PT04 Endocrine-Disrupting Chemicals in Wastewater Treatment Effluents
Exhibit Hall
8:00 AM - Tuesday
(PT048) Change of Estrogenic Activities in the Non-Cropping Paddy Field Receiving a Rural Sewage Effluent.
Hida, Y1, Kurata, T1, Kunimatsu, T1, Osaki, S1, Ogawa, M3, Shiraishi, F4, Shiraishi, H4, 1 Department of Ecosystem Studies, School of Environmental Science, The University of Shiga Prefecture, Hikone, Japan3 Shiga Prefectural Government, Otsu, Japan4 National Institute for Environmental Studies, Tsukuba, Japan
ABSTRACT- In order to prevent Lake Biwa, the symbol of Shiga Prefecture, from eutrophication, we have studied the cleaning-up method of rural sewage effluent by applicating paddy field ecosystem in rural area from August 2001. In this study, we investigated the estrogenic impact on water quality of the non-cropping paddy field receiving a rural sewage effluent to evaluate environmental risk of the method. The whole effluent of 84 m3/d from a rural sewage was inflowed everyday into the non-cropping paddy field (830 m2) involved the division of the canal into 7 areas. Watercress and round crucian carp (funa), the major constituent of a special food of Shiga Prefecture "Funazushi", are introduced into the forth and fifth divisions, respectively. We collected surface waters at an effluent entry point and 7 various distances downstream, the end point of each division, in the canal every other week from April 2003 to June 2004. We evaluated estrogenic activity of each sample using in vitro assay with the modified yeast two-hybrid assay system (human and medaka estrogen receptors: hER
and mER). The hER assay system is high sensitive specifically to natural estrogens, and the mER assay system, by contrast, has low sensitivity to natural estrogens, and is relatively high sensitive to estrogenic industrial chemicals and phytoestrogens, the so-called xenoestrogens. Thus we evaluated the total estrogenic activities of water samples and also their qualitative characters by using both assay systems at the same time. The total estrogenic activity of rural sewage effluent was rarely detected on both assay systems throughout the investigation period. However, it appeared after the effluent flowed into the non-cropping paddy field. It tended to increase along with the surface water flow on the mER assay system and rose downstream from the fifth division releasing round crucian carp on the hER assay system.
Key words: yeast two-hybrid assay system, estrogenic activity, non-cropping paddy field, rural sewage effluent