Estrogenic chemicals and estrogenicity in river waters of South Korea and seven Asian countries
Introduction
Recently, environmental research has increasingly focused on endocrine-disrupting chemicals (EDCs), which have proven to cause fertility reduction, feminization and other adverse effects in male animals within natural and laboratory settings (Fry and Toone, 1981, Colborn and Clement, 1992, Jobling et al., 1996). Among the endocrine disruptors, 17β-estradiol (E2), estrone (E1) and 17α-ethynylestradiol (EE2) are the major contributors of estrogenic activity in the environment. Other chemicals such as those carrying a phenolic group including nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), and phytoestrogen group (e.g., genistein – Gen) are also suspected to disrupt animal endocrine systems (Soto et al., 1991, Brzezinski and Debi, 1999).
The adverse effects of estrogenic compounds, both natural (i.e., E2 and E1) and synthetic (i.e., EE2) hormones have been widely evaluated in fish (Folmar et al., 1996, Kramer et al., 1998, Balch et al., 2004, Hirai et al., 2006a, Hirai et al., 2006b, Imai et al., 2007). Reproductive alterations such as female gonadal phenotype (i.e., testis–ova), fecundity and fertility were reported in male fish exposed to low concentrations of xenoestrogens by several ng E2 L−1 levels. The induction of Vtg and the reduced serum testosterone concentration in wild animals (e.g., feral male carp; Cyprinus carpio) were observed in areas near the discharged point of STP effluents (Folmar et al., 1996).
The occurrence and fate of estrogen mimics have been investigated in surface water and engineered systems in many countries from the beginning of the 1990s (Soto et al., 1991, Jobling and Sumpter, 1993, Bush et al., 1994, Purdom et al., 1994). These studies have reported the potencies of phenolic compounds (e.g., NP, OP, BPA) at about 1 × 10−6–1 × 10−4 the activity of E2. The potencies of other estrogenic compounds have also been examined in which E1 possessed about 0.01–0.2 the activity of E2 while that of Gen was about 1.3 × 10−3–1.6 × 10−3 (Campbell et al., 2006, Chrzan and Bradford, 2007). In developing countries with high birth rate (e.g., China, Vietnam), oral contraceptive pill could be frequently used for one of the birth control methods. In addition, E2 and EE2 are commonly used for clinical treatment in humans and administered growth in livestock, hormones excreted by humans and animals are considered to be the main sources of estrogenic discharge into the environment (Mellin and Erb, 1966, Palme et al., 1996, Ahmed and Kellie, 1972, Hanselman et al., 2003). In cattle, estrogen is mainly excreted through the feces (Mellin and Erb, 1966, Ivie et al., 1986), whereas estrogens excreted from swine and poultry have been detected mostly in the urine by 96% and 69%, respectively. Although the occurrence and fate of EDCs have been profoundly monitored in America, Europe and other Asian countries (Desbrow et al., 1998, Routledge et al., 1998, Belfroid et al., 1999, Ternes et al., 1999a, Tashiro et al., 2003, Li et al., 2004a, Schlenk et al., 2005, Khanal et al., 2006, Nakada et al., 2006), there is still a lack of information on estrogenicity in other parts of the world such developing countries. The water treatment systems, especially in crowded urban areas, might be insufficient to eliminate all estrogenic activity from municipal wastewaters. Moreover, rivers in developing countries have been polluted with organic waste that may contain a large amount of domestic wastewater, livestock manure, and agricultural waste products. These waste products have been recognized as the main sources of estrogenic compounds in aquatic environments (Hanselman et al., 2003).
The objectives of the present study were to monitor the occurrence and distribution of estrogen compounds in influents, effluents of STPs and surface water in Korea and to evaluate the effects of treatment processes on estrogenic activity before and after the STP. A further aim of this study was to investigate the estrogenicity of surface water in seven Asian countries in comparison to that of Korea. We believe that this study will contribute vastly to understanding the occurrence and estrogenic potency of surface waters in these countries.
Section snippets
Chemicals
All solvents (hexane, dichloromethane, and acetone) were at high performance liquid chromatography (HPLC) or trace analysis grades, and Pyrene-d10 and bisphenol A d16 (BPA-d16) were used as surrogate and internal standard chemicals, respectively (purchased from Aldrich (ISOTEC), Miamisburg, OH, USA). Target chemicals, including NP, OP, BPA, E1, E2, EE2 and Gen, and N-methyl-N-tert-(butyldimethyl)-trichloro-acetamide (MSTFA) were purchased from Aldrich (Steinheim, Germany). Florisil (purchased
EDCs in South Korea
Samples were collected to investigate the occurrence of estrogenic compounds from surface waters in Yeongsan River and Seomjin River, Korea and influents and effluents of STPs adjacent to the rivers. The EEQ (estradiol equivalent) concentrations of estrogenic chemicals may be varied according to the estradiol equivalent factor (EEF) obtained from different assays (Campbell et al., 2006, Chrzan and Bradford, 2007, Jin et al., 2008). In this study, EEQ values were calculated using potencies
Conclusion
Estrogenic compounds and estrogenicity were detected and estimated in river waters in Korea and other seven Asian countries. The concentrations of estrogenic chemicals were remarkably reduced after treatment processes of STP located along Yeongsan and Seomjin Rivers in Korea. Meanwhile, the EEQ values of samples from seven Asian countries showed a higher level than those in Europe and America. The EEQ values in samples from LS, CB, VN and CN indicated a higher level of estrogenic activity than
Acknowledgements
The authors would like to appreciate the support of Yeongsan River Research Laboratory. We also thank to Mr. Vibol Sao at the Royal University of Agriculture, Cambodia; Prof. Lei Duan at the Tsinghua University, China; Ms. Dwi Agustiyani at the Indonesian Institute of Sciences, Indonesia; Dr. Suthipong Sthiannopkao at the Gwangju Institute of Science and Technology (IERC), Korea, for collecting samples from various Asian countries through APN project (ARCP2008-04CMY-Park).
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