Relative Contribution of Endocrine-disrupting Chemicals to the Estrogenic Potency of Marine Sediments of Osaka Bay, Japan

Koyama, Jiro; Kitoh, Asami; Nakai, Makoto; Kohno, Kumiko; Tanaka, Hiroyuki; Uno, Seiichi

Relative Contribution of Endocrine-disrupting Chemicals to the Estrogenic Potency of Marine Sediments of Osaka Bay, Japan

2013

Although concentrations of endocrine-disrupting chemicals (EDCs) in seawaters of Japan are relatively low, vitellogenin and ovotestis inductions are still being observed in some males of mullet and flounder collected in coastal areas. These fish species are benthic and could be affected by EDCs in marine sediments. Therefore, the concentrations of EDCs in marine sediments of Osaka Bay were determined by LC-MS/MS. In addition, the estrogen receptor binding potencies as estrogenic potencies of these sediments were assessed by the medaka estrogen receptor-α binding assay. Results show that estrogenic potencies were higher in sediments of the inner part of the bay especially at station 13 (off Sakai City) where quite strong estrogenic potency was detected. Through calculation of total E2 equivalent concentration (EEQ) in sediments, it was established that approximately 50 % of estrogenic potency was due to nonylphenol (NP), estrone and 17β-estradiol, suggesting that these compounds play important roles as endocrine disruptors in coastal environments of Osaka Bay.

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