Abstract
Maternal transfer of persistent marine contaminants to offspring via milk has been documented in marine mammals, but temporal dynamics of this phenomenon throughout the lactation period are poorly understood. Exposures to organohalogens were investigated in harbor seal pups admitted to a rehabilitation center in north central California during the lactation periods of 2001 and 2002. Ten congeners of PCBs, three congeners of PBDEs, and p,p′ -DDE were quantified in whole blood samples. Levels of contaminants increased with admit date, assumed to correlate positively with pup age. This trend was significant when latitude of stranding site, body condition, and body length were included as variables in the model. Contaminant–admit date relationships appeared nonlinear (i.e., threshold or exponential), with greatest increases in contaminant concentrations during late lactation.
This project was supported in part by grants to J. Neale from the UC Marine Council (02 T CEQI 03 0104) and the NIH–NIEHS (5 T32 ES07059-25 Traineeship in Environmental Toxicology). B. N. Sacks provided helpful review of the article.