Tracking Dietary Sources of Short- and Medium-Chain Chlorinated Paraffins in Marine Mammals through a Subtropical Marine Food Web

Our previous study revealed an elevated accumulation Of Short-Chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in marine mammals from Hong Kong waters in the South China Sea. To examine the bioaccumulalion potential and biornagnification in these apex predators, we sampled the dietary items of marine mammals and tracked the sources;of SCCPs and MCCPs through a marine food web in this region. Sixteen fish species, seven crustacean species, and four mollusk species were collected, and the main, prey species were identified for two specieS of Marine mammals. Concentrations of ESCCPs and EMCCPs in these collected species suggested a moderate pollution level in Hong Kong waters compared to the global range. Lipid was found to mediate congener-specific bioaccumulation in these marine species. Significantly positive correlations were observed between trophic levels and concentrations of ZSCCPs or ZMCCPs (p < 0,05). Trophic magnification factors for ESCCPs and ZMCCPs were 4.29 and 4.79, indicating that both of them have trophic magnifiCation potentials. Elevated biomagnification of SCCPs and MCCPs from prey species to marine mammals was observed. This is the first report of dietary source tracking of SCCPs and MCCPs in marine mammals. The elevated biomagnification between prey and marine mammals raises environmental concerns about these contaminants.