Photo-induced Toxicity of Four Polycyclic Aromatic Hydrocarbons (PAHs) to Embryos and Larvae of the Carpet Shell Clam Ruditapes decussatus

In this work, we assessed the photo-toxicity of four polycyclic aromatic hydrocarbons (PAHs) to embryos and larvae of the European clam Ruditapes decussatus . The exposure of R. decussatus embryos (24 h) and larvae (96 h) to anthracene, fluoranthene, pyrene and benzo[a]pyrene resulted in reduction of normal D-veliger percentages and high larval mortality, both in darkness and under sunlight conditions. Based on the calculated EC 50 and LC 50 values, the toxicity of the forementioned PAHs was respectively enhanced 72, 35, 60 and 23 times in the embryotoxicity test and 32, 31, 12 and 61 times in the larval mortality test when exposures were performed under sunlight conditions. Simultaneous exposure to sunlight and these PAHs enhanced their toxicity in comparison to dark conditions. The clam embryos and larvae appear to be environmentally relevant life-stages in assessing the toxic and photo-toxic risk of PAHs that enter the marine environment.