E2 Equivalents Research Articles

Transiently gene-modulated cell reporter for ultrasensitive detection of estrogen-like compounds in tap water

Abnormal elevation of indispensable steroid hormone estrogens and exposure to exogenous estrogen-like compounds pose adverse health effects to aquatic animals and human alike. These compounds generally display functionally important estrogenic activity even at extremely low picomolar concentrations. In this study we identified one critical but lethal gene (TAF1) that remarkably represses estrogenic activity. This gene is selected as a candidate for genetically modulating an estrogen-responding cell line. To overcome its lethality, instead of adopting a gene knockout strategy, we developed a transient TAF1 depletion strategy using a designed small interfering RNA. By the transient knockdown of TAF1 in the estrogen-responding reporter cell line, the maximum induction signals for endogenous estrogen 17β-estradiol (E2) and environmental estrogens 17α-ethynyl estradiol (EE2) and bisphenol compounds were enhanced by 4.8–13.3 folds. The limit of detection for EE2 is about 8 × 10−15 mol/L. Moreover, by the established method, trace estrogenic activity (14.7–24.2 pg E2 equivalents (E2Eq)/L) can be detected in a portion of Tap water samples.

Bioavailability of estrogenic compounds from sediment in the context of flood events evaluated by passive sampling

Studies worldwide have demonstrated through in vitro bioassays and chemical analysis that endocrine-disrupting chemicals (EDCs) can accumulate in river sediments. However, remobilization of sediment-bound EDCs due to bioturbation or re-suspension during flood events remains poorly understood. The aim of this study was to evaluate the bioavailability of EDCs, more specifically estrogenic compounds (EC), from sediment under turbulent conditions using a passive sampling approach. Sediment was sampled along the Luppe River, Germany, previously described as a “hotspot” for ECs. The concentration of target ECs and estrogenic activity were investigated using chemical analysis (LC MS/MS) in addition to a novel screening tool (planar Yeast Estrogen Screen; p-YES) that utilizes high performance thin-layer chromatography plates in combination with an in vitro bioassay (YES). Estrone (50%, E1) and nonylphenol (35%, NP) accounted for the majority of estrogenic activity reported of up to 20 ± 2.4 μg E2 equivalents per kg dry weight in the Luppe sediments. Two types of passive samplers (polar organic chemical integrative sampler (POCIS) and Chemcatcher) were used to investigate the bioavailability of ECs from suspended sediment under laboratory conditions. NP, E1, E2 and ethynylestradiol (EE2) were remobilized from Luppe sediment when subjected to turbulent conditions, such as in a flood event, and were readily bioavailable at ecotoxicologically relevant concentrations (NP 18 μg/L, E1 14 ng/L, E2 0.2 ng/L, EE2 0.5 ng/L).

Modeling the exposure of wild fish to endocrine active chemicals: Potential linkages of total estrogenicity to field-observed intersex

Decades of studies on endocrine disruption have suggested the need to manage the release of key estrogens from municipal wastewater treatment plants (WWTP). However, the proposed thresholds are below the detection limits of most routine chemical analysis, thereby restricting the ability of watershed managers to assess the environmental exposure appropriately. In this study, we demonstrated the utility of a mechanistic model to address the data gaps on estrogen exposure. Concentrations of the prominent estrogenic contaminants in wastewaters (estrone, estradiol, and ethinylestradiol) were simulated in the Grand River in southern Ontario (Canada) for nine years, including a period when major WWTP upgrades occurred. The predicted concentrations expressed as total estrogenicity (E2 equivalent concentrations) were contrasted to a key estrogenic response (i.e., intersex) in rainbow darter (Etheostoma caeruleum), a wild sentinel fish species. A predicted total estrogenicity in the river of ≥10 ng/L E2 equivalents was associated with high intersex incidence and severity, whereas concentrations <0.1 ng/L E2 equivalents were associated with minimal intersex expression. Exposure to a predicted river concentration of 0.4 ng/L E2 equivalents, the environmental quality standard (EQS) proposed by the European Union for estradiol, was associated with 34% (95% CI:30–38) intersex incidence and a very low severity score of 0.6 (95% CI:0.5–0.7). This exposure is not predicted to cause adverse effects in rainbow darter. The analyses completed in this study were only based on the predicted presence of three major estrogens (E1, E2, EE2), so caution must be exercised when interpreting the results. Nevertheless, this study illustrates the use of models for exposure assessment, especially when measured data are not available.

Chemical and biological assessment of endocrine disrupting chemicals in a full scale dairy manure anaerobic digester with thermal pretreatment

Concentrated animal feeding operations are important sources of estrogens and their conjugates, which are introduced into the environment through manure land application. In this study, concentrations of estrogens were measured in an anaerobic co-digestion system with thermal pasteurization pretreatment. Free estrogens (estrone (E1), 17α-estradiol (E2α), 17β-estradiol (E2β), estriol (E3)) were analyzed by gas chromatography with mass spectrometry (GC/MS), and conjugated estrogens (sulfate- and glucuronide-conjugates) were analyzed by liquid chromatography with tandem mass spectrometry (LC/MS/MS). Additionally, yeast estrogen screen assay was used to determine the estrogenic potential of the manure. The total hormone concentrations (mainly E1, E2α, E2β, and sulfated estrogens) were observed at concentrations up to a total of 7100ng/L in the liquid fraction, while free estrogen levels were 630ng/kg in the solid fraction of the untreated manure. The total hormone concentration did not decrease significantly during digestion, however, the relative composition of the estrogens changed from E2α (65%) being the predominant species before digestion to mostly E1 (72%) after digestion. This conversion process has important implications because E1 is more estrogenic than E2α. Total E2 equivalents associated with E1, E2α and E2β concentrations as determined by GC/MS indicate that E1 is the most important contributor to the endocrine-disruption activity of the treated manure.

Risk of endocrine disruption to fish in the Yellow River catchment in China assessed using a spatially explicit model.

The global water availability assessment (GWAVA) model, incorporating regional water abstractions and reservoir information, was used to model the human-sourced steroid estrogens estrone (E1) and estradiol (E2) in the Yellow River catchment (China). The river flows in the main stem were calibrated using gauged flows. Following a review of Chinese data on estrogen discharge from a range of sewage treatment plants, low, median, and high discharge rates were identified and used as best, expected, and worst-case scenarios, respectively. For any given location, the temporal variation of modeled estrogen levels was summarized using the mean and upper 90th percentile, which is where the model predicts 90% of values would be below this concentration. The predicted means and 90th percentiles for E1 were comparable to previous E1 measurements reported in the river. For the whole catchment, only 19% (mean value) of the river system by length was predicted to exceed 1 ng/L E2 equivalents (EEQs) using expected estrogen sewage discharge. Only 3% of the network by length was predicted to exceed the dangerously high 10 ng/L EEQ when considering 90th percentile concentrations. The highest exposures were in the Fen and Wei tributaries. Endocrine disruption risk from estrogens was predicted to be minimal in the main stem. Only in the worst-case discharge scenario and 90th percentile predicted concentrations were the most downstream river reaches of the main stem predicted to be at risk. Reservoirs appeared to be helpful in reducing estrogen concentrations thanks to longer water residence facilitating biodegradation.

Estrogenic activity and identification of potential xenoestrogens in a coking wastewater treatment plant

In this study, the estrogenic activities in influent and effluents of coking wastewater from different treatment stages were studied using Yeast Estrogen Screen (YES) bioassays. Raw extracts were further fractioned to identify the potential xenoestrogens combined with YES bioassays and gas chromatography–mass spectrometry analysis. Influent, primary effluent, and anaerobic effluent showed high estrogenic activities, with potencies of 1136±269, 1417±320, and 959±69ng/L of 17β-estradiol (E2) equivalent (EEQ), respectively. The potency of estrogenic activity was gradually removed through the treatment processes. In the final effluent, the estrogenic activity was reduced to 0.87ng EEQ/L with a total removal efficiency of more than 99%, suggesting that the estrogenic activity was almost completely removed in the coking wastewater. For the fractions of raw extracts, bioassay results showed that the estrogenic activities were mostly present in the polar fractions. Correlation analysis between estrogenic activities and responses of identified chemicals indicated that potential xenoestrogens were the derivatives of indenol, naphthalenol, indol, acridinone, fluorenone, and carbazole. The estrogenic activity in the final effluent was higher than the predicted no effect concentration (PNEC) for E2, implying that the discharged effluent would probably exert estrogenic activity risk to the aquatic ecosystem in “the worst-case scenario.”

Consumption of Ground Beef Obtained from Cattle That Had Received Steroidal Growth Promotants Does Not Trigger Early Onset of Estrus in Prepubertal Pigs

Background:The earlier onset of puberty seen in young American girls has led researchers to question if a causal relation exists between dietary sources of estrogenic compounds and precocious puberty. Objective:Using the prepubertal gilt (young female pig) as an animal model, our hypothesis is that feeding beef obtained from cattle receiving growth-promoting steroidal implants postweaning does not alter the onset of puberty or the peripubertal body composition of gilts compared with contemporaries fed nonimplanted “natural” beef or a common meat alternative, tofu. Method:The base diet was formulated using canola meal replacing soybean meal to reduce diet estrogenicity. Feed intake was monitored and controlled to ensure similar intake. Gilts were assigned to treatments based on dam and initial body weight (mean: 24.5 ± 3.20 kg) at 61 d of age. The negative control base diet was supplemented with daily feedings of a cooked patty from nonimplanted steers (natural), from steers that had been treated with growth promotants [100 mg trenbolone acetate and 14 mg estradiol (E2) benzoate; implanted], or cooked tofu patty. Results:E2 equivalents (nanogram per kilogram, as fed as analyzed by E-Screen) of the tofu (a soy-based product) supplement were ∼570 times the natural and ∼170 times the implanted supplements. There were no observed differences across treatments in live weight gain (P = 0.90), longissimus muscle area developed at the 10th and 11th rib interface (P = 0.46), and subcutaneous fat deposition (P = 0.41) at the same location over time or in the number of days to reach estrus (P = 0.55). Conclusions:Consumption of beef from growth implanted or natural steers or tofu at levels similar to those typically consumed by humans did not impact growth or onset of estrus in these prepubertal gilts.

Estimating estrogen release and load from humans and livestock in shanghai, china.

The estrogens estrone (E1), 17β-estradiol (E2), and 17α-ethynylestradiol (EE2) cause potent endocrine disruptive effects on aquatic wildlife. Currently, four sources of released estrogens exist in Shanghai: treated effluent from municipal wastewater treatment plants (WTPs); wastewater discharge from livestock farms; untreated or simply digested sewage from rural households; and runoff from farmland with livestock manure (LM) applied and irrigated with livestock wastewater (LW). A modified estimation method for estrogen release, in consideration of the difference in estrogen excretion rates between Caucasian and Oriental people and estrogen reduction in livestock wastes, was presented in the study. Based on the estimation method, we estimated the amount of estrogen release from humans and livestock and analyzed the spatially explicit distribution of estrogen loads. By comparing the four estrogen sources, the amount of estrogens released to water environments from livestock (56.8 g d), in terms of E2 equivalents (EEQ), was nearly twofold higher than the EEQ from humans (35.2 g d), which accounted for 61.0% of the total EEQ in Shanghai. Regarding the livestock EEQ, land-applied and irrigated EEQ via surface runoff to water environments (0.11 g d) was obviously low compared with the EEQ of LW directly released into adjacent waterways (56.7 g d). Therefore, the LW was the major contributor to estrogenic risk to the water environment in Shanghai. The spatial distribution of estrogen loads indicated that the highest EEQ loads were in the southern region of Pudong New Area and the eastern and central regions of Fengxian District.

Elevated risk from estrogens in the Yodo River basin (Japan) in winter and ozonation as a management option

A simple model was set up to predict estrogen concentrations and endocrine disruption risk in the Yodo River, Japan. This catchment spans the conurbations of Kyoto and Osaka and is the main source of drinking water for Osaka City, Japan. From the river survey data (5 separate occasions between 2005 and 2008), a maximum of 32 g per day estrone (E1) load was observed in the most downstream site of the river. Predicted E1 concentrations were in reasonable agreement with the measurements taken at several points within the basin from a series of sampling campaigns. The predicted concentrations exceeded a net estradiol (E2) equivalent of 1 ng L(-1) on only a few occasions, suggesting that only limited endocrine disruption phenomena in fish along the Yodo River is likely. The model was then used to examine the impact on estrogen concentrations and endocrine disruption of a number of different scenarios. It was found that in-river biodegradation had little effect on predicted concentrations and the outcome of endocrine disruption along the catchment. However, reduced sewage treatment removal, as can be experienced in winter in Japan, led to levels of 3.1 ng L(-1) E2 equivalents being possible. The reduced river flow in winter in Japan exacerbates the situation as it offers less dilution. It was found that the application of the ozonation process as a tertiary sewage treatment in winter could prevent this higher risk endocrine disruption situation.

The isoflavone irilone contributes to the estrogenic potential of dietary supplements containing red clover

A recent intervention study demonstrated the occurrence of irilone as second most abundant isoflavone next to daidzein in human plasma after consumption of a red clover-based dietary supplement (RCDS) containing predominately formononetin ≫ biochanin A > irilone (12 % of these isoflavones). To elucidate the relevance of this finding, in the present study (1) the representativeness of the isoflavone composition of the RCDS and (2) the estrogenic activity of irilone were investigated. Thus, major isoflavones were quantified in eight commercially available RCDS. Furthermore, the estrogenic activities of irilone and other isoflavones were determined by marker gene expression in Ishikawa and cell proliferation in MCF-7 cells. Irilone amounted to 1.8-10.9 mg/g capsule content and 5-18 % of the three major isoflavones, respectively, demonstrating the general occurrence of irilone in RCDS. Moreover, irilone significantly induced the activity of alkaline phosphatase (AlP) as well as AlP, progesterone receptor, and androgen receptor mRNA levels in Ishikawa cells. Furthermore, irilone significantly induced MCF-7 cell proliferation. Neither 17β-estradiol (E2)-induced AlP activity nor E2-induced MCF-7 cell proliferation was affected by irilone. ICI182,780 antagonized IRI-induced effects on both AlP activity and cell proliferation, suggesting an estrogen receptor agonistic mode of action. Taking into account the estrogenic activity of red clover isoflavones (formononetin, biochanin A, prunetin, glycitein) and their biotransformation products (daidzein, genistein, ethylphenol) as well as published plasma levels of isoflavones after consumption of RCDS, irilone could contribute approximately 50 % of the E2 equivalents estimated for daidzein.

Removal of natural hormones in dairy farm wastewater using reactive and sorptive materials

The objective of this study was to examine the oestrogen and androgen hormone removal efficiency of reactive (Connelly zero-valent iron (ZVI), Gotthart Maier ZVI) and sorptive (AquaSorb 101 granular activated carbon (GAC) and OrganoLoc PM-100 organoclay (OC)) materials from HPLC grade water and constructed wetland system (CWS) treated dairy farm wastewater. Batch test studies were performed and hormone concentration analysis carried out using highly sensitive reporter gene assays (RGAs). The results showed that hormonal interaction with these materials is selective for individual classes of hormones. Connelly ZVI and AquaSorb 101 GAC were more efficient in removing testosterone (Te) than 17β-estradiol (E2) and showed faster removal rates of oestrogen and androgen than the other materials. Gotthart Maier ZVI was more efficient in removing E2 than Te. OrganoLoc PM-100 OC achieved the lowest final concentration of E2 equivalent (EEQ) and provided maximum removal of both oestrogens and androgens.

Bioanalytical and instrumental analysis of estrogenic activities in drinking water sources from Yangtze River Delta

The estrogenic activities of source water from Yangtze River, Huaihe River, Taihu Lake and groundwater in Yangtze River Delta in the dry and wet season were determined by use of reporter gene assays based on African green monkey kidney (CV-1) cell lines. Higher estrogenic activities were observed in the dry season, and the estrogenic potentials in water samples from Taihu Lake were greater than other river basins. None of the samples from groundwater showed estrogen receptor (ER) agonist activity. The 17β-Estradiol (E2) equivalents (EEQs) of water samples in the dry season ranged from 9.41×10−1 to 1.20×101ngE2L−1. In the wet season, EEQs of all the water samples were below the detection limit as 9.00×10−1 ngE2L−1 except for one sample from Huaihe River. The highest contribution of E2 was detected in Yangtze River as 99% of estrogenic activity. Nonylphenol (NP, 100% detection rate) and octylphenol (OP, 100% detection rate) might also be responsible for the estrogenic activities in water sources. Potential health risk induced by the estrogenic chemicals in source water may be posed to the residents through water drinking.

Occurrence of (Anti)estrogenic Effects in Surface Sediment from an E-Waste Disassembly Region in East China

Because of the report on the abnormal local fertility rate at Taizhou area, which is a famous e-waste disassembly center in China, the hormone-like effects in the surface sediment from the local river was investigated. Compared to the control site DG, significant estrogenic effects (p<0.01) were observed at e-waste recycling sites ranging from 6.01 to 29.31nmol/kg dw E2 equivalents by water extraction while ranging from 20.47 to 135.02nmol/kg dw by organic extraction. When coincubated with E2, the water and the organic extractions displayed significant (p<0.01) synergistic and anti-estrogenic effects respectively.

Assessment of source water contamination by estrogenic disrupting compounds in China

AbstractDetection of estrogenic disrupting compounds (EDCs) in drinking waters around China has led to rising concerns about health risks associated with these compounds. There is, however, a paucity of studies on the occurrence and identification of the main compounds responsible for this pollution in the source waters. To fill this void, we screened estrogenic activities of 23 source water samples from six main river systems in China, using a recombinant two-hybrid yeast assay. All sample extracts induced significant estrogenic activity, with E2 equivalents (EEQ) of raw water ranging from 0.08 to 2.40 ng/L. Additionally, 16 samples were selected for chemical analysis by gas chromatography-mass spectrometry. The EDCs of most concern, including estrone (E1), 17β-estradiol (E2), 17a-ethinylestradiol (EE2), estriol (E3), diethylstilbestrol (DES), estradiol valerate (EV), 4-t-octylphenol (4-t-OP), 4-nonylphenols (4-NP) and bisphenol A (BPA), were determined at concentrations of up to 2.98, 1.07, 2.67, 4.37, 2.52, 1.96, 89.52, 280.19 and 710.65 ng/L, respectively. Causality analysis, involving comparison of EEQ values from yeast assay and chemical analysis identified E2, EE2 and 4-NP as the main responsible compounds, accounting for the whole estrogenic activities (39.74% to 96.68%). The proposed approach using both chemical analysis and yeast assay could be used for the identification and evaluation of EDCs in source waters of China.

Estrogenic activity in extracts and exudates of cyanobacteria and green algae

Here is presented some of the first information on interactions of compounds produced by cyanobacteria and green algae with estrogen receptor signaling. Estrogenic potency of aqueous extracts and exudates (culture spent media with extracellular products) of seven species of cyanobacteria (10 different laboratory strains) and two algal species were assessed by use of in vitro trans-activation assays. Compounds produced by cyanobacteria and algae, and in particular those excreted from the cells, were estrogenic. Most exudates were estrogenic with potencies expressed at 50% of the maximum response under control of the estrogen receptor ranging from 0.2 to 7.2 ng 17β-estradiol (E 2) equivalents (EEQ)/L. The greatest estrogenic potency was observed for exudates of Microcystis aerigunosa, a common species that forms water blooms. Aqueous extracts of both green algae, but only one species of cyanobacteria ( Aphanizomenon gracile) elicited significant estrogenicity with EEQ ranging from 15 to 280 ng 17β-estradiol (E 2)/g dry weight. Scenedesmus quadricauda exudates and extracts of Aphanizomenon flos-aquae were antagonistic to the ER when coexposed to E 2. The EEQ potency was not correlated with concentrations of cyanotoxins, such as microcystin and cylindrospermopsin, which suggests that the EEQ was comprised of other compounds. The study demonstrates some differences between the estrogenic potency of aqueous extracts prepared from the same species, but of different origin, while the effects of exudates were comparable within species. The observed estrogenic potencies are important namely in relation to the possible mass expansion of cyanobacteria and release of the active compounds into surrounding water.

Estrogenic effects of dissolved organic matter and its impact on the activity of 17β-estradiol

The ubiquitous dissolved organic matter (DOM) is actually not inert as we always think, and the hormone-like effects of DOM have been reported. The objective of this study was to investigate the estrogenic effects of DOM and its impact on the activity of the natural estrogen 17β-estradiol (E2). DOM of three different sources, HA sodium salt, Suwannee River natural organic matter (NOM), and Nordic Reservoir NOM, were used. The estrogenic activity was detected by using the yeast estrogen screen (YES) assay. Estrogenic effects of DOM without and after solar irradiation were tested. Influences on the action of E2 by DOM were also investigated. No direct estrogenic effects of the DOM used were observed in the YES assay. However, the estrogenic activities after 24 h of irradiation increased to 0.0288, 0.0178, and 0.0195 μM of E2 equivalents for HA sodium salt, Suwannee River NOM, and Nordic Reservoir NOM, respectively. After incubation of DOM, the estrogenic activity of E2 was increased by low concentrations (8.33 and 83.3 μM) of DOM while decreased by higher concentrations (8.33 × 10(2) and 8.33 × 10(3) μM) of DOM. Though direct estrogenic effects of DOM were not observed, increase in the estrogenic activity of DOM after irradiation was significant. DOM shows amphoteric influence on the natural estrogen E2, which depends on the concentration of DOM used. Because of its ubiquity, DOM may be of great ecological significance, playing an important role in regulating the reproduction of aquatic organisms.

Removal of Natural Free Estrogens and their Conjugates in a Municipal Wastewater Treatment Plant

AbstractRemoval of natural free estrogens and estrogen conjugates in a municipal wastewater treatment plant (WWTP) was investigated and analyzed by GC‐MS, in which estrogen conjugates were first transformed to their corresponding free estrogens with an acid solvolysis procedure before their analysis. Natural free estrogens, E1‐3‐sulfate (E1‐3S), and E3‐3‐sulfate (E3‐3S) were detected with high concentrations in both the influent and effluent of the primary settling tank (PS), while no estrogen glucuronides were detected in any of the monitored wastewater samples. Regarding their removal efficiencies, all were almost completely removed, except for E1 with only a minor decrease. The estrogenic/androgenic removal of the same WWTP was also evaluated with estrogen receptor (androgen receptor) (ER (AR))‐binding assays, in which the removal efficiencies for E2 equivalents (EEQ) or testosterone equivalents (TEQ) were 68.5 and 72.2%. In addition, the chemically calculated EEQ from natural estrogens were about 20.6–39.3% that of the ER‐binding assay, in which E3 contributed the biggest proportion in both the influent and PS, while the calculated value of E1 increased from only 6.7% in the influent to as high as 20.6% in the effluent.

Estrogenic effects of leachates from industrial waste landfills measured by a recombinant yeast assay and transcriptional analysis in Japanese medaka

In Japan, the leachates from ‘stable type’ landfills for industrial wastes are not controlled, and this has given rise to concerns about the possible pollution of surrounding environmental waters, especially by endocrine disrupting chemicals leaching from plastic and rubber wastes. To accurately assess the estrogenic potential of the landfill leachates by both in vitro and in vivo approaches, we confirmed gene-transcriptional responses in recombinant yeast cells and in Japanese medaka fish to estrogenic compounds, and applied these transcription assays to leachate samples. The yeast carrying the estrogen receptor (ER) of medaka and an ER-mediated response pathway responded to both the natural estrogen, 17β-estradiol (E2), and an industrial compound, bisphenol A (BPA), and the effective concentration of BPA was about 2.0 × 10 3 times that of E2. Transcripts of all genes coding for precursors of yolk protein, vitellogenin ( vtg1 and vtg2), and precursors of egg envelope subunit proteins, choriogenins ( chgh and chgl), increased in a concentration dependent manner in the livers of male medaka exposed to BPA or E2, and, except for chgh, reached peaks at exposure times of 48 h. Although many fish in control groups did not have vtg transcripts, the incidence of vtg transcriptions also increased in a concentration dependent manner with exposure. The minimum effective concentrations of BPA at 48 h were 0.5 mg/L for chgh and vtg2, 2 mg/L for vtg1 and 4 mg/L for chgl, while those of E2 were 10 ng/L for chgh and chgl and 30 ng/L for vtg1 and vtg2. All leachates sampled at 3 landfill sites exerted in vitro estrogenic action. The E2 equivalent of the most potent leachate was 375 ng/L for the yeast ER assay. This leachate sample significantly increased the transcripts of chgh, vtg1 and vtg2, but not chgl, in the medaka. In addition, chemical analysis showed that bisphenol A, 4- tert-octylphenol and 4-nonylphenol were the main contributors to the estrogenicity of the leachates. This study indicated that this type of landfill may adversely affect the reproductive functions of fish living in the surrounding area by leakage of industrial estrogenic compounds.

The Effect of Estrogens, River Water, and Treated Wastewater on Vitellogenin Induction of Japanese Medaka1

Abstract: The objective of this study is to evaluate the effect of estrogens on fish endocrine disruption in river water and treated wastewater. Endogenous estrogen estrone (E1), 17β‐estradiol (E2), river water, and treated wastewater were used for exposure tests on male Japanese medaka. Vitellogenin induction in male medaka was regarded as the endpoint of endocrine disruption. The effective concentrations of E1 and E2 on vitellogenin induction in medaka were evaluated by breeding medaka for 14 days in tanks with various concentrations of E1 or E2. Vitellogenin induction increased with elapse of time during exposure, with higher estrogen concentrations causing greater vitellogenin induction. According to the test results, the lowest observed effect concentrations (LOECs) of E1 and E2 were estimated to be 31.6 and 5.0 ng/l, respectively; and the E2 equivalent (EEQ) LOEC value of E1 was 5.2 ng‐E2/l, derived by multiplying the relative potency of E1 by that of E2 as estimated in this study. In continuous exposure tests using river water or treated wastewater, the estrogenic activity, an index of total estrogenic potential measured by yeast screen assay and expressed as EEQ, varied widely during the exposure tests, and significant vitellogenin induction was observed after several days of high levels of estrogenic activity in water. Vitellogenin concentration tended to significantly increase if EEQ exceeded the level of 5 ng‐E2/l. The threshold value was substantially the same as the results for E1 and E2 exposure tests of medaka. Consequently, EEQ over 5 ng‐E2/l was revealed to have the potential to cause endocrine disruption of male medaka. As estrogenic activity exceeding 5 ng‐E2/l was observed in some rivers in Japan, total estrogenic potential needs to be further decreased at wastewater treatment plants to prevent fish endocrine disruption.

A national risk assessment for intersex in fish arising from steroid estrogens

The occurrence of intersex fish is widespread in the rivers of England and Wales. The extent of intersex in fish populations is believed to be strongly linked to their exposure to steroid estrogens. The present study presents, to our knowledge, the first national, catchment-based risk assessment for steroid estrogens in the world. A graphical information system-based model predicted the concentrations of estradiol (E2), estrone, and ethinylestradiol, which were combined and compared with known biological effect levels to predict the risk of endocrine disruption for 10,313 individual river reaches (21,452 km) receiving effluent from more than 2000 sewage treatment plants serving more than 29 million people. The large scale of this assessment underlines the usefulness of computer-based risk assessment methods. Overall, 61% [corrected] of the modeled reaches (all percentages are in terms of the total river length modeled) in England and Wales were predicted to be not at risk from endocrine disruption (mean concentrations, <1 ng/L E2 equivalents). A large range existed in the percentage of river reaches at risk in the various regions, from 5% in Wales to 67% in the Thames catchment. Important factors influencing this proportion are the population density, particularly their location, and the available dilution. A very small proportion of reaches (approximately 1-3%) were predicted to be at high risk (>10 ng/L E2 equivalents). Many of these high-risk reaches, however, were ditches, which were composed almost entirely of sewage effluent. The model could be applied equally well to any other chemical of concern emanating from the human population that would be impractical to assess by measurement.