Hormone discharges from a midwest tile-drained agroecosystem receiving animal wastes

Impacts of Exposure to Ultraviolet Radiation and an Agricultural Pollutant on Morphology and Behavior of Tadpoles (Limnodynastes tasmaniensis)

Amphibians are the most threatened vertebrate class globally. Multiple factors have been implicated in their global decline, and it has been hypothesized that interactions between stressors may be a major cause. Increased ultraviolet (UV) radiation, as a result of ozone depletion, has been identified as one such stressor. Exposure to UV radiation has been shown to have detrimental effects on amphibians and can exacerbate the effects of other stressors, such as chemical pollutants. Chemical pollution has likewise been recognized as a major factor contributing to amphibian declines, particularly, endocrine-disrupting chemicals. In this regard, 17β-trenbolone is a potent anabolic steroid used in the agricultural industry to increase muscle mass in cattle and has been repeatedly detected in the environment where amphibians live and breed. At high concentrations, 17β-trenbolone has been shown to impact amphibian survival and gonadal development. In the present study, we investigated the effects of environmentally realistic UV radiation and 17β-trenbolone exposure, both in isolation and in combination, on the morphology and behavior of tadpoles (Limnodynastes tasmaniensis). We found that neither stressor in isolation affected tadpoles, nor did we find any interactive effects. The results from our 17β-trenbolone treatment are consistent with recent research suggesting that, at environmentally realistic concentrations, tadpoles may be less vulnerable to this pollutant compared to other vertebrate classes. The absence of UV radiation-induced effects found in the present study could be due to species-specific variation in susceptibility, as well as the dosage utilized. We suggest that future research should incorporate long-term studies with multiple stressors to accurately identify the threats to, and subsequent consequences for, amphibians under natural conditions. Environ Toxicol Chem 2024;00:1-12. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

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.

Degradation kinetics of veterinary antibiotics and estrogenic hormones in a claypan soil

Veterinary antibiotics and estrogens are excreted in livestock waste before being applied to agricultural lands as fertilizer, resulting in contamination of soil and adjacent waterways. The objectives of this study were to 1) investigate the degradation kinetics of the VAs sulfamethazine and lincomycin and the estrogens estrone and 17β-estradiol in soil mesocosms, and 2) assess the effect of the phytochemical DIBOA-Glu, secreted in eastern gamagrass (Tripsacum dactyloides) roots, on antibiotic degradation due to the ability of DIBOA-Glu to facilitate hydrolysis of atrazine in solution assays. Mesocosm soil was a silt loam representing a typical claypan soil in portions of Missouri and the Central United States. Mesocosms (n = 133) were treated with a single target compound (antibiotic concentrations at 125 ng g-1 dw, estrogen concentrations at 1250 ng g-1 dw); a subset of mesocosms treated with antibiotics were also treated with DIBOA-Glu (12,500 ng g-1 dw); all mesocosms were kept at 60% water-filled pore space and incubated at 25 °C in darkness. Randomly chosen mesocosms were destructively sampled in triplicate for up to 96 days. All targeted compounds followed pseudo first-order degradation kinetics in soil. The soil half-life (t0.5) of sulfamethazine ranged between 17.8 and 30.1 d and ranged between 9.37 and 9.90 d for lincomycin. The antibiotics results showed no significant differences in degradation kinetics between treatments with or without DIBOA-Glu. For estrogens, degradation rates of estrone (t0.5 = 4.71-6.08 d) and 17β-estradiol (t0.5 = 5.59-6.03 d) were very similar; however, results showed that estrone was present as a metabolite in the 17β-estradiol treated mesocosms and vice-versa within 24 h. The antibiotics results suggest that sulfamethazine has a greater potential to persist in soil than lincomycin. The interconversion of 17β-estradiol and estrone in soil increased their overall persistence and sustained soil estrogenicity. This study demonstrates the persistence of these compounds in a typical claypan soil representing portions of the Central United States.

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.

Bigger and bolder: Widespread agricultural pollutant 17β-trenbolone increases growth and alters behaviour in tadpoles (Litoria ewingii)

Endocrine-disrupting chemicals-compounds that directly interfere with the endocrine system of exposed animals-are insidious environmental pollutants that can disrupt hormone function, even at very low concentrations. The dramatic impacts that some endocrine-disrupting chemicals can have on the reproductive development of wildlife are well documented. However, the potential of endocrine-disrupting chemicals to disrupt animal behaviour has received far less attention, despite the important links between behavioural processes and population-level fitness. Accordingly, we investigated the impacts of 14 and 21-day exposure to two environmentally realistic levels of 17β-trenbolone (4.6 and 11.2 ng/L), a potent endocrine-disrupting steroid and agricultural pollutant, on growth and behaviour in tadpoles of an anuran amphibian, the southern brown tree frog (Litoria ewingii). We found that 17β-trenbolone altered morphology, baseline activity and responses to a predatory threat, but did not affect anxiety-like behaviours in a scototaxis assay. Specifically, we found that tadpoles exposed to our high-17β-trenbolone treatment were significantly longer and heavier at 14 and 21 days. We also found that tadpoles exposed to 17β-trenbolone showed higher levels of baseline activity, and significantly reduced their activity following a simulated predator strike. These results provide insights into the wider repercussions of agricultural pollutants on key developmental and behavioural traits in aquatic species, and demonstrate the importance of behavioural studies in the ecotoxicological field.

Declines in Reproductive Condition of Male Largemouth Bass (Micropterus salmoides) Following Seasonal Exposure to Estrogenic Endocrine-Disrupting Compounds

Reproductive abnormalities, that could lead to possible effects at the population level, have been observed in wild fish throughout the United States, with high prevalence in largemouth bass (LMB; Micropterus salmoides) and smallmouth bass (Micropterus dolomieu). Estrone (E1) and atrazine (ATR) are common environmental contaminants often associated with agricultural land use. 17alpha-ethinylestradiol (EE2) is a contaminant associated with wastewater treatment effluent, and a representative, well-studied estrogen commonly used for fish toxicity testing. Our objective was to assess whether early gonad recrudescence in adult fish was a period of sensitivity for alterations in reproductive condition and function. Adult male LMB were exposed from post-spawning to early gonad recrudescence to either a mixture of E1 (47.9 ng/L) + ATR (5.4 µg/L), or EE2 (2.4 ng/L) in outdoor experimental ponds. Gonad samples were collected from fish just prior to the start of exposure (July), at the end of the exposure period (December), the following spring just prior to spawning (April), and post spawning (May). Gonadosomatic index (GSI) was significantly reduced in E1 + ATR-exposed and EE2-exposed males compared to control at every post-exposure time point. Reduced sperm count and sperm motility were observed in the mixture treatment (E1 + ATR) compared to the control. Sperm motility was also reduced in the EE2 treatment. These data together indicate that estrogenic endocrine-disrupting compounds can lessen the reproductive condition of adult male LMB, and that effects of exposure during early gonad recrudescence can persist at least through the subsequent spawning cycle.

Environmental fate and toxicity of androgens: A critical review

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

Exposure to 17α-Ethinylestradiol Results in Differential Susceptibility of Largemouth Bass (Micropterus salmoides) to Bacterial Infection

Disease outbreaks, skin lesions, mortality events, and reproductive abnormalities have been observed in wild populations of centrarchids. The presence of estrogenic endocrine disrupting compounds (EEDCs) has been implicated as a potential causal factor for these effects. The effects of prior EEDC exposure on immune response were examined in juvenile largemouth bass (Micropterus salmoides) exposed to a potent synthetic estrogen (17α-ethinylestradiol, EE2) at a low (EE2_Low, 0.87 ng/L) or high (EE2_High, 9.08 ng/L) dose for 4 weeks, followed by transfer to clean water and injection with an LD₄₀ dose of the Gram-negative bacteria Edwardsiella piscicida. Unexpectedly, this prior exposure to EE2_High significantly increased survivorship at 10 d post-infection compared to solvent control or EE2_Low-exposed, infected fish. Both prior exposure and infection with E. piscicida led to significantly reduced hepatic glycogen levels, indicating a stress response resulting in depletion of energy stores. Additionally, pathway analysis for liver and spleen indicated differentially expressed genes associated with immunometabolic processes in the mock-injected EE2_High treatment that could underlie the observed protective effect and metabolic shift in EE2_High-infected fish. Our results demonstrate that exposure to a model EEDC alters metabolism and immune function in a fish species that is ecologically and economically important in North America.

Effects of the agricultural pollutant 17β-trenbolone on morphology and behaviour of tadpoles (Limnodynastes tasmaniensis)

Pollutants, such as endocrine disrupting chemicals (EDCs), are increasingly being detected in organisms and ecosystems globally. Agricultural activities, including the use of hormonal growth promotants (HGPs), are a major source of EDC contamination. One potent EDC that enters into the environment through the use of HGPs is 17β-trenbolone. Despite EDCs being repeatedly shown to affect reproduction and development, comparatively little is known regarding their effects on behaviour. Amphibians, one of the most imperilled vertebrate taxa globally, are at particular risk of exposure to such pollutants as they often live and breed near agricultural operations. Yet, no previous research on amphibians has explored the effects of 17β-trenbolone exposure on foraging or antipredator behaviour, both of which are key fitness-related behavioural traits. Accordingly, we investigated the impacts of 28-day exposure to two environmentally realistic concentrations of 17β-trenbolone (average measured concentrations: 10 and 66 ng/L) on the behaviour and growth of spotted marsh frog tadpoles (Limnodynastes tasmaniensis). Contrary to our predictions, there was no significant effect of 17β-trenbolone exposure on tadpole growth, antipredator response, anxiety-like behaviour, or foraging. We hypothesise that the differences in effects found between this study and those conducted on fish may be due to taxonomic differences and/or the life stage of the animals used, and suggest further research is needed to investigate the potential for delayed manifestation of the effects of 17β-trenbolone exposure.

Gonadal Soma-Derived Factor Expression is a Potential Biomarker for Predicting the Effects of Endocrine-Disrupting Chemicals on Gonadal Differentiation in Japanese Medaka (Oryzias Latipes)

Chemicals with androgenic or estrogenic activity induce the sex reversal and/or intersex condition in various teleost fish species. Previously, we reported that exposure to 17α-methyltestosterone, bisphenol A, or 4-nonylphenol induces changes in expression of the gonadal soma-derived factor (gsdf) gene accompanied by disruption of gonadal differentiation in Japanese medaka (Oryzias latipes). These findings suggest that gsdf expression might be a useful biomarker for predicting the potential effect of chemicals on gonadal differentiation. We examined the gsdf expression in Japanese medaka exposed to chemicals with estrogenic or androgenic activity. Exposure to the androgenic steroid 17β-trenbolone at 0.5-22.1 μg/L induced the development of ovotestis (presence of ovarian tissue with testicular tissue) and female-to-male sex reversal in XX embryos, and exposure at 6.32 and 22.1 μg/L significantly increased gsdf expression in XX embryos compared with controls at developmental stage 38 (1 day before hatching). In the present study, no statistically significant difference in gsdf mRNA expression was observed after exposure to 17β-estradiol, 17α-ethinylestradiol, and 4-t-octylphenol, which have estrogenic activity. In addition, antiandrogenic chemicals or chemicals without endocrine-disrupting activity did not induce changes in gsdf expression in XX or XY embryos. Thus, an increase in gsdf expression after androgen exposure was observed in XX embryos. Together, these findings indicate that gsdf expression might be useful for predicting the adverse effect of chemicals on gonadal differentiation. Environ Toxicol Chem 2022;41:1875-1884. © 2022 SETAC.

Fate, occurrence, and removal of estrogens in livestock wastewaters

During the last decades, livestock and animal feeding operations have been expanded. In parallel, these activities are among the major sources of estrogens in the environment. Thus, considering the environmental and health risks associated with estrogenic compounds, this work reviews the fate, occurrence, and removal of free and conjugated E1, E2, and E3 in livestock wastewaters. A systematic literature review was carried out, and after applying the eligibility criteria, 66 peer-reviewed papers were selected. Results suggest high estrogen concentrations and, consequently, high estrogenic activity, especially in samples from swine farming. E1 and E2 are frequently found in wastewaters from bovine, swine, and other livestock effluents. Aerobic treatment processes were more efficient for estrogen removal, whereas anaerobic systems seem poorly effective. Removal efficiencies of estrogens and estrogenic activity of up to 90% were reported for constructed wetlands, advanced pond systems, trickling filters, membrane bioreactors, aerated and nitrifying reactors, combined air flotation, and vegetable oil capture processes. High concentrations found in wastewaters from livestock allied to the removal efficiencies reported for anaerobic processes (usually used to treat livestock wastewaters) evidence the importance of monitoring these compounds in environmental matrices.

17β-Trenbolone binds to androgen receptor, decreases number of primordial germ cells, modulates expression of genes related to sexual differentiation, and affects sexual differentiation in zebrafish (Danio rerio)

Exposure to 17β-trenbolone caused a skewed sex ratio in fish. However, the molecular initiating event and key molecular event(s) remain unknown. In this study, zebrafish were exposed to 17β-trenbolone at nominal concentrations of 2 ng/L, 20 ng/L, 200 ng/L, and 2000 ng/L from fertilization to 60 days post fertilization (dpf). First, the sex ratio at 60 dpf was calculated to evaluate adverse outcomes on sexual differentiation. 17β-Trenbolone caused a skewed sex ratio toward males, with intersex individuals observed in the 20 ng/L group and all-male populations found in the 200 ng/L and 2000 ng/L groups. Then, the distribution and number of primordial germ cells, the expression of sex differentiation-related genes, and plasma vitellogenin concentrations were detected in wild-type zebrafish and the EGFP-nanos-3'UTR transgenic line using whole-mount in situ hybridization, real-time PCR, EGFP fluorescence quantification, and enzyme-linked immunosorbent assay. The results indicated that 17β-trenbolone exposure decreased the number of primordial germ cells at 1 dpf and 3 dpf, decreased expression of ovarian differentiation-related genes foxl2 and cyp19a1a at 60 dpf, increased expression of testis differentiation-related genes dmrt1, sox9a, and amh at 60 dpf, and decreased plasma vitellogenin levels at 60 dpf, revealing the key molecular events at different time points involved in affected sexual differentiation by 17β-trenbolone. Finally, molecular docking showed that 17β-trenbolone docked into ligand-binding domain of zebrafish androgen receptor with high binding energy (-3.72 kcal/mol), suggesting that binding to androgen receptor is the molecular initiating event affecting sexual differentiation by 17β-trenbolone. We found that 17β-trenbolone can bind to the zebrafish androgen receptor, decrease the number of primordial germ cells during the early embryonic stage, modulate the expression of genes related to sexual differentiation during gonadal differentiation, and eventually cause a skewed sex ratio toward males in adults.

Brightened body coloration in female guppies (Poecilia reticulata) serves as an in vivo biomarker for environmental androgens: The example of 17β-trenbolone

In vivo testing systems for environmental androgens are scarce. The aim of this study was to evaluate the potential of male-specific brightened body coloration in female guppies (Poecilia reticulata) to serve as an in vivo biomarker of environmental androgens using 17β-trenbolone as an example. The high bioaccumulation of 17β-trenbolone in the skin of female guppies suggests that it is a potential target tissue of environmental androgens. The coloration index, pigment cell ultrastructure, pigment levels, sexual attractiveness, and reproductive capability of female guppies were analyzed following 28 days of exposure to 20 ng/L, 200 ng/L, and 2000 ng/L 17β-trenbolone. Increases in the coloration index caused by 17β-trenbolone exposure were attributable to increased pteridine and melanin levels. Decreases in the sexual attractiveness, number of offspring, and survival rate of offspring suggested that the changes in body coloration translated into adverse outcomes. Finally, mRNA sequencing indicated that 17β-trenbolone increased pteridine levels by activating genomic effects of androgen receptor on xanthine dehydrogenase and increased melanin levels by exerting non-genomic effects targeting microphthalmia-associated transcription factor, tyrosinase, and tyrosinase-related protein 1 that were mediated by mitogen-activated protein kinase and calcium signaling pathways. We have derived a robust adverse outcome pathway of environmental androgens, and our findings suggest that indicators at different biological levels related to brightened body coloration in female guppies can serve as less-invasive or noninvasive in vivo biomarkers of short-term exposure to environmental androgens.

Natural estrogen emissions to subsurface tile drains from experimental grassland fields in Switzerland after application of livestock slurries and free compounds

Natural estrogens are present in high concentrations in livestock slurries, which are often applied to agricultural fields in large quantities. As such, the export of slurry-derived natural estrogens from tile-drained fields is a potential source for estrogenic pollution in surface waters. Yet despite the abundance of tile-drained fields in Central Europe, export of natural estrogens from agricultural fields receiving livestock slurries is rarely studied in this region. In an effort to fill this knowledge gap, here we applied natural estrogens to Swiss experimental fields in the form of cattle slurry, pig slurry or dissolved in water, and quantified them in flow-proportionally collected drainage water over 18 months. After pig and cattle slurry applications, concentration maxima in drainage water of 73, 8, 37, and 60 ng L^-1 for 17α-estradiol (E2α), 17β-estradiol (E2β), estrone (E1), and estriol (E3), respectively, were observed shortly after rain events. The exported fractions of individual natural estrogens to tile drains were on average 0.26% (ranging from 0.08 to 0.41%) after cattle, and 0.18% (0.03-0.40%) after pig slurry applications. Such numbers were higher than expected from the leaching potential based on substance properties, and comparable to those of more mobile micropollutants previously studied on the same fields. Natural estrogens were mainly exported to tile drains through preferential flow. Exported fractions were lower when applied in aqueous solution than when applied in slurry, pointing to particle-facilitated transport to tile drains when applied in slurry. In Switzerland, the estimated 6.3, 0.6, 7.4, and 7.7 g of E2α, E2β, E1, and E3, respectively, exported through the tile-drained agricultural area per year contribute little to the total natural estrogen load received by surface waters. However, after slurry applications in highly drained catchments, natural estrogen emissions to tile drains can cause short term (i.e. less than 1 week) estrogenic exposure in nearby streams.

Ractopamine and Other Growth-Promoting Compounds in Beef Cattle Operations: Fate and Transport in Feedlot Pens and Adjacent Environments

The current study represents a comprehensive investigation of the occurrence and fates of trenbolone acetate (TBA) and metabolites 17α-trenbolone (17α-TBOH), 17β-TBOH, and trendione (TBO); melengesterol acetate (MGA); and the less commonly studied β-andrenergic agonist ractopamine (RAC) in two 8 month cattle feeding trials and simulated rainfall runoff experiments. Cattle were administered TBA, MGA, or RAC, and their residues were measured in fresh feces, pen floor material, and simulated rainfall runoff from pen floor surfaces and manure-amended pasture. Concentrations of RAC ranged from 3600 ng g^-1, dry weight (dw), in pen floor to 58 000 ng g^-1 in fresh feces and were, on average, observed at 3-4 orders of magnitude greater than those of TBA and MGA. RAC persisted in pen floors (manure t_1/2 = 18-49 days), and contamination of adjacent sites was observed, likely via transport of windblown particulates. Concentrations in runoff water from pen floors extrapolated to larger-scale commercial feedlots revealed that a single rainfall event could result in mobilization of gram quantities of RAC. This is the first report of RAC occurrence and fate in cattle feedlot environments, and will help understand the risks posed by this chemical and inform appropriate manure-management practices.

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

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

Estrogenicity of agricultural runoff: A rainfall simulation study of worst-case scenarios using fresh layer and roaster litter, and farrowing swine manure

Scientists have correlated land application of animal wastes as fertilizer with the feminization of fish. Two questions were asked. 1) Under a worst case scenario when animal waste (layer and roaster litter, or farrowing swine slurry) is applied and tilled in 24 h prior to a surface-runoff producing rainfall, will estrogenic equivalents exceed the Lowest Observable Effect Concentration (LOEC) for fish (10 ng/L)? 2) Can calcium concentrations in runoff, measured using a rapid meter-based method, be used as a sentinel of elevated estrogenic activity? In a 3-yr study wastes were surface-applied and incorporated and 24 h later, 1.5 by 3 m plots were subjected to simulated rainfall and again 1 wk. and 3 wk. later. Nutrients in runoff were also measured, and in year 1 total coliforms and E. coli. were assessed. Except for an initial preliminary test run, runoff from all plots and years never exceeded 10 ng/L E2Eq equivalent. Calcium concentrations in runoff were not related to estrogenicity, negating its use as a sentinel marker. Specific estrogens in animal waste and runoff were identified by mass spectrometry with concentrations in runoff dependant on manure source and timing of rainfall. As expected, total coliform and E. coli concentrations in runoff were increased by the application of layer litter. Concentrations of nutrients in runoff would not be expected to result in surface water concentrations higher than guidelines for protection of aquatic species. Animal wastes applied in quantities appropriate for crop nutrient requirements, tilled into the soil surface, in observance of regulations avoiding application within 24 h of a predicted rain event, should not result in estrogen levels of environmental concern.

Effects of early life stage exposure of largemouth bass to atrazine or a model estrogen (17α-ethinylestradiol)

Endocrine disrupting contaminants are of continuing concern for potentially contributing to reproductive dysfunction in largemouth and smallmouth bass in the Chesapeake Bay watershed (CBW) and elsewhere. Exposures to atrazine (ATR) have been hypothesized to have estrogenic effects on vertebrate endocrine systems. The incidence of intersex in male smallmouth bass from some regions of CBW has been correlated with ATR concentrations in water. Fish early life stages may be particularly vulnerable to ATR exposure in agricultural areas, as a spring influx of pesticides coincides with spawning and early development. Our objectives were to investigate the effects of early life stage exposure to ATR or the model estrogen 17α-ethinylestradiol (EE2) on sexual differentiation and gene expression in gonad tissue. We exposed newly hatched largemouth bass (LMB, Micropterus salmoides) from 7 to 80 days post-spawn to nominal concentrations of 1, 10, or 100 µg ATR/L or 1 or 10 ng EE2/L and monitored histological development and transcriptomic changes in gonad tissue. We observed a nearly 100% female sex ratio in LMB exposed to EE2 at 10 ng/L, presumably due to sex reversal of males. Many gonad genes were differentially expressed between sexes. Multidimensional scaling revealed clustering by gene expression of the 1 ng EE2/L and 100 µg ATR/L-treated male fish. Some pathways responsive to EE2 exposure were not sex-specific. We observed differential expression in male gonad in LMB exposed to EE2 at 1 ng/L of several genes involved in reproductive development and function, including star, cyp11a2, ddx4 (previously vasa), wnt5b, cyp1a and samhd1. Expression of star, cyp11a2 and cyp1a in males was also responsive to ATR exposure. Overall, our results confirm that early development is a sensitive window for estrogenic endocrine disruption in LMB and are consistent with the hypothesis that ATR exposure induces some estrogenic responses in the developing gonad. However, ATR-specific and EE2-specific responses were also observed.

Photolysis of Trenbolone Acetate Metabolites in the Presence of Nucleophiles: Evidence for Metastable Photoaddition Products and Reversible Associations with Dissolved Organic Matter

Photolysis of trenbolone acetate (TBA) metabolites in the presence of various nitrogen-, sulfur-, or oxygen-containing nucleophiles (e.g., azide, ammonia, or thiosulfate, respectively) results in rapid (half-lives ∼20-60 min), photochemically induced nucleophile incorporation across the parent steroid's trienone moiety. The formation of such nucleophile adducts limits formation of photohydrates, suggesting competition between the nucleophile and water for photochemical addition into the activated steroid structure. Analogous to previously reported photohydration outcomes, LC/MS analyses suggest that such photonucleophilic addition reactions are reversible, with more rapid elimination rates than thermal dehydration of photohydrates, and regenerate parent steroid structures. Beyond photonucleophilic addition pathways, we also found that hydroxylamine and presumed nucleophilic moieties in model dissolved organic matter (DOM; Fluka humic acid) can react via thermal substitution with TBA metabolite photohydrates, although this reaction with model DOM was only observed for photohydrates of trendione. Most nucleophile addition products [i.e., formed via (photo)reaction with thiosulfate, hydroxylamine, and ammonia] are notably more polar relative to the parent metabolite and photohydration products. Thus, if present, both nucleophilic adducts and bound residues in organic matter will facilitate transport and help mask detection of TBA metabolites in surface waters and treatment systems.

Melatonin attenuates 17β-trenbolone induced insomnia-like phenotype and movement deficiency in zebrafish

17β-trenbolone (17β-TBOH) is one of the dominant metabolites of trenbolone acetate, which is widely applied in beef cattle operations around the globe. The effects of environmental concentrations of 17β-trenbolone on the early development of zebrafish embryos have received very little attention. Melatonin could regulate sleep-wake cycle and plays a protective role in various adverse conditions. Here, environmentally realistic concentrations of 17β-trenbolone (1 ng/L, 10 ng/L, 50 ng/L) has been exposure to zebrafish embryos at 2 h postfertilization (hpf). The results showed that 10 ng/L and 50 ng/L 17β-trenbolone disturbed the distribution of caudal primary motoneurons and downregulated expression of motoneuron development related genes along with locomotion decreasing. While melatonin could recover the detrimental effects caused by 17β-trenbolone. Interestingly, 17β-trenbolone exposure increased waking activity and decreased rest even in a low dose (1 ng/L). Moreover, it upregulated hypocretin/orexin (Hcrt) signaling which promotes wakefulness. Melatonin restored the insomnia-like alternation induced by 17β-trenbolone exposure. Collectively, we conclude that 17β-trenbolone disturbed motoneuron development and altered sleep/wake behavior, while melatonin could alleviate the deleterious influence on motoneuron development and recover the circadian rhythm.

Steroid androgen 17 alpha methyltestosterone used in fish farming induces biochemical alterations in zebrafish adults

The 17 alpha methyltestosterone (MT) hormone is fed to Oreochromis niloticus larvae in fish farms with the purpose of inducing sex reversal. The aim of this study was to evaluate the toxicity and sub-lethality of MT (99.9% purity) and cMT (a commercial MT with 90% purity) in zebrafish (Danio rerio) adults, where the animals were exposed to concentrations of 0, 4, 23, 139, 833 and 5000 µg/L for 96 hours. Genotoxicity was evaluated by micronucleus test (MN), nuclear abnormalities (NA) and comet assay. A low genotoxic potential of MT was showed, inducing micronucleus, nuclear abnormalities and DNA damage in Danio rerio, depending on the use of MT or cMT, gender and tested concentrations. In the sub-lethality trials, there was a basal difference in the activity of the enzymatic biochemical markers for males and females, while the Glutatione S transferase (GST) activity decreased in all analyzed tissues, and for males the enzymatic activity decreased only in the intestine. Results suggest that MT has a toxic potential to fish because it alters enzymatic metabolic pathways and may pose a risk to the ecosystems.

Influence of hydrologic and anthropogenic drivers on emerging organic contaminants in drinking water sources in the Susquehanna River Basin

Occurrence of emerging organic contaminants (EOCs) in surface water bodies can cause adverse effects on non-target organisms. When surface waters are used as drinking water sources, temporal variability in EOC concentrations can potentially impact drinking water quality and human health. To better understand spatiotemporal variability of EOCs in drinking water sources in Central Pennsylvania, EOCs were evaluated in six drinking water sources during a two-year study period (April 2016-June 2018) in the Susquehanna River Basin (SRB). The study was conducted in two phases: Phase I was a spatially distributed sampling approach within the SRB focusing on seven human pharmaceuticals and Phase II was a temporally intensive sampling regime at a single site focusing on a broader range of EOCs. Concentration-discharge relationships were utilized to classify EOC transport dynamics and understand the extent to which hydrologic and anthropogenic factors, such as surface runoff and wastewater effluent, may contribute to EOC occurrence. Overall, EOCs were present at higher concentrations in colder seasons than warmer seasons. Thiamethoxam, a neonicotinoid insecticide, and caffeine exhibited accretion dynamics during high-flow periods, suggesting higher transport during surface runoff events. Human pharmaceuticals known to persist in wastewater effluent were inversely correlated with discharge, indicating dilution characteristics consistent with diminished wastewater signals during high-flow periods. Acetaminophen exhibited near-chemostatic transport dynamics, indicating nonpoint source inputs during high-flow periods. Risk calculations revealed that although EOCs posed medium-to-high risk to aquatic organisms, human health risk through fish consumption was low.

Free and conjugated estrogens detections in drainage tiles and wells beneath fields receiving swine manure slurry

Although livestock manure, such as from swine (Sus scrofa domestica), have high capacity to introduce endocrine-disrupting free estrogens into the environment, the frequency of estrogen detections from reconnaissance studies suggest that these compounds are ubiquitous in the environment, perhaps resulting from historic manure inputs (e.g. cattle grazing residues, undocumented historic manure applications) or uncontrolled natural sources. Compared to free estrogens, conjugates of estrogens are innocuous but have greater mobility in the environment. Estrogen conjugates can also hydrolyze to re-form the potent free estrogens. The objective of this study was to identify the transport of free and conjugated estrogens to subsurface tile drains and groundwater beneath fields treated with swine manure slurry. Three field treatments were established, two receiving swine lagoon manure slurry and one with none. Manure slurry was injected into soils at a shallow depth (∼8 cm) and water samples from tile drains and shallow wells were sampled periodically for three years. Glucuronide and sulfate conjugates of 17β-estradiol (E2) and estrone (E1) were the only estrogen compounds detected in the tile drains (total detects = 31; 5% detection frequency; conc. range = 3.9-23.1 ng L^-1), indicating the important role conjugates played in the mobility of estrogens. Free estrogens and estrogen conjugates were more frequently detected in the wells compared to the tile drains (total detects = 70; 11% detection frequency; conc. range = 4.0-1.6 × 10³ ng L^-1). No correlations were found between estrogen compound detections and dissolved or colloidal organic carbon (OC) fractions or other water quality parameters. Estrogenic compounds were detected beneath both manure treated and non-treated plots; furthermore, the total potential estrogenic equivalents (i.e. estrogenicity of hydrolyzed conjugates + free estrogens) were similar between treated and non-treated plots.

Genotoxic biomarkers and histological changes in marine medaka (Oryzias melastigma) exposed to 17α-ethynylestradiol and 17β-trenbolone

Endocrine-disrupting pollutants in marine environments have aroused great concern for their adverse effects on the reproduction of marine organisms. This study aimed to seek promising biomarkers for estrogenic/androgenic chemicals. First, two possible male-specific genes, SRY-box containing gene 9a2 (sox9a2) and gonadal soma-derived factor (gsdf), were cloned from marine medaka (Oryzias melastigma). Then the responses of sox9a2, gsdf, choriogenin (chgH and chgL), vitellogenin (vtg1 and vtg2), and cytochrome P450 aromatase (cyp19a and cyp19b) were investigated after exposure to 17α-ethynylestradiol (EE₂) and 17β-trenbolone (TB) at 2, 10, and 50 ng/L. The results showed that gsdf was specifically expressed in the testes and easily induced in the ovaries after TB exposure, indicating that gsdf was a potential biomarker of environmental androgens. ChgL was a useful biomarker of weak estrogen pollution for its high sensitivity to low levels of EE₂. In addition, both EE₂ and TB exposure damaged gonadal structures and inhibited gonadal development.

Attenuation, transport, and management of estrogens: A review

Overabundance of endocrine disruptors (EDs), such as steroid estrogens, in the natural environment disrupts hormone synthesis in aquatic organisms. Livestock and wastewater outflows contribute measurable quantities of steroid estrogens into the environment where they are picked up and transported via surface runoff and feedlot effluents into water matrices. E1, E2β, E2α, E3 and EE2 are the most prevalent estrogens in these environmental systems. Estrogens in soils and water undergo several concurrent attenuation processes including sorption to particles, biotransformation, photo-transformation, and plant uptake. This review summarizes current studies on the attenuation and transport of steroid estrogens with a focus on estrogen attenuation and transport modeling. The authors use this information to synthesize appropriate strategies for reducing estrogenicity in the environment.

Persistence of androgens, progestogens, and glucocorticoids during commercial animal manure composting process

Animal manure contains various organic contaminants such as steroids. The fate of these steroids during composting is still unknown. Here we investigated the fate of androgens, progestogens, and glucocorticoids during animal manure composting and evaluated their residues in compost-applied soils. The results showed the presence of 16 steroid hormones in the initial compost with concentrations ranging from 3.26 ng/g dw (Cortisol) to 2520 ng/g dw (5α-dihydroprogesterone). The concentrations of almost all detected hormones increased on the 2nd day of composting, and some of them increased several or even dozens of times. Steroids such as hydroxyprogesterone caproate, melengestrol acetate, and methyltestosterone were not found in the initial compost but later detected during the composting process. After 171 days of composting, only 40.4% of detected steroid hormones was removed, and the total concentration of detected steroids was still as high as 3210 ng/g dw. The removal rates of some target compounds were negative, especially for the natural androgens androsta-1,4-diene-3,17-dione and the synthetic androgen 17β-boldenone whose concentrations significantly increased by the end of composting, indicating conversion from their conjugates or transformation from other steroids. The steroid hormones were mainly eliminated in the first three weeks; prolonged composting time did not obviously promote further removal. The variations in steroid concentration were related to the changes in compost properties such as pH and temperature during the composting process. The dissipation of steroid hormones was also linked to the changes of microbial communities in the compost to some extent. Twelve steroids were detected in the compost-treated soils of a kailyard, while 26 steroid hormones were detected in the roots of Chinese cabbages grown on the soil. The results suggest that the application of manure compost product can lead to soil contamination and plant uptake.

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

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

Molecular signaling pathways elicited by 17α-ethinylestradiol in Japanese medaka male larvae undergoing gonadal differentiation

Estrogenic contaminants released into water bodies are potentially affecting the reproduction of aquatic organisms. Exposure to 17α-ethinylestradiol (EE2), a synthetic estrogen agonist commonly found in sewage effluents, has been shown to cause gonadal changes in male gonochoristic fish ranging from gonadal intersex to complete sex reversal. Although these gonadal changes have been well studied in Japanese medaka Oryzias latipes, the molecular mechanisms behind them are poorly understood. Our objective was to study the signaling pathways elicited by exposure to different concentrations of EE2 in this species. Embryos and larvae were sexed by the presence of leucophores and dmy expression (only in males). Male medaka were exposed to two EE2 concentrations (30 and 300 ng/L) during their gonadal differentiation period (7-22 dpf). The transcriptome of larvae was analyzed using RNA sequencing followed by pathway analysis. Genes involved in sex differentiation and gonadal development (e.g., cldn19, ctbp1, hsd17b4) showed a female-like expression pattern in EE2-exposed males with some genes changing in expression in an EE2 concentration-dependent manner. However, not all genes known to be involved in sex differentiation and gonadal development (e.g., wnt4b) were altered by EE2. Several of the prominently affected signaling pathways involved genes associated with steroidogenesis, steroid receptor signaling and steroid metabolism, such as cyp2b3, cyp3b40, cyp1a, hsd17b4. We also report on novel genes and pathways affected that might play a role in gonadal changes, including several genes associated with FXR/RXR and LXR/RXR activation networks. This study is the first to examine the transcriptomic changes in male fish resulting from exposure to EE2 during the gonadal differentiation period, providing new insights on the signaling pathways involved in the development of gonadal changes in gonochoristic fish.

Fish on steroids: Temperature-dependent effects of 17β-trenbolone on predator escape, boldness, and exploratory behaviors

Hormonal growth promoters (HGPs), widely used in beef cattle production globally, make their way into the environment as agricultural effluent-with potential impacts on aquatic ecosystems. One HPG of particular concern is 17β-trenbolone, which is persistent in freshwater habitats and can affect the development, morphology and reproductive behaviors of aquatic organisms. Despite this, few studies have investigated impacts of 17β-trenbolone on non-reproductive behaviors linked to growth and survival, like boldness and predator avoidance. None consider the interaction between 17β-trenbolone and other environmental stressors, such as temperature, although environmental challenges confronting animals in the wild seldom, if ever, occur in isolation. Accordingly, this study aimed to test the interactive effects of trenbolone and temperature on organismal behavior. To do this, eastern mosquitofish (Gambusia holbrooki) were subjected to an environmentally-relevant concentration of 17β-trenbolone (average measured concentration 3.0 ± 0.2 ng/L) or freshwater (i.e. control) for 21 days under one of two temperatures (20 and 30 °C), after which the predator escape, boldness and exploration behavior of fish were tested. Predator escape behavior was assayed by subjecting fish to a simulated predator strike, while boldness and exploration were assessed in a separate maze experiment. We found that trenbolone exposure increased boldness behavior. Interestingly, some behavioral effects of trenbolone depended on temperature, sex, or both. Specifically, significant effects of trenbolone on male predator escape behavior were only noted at 30 °C, with males becoming less reactive to the simulated threat. Further, in the maze experiment, trenbolone-exposed fish explored the maze faster than control fish, but only at 20 °C. We conclude that field detected concentrations of 17β-trenbolone can impact ecologically important behaviors of fish, and such effects can be temperature dependent. Such findings underscore the importance of considering the potentially interactive effects of other environmental stressors when investigating behavioral effects of environmental contaminants.

Watershed scale patterns in steroid hormones composition and content characters at a typical eutrophic lake in southeastern China

Natural steroid hormones in the aquatic environment have attracted increasing attention because of their strong endocrine disrupting potency. Seven steroid hormones (estrone, 17α-estradiol, 17β-estradiol, estriol, testosterone, androstenedione, and progesterone) were analyzed from surface water and sediment sampled from Chaohu Lake, its upstream rivers (the Hangbu River, Nanfei River, Shiwuli River, and Pai River), drainage from the adjacent farmland, and treated and untreated municipal sewage. Concentrations of the seven target steroid hormones ranged from below the detection limit (ND) to 69.5 ng L^-1 in the water of Chaohu Lake and the upstream rivers. Three steroids-estrone, estriol, and 17α-estradiol-were found in relatively high residual concentrations in the water, with maximum concentrations of 69.5 ng L^-1, 51.5 ng L^-1, and 23.3 ng L^-1, respectively. All of the target steroid hormones except estriol were detected in the sediment in concentrations of ND-16344 ng kg^-1. The dominant steroid hormone in the sediment of Chaohu Lake and the upstream rivers was 17α-estradiol. In the Shiwuli River and the Pai River, the dominant steroid hormones (estrone and estriol) were the same as those in the untreated municipal sewage. This confirmed the deduction that untreated municipal sewage was the major source of steroid hormone residues in these two rivers. The main steroid hormone in the water of the Hangbu River and Chaohu Lake was 17α-estradiol, the same as that in the farmland drainage. In addition, 17α-estradiol was verified as the major factor in the contribution of farmland drainage to the pollution in these rivers. The water in the Nanfei River had high concentrations of estriol and 17α-estradiol. This indicates that both untreated municipal sewage and farmland drainage were the major sources. The discharge of steroid hormones from the four rivers to Chaohu Lake was approximately 75.1 kg year^-1, with the highest contributor being 17α-estradiol (24 kg year^-1). Therefore, based on the results of this study, the farmland drainage should be controlled to reduce the steroid hormone pollution in Chaohu Lake.

Emerging contaminants in a river receiving untreated wastewater from an Indian urban centre

Research over the last decade on emerging trace organic contaminants in aquatic systems has largely focused on sources such as treated wastewaters in high income countries, with relatively few studies relating to wastewater sources of these contaminants in low and middle income countries. We undertook a longitudinal survey of the Ahar River for a number of emerging organic contaminants (including pharmaceuticals, hormones, personal care products and industrial chemicals) which flows through the city of Udaipur, India. Udaipur is a city of approximately 450,000 people with no wastewater treatment occurring at the time of this survey. We found the concentrations of many of the contaminants within the river water were similar to those commonly reported in untreated wastewater in high income countries. For example, concentrations of pharmaceuticals, such as carbamazepine, antibiotics and non-steroidal anti-inflammatory drugs, ranged up to 1900 ng/L. Other organic contaminants, such as steroid estrogens (up to 124 ng/L), steroid androgens (up to 1560 ng/L), benzotriazoles (up to 11 μg/L), DEET (up to 390 ng/L), BPA (up to 300 ng/L) and caffeine (up to 37.5 μg/L), were all similar to previously reported concentrations in wastewaters in high income countries. An assessment of the population densities in the watersheds feeding into the river showed increasing population density of a watershed led to a corresponding downstream increase in the concentrations of the organic contaminants, with quantifiable concentrations still present up to 10 km downstream of the areas directly adjacent to the highest population densities. Overall, this study highlights how a relatively clean river can be contaminated by untreated wastewater released from an urban centre.

Transport of Potential Manure Hormone and Pharmaceutical Contaminants through Intact Soil Columns

Although adding manure to agricultural soils is a commonly practiced disposal method and a means to enhance soil productivity, potential environmental contamination by any associated chemicals of emerging concern (CECs) such as hormones and pharmaceuticals is not well understood. Our objective was to provide field-relevant predictions of soil transport and attenuation of 19 potential manure CECs using undisturbed soil columns irrigated under unsaturated conditions. The CEC concentrations in leached water were monitored for 13 wk using high performance liquid chromatography-time of flight-mass spectrometry (HPLC-TOF-MS), after which time soil in the cores was removed and sampled for extractable CECs. Compounds quantified in column leachate included all four of the added sulfonamide antibiotics and the nonsteroidal, anti-inflammatory drug flunixin. Only trace amounts of several of the seven hormones, five remaining antibiotics, and two antimicrobials leached from the columns from exogenous soil additions. Soil residues of all 19 compounds were detected, with highest extractable amounts for 17α-hydroxyprogesterone > triclosan (antimicrobial) > flunixin > oxytetracycline. Those CECs with the highest recoveries as calculated by summing leached and extractable amounts were flunixin (14.5%), 17α-hydroxyprogesterone (5.3%), triclosan (4.6%), and sulfadimethoxine (4.8%). Manure management to prevent CEC contamination should consider the potential environmental problems caused by negatively charged compounds with the greatest mobility (flunixin and sulfadimethoxine) and those that have long residence times in soil (triclosan, 17α-hydroxyprogesterone, flunixin, and oxytetracycline). Flunixin is particularly important given its mobility and long residence time in soil.

Field-realistic exposure to the androgenic endocrine disruptor 17β-trenbolone alters ecologically important behaviours in female fish across multiple contexts

The capacity of pharmaceutical pollution to alter behaviour in wildlife is of increasing environmental concern. A major pathway of these pollutants into the environment is the treatment of livestock with hormonal growth promotants (HGPs), which are highly potent veterinary pharmaceuticals that enter aquatic ecosystems via effluent runoff. Hormonal growth promotants are designed to exert biological effects at low doses, can act on physiological pathways that are evolutionarily conserved across taxa, and have been detected in ecosystems worldwide. However, despite being shown to alter key fitness-related processes (e.g., development, reproduction) in various non-target species, relatively little is known about the potential for HGPs to alter ecologically important behaviours, especially across multiple contexts. Here, we investigated the effects of exposure to a field-realistic level of the androgenic HGP metabolite 17β-trenbolone-an endocrine-disrupting chemical that has repeatedly been detected in freshwater systems-on a suite of ecologically important behaviours in wild-caught female eastern mosquitofish (Gambusia holbrooki). First, we found that 17β-trenbolone-exposed fish were more active and exploratory in a novel environment (i.e., maze arena), while boldness (i.e., refuge use) was not significantly affected. Second, when tested for sociability, exposed fish spent less time in close proximity to a shoal of stimulus (i.e., unexposed) conspecific females and were, again, found to be more active. Third, when assayed for foraging behaviour, exposed fish were faster to reach a foraging zone containing prey items (chironomid larvae), quicker to commence feeding, spent more time foraging, and consumed a greater number of prey items, although the effect of exposure on certain foraging behaviours was dependent on fish size. Taken together, these findings highlight the potential for exposure to sub-lethal levels of veterinary pharmaceuticals to alter sensitive behavioural processes in wildlife across multiple contexts, with potential ecological and evolutionary implications for exposed populations.

Removal of non-point source pollutants from domestic sewage and agricultural runoff by vegetated drainage ditches (VDDs): Design, mechanism, management strategies, and future directions

Domestic wastewater and agricultural runoff are increasingly viewed as major threats to both aquatic and terrestrial ecosystems due to the introduction of non-point source inorganic (e.g., nitrogen, phosphorus and metals) and organic (e.g., pesticides and pharmaceutical residues) pollutants. With rapid economic growth and social change in rural regions, it is important to examine the treatment systems in rural and remote areas for high efficiency, low running costs, and minimal maintenance in order to minimize its influence on water bodies and biodiversity. Recently, the use of vegetated drainage ditches (VDDs) has been employed in treatment of domestic sewage and agricultural runoff, but information on the performance of VDDs for treating these pollutants with various new management practices is still not sufficiently summarized. This paper aims to outline and review current knowledge related to the use of VDDs in mitigating these pollutants from domestic sewage and agricultural runoff. Literature analysis has suggested that further research should be carried out to improve ditch characteristics and management strategies inside ditches in order to ensure their effectiveness. Firstly, the reported major ditch characteristics with the most effect on pollutant removal processes (e.g., plant species, weirs, biofilms, and substrates selection) were summarized. The second focus concerns the function of ditch characteristics in VDDs for pollutant removal and identification of possible removal mechanisms involved. Thirdly, we examined factors to consider for establishing appropriate management strategies within ditches and how these could influence the whole ditch design process. The current review promotes areas where future research is needed and highlights clear and sufficient evidence regarding performance and application of this overlooked ditch system to reduce pollutants.

A critical review of the environmental occurrence and potential effects in aquatic vertebrates of the potent androgen receptor agonist 17β-trenbolone

Trenbolone acetate is widely used in some parts of the world for its desirable anabolic effects on livestock. Several metabolites of the acetate, including 17β-trenbolone, have been detected at low nanograms per liter concentrations in surface waters associated with animal feedlots. The 17β-trenbolone isomer can affect androgen receptor signaling pathways in various vertebrate species at comparatively low concentrations/doses. The present article provides a comprehensive review and synthesis of the existing literature concerning exposure to and biological effects of 17β-trenbolone, with an emphasis on potential risks to aquatic animals. In vitro studies indicate that, although 17β-trenbolone can activate several nuclear hormone receptors, its highest affinity is for the androgen receptor in all vertebrate taxa examined, including fish. Exposure of fish to nanograms per liter water concentrations of 17β-trenbolone can cause changes in endocrine function in the short term, and adverse apical effects in longer exposures during development and reproduction. Impacts on endocrine function typically are indicative of inappropriate androgen receptor signaling, such as changes in sex steroid metabolism, impacts on gonadal stage, and masculinization of females. Exposure of fish to 17β-trenbolone during sexual differentiation in early development can greatly skew sex ratios, whereas adult exposures can adversely impact fertility and fecundity. To fully assess ecosystem-level risks, additional research is warranted to address uncertainties as to the degree/breadth of environmental exposures and potential population-level effects of 17β-trenbolone in sensitive species. Environ Toxicol Chem 2018;37:2064-2078. Published 2018 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Tracking the fate and transport of estrogens following rainfall events

Surface runoff following rainfall events can transport estrogens from agricultural land to water systems, causing potential risks to aquatic biota. This study adopted two simple models, the wash-off and empirical models, to quantify the pathway of three prevalent manure-borne estrogens, estrone (E1), 17β-estradiol (E2β) and 17α-estradiol (E2α), from agricultural land to the receiving water following rainfall events. The complex interconversion of the three estrogens during attenuation was considered in the models. These two models were calibrated and validated using the data obtained from three artificial rainfall events from the literature. The data from the first two rainfall events were used to quantify key model parameters and the data from the third rainfall event were used to validate the models. The performances of the models were then evaluated through a statistical analysis. Results show that both models can closely reproduce the mass loads of estrogens during rainfall events and that the wash-off model shows a better overall performance than the empirical model for the data used in this study.

An endocrine-disrupting agricultural contaminant impacts sequential female mate choice in fish

The environmental impact of endocrine-disrupting chemicals (EDCs)-compounds that interfere with endocrine system function at minute concentrations-is now well established. In recent years, concern has been mounting over a group of endocrine disruptors known as hormonal growth promotants (HGPs), which are natural and synthetic chemicals used to promote growth in livestock by targeting the endocrine system. One of the most potent compounds to enter the environment as a result of HGP use is 17β-trenbolone, which has repeatedly been detected in aquatic habitats. Although recent research has revealed that 17β-trenbolone can interfere with mechanisms of sexual selection, its potential to impact sequential female mate choice remains unknown, as is true for all EDCs. To address this, we exposed female guppies (Poecilia reticulata) to 17β-trenbolone at an environmentally relevant level (average measured concentration: 2 ng/L) for 21 days using a flow-through system. We then compared the response of unexposed and exposed females to sequentially presented stimulus (i.e., unexposed) males that varied in their relative body area of orange pigmentation, as female guppies have a known preference for orange colouration in males. We found that, regardless of male orange pigmentation, both unexposed and exposed females associated with males indiscriminately during their first male encounter. However, during the second male presentation, unexposed females significantly reduced the amount of time they spent associating with low-orange males if they had previously encountered a high-orange male. Conversely, 17β-trenbolone-exposed females associated with males indiscriminately (i.e., regardless of orange colouration) during both their first and second male encounter, and, overall, associated with males significantly less than did unexposed females during both presentations. This is the first study to demonstrate altered sequential female mate choice resulting from exposure to an endocrine disruptor, highlighting the need for a greater understanding of how EDCs may impact complex mechanisms of sexual selection.

Validation of Arxula Yeast Estrogen Screen assay for detection of estrogenic activity in water samples: Results of an international interlaboratory study

Endocrine-active substances can adversely impact the aquatic ecosystems. A special emphasis is laid, among others, on the effects of estrogens and estrogen mimicking compounds. Effect-based screening methods like in vitro bioassays are suitable tools to detect and quantify endocrine activities of known and unknown mixtures. This study describes the validation of the Arxula-Yeast Estrogen Screen (A-YES®) assay, an effect-based method for the detection of the estrogenic potential of water and waste water. This reporter gene assay, provided in ready to use format, is based on the activation of the human estrogen receptor alpha. The user-friendly A-YES® enables inexperienced operators to rapidly become competent with the assay. Fourteen laboratories from four countries with different training levels analyzed 17β-estradiol equivalent concentrations (EEQ) in spiked and unspiked waste water effluent and surface water samples, in waste water influent and spiked salt water samples and in a mixture of three bisphenols. The limit of detection (LOD) for untreated samples was 1.8ng/L 17β-estradiol (E2). Relative repeatability and reproducibility standard deviation for samples with EEQ above the LOD (mean EEQ values between 6.3 and 20.4ng/L) ranged from 7.5 to 21.4% and 16.6 to 28.0%, respectively. Precision results are comparable to other frequently used analytical methods for estrogens. The A-YES® has been demonstrated to be an accurate, precise and robust bioassay. The results have been included in the ISO draft standard. The assay was shown to be applicable for testing of typical waste water influent, effluent and saline water. Other studies have shown that the assay can be used with enriched samples, which lower the LOD to the pg/L range. The validation of the A-YES® and the development of a corresponding international standard constitute a step further towards harmonized and reliable bioassays for the effect-based analysis of estrogens and estrogen-like compounds in water samples.

Response and recovery of fathead minnows (Pimephales promelas) following early life exposure to water and sediment found within agricultural runoff from the Elkhorn River, Nebraska, USA

Agricultural runoff is a non-point source of chemical contaminants that are seasonally detected in surface water and sediments. Agrichemicals found within seasonal runoff can elicit endocrine disrupting effects in organisms as adults, juveniles and larvae. The objectives of this study were (1) to determine if exposure to water, sediment or the water-sediment combination collected from an agricultural runoff event was responsible for changes in endocrine-responsive gene expression and development in fathead minnow larvae, and (2) whether such early life exposure leads to adverse effects as adults. Larvae were exposed during the first month post-hatch to water and sediment collected from the Elkhorn River and then allowed to depurate in filtered water until reaching sexual maturity, exemplifying a best-case recovery scenario. Gas chromatography mass spectrometry (GC/MS) analysis of the water and sediment samples detected 12 pesticides including atrazine, acetochlor, metolachlor and dimethenamid. In minnow larvae, exposure to river water upregulated androgen receptor gene expression whereas exposure to the sediment downregulated estrogen receptor α expression. Adult males previously exposed to both water and sediment were feminized through the induction of an ovipositor structure whereas no impacts were observed in other reproductive or sex characteristic endpoints for either sex based on exposure history. Results from this study indicate that both water and sediments found in agricultural runoff elicit responses from minnow larvae, and larvae can recover following early life exposure under a best-case scenario.

Pharmaceuticals and other anthropogenic chemicals in atmospheric particulates and precipitation

Air and precipitation samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) for pharmaceuticals, personal care products, and other commercial chemicals within the St. Paul/Minneapolis metropolitan area of Minnesota, U.S. Of the 126 chemicals analyzed, 17 were detected at least once. Bisphenol A, N,N-diethyl-meta-toluamide (DEET), and cocaine were the most frequently detected; their maximum concentrations in snow were 3.80, 9.49, and 0.171ng/L and in air were 0.137, 0.370, and 0.033ng/m³, respectively. DEET and cocaine were present in samples of rain up to 14.5 and 0.806ng/L, respectively. Four antibiotics - ofloxacin, ciprofloxacin, enrofloxacin, and sulfamethoxazole - were detected at concentrations up to 10.3ng/L in precipitation, while ofloxacin was the sole antibiotic detected in air at 0.013ng/m³. The X-ray contrast agent iopamidol and the non-steroidal anti-inflammatory drug naproxen were detected in snow up to 228ng/L and 3.74ng/L, respectively, while caffeine was detected only in air at 0.069 and 0.111ng/m³. Benzothiazole was present in rain up to 70ng/L, while derivatives of benzotriazole - 4-methylbenzotriazole, 5-methylbenzotriazole, and 5-chlorobenzotriazole - were detected at concentrations up to 1.5ng/L in rain and 3.4ng/L in snow. Nonylphenol and nonylphenol monoethoxylate were detected once in air at 0.165 and 0.032ng/m³, respectively. Although the sources of these chemicals to atmosphere are not known, fugacity analysis suggests that wastewater may be a source of nonylphenol, nonylphenol monoethoxylate, DEET, and caffeine to atmosphere. The land-spreading of biosolids is known to generate PM10 that could also account for the presence of these contaminants in air. Micro-pollutant detections in air and precipitation are similar to the profile of contaminants reported previously for surface water. This proof of concept study suggests that atmospheric transport of these chemicals may partially explain the ubiquity of these contaminants in the aquatic environment.

Hormones and fish monosex farming: A spotlight on immunity

Aquaculture is a promising and developing industry worldwide. One of the first step in monosex culturing, particularly in Nile tilapia, is the production of all-male fry; hormones are widely used in this respect. It is known that exogenous treatment with hormones disrupts various systems in the body including the immune and endocrine systems. There has been a growing interest in how hormones shape the biology of the fish. Many researchers all over the world explored how androgen can interact with many of the body systems; however, rarely any of them tried to improve the hormonal method or to find an alternative. The gate is open for research in this field. This review focusses on the potential effects of hormones, particularly androgens on fish immunity, and the up to date solutions (however, they are rare).

Testicular oocytes in smallmouth bass in northeastern Minnesota in relation to varying levels of human activity

Testicular oocytes (TOs) have been found in black bass (Micropterus spp.) from many locations in North America. The presence of TOs is often assumed to imply exposure to estrogenic endocrine disrupting compounds (EDCs); however, a definitive causal relationship has yet to be established, and TO prevalence is not consistently low in fish from areas lacking evident EDC sources. This might indicate any of a number of situations: 1) unknown or unidentified EDCs or EDC sources, 2) induction of TOs by other stressors, or 3) testicular oocytes occurring spontaneously during normal development. In the present study, we analyzed TO occurrence in smallmouth bass (Micropterus dolomieu) from 8 populations in northeastern Minnesota watersheds with differing degrees of human development and, hence, presumed likelihood of exposure to anthropogenic chemicals. Three watersheds were categorized as moderately developed, based on the presence of municipal wastewater discharges and higher human population density (4-81 per km² ), and 5 watersheds were minimally developed, with very low human population density (0-1 per km² ) and minimal built environment. Testicular tissues from mature fish were evaluated using a semiquantitative method that estimated TO density, normalized by cross-sectional area. Testicular oocyte prevalence and density among populations from moderately developed watersheds was higher than in populations from minimally developed watersheds. However, TO prevalence was unexpectedly high and variable (7-43%) in some populations from minimally developed watersheds, and only weak evidence was found for a relationship between TO density and watershed development, suggesting alternative or more complex explanations for TO presence in smallmouth bass from this region. Environ Toxicol Chem 2017;36:3424-3435. © 2017 SETAC.

Continuous Hydrologic and Water Quality Monitoring of Vernal Ponds

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. However, they are vulnerable parts of the landscapes that are often poorly understood and understudied. Land use and management practices, as well as climate change are thought to be a contribution to the global amphibian decline. However, more research is needed to understand the extent of these impacts. Here, we present methodology for characterizing a vernal pond's morphology and detail a monitoring station that can be used to collect water quantity and quality data over the duration of a vernal pond's hydroperiod. We provide methodology for how to conduct field surveys to characterize the morphology and develop stage-storage curves for a vernal pond. Additionally, we provide methodology for monitoring the water level, temperature, pH, oxidation-reduction potential, dissolved oxygen, and electrical conductivity of water in a vernal pond, as well as monitoring rainfall data. This information can be used to better quantify the ecosystem services that vernal ponds provide and the impacts of anthropogenic activities on their ability to provide these services.

Modeling the fate and transport of 17β-estradiol in the South River watershed in Virginia

Hormones excreted by livestock metabolisms often enter surface water through feces and urine and can potentially cause adverse impacts to aquatic biota. This study involved a modeling analysis of 17β-estradiol (E2), a prevalent estrogen, in the South River watershed located in Augusta County, Virginia from 2013 to 2015. Cattle manure, poultry litter, biosolids, septic systems, and wastewater treatment plants (WWTPs) were considered as sources of E2 in this study. The EPA's BASINS modeling framework was configured to track the fate and transport of E2. The first-order kinetics and the wash-off model were adopted to characterize the attenuation and the transport of E2. The modeling results indicated that the flow rate was a major input affecting the simulated E2 levels in the water. During storm events, E2 on the land surface was transported into the rivers by the surface runoff and the E2 released into streams was diluted by the high water flow. Variations of the simulated E2 concentrations in the South River depended on the relative magnitudes of the loads from point and nonpoint sources. Modeling results showed that E2 levels in the South River were below the lowest observable effect level (LOEL) for fish. However, the practices of storing manure before land application and fencing off rivers to keep cattle out of the water are encouraged to prevent the potential for high E2 levels in streams receiving feedlot runoff.

The agricultural contaminant 17β-trenbolone disrupts male-male competition in the guppy (Poecilia reticulata)

Despite a growing literature highlighting the potential impact of human-induced environmental change on mechanisms of sexual selection, relatively little is known about the effects of chemical pollutants on male-male competition. One class of environmental pollutant likely to impact male competitive interactions is the endocrine-disrupting chemicals (EDCs), a large and heterogeneous group of chemical contaminants with the potential to influence morphology, physiology and behaviour at minute concentrations. One EDC of increasing concern is the synthetic, androgenic steroid 17β-trenbolone, which is used globally to promote growth in beef cattle. Although 17β-trenbolone has been found to cause severe morphological and behavioural abnormalities in fish, its potential impact on male-male competition has yet to be investigated. To address this, we exposed wild male guppies (Poecilia reticulata) to an environmentally realistic concentration of 17β-trenbolone (average measured concentration: 8 ng/L) for 21 days using a flow-through system. We found that, in the presence of a competitor, 17β-trenbolone-exposed males carried out more frequent aggressive behaviours towards rival males than did unexposed males, as well as performing less courting behaviour and more sneak (i.e., coercive) mating attempts towards females. Considering that, by influencing mating outcomes, male-male competition has important consequences for population dynamics and broader evolutionary processes, this study highlights the need for greater understanding of the potential impact of EDCs on the mechanisms of sexual selection.

Salinity and sensitivity to endocrine disrupting chemicals: A comparison of reproductive endpoints in small-bodied fish exposed under different salinities

The influence of salinity on toxicity outcomes has been demonstrated for various contaminants, but has received limited attention for endocrine disrupting chemicals (EDCs). Short-term laboratory tests using small-bodied fish are an important tool for evaluating impacts of EDCs on reproduction. Tests have been developed for both freshwater and estuarine/marine species, providing an opportunity to assess whether concentrations at which small-bodied fish respond to EDCs may be influenced by salinity. We conducted a semi-quantitative review of short-term laboratory tests with small-bodied fish exposed to EDCs, including 59 studies under freshwater conditions (7 species) and 23 studies conducted under saline conditions (5 species). We focused on two model estrogens [17α-ethinylestradiol and 17β-estradiol (E2)], and three androgens (17β-trenbolone, 5α-dihydrotestosterone and 17α-methyltestosterone). The lowest observed adverse effect concentration (LOAEC_LOW) for key reproductive endpoints was recorded, including sex-steroid and vitellogenin (VTG) levels, fecundity and fertilization. In 65.2% of cases, responses occurred at lower doses under freshwater compared to saline conditions, compared to only 4.3% of cases where fish responded to lower doses under saline conditions. The potential influence of salinity was more pronounced when estrogenic compounds were considered separately, with fish responding to lower doses under fresh compared to saline conditions in 90.5% of cases. Fecundity and E2 level were identified as the most sensitive endpoints for evaluating EDCs regardless of salinity. Interestingly, female VTG levels were a sensitive endpoint under freshwater but not saline conditions. Overall, our results suggest that salinity may be an important factor influencing how small-bodied fish respond to environmental EDCs.

Androgens and androgenic activity in broiler manure assessed by means of chemical analyses and in vitro bioassays

The use of manure as an agricultural amendment is increasing the release of steroid hormones into the environment. Most research in this field has focused on estrogenic phenomena, with less attention paid to androgenic substances. The present study assessed androgenic activity in broiler manure using in vitro approaches based on cells stably transfected with androgen receptor. Leaching experiments were also performed to observe whether endocrine disruptors present in manure pass through a soil column and potentially reach groundwater. In parallel, an analytical chemistry method was used to determine the contribution of the most important natural androgens to androgenicity. Samplings were performed at 4 farms in 2 seasons. All but 2 samples showed androgen activity. In leakage experiments, however, no androgenic activity was detectable in leachates or in soils after leaching. According to the analytical results, androgenicity can be attributed mainly (but not completely) to androstenedione, and dihydrotestosterone. Similarly to the bioassays, chemical analysis did not reveal the presence of any androgen in leachates or soils. These results point to a rapid degradation of the substances responsible for androgenic activity in soils under the experimental conditions of the present study. However, the long-term effects associated with the constant and intensive application of manure to agricultural land require further attention. Environ Toxicol Chem 2017;36:1746-1754. © 2016 SETAC.

Degradation and transformation of 17α-trenbolone in aerobic water-sediment systems

Synovex® ONE is an extended-release implant containing the active ingredients estradiol benzoate and trenbolone acetate for use in beef steers and heifers. Trenbolone acetate is rapidly hydrolyzed in cattle to form 17β-trenbolone and its isomer, 17α-trenbolone, which are further transformed to a secondary metabolite, trendione. As part of the environmental assessment for the use of Synovex ONE, data were generated to characterize the fate of 17α-trenbolone, which is the principal metabolite found in cattle excreta, in the environment. A study was conducted to determine the degradation and transformation of [¹⁴ C]-17α-trenbolone in 2 representative water-sediment systems under aerobic conditions. The same transformation products, 17β-trenbolone and trendione, were formed, principally in the sediment phase, in both systems. From the production of these transformation products, the 50% disappearance time (DT50) values of 17β-trenbolone and trendione were determined, along with the DT50 values of the parent compound and the total drug (17α-trenbolone + 17β-trenbolone + trendione). The DT50 values for the total system (aqueous and sediment phase) and for the total residues (17α-trenbolone + 17β-trenbolone + trendione) in the 2 systems were 34.7 d and 53.3 d, respectively. Environ Toxicol Chem 2017;36:630-635. © 2016 SETAC.