yPaperz
Effects of Short-term Exposure of Leachate to MedakaiOryzias latipesj
Makiko Doi*, Kazuhiko Fukatsu*, Ryota Shinohara*, Masataka Hanashima**, Sotarou Higuchi*** and Keijirou Tomoda****
* Faculty of Environmental & Symbiotic Sciences, Prefectural University of Kumamoto
** Fukuoka Research Center for Recycling Systems
*** Recycling and Eco-Technology Speciality, Graduate School of Engineering, Fukuoka University
**** Towa Kagaku Co. Ltd.
ő Correspondence should be addressed to Makiko Doi:
Recycling and Eco-Technology Speciality, Graduate School of Engineering, Fukuoka University
iCollaboration Center 3F, 2-1 Hibikino, Wakamatsu-ku, Kitakyushu-city, 808-0135 Japanj
Abstract
Local residents are opposed to landfill projects because of doubtful long-term safety: groundwater may be contaminated by leachate or processing water. Continuous long-term monitoring is necessary to accumulate data on substances that affect natural populations because leachate contains a complex mix of unknown substances. We have devised a method for monitoring drainage using an ecosystem model and medaka. We studied the effect of short-term exposure to leachate or treated leachate on the reproductive capability of medaka.
Estrogenic substances\benzophenon, nonylphenol, and bisphenol A\were detected in the leachate sample. Leachate toxicity is inferred to result from compounds that make up the total organic carboniTOCjrather than from ammonia or salts. Untreated leachate with a short reclamation period and a high TOC was very toxic. Untreated leachate with a TOC of 1,360 mg/L was diluted to 2, 4, 8, and 16 with water. Then adult fish were exposed to it for two weeks. The HSI of adult fish increased in 8 and 16 leachate compared with the control. These leachate samples and treated leachate did not induce VTG in medaka. Moreover, normal reproduction of medaka was blocked by exposure to 2 leachate and treated leachate. Further studies are necessary to monitor long-term effects of leachate and treated leachate on medaka.
Key words: medaka, leachate, acute toxicity, unregulated chemicals, monitoring