Keywords: 
• benzo(a)pyrene /
• dichlorodiphenyl trichloroethane /
• Perna viridis /
• embryonic toxicity /
• enzyme activities /
• integrated biomarker response (IBR)

Abstract: To illustrate the toxic effects of different concentrations of BaP and DDT on Perna viridis embryo, the activities of antioxidant enzymes (SOD, GSH-Px) and non-specific immune enzymes (ACP, AKP) in P. viridis embyro were measured after 24 h and 48 h exposure to BaP or DDT with the concentrations of 25 and 50 μg·L^-1, respectively. Additionally, Integrated Biomarker Response (IBR) index was utilized to evaluate integrated toxicological effects of P. viridis embryo exposed to Bap and DDT. The results showed that the activities of antioxidant and non-specific immune enzymes in P. viridis embryo were affected significantly by BaP and DDT. Compared a control group, SOD and AKP activities in the treated groups exhibited an inhibition-induction pattern. Furthermore, the ACP activity was inhibited and then induced after BaP treatment while it was only slightly influenced after DDT exposure. We quantified the toxicity of BaP and DDT via the IBR index. These results suggested that R_IB varied in a trend, i.e. it rises at the beginning and then falls, and R_IB of DDT group was higher than BaP group, suggesting that toxicity of DDT was higher than BaP. This study provided the scientific basis for screening of sensitive biomarkers, which may be used for monitoring the marine environment pollution.