Toxicity of lead, cadmium and mercury on embryogenesis, survival, growth and metamorphosis of Meretrix meretrix larvae.

In order to assess the toxicity of heavy metals on the early development of Meretrix meretrix, the effects of mercury (Hg), cadmium (Cd) and lead (Pb) on embryogenesis, survival, growth and metamorphosis of larvae were investigated. The EC(50) for embryogenesis was 5.4 microg l(-1) for Hg, 1014 microg l(-1) for Cd and 297 microg l(-1) for Pb, respectively. The 96 h LC(50) for D-shaped larvae was 14.0 microg l(-1) for Hg, 68 microg l(-1) for Cd and 353 microg l(-1) for Pb, respectively. Growth was significantly retarded at 18.5 microg l(-1) (0.1 microM) for Hg, 104 microg l(-1) (1 microM) for Cd and 197 microg l(-1) (1 microM) for Pb, respectively. The EC(50) for metamorphosis, similar to 48 h LC(50), was higher than 96 h LC(50). Our results indicate that the early development of M. meretrix is highly sensitive to heavy metals and can be used as a test organism for ecotoxicology bioassays in temperate and subtropical regions.