The chironomid acute toxicity test: development of a new test system.

This paper describes the basis for a water-only acute chironomid toxicity test guideline using first-instar larvae. The method is based on the OECD test guidelines for the acute Daphnia sp. immobilization test and the long-term tests with Chironomus sp., reflecting the common test procedures currently used by the European agrochemical industry. Development of this guideline proposal is important under the European Plant Protection Products Directive (91/414/EEC), under which an insect species may be required to be tested, particularly for certain insecticides, for which Daphnia sp. may not be representative of the sensitivity of nontarget aquatic invertebrates. Chironomus sp. is a freshwater insect currently used in different international test guidelines. Because their ready availability as a test organism, with culturing conditions and certain test methods already established, Chironomus sp. is regarded as a suitable additional freshwater invertebrate species for regulatory testing.