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Toxicity Test Assay of Waterborne Methylmercury on the Japanese Flounder (Paralichthys olivaceus) at Embryonic-Larval Stages

Ren, Zhonghua, Cao, Liang, Huang, Wei, Liu, Jinhu, Cui, Wenting, Dou, Shuozeng
Bulletin of environmental contamination and toxicology 2019 v.102 no.6 pp. 770-777
Paralichthys olivaceus, absorption, acute toxicity, dose response, ecotoxicology, flounder, larvae, lethal concentration 50, marine ecosystems, marine fish, methylmercury compounds, mortality, pollutants
Methylmercury (MeHg) is a widespread pollutant in aquatic ecosystems, but its toxicity to the early life stages of marine fish has not been adequately investigated. This study used acute toxicity tests on embryonic-larval stages of a marine flounder Paralichthys olivaceus to determine the LC₅₀ values for embryos and larvae and evaluate the responses of several biological endpoints to subacute MeHg exposure. Under exposures (0–15 μg L⁻¹) below LC₅₀ values (< 15.3 μg L⁻¹ for embryos and 16.3 μg L⁻¹ for larvae), embryos were more sensitive to MeHg than were the larvae. MeHg exposures at ≥ 13 μg L⁻¹ increased morphological deformities and mortality, reduced growth and yolk absorption rate of the embryonic-larval flounder. These endpoints were sensitive to MeHg and their responses were dose-dependent. They could be used as bioindicators for assessing MeHg toxicity to the ELS of the flounder. Embryonic-larval flounder could be a useful fish for ecotoxicological assessment of MeHg in marine ecosystems.