簡便法(半止水式)による2,4-ジクロロフェノールのヒメダカ胚及び稚魚に対する毒性試験

概要

論文の詳細を見る
Test conditions for fish early life stage toxicity (ELST) of U.S.EPA were examined and established by use of Japanese Medaka, Oryzias latipes, as a test species. The semi-static method by renewing test water in every 48 h was adopted instead of EPA's flow-through test system. After the establishment of some testing conditions such as collection of embryo and feeding for juvenile, embryos and larvae after hatch were exposed to 2,4-dichlorophenol (2,4-DCP) for 40 d for the evaluation of maximum acceptable toxicant concentration (MATC). Both hatching of embryos and survival of juveniles were significantly reduced by exposure to 2,4-DCP of 0.63 mg/l, whereas the growth rate was not affected at the highest concentration tested, 1.25 mg/l. Therefore, both hatching of embryo and survival were more sensitive indicators than the growth of juveniles for toxic effects of 2,4-DCP. On the basis of the above results, MATC for Japanese Medaka was estimated to be 0.32-0.63 mg/l and this value almost agreed with the MATC value for fathead minnow, 0.29-0.46 mg/l and ELST is much more sensitive than acute toxicity to Medaka, 96 h-LC_<50> of 6.3 mg/l. It is concluded that Japanese Medaka is a good test species for ELST test in the simple semi-static test water renewal system.
1988-06-30