Individual and Combined Toxicities of Benzo[a]pyrene and 2,2',4,4'-Tetrabromodiphenyl Ether on Early Life Stages of the Pacific Oyster, Crassostrea gigas.

Persistent organic pollutants (POPs) are ubiquitous and coexisted in the aquatic environment. Individual and combined toxic effects of benzo[a]pyrene (BaP) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on embryogenesis, and larval survival of the Pacific oyster were investigated. The EC50 values of BaP, BDE-47 and their mixture on embryogenesis were 18.4, 203.3 and 72.0 µg/L respectively, while the LC50 values for 96 h larval mortality were 26.8, 244.5 and 108.9 µg/L respectively. The Marking-Dawson additive toxicity indices were -0.02 and -0.19, indicating an additive effect with a trend to antagonism. In addition, DNA strand breaks were also observed in oyster embryos after exposure. Our study suggests that BaP and BDE-47 exposure can cause developmental abnormalities, DNA damage and larval mortality. Furthermore, the toxicity of the mixture is slightly lower than individual pollutant. These data will be helpful to predict the toxicity of organic pollutants, and provide criteria for marine water quality standards.