Development of Acute Toxicity Test of Hazardous Chemicals Using Marine Zooplankton as Test Organism

Abstract

In order to develop the acute toxicity test using marine zooplankton, applicability of Tigriopas japonicas (Copepoda, Harpacticoida) as test organisms was investigated from the view point of sensitivities to pollutants and the rearing procedures.
T. japonicus survived for 14 days under the experimental conditions feeding Tetraselmis tetrothele as diet, and nauplius larvae were spawned from the experimentally reared female adult.
The nauplius larvae used for the acute toxicity test were separated effectively from the female adults by filtration with the plankton net of 200 &mico;m mesh size. The nauplius larvae can swim actively in the filtered seawater during 24 hours from the collection without feeding. EC₅₀ based on the suppression of swimming activity changed by the variation of water temperature and salinity, and appropriate value was 20-25°C and 32-34, respectively. EC₅₀ values of PCP-Na and organotin compounds to T. japonicus were similar to those values of freshwater zooplankton Daphnia magna (Branchiopoda, Cladocera ), therefore T. japonicus was a sensitive to hazardous chemicals. From these results, it is considered that the nauplius of T. japonicus is appropriate test organisms for acute toxicity test. The procedure of acute toxicity test using T. japonicus was established by summarizing the results of present research.