Introduction: The ecological relevance of chemically induced endocrine disruption in wildlife

Extensive rain events have a more substantial impact than advanced effluent treatment on the endocrine-disrupting activity in an effluent-dominated small river

Wastewater treatment plants (WWTPs) remain an important primary source of emission for endocrine-disrupting compounds in the environment. As an advanced wastewater treatment process, ozonation is known to reduce endocrine-disrupting activity. However, it remains unclear to which extend improved wastewater treatment may reduce the endocrine-disrupting activity in the receiving water body. The present study investigated possible factors for the endocrine-disrupting activity in a small receiving water body, the Wurm River (North-Rhine Westphalia, Germany), up- and downstream of a local WWTP. The cell-based reporter gene CALUX® assay was applied to identify the endocrine-disrupting activity in the water, sediment, and suspended particulate matter. The water phase and the effluent sampling were primarily driven by applying the full-scale effluent ozonation (sampling campaigns in June 2017 and March 2019). In contrast, the sediment sampling aimed to compare the particle-bound endocrine-disrupting activity during dry (June 2017) and rainy summer (June 2018) seasons. The water phase showed low to moderate estrogenic/antiandrogenic activity. Advanced effluent treatment by ozonation led to a complete reduction of the endocrine-disrupting activity according to the limit of detection of the CALUX® assays. The suspended particulate matter originated from the water phase of the second sampling campaign revealed antiandrogenic activity only. Sediments at the sampling sites along the local WWTP revealed higher estrogenic and antiandrogenic activity after extensive rain events and were not affected by the ozonated effluent. Fluctuation patterns of the endocrine-disrupting activity in sediments were in line with fluctuated concentrations of polycyclic aromatic hydrocarbons. Rainwater overflow basin release was suggested as a vector for particle-bound and dissolved endocrine-disrupting activity in the receiving water body. The present study underlined the necessity for monitoring both water and sediment phases to achieve reliable profiling of the endocrine-disrupting activity. The receptor-mediated CALUX® assays were proven to be suitable for investigating the endocrine-disrupting activity distribution in different river compartments and WWTP effluents.

Combined Effects of Different Endocrine-Disrupting Chemicals (EDCs) on Prostate Gland

Endocrine-disrupting chemicals (EDCs) belong to a heterogeneous class of environmental pollutants widely diffused in different aquatic and terrestrial habitats. This implies that humans and animals are continuously exposed to EDCs from different matrices and sources. Moreover, pollution derived from anthropic and industrial activities leads to combined exposure to substances with multiple mechanisms of action on the endocrine system and correlated cell and tissue targets. For this reason, specific organs, such as the prostate gland, which physiologically are under the control of hormones like androgens and estrogens, are particularly sensitive to EDC stimulation. It is now well known that an imbalance in hormonal regulation can cause the onset of various prostate diseases, from benign prostate hyperplasia to prostate cancer. In this review, starting with the description of normal prostate gland anatomy and embryology, we summarize recent studies reporting on how the multiple and simultaneous exposure to estrogenic and anti-androgenic compounds belonging to EDCs are responsible for an increase in prostate disease incidence in the human population.

Cumulative effects of antiandrogenic chemical mixtures and their relevance to human health risk assessment

Toxicological studies of defined chemical mixtures assist human health risk assessment by establishing how chemicals interact with one another to induce an effect. This paper reviews how antiandrogenic chemical mixtures can alter reproductive tract development in rats with a focus on the reproductive toxicant phthalates. The reviewed studies compare observed mixture data to mathematical mixture model predictions based on dose addition or response addition to determine how the individual chemicals in a mixture interact (e.g., additive, greater, or less than additive). Phthalate mixtures were observed to act in a dose additive manner based on the relative potency of the individual phthalates to suppress fetal testosterone production. Similar dose additive effects have been reported for mixtures of phthalates with antiandrogenic pesticides of differing mechanisms of action. Overall, data from these phthalate experiments in rats can be used in conjunction with human biomonitoring data to determine individual hazard indices, and recent cumulative risk assessments in humans indicate an excess risk to antiandrogenic chemical mixtures that include phthalates only or phthalates in combination with other antiandrogenic chemicals.

Ecopharmacovigilance: Current state, challenges, and opportunities in China

In a context of severe pharmaceutical pollution, “ecopharmacovigilance” (EPV) has been an area of novel interest. It aims to ensure that significant environmental issues associated with pharmaceuticals in the environment are identified in a timely way, and managed appropriately. EPV has become a research hotspot as a comprehensive and boundary science in Europe and North America, and regulatory requirements governing the comprehensive environmental risk assessment (ERA) of pharmaceuticals exist in these regions. A speedy Chinese pharmaceutical industry development and drug consumption, China should shoulder more international responsibility and contribute to the worldwide EPV. Compared to the west, EPV in China is in its infancy. We analyzed the current state of EPV-related practice in China and found that many efforts have been made by the Chinese government and specialists to control the ever-worsening environmental pharmaceutical pollution problems, including consummating related policies and regulations, revealing the occurrence and behavior of pharmaceutical residues in environment and developing new technologies to improve their removal performance. Besides, we posed some recommendations on appropriate EPV implementation that can be taken with China in future. These include, building perfect laws and regulation system on EPV, defining the evaluation index for EPV, continuing the clinical rational medication and the pharmaceutical take-back programs in China, popularizing the concept of EPV in China, and strengthening the policy-guided and scientific researches of EPV in pharmaceutical firms and academia.

Are in vitro methods for the detection of endocrine potentials in the aquatic environment predictive for in vivo effects? Outcomes of the Projects SchussenAktiv and SchussenAktivplus in the Lake Constance Area, Germany

Many studies about endocrine pollution in the aquatic environment reveal changes in the reproduction system of biota. We analysed endocrine activities in two rivers in Southern Germany using three approaches: (1) chemical analyses, (2) in vitro bioassays, and (3) in vivo investigations in fish and snails. Chemical analyses were based on gas chromatography coupled with mass spectrometry. For in vitro analyses of endocrine potentials in water, sediment, and waste water samples, we used the E-screen assay (human breast cancer cells MCF-7) and reporter gene assays (human cell line HeLa-9903 and MDA-kb2). In addition, we performed reproduction tests with the freshwater mudsnail Potamopyrgus antipodarum to analyse water and sediment samples. We exposed juvenile brown trout (Salmo trutta f. fario) to water downstream of a wastewater outfall (Schussen River) or to water from a reference site (Argen River) to investigate the vitellogenin production. Furthermore, two feral fish species, chub (Leuciscus cephalus) and spirlin (Alburnoides bipunctatus), were caught in both rivers to determine their gonadal maturity and the gonadosomatic index. Chemical analyses provided only little information about endocrine active substances, whereas the in vitro assays revealed endocrine potentials in most of the samples. In addition to endocrine potentials, we also observed toxic potentials (E-screen/reproduction test) in waste water samples, which could interfere with and camouflage endocrine effects. The results of our in vivo tests were mostly in line with the results of the in vitro assays and revealed a consistent reproduction-disrupting (reproduction tests) and an occasional endocrine action (vitellogenin levels) in both investigated rivers, with more pronounced effects for the Schussen river (e.g. a lower gonadosomatic index). We were able to show that biological in vitro assays for endocrine potentials in natural stream water reasonably reflect reproduction and endocrine disruption observed in snails and field-exposed fish, respectively.

Photolysis of estrone generates estrogenic photoproducts with higher activity than the parent compound

In the present study, we aimed to evaluate the effect of UV-visible irradiation on the estrogenicity of an estrone aqueous solution by using chemical analysis associated with an in vitro bioassay and in silico analysis. An estrone aqueous solution was irradiated with an UV-visible high-pressure mercury lamp. By using the MELN in vitro cellular bioassay, based on the induction of a luciferase reporter gene upon the activation of the estrogen receptor by chemicals, we showed that the estrogenic potency of the solution increased after irradiation. High-performance liquid chromatography fractionation of the photolyzed solution followed by in vitro testing of fractions allowed the quantitation of the estrogenic potency of each fraction. Nine photoproducts were detected and characterized by liquid chromatography-mass spectrometry coupling. The observed estrogenic activity is mediated by mono- and multi-hydroxylated photoproducts; it is influenced by the position of hydroxyl groups on the steroidal skeleton. In addition, a structure-activity analysis of the hydroxylated photoproducts confirmed their ability to act as estrogen receptor ligands.

Implementing ecopharmacovigilance in practice: challenges and potential opportunities

Ecopharmacovigilance (EPV) is a developing science and it is currently very unclear what it might mean in practice. We have performed a comparison between pharmacovigilance (PV) and EPV and have identified that there are similarities, but also some important differences that must be considered before any practical implementation of EPV. The biggest difference and greatest challenge concerns signal detection in the environment and the difficulty of identifying cause and effect. We reflect on the dramatic vulture decline in Asia, which was caused by the veterinary use of diclofenac, versus the relative difficulty in identifying the specific causes of intersex fish in European rivers. We explore what EPV might mean in practice and have identified that there are some practical measures that can be taken to assess environmental risks across product life cycle, particularly after launch of a new drug, to ensure that our risk assessments and scientific understanding of pharmaceuticals in the environment remain scientifically and ecologically relevant. These include:

Tracking environmental risks after launch of the product, via literature monitoring for emerging data on exposure and effects

Using Environmental Risk Management Plans (ERMPs) as a centralized resource to assess and manage the risks of a drug throughout its life cycle

Further research, testing or monitoring in the environment when a risk is identified

Keeping a global EPV perspective

Increasing transparency and availability of environmental data for medicinal products.

These measures will help to ensure that any significant environmental issues associated with pharmaceuticals in the environment (PIE) are identified in a timely way, and can be managed appropriately.

Feminization and altered gonadal gene expression profile by ethinylestradiol exposure to pejerrey, Odontesthes bonariensis, a South American teleost fish

In pejerrey (Odontesthes bonariensis), ovarian differentiation has been associated with gonadal aromatase expression. It is also known that exposure of pejerrey larvae to estradiol (E(2)) produces all female populations. During the last few years, the presence of ethinylestradiol (EE(2)), a synthetic E(2) analogue, has been reported in water reservoirs of different parts of the world. In the present study, the effects of EE(2) were assessed on sex ratio bias and gene expression levels of gonadal aromatase (cyp19a1a), 11β-hydroxysteroid dehydrogenase type 2 (hsd11b2), estrogens (erα, erβ1), and androgen receptors (arα, arβ). Pejerrey larvae were fed with commercial food containing EE(2) (0.1 and 1 µg/g) and E(2 ) (50 µg/g) as a positive control for six weeks after hatching. The gonadal histological analysis showed that 42 to 46% of the fish had clearly differentiated ovaries in both the EE(2) - and E(2) -treated groups, compared with 27% in the control group. Moreover, in the EE(2) - (1 µg/g) and E(2) -treated groups, no fish presented signs of testicular development compared with controls. In addition, expression of cyp19a1a and hsd11b2 was significantly up- and downregulated, respectively, by EE(2) and E(2) . The authors' results suggested that the feminization process driven by EE(2) depends on the positive balance of cyp19a1a in relation to hsd11b2. Thus, these genes can be used as early indicators of exposure to xenoestrogens in this species.

Estrone direct photolysis: by-product identification using LC-Q-TOF

The identification of degradation products generated upon photolysis of estrone (E1), a natural estrogenic hormone, under simulated UV irradiation conditions was addressed by the use of LC-Q-TOF mass spectrometry. The structures of the main degradation products were elucidated, demonstrating how the use of model molecules 5,6,7,8-tetrahydro-2-naphtol (THN), 2-methylcyclopentanone (MCP), labeled molecule estrone D(4) (E1-D(4)), the investigation of the fragmentation pathways of the parent E1, the concurrent use of CID and exact mass measurements permit the characterization of structural modifications induced by photodegradation processes. In the present study, we identified nine major by-products of which seven photoproducts correspond to E1H(+) modified in positions other than the C-2, C-4 and C-16 of E1. Most of them showed one to three additional hydroxylations preferentially located on the aromatic ring of the parent E1, which confirms that these products may present environmental risk. Applications to real water samples have been conducted to extend the validity of the present study to environmental samples.

How seasonality affects the flow of estrogens and their conjugates in one of Japan's most populous catchments

A detailed study of the free and conjugated estrogen load discharged by the eight major sewage treatment plants into the Yodo River basin, Japan was carried out. Sampling campaigns were focused on the winter and autumn seasons from 2005 to 2008 and the free estrogens estrone(E1), 17β-estradiol(E2), estriol(E3), 17α-ethynylestradiol(EE2) as well as their conjugated (sulfate and glucuronide) forms. For both sewage effluent and river water E2 and E1 concentrations were greatest during the winter period (December-March). This coincides with the period of lowest rainfall and lowest temperatures in Japan. E1 was the dominant estrogenic component in effluent (means of 10-50 ng/L) followed by E2 (means of 0.5-3 ng/L). The estrogen sulfate conjugates were found intermittently in the 0.5-1.7 ng/L concentration range in the sewage effluents. The greatest estrogen exposure was found to be in the Katsura River tributary which exceeded 1 ng/L E2-equivalents during the winter period.

A yeast estrogen screen without extraction provides fast, reliable measures of estrogenic activity

Yeast estrogen screen (YES) has been used since 1996 as a bioassay to quantify activity in wastewater. Here we present a modification of YES to measure estrogenic activity in water. This modification, called yeast estrogen screen no extraction (YESne), is faster and easier than the common method. The modified method can detect 17β-estradiol equivalent concentrations down to 1.1 ng/L. The median effective concentration value (EC50) is 1.2E-10. It detected average influent concentrations of 16.4 and 17.5 ng/L of 17β-estradiol equivalent at four Lehigh Valley, Pennsylvania, USA, wastewater treatment plants on September 18 and October 23, 2008, respectively, and average effluent concentrations of 5.1 and 8.1 ng/L of 17β-estradiol equivalent at the same plants on the two dates, respectively. Reduction in 17β-estradiol equivalent activity for the four wastewater treatment plants averaged 67.8 and 52.3%, respectively, for the September 18 and October 23 samples. The YESne is a simple, quick method for quantifying estrogenic activity that has been used successfully in nonmajor undergraduate classes and could be adapted by wastewater treatment plant laboratory technicians to measure influent and effluent estrogenicity on a regular basis. This practice will greatly increase our knowledge base of estrogenicity in wastewater before and after treatment.

Ozonation and activated carbon treatment of sewage effluents: removal of endocrine activity and cytotoxicity

Concerns about endocrine disrupting compounds in sewage treatment plant (STP) effluents give rise to the implementation of advanced treatment steps for the elimination of trace organic contaminants. The present study investigated the effects of ozonation (O(3)) and activated carbon treatment (AC) on endocrine activities [estrogenicity, anti-estrogenicity, androgenicity, anti-androgenicity, aryl-hydrocarbon receptor (AhR) agonistic activity] with yeast-based bioassays. To evaluate the removal of non-specific toxicity, a cytotoxicity assay using a rat cell line was applied. Wastewater (WW) was sampled at two STPs after conventional activated sludge treatment following the secondary clarifier (SC) and after subsequent advanced treatments: O(3), O(3) + sand filtration (O(3-SF)), and AC. Conventional treatment reduced estrogenicity, androgenicity, and AhR agonistic activity by 78-99% compared to the untreated influent WW. Anti-androgenicity and anti-estrogenicity were not detectable in the influent but appeared in SC, possibly due to the more effective removal of respective agonists during conventional treatment. Endocrine activities after SC ranged from 2.0 to 2.8 ng/L estradiol equivalents (estrogenicity), from 4 to 22 μg/L 4-hydroxytamoxifen equivalents (anti-estrogenicity), from 1.9 to 2.0 ng/L testosterone equivalents (androgenicity), from 302 to 614 μg/L flutamide equivalents (anti-androgenicity), and from 387 to 741 ng/L β-naphthoflavone equivalents (AhR agonistic activity). In particular, estrogenicity and anti-androgenicity occurred in environmentally relevant concentrations. O(3) and AC further reduced endocrine activities effectively (estrogenicity: 77-99%, anti-androgenicity: 63-96%, AhR agonistic activity: 79-82%). The cytotoxicity assay exhibited a 32% removal of non-specific toxicity after O(3) compared to SC. O(3) and sand filtration reduced cytotoxic effects by 49%, indicating that sand filtration contributes to the removal of toxicants. AC was the most effective technology for cytotoxicity removal (61%). Sample evaporation reduced cytotoxic effects by 52 (AC) to 73% (O(3)), demonstrating that volatile substances contribute considerably to toxic effects, particularly after O(3). These results confirm an effective removal or transformation of toxicants with receptor-mediated mode of action and non-specific toxicants during O(3) and AC. However, due to the limited extractability, polar ozonation by-products were neglected for toxicity analysis, and hence non-specific toxicity after O(3) is underestimated.

Cumulative effects of in utero administration of mixtures of reproductive toxicants that disrupt common target tissues via diverse mechanisms of toxicity

Although risk assessments are typically conducted on a chemical-by-chemical basis, the 1996 Food Quality Protection Act required the US Environmental Protection Agency to consider cumulative risk of chemicals that act via a common mechanism of toxicity. To this end, we are conducting studies with mixtures of chemicals to elucidate mechanisms of joint action at the systemic level with the goal of providing a framework for assessing the cumulative effects of reproductive toxicants. Previous mixture studies conducted with antiandrogenic chemicals are reviewed briefly and two new studies are described. In all binary mixture studies, rats were dosed during pregnancy with chemicals, singly or in pairs, at dosage levels equivalent to approximately one-half of the ED50 for hypospadias or epididymal agenesis. The binary mixtures included androgen receptor (AR) antagonists (vinclozolin plus procymidone), phthalate esters [di(n-butyl) phthalate (DBP) plus benzyl n-butyl phthalate (BBP) and diethyl hexyl phthalate (DEHP) plus DBP], a phthalate ester plus an AR antagonist (DBP plus procymidone), a mixed mechanism androgen signalling disruptor (linuron) plus BBP, and two chemicals which disrupt epididymal differentiation through entirely different toxicity pathways: DBP (AR pathway) plus 2,3,7,8 TCDD (AhR pathway). We also conducted multi-component mixture studies combining several 'antiandrogens'. In the first study, seven chemicals (four pesticides and three phthalates) that elicit antiandrogenic effects at two different sites in the androgen signalling pathway (i.e. AR antagonist or inhibition of androgen synthesis) were combined. In the second study, three additional phthalates were added to make a 10 chemical mixture. In both the binary mixture studies and the multi-component mixture studies, chemicals that targeted male reproductive tract development displayed cumulative effects that exceeded predictions based on a response-addition model and most often were in accordance with predictions based on dose-addition models. In summary, our results indicate that compounds that act by disparate mechanisms of toxicity to disrupt the dynamic interactions among the interconnected signalling pathways in differentiating tissues produce cumulative dose-additive effects, regardless of the mechanism or mode of action of the individual mixture component.

In utero exposure to an AR antagonist plus an inhibitor of fetal testosterone synthesis induces cumulative effects on F1 male rats

Risk assessments are typically conducted on a chemical-by-chemical basis; however, many regulatory bodies are developing frameworks for assessing the cumulative risk of chemical mixtures of chemicals. The current investigation examined how chemicals that disrupt rat sex differentiation via two diverse mechanisms disrupt F1 male rat reproductive development, when administered together orally on days 14-18 of gestation. Experiment 1 used a mixture of 50 mg/kg-d procymidone and 500 mg/kg-d dibutyl phthalate (DBP), whereas experiment 2 used 150 mg/kg-d procymidone and 1125 mg/kg-d DBP (top dose), or 0, 4.17, 8.33, 16.7, 33.3, 50, 66.7, and 83.3% of the top dose. When we compared the dose and response addition predictions to the observed effects we found that dose addition models were more accurate than response addition models, indicating that compounds that act by different mechanisms of toxicity produce cumulative dose-additive effects.

Comparative responses in rare minnow exposed to 17beta-estradiol during different life stages

Present in the excrement of humans and animals, 17beta-estradiol (E(2)) has been detected in the aquatic environment in a range from several nanograms to several hundred nanograms per liter. In this study, the sensitivities of rare minnows during different life stages to E(2) at environmentally relevant (5, 25, and 100 ng l(-1)) and high (1000 ng l(-1)) concentrations were compared using vitellogenin (VTG) and gonad development as biomarkers under semistatic conditions. After 21 days of exposure, VTG concentrations in whole-body homogenates were analyzed; the results indicated that the lowest observed effective concentration for VTG induction was 25 ng l(-1) E(2) in the adult stage, but 100 ng l(-1) E(2) in the larval and juvenile stages. After exposure in the early life stage, the larval and juvenile fish were transferred to clean water until gonad maturation. No significant difference in VTG induction was found between the exposure and control groups in the adults. However, a markedly increased proportion of females and appearance of hermaphrodism were observed in the juvenile-stage group exposed to 25 ng l(-1) E(2). These results showed that VTG induction in the adult stage is more sensitive than in larval and juvenile stages following exposure to E(2). The juvenile stage may be the critical period of gonad development. Sex ratio could be a sensitive biomarker indicating exposure to xenoestrogens in early-life-stage subchronic exposure tests. The results of this study provide useful information for selecting sensitive biomarkers properly in aquatic toxicology testing.

Endocrine disruption in aquatic vertebrates

Environmental compounds can interfere with endocrine systems of wildlife and humans. The main sink of such substances, called endocrine disrupters (ED), are surface waters. Thus, aquatic vertebrates, such as fish and amphibians, are most endangered. ED can adversely affect reproductive biology and the thyroid system. ED act by (anti)estrogenic and (anti)androgenic modes of action, resulting in abnormal sexual differentiation and impaired reproduction. These effects are mainly driven by direct interferences of ED with sex steroid receptors rather than indirectly by impacting synthesis and bioavailability of sex steroids, which in turn might affect the hypothalamic-pituitary-gonadal axis. Recent findings reveal that, in addition to the human-produced waste of ED, natural sources, such as parasites and decomposition of leaves, also might act as ED, markedly affecting sexual differentiation and reproduction in fish and amphibians. Although the thyroid system has essential functions in both fish and amphibians, amphibian metamorphosis has been introduced as the most sensitive model to detect thyroidal ED; no suitable fish model exists. Whereas ED may act primarily on only one specific endocrine target, all endocrine systems will eventually be deregulated as they are intimately connected to each other. The recent ecotoxicological issue of pharmaceutically active compounds (PhACs) present in the aquatic environment indicates a high potential for further endocrine modes of action on aquatic vertebrates by ED derived from PhACs, such as glucocorticoids, progestins, and beta-agonists.

Monitoring and reducing exposure of infants to pollutants in house dust

The health risks to babies from pollutants in house dust may be 100 times greater than for adults. The young ingest more dust and are up to ten times more vulnerable to such exposures. House dust is the main exposure source for infants to allergens, lead, and PBDEs, as well as a major source of exposure to pesticides, PAHs, Gram-negative bacteria, arsenic, cadmium, chromium, phthalates, phenols, and other EDCs, mutagens, and carcinogens. Median or upper percentile concentrations in house dust of lead and several pesticides and PAHs may exceed health-based standards in North America. Early contact with pollutants among the very young is associated with higher rates of chronic illness such as asthma, loss of intelligence, ADHD, and cancer in children and adults. The potential of infants, who live in areas with soil contaminated by automotive and industrial emissions, can be given more protection by improved home cleaning and hand washing. Babies who live in houses built before 1978 have a prospective need for protection against lead exposures; homes built before 1940 have even higher lead exposure risks. The concentration of pollutants in house dust may be 2-32 times higher than that found in the soil near a house. Reducing infant exposures, at this critical time in their development, may reduce lifetime health costs, improve early learning, and increase adult productivity. Some interventions show a very rapid payback. Two large studies provide evidence that home visits to reduce the exposure of children with poorly controlled asthma triggers may return more than 100% on investment in 1 yr in reduced health costs. The tools provided to families during home visits, designed to reduce dust exposures, included vacuum cleaners with dirt finders and HEPA filtration, allergy control bedding covers, high-quality door mats, and HEPA air filters. Infants receive their highest exposure to pollutants in dust at home, where they spend the most time, and where the family has the most mitigation control. Normal vacuum cleaning allows deep dust to build up in carpets where it can be brought to the surface and become airborne as a result of activity on the carpet. Vacuums with dirt finders allow families to use the three-spot test to monitor deep dust, which can reinforce good cleaning habits. Motivated families that receive home visits from trained outreach workers can monitor and reduce dust exposures by 90% or more in 1 wk. The cost of such visits is low considering the reduction of risks achieved. Improved home cleaning is one of the first results observed among families who receive home visits from MHEs and CHWs. We believe that proven intervention methods can reduce the exposure of infants to pollutants in house dust, while recognizing that much remains to be learned about improving the effectiveness of such methods.