Distribution, Source Apportionment, and Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in the Surficial Sediments from the Coastal Areas of Bangladesh

The surficial sediments were collected in winter and summer (2015) from the coastal areas of Bangladesh and analyzed for 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs). The total concentration of PAHs (Sigma PAHs) were 349.8-11,058.8 and 199.9-17,089.1ng/g dry weight (dw) in winter and summer, respectively. Sediements from the areas with recent urbanization and industrialization (Chittagong, Cox's Bazar, and Sundarbans) were more contaminated with PAHs than the unindustrialized area (Meghna Estuary). The concentrations of Sigma PAHs were slightly higher in summer than those in winter, but the seasonal variations were not statistically significant (p>0.05). Molecular ratios suggested mixed sources of PAHs in the Bangladeshi coastal areas with a slight imposition of pyrolytic inputs closely related to shipping and fishing activities as well as industrial and municipal sewage discharge. According to ecological risk assessment, the measured levels of sedimentary PAHs exceeded some of the existing national and international environmental quality guidelines/standards, and thus might cause acute biological damage in the studied areas of the Bay of Bengal coast of Bangladesh.