ABSTRACT
The Southern California Bight (SCB) is thought to be a nursery ground for the White Shark (Carcharodon carcharias) in the eastern north Paci¢c. Because of their proximity to highly urbanized coastline in the SCB, juvenile White Sharks are potentially exposed to relatively high levels of trace elements, heavy metals, and organochlorines. To assess potential exposure levels, concentrations of 17 elements, 6 isomers of dichlorodiphenyltrichloroethane (DDT), 54 congeners of polychlorinated biphenyls (PCBs), and 24 chlorinated pesticides were measured in the muscle and liver tissue of juvenile White Sharks using inductively coupled plasma mass spectrometry (ICP-MS) and gas chromatography-mass spectrometry (GC-MS). Average total mercury concentrations were signi¢cantly higher in muscle (3.01 ± 0.61 μg/g wet weight) than liver (0.206 ± 0.07 μg/g wet weight) (p < 0.01). Mean total mercury level in muscle was six times higher than the established wildlife screening value of concern (0.5 μg/g). Lipophilic DDT, PCBs, and chlordanes were the predominant
organic contaminants found in liver tissue. Levels of DDT (72.37 ± 72.86 μg/g lipid) and PCBs (17.53 ± 12.75 μg/g lipid) in the liver were the highest observed in any elasmobranch reported to date and were signi¢cantly higher than those observed in red muscle and white muscle. These levels are known to have deleterious effects in marine vertebrates, suggesting that there is the potential for physiological impairment caused by contaminant exposure.
