Assessment of estrogenic contamination and biological effects in Lake Taihu

Abstract

Lake Taihu is the third largest freshwater lake in China and is contaminated with xenoestrogens associated with high population density, intensive livestock and aquatic breeding activities. A field study in Lake Taihu was conducted using the goldfish (Carassius auratus) as an indicator organism. Several biological markers were selected to assess the extent of estrogenic contamination. Changes in serum vitellogenin (VTG), and gill 7-Ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST) and reduced glutathione (GSH) were measured in caged juvenile goldfish for 28 days in seven locations in northern Lake Taihu. Bioassay showed VTG increased 0.64-2.42 folds over time in goldfish collected from five stations and GSH decreased in samples from all seven stations after 7 days of exposure. EROD levels increased continually in fish collected at all the seven stations and the highest concentrations occurred at day 21. GST activity increased significantly at 7 days. The concentration of the target estrogens estrone (E(1)), 17β-estradiol (E(2)), ethinylestradiol (EE(2)), octylphenol (OP), diethylstilbestrol (DES), nonylphenol (NP) and bisphenol A (BPA) were determined in lake water at the sampling stations. Each individual estrogen concentration measured was multiplied by its relative potency to gain the estradiol equivalent (EEQ). There was an obvious correlation between the concentration of VTG and the total EEQ for all seven locations (P < 0.001). The biomarker VTG, EROD, GST and GSH assays and chemical analysis might be used to illustrate the potential risk in Lake Taihu.

Single and combined effects of selected pharmaceuticals at sublethal concentrations on multiple biomarkers in Carassius auratus

“…As the levels of VTG in fish were found to increase with the periods of exposure when exposed environmental estrogens (Lu et al 2011), VTG in goldfish were determined only after 7 days of exposure in this study. Serum VTG levels were measured following a competitive enzyme-linked immunosorbent assay (ELISA), as described by Rempel et al (2006).…”

Occurrence and distribution of endocrine-disrupting compounds in the Honghu Lake and East Dongting Lake along the Central Yangtze River, China

“…The EDCs in the water environment have posed threats to human health via drinking and/or food chain (Chang et al 2009;Falconer et al 2006). The EDCs were also widely detected in some lakes, such as Donghu Lake (Jin et al 2013), Lake Malta (Zgola-Grzeskowiak et al 2010), Dianchi Lake (Wang et al 2012), and Lake Taihu (Lu et al 2011). In this study, bisphenol A (BPA), 4-nonylphenol (NP), 4-octylphenol (OP), 17α-ethinylestradiol (EE2), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (βE2), and estriol (E3) were selected for study of the occurrence and distribution of estrogens in the East Dongting Lake and Honghu Lake.…”

Cytotoxic effects of 4-octylphenol on fish hepatocytes

“…Our results show that 4-OP caused significant increase in GST activity. Increased GST activity has also been reported in various fish species exposed to environmental contaminants such as polychlorinated biphenyls, polyaromatic hydrocarbons and estrogens (Otto and Moon 1996;Lu et al 2011). Du et al (2008) also reported elevated levels of hepatic GST activity in rabbitfish (Siganus oramin) exposed to t-OP, possibly related to increased free radical production.…”