural estrogens in municipal WWTP sludge. Nevertheless, activity in a sample originating from a car-wash facility was dominantly caused by partial agonists - nonylphenols - and only a model enabling prediction of all dose-response curve parameters of the final mixture curve explained these results. Antiestrogenic effects were negligible, and effect-directed analysis identified the causative chemicals.

CeO2 nanostructured electrochemical sensor for the simultaneous recognition of diethylstilbestrol and 17β-estradiol hormones

A new highly sensitive, selective, and inexpensive electrochemical method has been developed for simultaneously detecting diethylstilbestrol (DES) and 17β-estradiol (E2) in environmental samples (groundwater and lake water) using a graphite sensor modified by cerium oxide nanoparticles (CPE-CeO₂ NPs). The developed sensor and the materials used in its preparation were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The ab initio simulation was used to evaluate the adsorption energies between both DES and E2 with the surface of the sensor. The peak current of oxidation of both hormones showed two regions of linearity. The region of greatest sensitivity was observed for the linear range of 10 nM-100 nM. The detection and quantification limits for this concentration range were 0.8/2.6 nM and 1.3/4.3 nM for DES and E2, respectively. The analytical performance of the developed method showed high sensitivity, precision, repeatability, reproducibility, and selectivity. The CPE-CeO₂ NPs sensor was successfully applied to simultaneously detect DES and E2 in real samples with recovery levels above 98%.

Steroid hormones in the aquatic environment

Steroid hormones are extremely important natural hormones in all vertebrates. They control a wide range of physiological processes, including osmoregulation, sexual maturity, reproduction and stress responses. In addition, many synthetic steroid hormones are in widespread and general use, both as human and veterinary pharmaceuticals. Recent advances in environmental analytical chemistry have enabled concentrations of steroid hormones in rivers to be determined. Many different steroid hormones, both natural and synthetic, including transformation products, have been identified and quantified, demonstrating that they are widespread aquatic contaminants. Laboratory ecotoxicology experiments, mainly conducted with fish, but also amphibians, have shown that some steroid hormones, both natural and synthetic, can adversely affect reproduction when present in the water at extremely low concentrations: even sub-ng/L. Recent research has demonstrated that mixtures of different steroid hormones can inhibit reproduction even when each individual hormone is present at a concentration below which it would not invoke a measurable effect on its own. Limited field studies have supported the conclusions of the laboratory studies that steroid hormones may be environmental pollutants of significant concern. Further research is required to identify the main sources of steroid hormones entering the aquatic environment, better describe the complex mixtures of steroid hormones now known to be ubiquitously present, and determine the impacts of environmentally-realistic mixtures of steroid hormones on aquatic vertebrates, especially fish. Only once that research is completed can a robust aquatic risk assessment of steroid hormones be concluded.

Recognition and Selectivity Analysis Monitoring of Multicomponent Steroid Estrogen Mixtures in Complex Systems Using a Group-Targeting Environmental Sensor

The same class of steroid estrogen mixtures, coexisting in the environment of 17β-estradiol, estrone (E1), and ethinyl estradiol (EE2), have strong ability to disrupt the human endocrine system and are seriously prejudicial to the health of the organism and environmental safety. Herein, a highly sensitive and group-targeting environmental monitoring sensor was fabricated for a comprehensive analysis of multicomponent steroid estrogens (multi-SEs) in complex systems. This breakthrough was based on the highly sensitive photoelectrochemical response composite material CdSe NPs-TiO₂ nanotube and highly group-specific aptamers. The optimized procedure exhibited not only high sensitivity in a wide range of concentrations from 0.1 to 50 nM, indeed, the minimum detection limit was 33 pM, but also strong resistance to interference. The affinity and consistent action pockets of this sensor enable selective detection of multi-SEs in complex systems. It subsequently was applied for the analysis of multi-SEs from three real samples in the environment including medical wastewater, river water, and tap water to provide a means to clarify the fate of multi-SEs in the process of migration and transformation. This monitoring sensor has a brilliant application prospect for the identification and monitoring of the same class of endocrine-disrupting chemical mixtures in environmental complex systems.

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.

In situ formation of environmental endocrine disruptors from phytosterol degradation: a temporal model for agricultural soils

We propose a conceptual model that describes the in situ formation of androstenedione in agricultural soil from a phytosterol, β-sitosterol, released after crop harvest and soil fertiliser amendment. Based on the recorded agricultural practice at a spring barley field, β-sitosterol and androstenedione concentrations were modelled over the year. While decomposition of crop residues created low soil levels, the application of pig slurry led to an androstenedione soil concentration of 54 μg kg-1. The elevated soil concentration of androstenedione is not due to the introduction of the endocrine disruptor in the fertiliser, but a result of the addition of large concentrations of β-sitosterol as a natural precursor. The limited available data on β-sitosterol and androstenedione concentration in soil prohibited their accurate prediction by our model. However, the potential implication of endocrine-disrupting steroid hormones being formed in situ from currently little considered phytosterols justifies a conceptual description and further research.