Evaluation of the impact of bioaccumulation of PAH from the marine environment on DNA integrity and oxidative stress in marine rock oyster (Saccostrea cucullata) along the Arabian sea coast.

Abstract

Marine pollution due to oil spills is of great concern globally for their impact on the health of marine ecosystems. We assessed the genotoxic effects and oxidative stress due to genotoxic pollutants accumulated from the ambient marine environment in the tissues of marine rock oyster, Saccostrea cucullata along the Arabian Sea coast around Goa, India. The extent of DNA damage in S. cucullata was determined by comet assay as variation of comet parameter: mean % tail DNA along the coast with respect to that at the reference site (Tiracol, Goa, India). In addition, the oxidative stress responses of rock oysters exposed to marine pollutants such as polycyclic aromatic hydrocarbons (PAHs) were assessed as a function of variation in antioxidant enzyme activities such as glutathione-s-transferase (GST), catalase (CAT) and superoxide dismutase (SOD) along the coast. Spearman correlation analysis showed significant correlation between different components of PAHs (viz., 2-3-PAH, 4-6-PAH and oxy-PAH) in the tissues of the rock oysters and the antioxidant enzyme activities. The antioxidant enzyme activities in S. cucullata increased with increasing concentrations of PAHs in tissues in the following order of sampling sites: Tiracol < Arambol < Betul < Velsao. Among the PAHs, oxy-PAH was found to be most predominant in causing DNA damage in S. cucullata. These results provide an insight into environmental genotoxicity and oxidative stress induced by PAHs along the Arabian Sea coast, India.