Results of the harmful effects of water pollutants to Daphnia magna in the 21 day reproduction test

Abstract

Investigations were carried out in order to determine the “no observed effect concentration” (NOEC) of 73 environmentally relevant substances in the 21 d Daphnia reproduction test. The test was conducted in line with the provisional procedure proposed by the Federal Environmental Agency (Umweltbundesamt) (as of 1 January 1984). Daphnia magna Straus was used as the test organism. Evaluation parameters for fixing the NOEC were the mortality of the parent animals, the reproduction rate and the appearance of the first offspring during the test period. The concentrations of substances in the test preparations were chemically quantified. The NOEC values obtained for ethyl parathion, bis(tri- n-butyltin)oxide and the active ion Cd (II) were in the concentration range 1 ng 1 −1 −1 μg 1 −1, for I3 tested substances in the range 1 μg 1 −1 −< 0.1 mg 1 −1 and for 23 substances in the range 0.1 −< 1 mg 1 −1. In further evaluation of the results, it could be calculated that the substance concentration of the NOEC for three substances was more than 3 logs, in the case of 13 substances more than 2 logs, for 10 substances 50–90 times, for 24 substances 10–40 times and for 14 substances 5–9 times lower than the 24 h EC 50 of the corresponding substance.