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2F - Site Specific Testing (MOP/108) Acute toxicity of phenols to aquatic species: Changes of bioavailability in natural waters. Kim, Sang1, Lee, Yong1, Yim, Jin1, 1 Department of Environmental Science and Engineering, Kwangju Institute of Science and Technology (K-JIST), Kwangju, City, Korea ABSTRACT- The bioassay experiments using Selenastrum capricornutum, Daphnia magna and Japanese medaka, which are commonly used in standardized toxicity tests due to the importance of relationship in the aquatic food chain, were performed to evaluate the toxicity of the phenols. First, the toxicity of phenols containing different numbers of chloro-, nitro- and alkyl- groups on test organisms was compared in terms of their octanol-water partition coefficient (Kow). In this study, we examined 7 chloro-phenols, 3 nitro-phenols and 3 alkyl-phenols. The chlorinated phenols having higher values of Kow showed the higher toxicity in the aquatic environment as expected. The results were compared in the relationship between Kow and its toxicity to each test organism. Secondly, to examine the changes of bioavailability of phenols in the different water conditions, the physical and chemical conditions of site waters were considered. The toxicity of phenols to aquatic organisms was determined to derive Water Effect Ratio (WER) in the site waters and in the reference water. The site waters were obtained from the Youngsan River and from the discharged effluent of wastewater treatment plant around Kwangju area in Korea, and the toxicity of phenols was determined in the site waters. To illustrate the importance of chemical properties and species sensitivity to WER, WERs were calculated using acute toxicity values from 3 species with 13 phenols having different values of Kow for the reference and site waters. The result of WER values indicated that the discharge permit could be affected by the environmental conditions and thereby different toxicity values. Key words: phenols, acute toxicity, WER |
