Abstract: Zebrafish was chosen as a subject in tests on shallow groundwaters (GW1, GW2 and GW3) sampled from 3 different sites, a hazardous chemical storage, chlorinated paraffin workshop and a place outside the chemical plant, for acute toxicity to zebrafish and toxicity affecting the development of zebrafish embryos. Results show that to adult zebrafish φ(72h，LC₅₀) of GW1 was 79.12%, and of GW2 and GW3 both greater than 100%. Dfferent degrees of toxic effects of the three shallow groundwaters on development of zebrafish embryos were recorded. The biotoxicity indices, like egg coagulation rate in 24h, non-spontaneous movement within 20s and hatching rate in 72h, were found to be closely related to dosage of the pollutant. The waters also had certain teratogenic effects on zebrafish, which would display pericardial cyst, spinal curvature, tail curvature or lack of melanin. The waters followed an order of GW 1 > GW 2 > GW 3 in biotoxicity. It is suggested that the toxicity test on zebrafish embryos is higher in sensitivity than the acute toxicity test. Moreover, the former is simple and rapid, and hence can be used in rapid screening of contaminated groundwater, which provides scientific basis for further hazard identification and risk assessment.

Key words: contaminated sites, shallow groundwater, zebrafish embryo, bio-toxicity, pollution diagnosis