CHRONIC TOXICITY OF ACRYLONITRILE AND ACETONITRILE TO DAPHNIA-MAGNA IN 14-D AND 21-D TOXICITY TESTS

Daphnia magna 21-d survival and reproduction test has been used as the standard method to evaluate chronic toxicity of pollutants and wastew ater to aquatic invertebrate (OECD 1986; U.S. EPA 1973; ASTM 1981). Th e requirement of a 21-d exposure period makes this a costly test. In a ddition, numerous laboratories have reported problems with the lack of consistent and sustained reproduction as Hell as inadequate survival over the 21-d period, These realities often detract from the overall c redibility of daphnia test data and the utility of the test species (A dams and Heidolph 1985). Adams and Heidolph (1985) compared the Daphni a magna 21-d and 14-d survival and reproduction test methods with 30 t ests of 21-d chronic toxicity and 18 tests of 48-hr acute toxicity. Th e results showed that the MATC (Maximum Allowable Toxicant Concentrati on) after 21-d exposure might be exactly estimated with the reproducti on and survival data of 14-d tests. So they suggested that the standar d protocols For D. magna chronic test be changed to a requirement of o nly a 14-d period of exposure instead of 21-d. This proposal was suppo rted by the test results of other researchers (Gersich 1990). This stu dy performed Daphnia magna 21-d and 14-d survival and reproduction tes ts of two pollutants, acrylonitrile and acetonitrile, which were the i mportant pollutants in the wastewater from the petro-chemical industry . Acrylonitrile is the priority pollutant in many countries including the United States, China and Germany. The sensitivity of the two metho ds was compared according to the results. This paper also discussed Ad ams and Heidolph's suggestion about using 14-d test method instead of 21-d test method. The purpose of this study is to evaluate the feasibi lity of D. magna 14-d test in the chronic toxicity assay for invertebr ate animals.