This paper investigated some selected estrogenic compounds (4-t-octylphenol: 4-t-OP; 4-nonylphenols: 4-NP; bisphenol-A: BPA; diethylstilbestrol: DES; estrone: E1; 17β-estradiol: E2; 17α-Ethinylestradiol: EE2; triclosan: TCS) and estrogenicity in the Liao River system using the combined chemical and in vitro yeast screen bioassay and assessed their ecological risks to aquatic organisms. The estrogenic compounds 4-t-OP, 4-NP, BPA, E1, E2 and TCS were detected in most of the samples, with their concentrations up to 52.1 2065.7, 755.6, 55.8, 7.4 and 81.3ng/L in water, and up to 8.6, 558.4, 33.8, 7.9, <LOQ and 33.9ng/g in sediment, respectively. However, DES and EE2 were not detected in the Liao River. The estrogen equivalents (EEQ) of the water and sediment samples were also measured by the bioassay. High estrogenic risks to aquatic organisms were found in the river sections of metropolitan areas and the lower reach of the river system.

The distribution and bioaccumulation of steroidal and phenolic endocrine disrupting chemicals (EDCs) were studied in various tissues of wild fish species from Dianchi Lake, China. In muscle tissue, 4-tert-octylphenol, 4-cumylphenol, 4-nonlyphenol and bisphenol A were detected in fish from each sampling site, with maximal concentrations of 4.6, 4.4, 18.9 and 83.5ng/g dry weight (dw), respectively. Steroids (estrone, 17β-estradiol 17α-ethynylestradiol and estriol) were found at lower levels (<11.3ng/g dw) and less frequently in muscle samples. The highest concentrations of steroids and phenols were found in liver, followed by those in gill and the lowest concentration was found in muscle. The field bioconcentration factors (BCFs) of phenols were calculated in fish species ranged from 18 to 97. Moreover, the measured tissue concentrations were utilized in order to estimate water concentration of steroids (4.4–18.0ng/L). These results showed that steroidal and phenolic EDCs were likely ubiquitous contaminants in wild fish.

In streams, chemicals such as 17β-estradiol (E2) are likely to occur in pulses. We investigated uptake and biomarker responses in juvenile brown trout (Salmo trutta) of 3- or 6-h pulses of concentrations up to 370 ng E2 L⁻¹. Uptake by the fish was estimated from disappearance of E2 from tank water. A single 6-h pulse of 370 ng E2 L⁻¹ increased the plasma vitellogenin concentration, liver Erα- and vitellogenin-mRNA. Exposure to 150–160 ng E2 L⁻¹ for 6 h increased vitellogenin in one experiment but not in another. Two 6-h pulses had a larger effect one pulse. Brown trout in the size range 24–74 g took up E2 linearly with time and exposure concentration with a concentration ratio rate of 20.2 h⁻¹. In conclusion, the threshold for induction of estrogenic effects in juvenile brown trout at short term pulse exposure appears to be in the range 150–200 ng E2 L⁻¹.

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.

Isomer-specific concentrations of nonylphenol (NP) and their predicted estrogenic potency were investigated in Sri Lankan waters for the first time. The total concentration of 13 NP isomers ranged from 90 to 1835ng/L, while the predicted estrogenic equivalent concentration ranged from 0.072 to 1.38ng 17β-estradiol (E2)/L. Bire Lake, located in the central area of the commercial capital, Colombo, had the highest contamination among the studied locations. These data show that NP levels in Sri Lankan waters are well within the recently reported concentrations in other regions of the world. The spatial differences in NP concentrations suggest that NP contamination in Sri Lanka may be widespread, and comprehensive study is vital.

The endocrine-disrupting chemicals (EDCs) was investigated in 28 riverine sediments from the Pearl River system, China and analyzed by an ultrasonication extraction and GC–MS method. The concentrations of 4-tert-octylphenol (OP), 4-nonylphenol (NP), and bisphenol A (BPA) in the sediments were in the ranges of <2.0–210, 107–16198 and <1.7–430ng/g dw, respectively. The steroid estrogens estrone (E1) and 17β-estradiol (E2) in the sediments ranged from <1.3 to 10.9ng/gdw and from <0.9 to 2.6ng/gdw, respectively. The spatial distribution of these chemicals was related to the discharge of domestic and industrial wastewater along the rivers. The positive correlation between EDCs and total organic carbon indicates that sedimentary organic carbon is an important factor in controlling the distributions of EDCs. Compared with other previous studies, the ZR and DR rivers from the PRD were heavily contaminated by APs and BPA.

Polybrominated diphenyl ethers (PBDEs) are now found ubiquitously in the aquatic environment and biota, and there is a growing concern that PBDEs may disrupt endocrine systems, leading to reproductive impairments of aquatic animals. In our study, zebrafish (Danio rerio) were exposed to the 5ng/L, 1μg/L and 50μg/L of DE-71 for the duration of the whole life cycle (120days, from eggs to adults). The expression of selected genes along the brain–pituitary–gonadal (BPG) axis and liver, and the levels of plasma sex hormones were examined. In male fish, up-regulation of GnRH in brain, FSHβ and LHβ in pituitary, FSH-receptor, LH-receptor, and CYP19a in testis was clearly evident, while down-regulation of CYP11a and 3β-HSD was found in testis. In female fish, a 2.4-fold up-regulation of 3β-HSD was found in ovary upon exposure to 50μg/L of DE-71. GnRH in brain, FSHβ and LHβ in pituitary were also up-regulated, while ERβ, TH and TPH in brain and GnRH-receptor in pituitary were significantly down-regulated. Hepatic ERα, AR and VTG in males were all down-regulated, while hepatic ERα and AR in female were up-regulated. Serum estradiol (E₂) was reduced in both male and female upon exposure to DE-71, while significant increases in serum testosterone (T) and 11-keto-testosterone (11-KT) were only found in male but not female fish. The ratio of T/E₂ as well as the ratio of 11-KT/E₂ in male fish increased in a dose-dependent manner upon exposure to DE-71. Our overall results showed that whole life exposure of DE-71 altered the expression of regulatory genes and receptors at all three levels of the BPG axis in zebrafish, and the responses are sex dependent. The observed disruption of GnRH and GtHs can be further related to the subsequent disruption in both levels and balance sex steroid hormones.

The concentrations of major heavy metals in organs of two cyprinid fish and in water collected from three sections of the Kor River, Iran, were determined using the induction coupled plasma method. The concentrations of heavy metals in tissue of fish from the middle sampling zone were significantly higher (p < 0.05) than those from the other two sampling zones, whereas no significant differences (p > 0.05) were detected between the two sexes and species. Estradiol in females and progesterone and testosterone in males from the middle study site were significantly (p < 0.05) lower than values from the other two sites. Pathological changes in blood cells, liver, and kidneys of fishes were significantly higher in highly polluted areas (middle sampling zone). So heavy metals exposure can effectively decreases estrogenic and androgenic secretion in fish. These results show that industrial activities have polluted the river and that heavy metals exposure can induce pathological changes in fish organs.

The number of chemical compounds in sewage and consequently their release into the environment is increasing. Some of them are toxic and many of them are considered endocrine disrupters. Here, the capacity of three wastewater treatment plants (WWTPs) to remove caffeine, hormones and bisphenol-A was investigated. Bisphenol-A and caffeine are highly water-soluble compounds, as opposed to hormones (estradiol, estriol, and ethynilestradiol) which are hydrophobic compounds. In the Sewage Treatment Plant (SWT)1 the sewage is treated by activated sludge process, in the second plant, SWT2, sewage is treated by upflow anaerobic sludge blanket reactors followed by dissolved air flotation, and in the third, SWT3 sewage is treated by stabilization lagoons. The first lagoon is 3.5 m deep, thus facultative and polishment processes occur. It was speculated that there was a difference in efficiency between the three plants in removing micropollutants. Small differences were found in the amounts removed, probably accounted for by retention time. The caffeine and bisphenol-A were almost completely removed, higher than 90% for both compounds (bisphenol-A and caffeine) in all WWTPs. The hormones, however, had a smaller rate of removal, between 70% and 87%. It is suspected that retention time is essential for removal efficiency, together with type of treatment. In fact, the hormones, caffeine, and bisphenol-A found in the environment definitely come from untreated sewage.

Introduction The present study was part of a comprehensive weight-of-evidence approach with the goal of identifying potential causes for the declines in fish populations, which have been observed during the past decades in the Upper Danube River. Methods The specific goal was the investigation of the endocrine disrupting potential of sediment extracts from different sites along the Danube River. Parallel to the identification and quantification of target estrogens, two in vitro bioassays were employed to assess the estrogenic potential (yeast estrogen screen, YES) of the sediment samples and to evaluate their effects on the production of testosterone (T) and E2 (H295R Steroidogenesis Assay). Using a potency balance approach, the contribution of the measured compounds (Chem-EEQs) to the total endocrine activity measured by the YES (YES-EEQs) was calculated. Results and discussion Of the nine sediment extracts tested five extracts exhibited significant estrogenic activities in the YES, which suggested the presence of ER agonists in these samples. The xenoestrogens nonylphenol (NP) and bisphenol A (BPA) and the natural estrogen estrone (E1) were detected while concentrations of 17β-estradiol (E2) and ethinylestradiol (EE2) were less than their respective limits of quantification in all sediment extracts. A comparison of the measured YES-EEQs and the calculated Chem-EEQs revealed that as much as 6% of estrogenic activity in extracts of most sediments could be explained by two xeno- and one natural estrogen. Exposure of H295R cells to sediment extracts from four different locations in the Danube River resulted in significantly increased concentrations of E2, but only slight inhibition of T synthesis. Furthermore, application of the H295R Steroidogenesis Assay provided evidence for endocrine disrupting potencies in sediment samples from the Upper Danube River, some of which were not detectable with the YES. In conclusion, differential endocrine activities were associated with several sediments from the Upper Danube River. Further investigations will have to show whether the observed activities are of biological relevance with regard to declines in fish populations in the Upper Danube River.