Estrogenic Contaminants Research Articles

Effects of Estrogen Contamination on Human Cells: Modeling and Prediction Based on Michaelis-Menten Kinetics

In this paper, we propose a novel prevention strategy to alert citizens when water is contaminated by estro-gen. Epidemiological studies have shown that chronic exposure to high blood level of estrogen is associated with the development of breast cancer. The preventive strategy proposed in this paper is based on the predic-tion of estrogen effects on human living cells. Based on first principle insights, we develop in this work, a mathematical model for this prediction purpose. Dynamic measurements of cell proliferation response to es-trogen stimulation were continuously monitored by a real-time cell electronic sensor (RT-CES) and used in order to estimate the parameters of the model developed.

Estrogenic compounds in seawater and sediment from Halifax Harbour, Nova Scotia, Canada

Abstract-Samples of seawater and surface sediment were collected from seven locations around Halifax Harbour, Nova Scotia, Canada, and analyzed for the presence of the organic estrogenic contaminants, bisphenol A (BPA), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2). Samples were extracted using solid phase extraction (seawater) or sonication (sediments), followed by fractionation on a two-layer alumina/silica gel column prior to analysis by liquid chromatography-tandem mass spectrometry (LCMS/MS) with negative-ion electrospray ionization. Levels of the three compounds consistently ranked as BPA > E2 > EE2. The least potent compound and plasticizer BPA reached levels of up to 2.6 ng/L in seawater and 9.5 ng/g in sediments; the natural product E2 was detected at concentrations up to 0.57 ng/L and 0.86 ng/g; while the synthetic estrogen EE2 was in most cases below the method detection limit (0.14 ng/L and 0.28 ng/g). The highest levels were observed in the influent of a secondary treatment plant that discharges into the harbor, with concentrations of 32.4 ng/L for BPA and 5.3 ng/L for E2. Overall, the results indicate that these compounds readily associate with suspended particles rather than remaining in the soluble phase. Measurement of the octanol-water partition coefficient (log K(OW)) confirmed these results, with values of 3.41, 3.89, and 4.16 for BPA, E2, and EE2, respectively. Partitioning experiments using spiked field samples further confirmed these findings, with sorption directly related to sediment total organic content and following the order EE2 > E2 > BPA.

Ligninase-Mediated Removal of Natural and Synthetic Estrogens from Water: I. Reaction Behaviors

Our experiments revealed that a few natural and synthetic estrogens can be effectively transformed through reactions that are mediated by lignin peroxidase (LiP), an extracellular enzyme that is produced by a white rot fungus Phanerochaete chrysosporium and is widely present in the natural environment We systematically assessed the reaction efficiencies at varying important conditions and identified the reaction products using mass spectrometry. In particular, we compared the reaction behaviors for systems variously containing natural organic matter and/or veratryl alcohol, a secondary metabolite that P. chrysosporium produces along with LiP in nature to play a role in mediating LiP activity. On the basis of the observed reaction behaviors and the molecular characteristics of the substrates and the enzyme, we postulate that the active binding site for estrogens is located within the LiP heme cavity, whereas that for veratryl alcohol is on the enzyme surface. Our study suggests that the processes mediated by LiP and other naturally occurring enzymes of similar nature may influence the environmental transformation and fate of estrogen contaminants. The findings in this study provide useful information for understanding LiP-mediated estrogen reactions and for potential development of novel enzymatic method to control estrogen contamination.

Occurrence and environmental risk of endocrine-disrupting chemicals in surface waters of the Pearl River, South China

The occurrence and environmental risk of endocrine-disrupting chemicals was investigated in the surface water samples of the Zhujiang and Dongjiang rivers, Pearl River Delta (PRD) of South China. Thirty surface water samples were collected in the dry season and analyzed by using an MSTFA derivation and a GC-MS-SIM method. Concentrations of biphenol A (BPA) ranged from 43.5 to 639.1 ng L( - 1), and concentrations of estrone (E1) and 17beta-estradiol (E2) ranged from <1.5 to 8.2 ng L( - 1) and from <1.1 to 1.7 ng L( - 1), respectively. The spatial distribution of these chemicals was related to the discharge of domestic and industrial wastewater along the rivers. The highly significant correlation among BPA, E1, and dissolved organic carbon (DOC) might be related to their same contamination source and/or their association with colloidal organic carbon of DOC in the river samples. Compared with other studied rivers in the world, the estrogenic contamination in the investigated rivers was high for BPA and moderate for E1. As the average estrogenic activity in E2 activity equivalent (E2eq; 1.16 ng E2eq L( - 1)) for the target BAP, E1, and E2 combined with those for nonyphenol and octylphenol, which were previously reported, exceeds documented effect levels in the investigated river waters for some aquatic species, they may pose a high risk to the local aquatic organisms.

Estrogenic Endocrine Disruption in Switzerland: Assessment of Fish Exposure and Effects

Estrogenic exposure has been reported to occur in Swiss rivers, and there is concern that reduced reproductive health, caused by disturbances of the endocrine system, may contribute to the observed decline in brown trout catch. Consequently, we aimed to determine if disturbances of the endocrine system do occur in wild brown trout (Salmo trutta) in Switzerland and, in the affirmative case, if these might affect trout population status. Our first task was to characterize the estrogenicity of Swiss midland rivers that receive effluents from sewage treatment plants (STP). Next, we performed a set of laboratory and field exposure experiments aimed at elucidating how estrogens affect sexual development and reproductive parameters as estrogen-sensitive targets in the life cycle of brown trout. Subsequently, we assessed the demographic status of brown trout populations in the field which were exposed to the cumulative impact of estrogen-active compounds and other stressors. Finally, we integrated the data into a life-cycle model to predict potential population-level consequences of the (xeno)estrogenic exposure. The estrogenicity of 18 Swiss midland rivers was characterized bioanalytically by applying the YES bioassay to water samples and by measuring plasma vitellogenin (VTG) levels in resident brown trout. Generally, estrogenic contamination of the rivers appears to occur only locally and at comparatively low levels (0.2–2 ng/l 17?-estradiol equivalents). In laboratory experiments, potential disruptive effects of estrogens on gonadal differentiation and reproduction of brown trout were investigated. The estrogen-sensitive window of brown trout gonad differentiation was found to differ from other salmonid species. Feminisation of the developing gonads occurred only after exposure to rather high estrogen concentrations. Analysis of VTG mRNA levels indicated that the yolk may accumulate environmental estrogens and act as a long-term reservoir. The experiments to study the effects of prolonged estrogen exposure on reproduction of mature brown trout showed that, while VTG was induced at low concentrations (20 ng/l estrone (E1), 2 ng/l 17?-estradiol (E2) and 400 ng/l 4-nonylphenol (NP)), effects on reproductive parameters such as fertility became evident only at the higher dose (100 ng/l estrone, 10 ng/l 17?-estradiol and 4000 ng/l 4-nonylphenol). For the field study, the river Lützelmurg (Canton Thurgau) was selected as our study site. This river is impacted by the estrogen-active effluents of one sewage treatment plant (STP). Estrogenic levels in the river were found to be highly variable over time, but showed a distinct difference between sites upstream and downstream from the STP effluent – a difference which was also reflected by the VTG levels of caged and resident brown trout. From the brown trout demographic data, it is evident that factors other than estrogen exposure, including habitat quality, strongly influence population structure. The results from the modelling supported this finding and showed that the trout population in the Lützelmurg is likely to be more sensitive to changes of survival rates in the first winter and beyond than to changes in early life stage survival or reproductive parameters. From the overall results of our project, we conclude that a significant influence of estrogenic contamination on brown trout population densities in the majority of Swiss rivers appears not to be likely.

Bisphenol A concentration-dependently increases human granulosa-lutein cell matrix metalloproteinase-9 (MMP-9) enzyme output

Bisphenol A (BPA) is an estrogenic contaminant that has been quantified at higher levels in the follicular fluid of women with polycystic ovarian syndrome (PCOS) compared to healthy fertile controls. However, the effect of BPA on granulosa cell function is unknown. Therefore, the objective of the present study was to quantify the effect of BPA on granulosa cell progesterone (P 4) output and matrix metalloproteinase (MMP)-2, and -9 output and activity. Granulosa-lutein cells (GLCs) were collected from women undergoing oocyte retrieval in an academic in vitro fertilization (IVF) program. Granulosa-lutein cells were treated with increasing log concentrations of BPA (1–10,000 ng/ml) or 17β-estradiol (E 2, 272 pg/ml or 1.0 nM) and treatment effects on MMP-2 and -9 activity and output, cell viability and cell proliferation were measured by commercial gelatin zymography, MMP-ELISA, MTS and BrdU incorporation assays, respectively. Granulosa-lutein cells in culture secrete MMP-2 and MMP-9. Bisphenol A treatment concentration-dependently increased MMP-9 output by GLCs with a maximal effect observed at 1000 ng/ml. Cell viability/proliferation was unaffected by BPA treatment at concentrations ≤100 ng/ml; however, higher concentrations of BPA were cytotoxic. Progesterone output by the GLCs was unaffected by increasing BPA concentrations in the media. In conclusion, GLCs in culture secrete MMP-2 and MMP-9. At lower concentrations, compatible with human exposure levels (100–1000 ng/ml), BPA stimulates GLC MMP-9 output; however, higher concentrations are cytotoxic. Our findings suggest that BPA treatment can modulate ovarian extracellular matrix stability.

Variation in somatic and ovarian development: Predicting susceptibility of amphibians to estrogenic contaminants

Although amphibian sex determination is genetic, it can be manipulated by exogenous hormone exposure during sexual differentiation. The timing of sexual differentiation varies among anuran amphibians such that species may or may not be a tadpole during this period, and therefore, may or may not be exposed to aquatic contaminants. Estrogenic contamination is present in amphibian habitats worldwide. We examined three species with varying somatic and ovarian developmental rates to assess their susceptibility to estrogenic contaminants. American toads (Bufo americanus), gray treefrogs (Hyla versicolor), and Southern leopard frogs (Ranasphenocephala) were exposed as larvae to 17-β-estradiol (10−7M), three concentrations of a widespread herbicide (1, 3, 30ppb atrazine), or a solvent control (ethanol). Somatic and ovarian developmental stages as well as time to metamorphosis were recorded. Toads and treefrogs were examined at three weeks and metamorphosis, while leopard frogs were examined at three, six, and nine weeks as well as at metamorphosis. Our results demonstrate that each species displays heterochronic somatic and ovarian development. Further, the more rapid of the two rates determines the susceptibility to estrogenic contaminants. These results suggests that amphibians with shorter larval periods, and therefore quicker somatic developmental rates (i.e. American toads, gray treefrogs), are more susceptible to somatic treatment effects (i.e. prolonged time to metamorphosis) due to estrogenic contaminants. Moreover, the results suggest that amphibians with relatively rapid ovarian development (i.e. Southern leopard frogs) are more susceptible to gonadal treatment effects caused by estrogenic contaminants.

Oestrogenic activity using a recombinant yeast screen assay (RCBA) in South African laboratory water sources

Many chemicals released into the environment are believed to disrupt normal endocrine functions in humans and animals. These endocrine disrupting chemicals (EDCs) affect reproductive health and development. A major group of EDCs that could be responsible for reproductive effects are those that mimic natural oestrogens, known as xeno-oestrogens. A number of in vivo and in vitro screening strategies are being developed to identify and classify xeno-oestrogens, in order to determine whether they pose a health risk to humans and animals. It is also important to be able to apply the assays to environmental samples for monitoring purposes. In South Africa information on the levels of EDCs in water is limited. While establishing the recombinant yeast screen bioassay (RCBA) using the yeast strain Sacchyromyces cerivisiae for oestrogenic activity, problems were experienced with contamination. Four South African laboratory water sources were assessed. From the results it was clear that the water used in the preparation of the medium for the assay was the source of oestrogenic contamination. Care should be taken to eliminate all possible sources of contamination in the test procedures to eliminate the reporting of false positive results. The fact that South African laboratory and surface waters tested positive for estrogenic activity has far reaching implications regarding reproductive and general health. Water SA Vol. 31 (2) 2005: pp.253-256

Distinct expression and activity profiles of largemouth bass (Micropterus salmoides) estrogen receptors in response to estradiol and nonylphenol

The estrogen receptor (ER) signaling cascade is a vulnerable target of exposure to environmental xenoestrogens, like nonylphenol (NP), which are causally associated with impaired health status. However, the impact of xenoestrogens on the individual receptor isotypes (alpha, beta a, and beta b) is not well understood. The goal of these studies was to determine the impact of NP on largemouth bass (Micropterus salmoides) ER isotype expression and activity. Here, we show that hepatic expression levels of three receptors are not equivalent in male largemouth bass exposed to NP by injection. Transcript levels of the ER alpha subtype were predominantly induced in concert with vitellogenin similarly to fish exposed to 17beta-estradiol (E(2)) as measured by quantitative real-time PCR. NP also induced circulating plasma levels of estrogen, which may contribute to overall activation of the ERs. To measure the activation of each receptor isotype by E(2) and NP, we employed reporter assays using an estrogen response element (ERE)-luciferase construct. Results from these studies show that ER alpha had the greatest activity following exposure to E(2) and NP. This activity was inhibited by the antagonists ICI 182 780 and ZM 189 154. Furthermore, both beta b and beta a subtypes depressed ER alpha activation, suggesting that the cellular composition of receptor isotypes may contribute to the overall actions of estrogen and estrogenic contaminants via the receptors. Results from these studies collectively reveal the differential response of fish ER isotypes in response to xenoestrogens.

Impaired Reproduction in Three-Spined Sticklebacks Exposed to Ethinyl Estradiol as Juveniles1

To investigate the population-level effects of exposure to environmental endocrine disrupters, a mesocosm-scale study was carried out in which the reproductive performance of groups of free-spawning three-spined sticklebacks, Gasterosteus aculeatus, exposed as juveniles to a model estrogen, was assessed. Juvenile sticklebacks were exposed to ethinyl estradiol (EE(2)) at measured concentrations of (mean +/- SEM) 1.75 +/- 0.37 ng L(-1) and 27.7 +/- 1.08 ng L(-1) for 4 wk posthatch and then reared thereafter in pristine lake water until they reached adulthood. Exposure to the higher EE(2) concentration resulted in the occurrence of ovotestis among males, whereas no gonadal abnormalities were evident among males exposed to the lower concentration of EE(2). In addition, when spawning was allowed in the mesocosm environment, fewer nests were built per male, and fewer eggs were deposited per nest, in the group exposed to 27.7 ng L(-1). Males from this group also exhibited a less intense nuptial coloration than control males. In the group exposed to 1.75 ng L(-1) EE(2) posthatch, significantly fewer nests were built than in the control group. These results demonstrate that the timing of exposure to estrogenic contaminants, in developmental terms, is critically important. Short-term exposure to estrogens as juveniles can clearly influence reproductive performance as adults, despite all growth and development subsequent to the exposure period taking place in an estrogen-free environment. In addition, these results suggest that reproductive dysfunction can occur even in fish with no gross abnormalities in gonadal structure. This suggests that the absence of gonadal intersex is not a reliable indicator of the reproductive potential, or estrogen-exposure history, of fish populations or the only important factor involved in compromising the reproduction of estrogen-exposed fish.

Profiles of environmental and endogenous estrogens in the zebra mussel Dreissena polymorpha

Contamination of freshwater environments by estrogenic compounds has led to concern over potential impacts on invertebrate species. The uptake of the environmental estrogen 17β-estradiol (E2) by the freshwater bivalve Dreissena polymorpha and the nature of estrogenic substances in tissues of D. polymorpha mussels collected from four freshwater sites were investigated. Exposure of mussels to [ 14C]-E2 (7.5 ng l −1, 13 days) revealed that the estrogen bioconcentrated 840 ± 58 (males) and 580 ± 77 (females) fold (mean ± 95% confidence limits) and was metabolised in tissues to a persistent lipophilic ester. Estrogenic activity, measured using a recombinant human estrogen receptor transcription screen (YES), was detected in tissue extracts of all mussels sampled from freshwater sites. At two reference sites the estrogenic activities of mussel tissues were <1 ng E2 equivalents g −1 wet weight tissue (ng EEQ g −1 ww) which increased to 7.4–45.7 ng EEQ g −1 ww for both free and esterified estrogens extracted from hydrolysed tissue extracts. In mussels collected from two contaminated river sites, estrogenic activity was 0.2–6.7 ng EEQ g −1 ww (free estrogens) and 25.6–316.2 ng EEQ g −1 ww for total estrogens. Fractionation of the tissue extracts revealed that E2 (as the ester) was the predominant estrogen detected in both sexes of D. polymorpha, however, the xenoestrogen nonylphenol (NP) was also detected in mussels sampled from contaminated rivers. The detection of endogenous esterified E2 and the potential for accumulation of exogenous E2 and NP in D. polymorpha tissues suggests that this bivalve could be susceptible to exposure to estrogenic contaminants in the aquatic environment.

Biological assessments of a mixture of endocrine disruptors at environmentally relevant concentrations in water following UV/H2O2 oxidation

Numerous studies have investigated degradation of individual endocrine disrupting compounds (EDCs) in lab or natural waters. However, natural variations in water matrices and mixtures of EDCs in the environment may confound analysis of the treatment efficiency. Because chemical based analytical methods cannot represent the combined or synergistic activities between water quality parameters and/or the EDC mixtures at environmentally relevant concentrations (microg L(-1)-ng L(-1)), bioanalytical assessments of residual estrogenic activity in treated water were used to evaluate the performance of the UV based advanced oxidation process for estrogenic contaminants in water. Four EDCs including estradiol (E(2)), ethinyl estradiol (EE(2)), bisphenol-A (BPA) and nonylphenol (NP) were spiked individually or as a mixture at mug L(-1)-ng L(-1) in laboratory or natural river water. The removal rates of estrogenic activity were quantitatively evaluated by in vitro yeast estrogen screen (YES) and in vivo Vitellogenin (VTG) assays with Japanese medaka fish (Oryzias latipes). UV in combination with 10 ppm H(2)O(2) as an oxidation process was capable of decreasing in vitro and in vivo estrogenic activity, however, in vivo estrogenic activity of the EDC mixture in natural water was not completely removed at UV fluence up to 2000 mJ cm(-2). The removal rates of in vitro estrogenic activity of the EDC mixtures were lower than those observed for single compounds, and slower in natural waters, likely due to lower steady-state concentrations of hydroxyl radicals (*OH) in the presence of *OH scavengers from the water matrix and EDC mixture.

Novel approaches to the analysis of steroid estrogens in river sediments

A wide range of estrogenic contaminants has been detected in the aquatic environment. Among these, natural and synthetic steroid estrogens, typically present in municipal sewage-treatment plant (STP) effluents, are the most potent. In this study a new GC-MS method has been developed for direct analysis of five major steroid estrogens (estrone, 17beta-estradiol, 17alpha-ethinylestradiol, dienestrol, and diethylstilbestrol) in river sediments. Four GC-MS systems used for analysis of underivatized analytes in purified extracts were compared. Relatively low detection limits (1.5-5 ng g(-1) dried sediment) and good repeatability of GC splitless injection (RSD 1-2%) were achieved by use of a system combining low-pressure gas chromatography with a single-quadrupole mass analyzer (LP-GC-MS). Use of orthogonal gas chromatography (GCxGC) hyphenated with high-speed time-of-flight mass spectrometry (HSTOF-MS) enabled not only significantly better resolution of target analytes, and their unequivocal identification, but also further improvement (decrease) of their detection limits. In addition to these outcomes, use of this unique GCxGC-TOF-MS system enabled identification of several other non-target chemicals, including pharmaceutical steroids, present in purified sediment extracts.

Raised Plasma Vitellogenin in Male Wild Brown Trout (Salmo trutta) near a Waste Water Treatment Plant in Ireland

Ovotestis (intersex) and raised plasma vitellogenin in male fish are widely employed biomarkers of estrogen contamination in the aquatic environment. In the present study, these biomarkers were used to determine whether Irish rivers contain estrogenic chemicals at levels capable of affecting the reproductive health and success of exposed fish populations. A number of aquatic ecosystems were investigated (the rivers Liffey, Lee, and Bandon and the Killarney lakes). A survey of male wild brown trout (Salmo trutta) was carried out to assess the incidence of endocrine disruption in the feral fish population; no evidence of intersex was found in any of the wild fish sampled. Raised plasma vitellogenin was detected, however, in the wild brown trout downstream of a major municipal wastewater treatment plant on the river Liffey.

Assessment of estrogenic exposure in brown trout (Salmo trutta) in a Swiss midland river: Integrated analysis of passive samplers, wild and caged fish, and vitellogenin mRNA and protein

This field study examined the vitellogenin (VTG) biomarker response under conditions of low and fluctuating activities of environmental estrogenicity. The present study was performed on immature brown trout (Salmo trutta) exposed to the small river Luetzelmurg, which is located in the prealpine Swiss midland region and receives effluents from a single sewage treatment plant (STP). To understand better factors influencing the relationship between estrogenic exposure and VTG induction, we compared VTG levels in caged (stationary) and feral (free-ranging) fish, VTG levels in fish from up- and downstream of the STP, and two different methods for quantifying VTG (enzyme-linked immunosorbent assay vs real-time reverse transcription-polymerase chain reaction), and we used passive samplers (polar organic chemical integrative sampler [POCIS]) to integrate the variable, bioaccumulative estrogenic load in the river water over time. The POCIS from the downstream site contained approximately 20-fold higher levels of bioassay-derived estrogen equivalents than the POCIS from the upstream site. In feral fish, this site difference in estrogenic exposure was reflected in VTG protein levels but not in VTG mRNA. In contrast, in caged fish, the site difference was evident only for VTG mRNA but not for VTG protein. Thus, the outcome of VTG biomarker measurements varied with the analytical detection method (protein vs mRNA) and with the exposure modus (caged vs feral). Our findings suggest that for environmental situations with low and variable estrogenic contamination, a multiple-assessment approach may be necessary for the assessment of estrogenic exposure in fish.

Are endocrine disrupting compounds a health risk in drinking water?

There has been a great deal of international discussion on the nature and relevance of endocrine disrupting compounds in the environment. Changes in reproductive organs of fish and mollusks have been demonstrated in rivers downstream of sewage discharges in Europe and in North America, which have been attributed to estrogenic compounds in the effluent. The anatomical and physiological changes in the fauna are illustrated by feminization of male gonads. The compounds of greatest hormonal activity in sewage effluent are the natural estrogens 17Beta-estradiol, estrone, estriol and the synthetic estrogen ethinylestradiol. Androgens are also widely present in wastewaters. Investigations of anthropogenic chemical contaminants in freshwaters and wastewaters have shown a wide variety of organic compounds, many of which have low levels of estrogenic activity. In many highly populated countries the drinking water is sourced from the same rivers and lakes that are the recipients of sewage and industrial discharge. The River Thames which flows through London, England, has overall passed through drinking water and sewage discharge 5 times from source to mouth of the river. Under these types of circumstance, any accumulation of endocrine disrupting compounds from sewage or industry potentially affects the quality of drinking water. Neither basic wastewater treatment nor basic drinking water treatment will eliminate the estrogens, androgens or detergent breakdown products from water, due to the chemical stability of the structures. Hence a potential risk to health exists; however present data indicate that estrogenic contamination of drinking water is very unlikely to result in physiologically detectable effects in consumers. Pesticide, detergent and industrial contamination remain issues of concern. As a result of this concern, increased attention is being given to enhanced wastewater treatment in locations where the effluent is directly or indirectly in use for drinking water. In some places at which heavy anthropogenic contamination of drinking water sources occurs, advanced drinking water treatment is increasingly being implemented. This treatment employs particle removal, ozone oxidation of organic material and activated charcoal adsorption of the oxidation products. Such processes will remove industrial organic chemicals, pesticides, detergents, pharmaceutical products and hormones. Populations for which only basic wastewater and drinking water treatment are available remain vulnerable.

Biodegradation of estrone and 17 β-estradiol in grassland soils amended with animal wastes

The release of endocrine disrupting chemicals into the environment is of increasing concern due to the formation of an intersex state in freshwater organisms and potential risks to human health. The aim of this study was to investigate the persistence of the naturally occurring hormones, estrone and 17 β-estradiol in three agricultural grassland soils in the presence and absence of cattle and sheep wastes (urine and manure). Biodegradation was investigated using 14C-labelled hormones which were applied to soil in three different solvents (water, artificial urine and natural sheep urine). When applied directly to soil the two hormones degraded at a similar rate, however, the speed of mineralization was soil type and solvent dependant. The half-life ( t 1 / 2 ) of the hormones in soils ranged from 5 to 25 d. The hormones were also applied to the soils in sheep and cattle manure of different ages (7 d to 2 yr). Generally, the rate of degradation in the animal manure amended soils was more rapid than in the unamended soils ( t 1/2=1–9 d), with mineralization being largely independent of manure age and type. We conclude that in comparison to many xenobiotics, estrogens are not persistent in agricultural soils. However, our calculations suggest that if they are lost to freshwater via runoff or leaching then they may have an appreciable effect on freshwater organisms. Assuming normal landspreading rates our results suggest that the risk of estrogen contamination of freshwater associated with manure spreading is very low.

Measurement of estrogenic activity in sediments from Haihe and Dagu River, China

Sediments from two rivers in China, the Haihe and Dagu Rivers, were examined for estrogenic activity using an estrogen receptor (ER)-mediated in vitro bioassay system. ER-active compounds were isolated from sediments by Soxhlet extraction, and the crude extracts were fractionated using a florisil column into three fractions. The estrogenic activity of each extract was detected by measuring luciferase activity in the human breast cancer cell line MCF-7 transfected with a luciferase receptor gene. Significant estrogenic activity was observed in each total extract. The 17β-estradiol equivalents (E2-EQs) ranged from 8.24 to 95.28 ng E2 g − 1 dw. As a result, the relative estrogenic potencies of three fractions in this study descended in the order of Fraction 3 > Fraction 2 > Fraction 1. The results of the bioassay analysis indicated the heavy pollution status of these sites with estrogenic contaminants. In this study, five selected chemicals, the natural estrogens 17β-estradiol (E2) and estrone (E1), and the xeno-estrogens 4-octylphenol (OP), 4-nonylphenol (NP), and Bisphenol A (BPA) were also analyzed using the in vitro bioassay. The estrogenic activity of these chemicals were E2 > E1 > NP > OP > BPA.

Natural Estrogens in the Surface Water of Shenzhen and the Sewage Discharge of Hong Kong

ABSTRACT Despite the fact that estrogens cause hormonal disturbances in aquatic organisms, few studies on the estrogen contamination in our surface waters have been conducted. This study was thus conducted (1) to investigate the level of estrogens in the surface waters in Shenzhen and (2) to examine the estrogen levels in the sewage discharges in Hong Kong. Total estrogens (estrone E1, estradiol E2, and estriol E3) in the samples taken from two reservoirs, five rivers, and thirty sampling locations of the seawater in Shenzhen were measured by using ELISA kits. The preliminary results have revealed that the level of estrogens in the surface waters of Shenzhen is generally higher than that in the similar water bodies in well-developed nations. Sewage could be the major source of the estrogen contamination in these waters. The total estrogens levels in the Xili and Shenzhen Reservoirs were in a range of 3–11 ng/L with a mean value of 7 ng/L, where that in four rivers in Shenzhen were found to be 47–90 ng/L and 60.25 ng/L, respectively. In the seawater near the sewage discharge points they were 260–300 ng/L and 287 ng/L, respectively. The estradiol levels in the influent and effluent of three sewage treatment works (STWs) in Hong Kong were also monitored. The activated sludge process used in these STWs removed more than 80% whereas the chemical coagulation processed used at the Stonecutters Island STW removed less estrogens. Biological treatment appears to play a significant role in removing estrogens from wastewater.

Effect of chlorination on estrogenicity in chlorinated treated effluent

Effluents from sewage treatment plants can be discharged into rivers with estrogenic contaminants at levels sufficient to induce adverse reproductive and fertility developments in humans and wildlife. Of great concern in recent years are the estrogenic activities of chlorinated by-products (CBPs) in effluents. Simplified cell proliferation tests using the human estrogen receptor-positive MCF-7 ATCC breast cancer cells (E-SCREEN) were performed to investigate the influence of chlorination on the estrogenicity in effluents. It was found that the increase of chlorine dosages from 0 mg/L to 4 mg/L led to the decrease of total content of estrogenic activity: the 17ß-estradiol equivalent concentration (EEQ) from 22.40 to 8.35 ng/L. However, the increase of contact time from 10–30 minutes increased EEQ from 14.04 to 29.97 ng/L. Furthermore, increasing TOC level using humic acid from 5 mg/L to 15 mg/L in effluents correspondingly resulted in an increase of EEQ from 19.69–27.20 ng/L; it was thus confirmed that chlorination of humic acid could produce estrogenic by-products.