A method for the determination of environmental contaminants in living marine mammals using microscale samples of blubber and blood

As part of a study examining the possible effects of organochlorine compounds on juvenile northern elephant seals (Mirounga angustirostris), blubber and blood samples were taken from animals present on the Año Nuevo (California) rookery, and from animals admitted for rehabilitation at The Marine Mammal Center (Sausalito CA). Blubber samples were collected from immobilized seals. A pre-cleaned 6 mm K-medic biopsy punch was used to extract the blubber from a 1 cm incision near the hip, near the dorsal mid point. Blood samples were taken from the extradural vein; two mL of serum was analyzed for organochlorine compounds. Blubber samples (approximately 0.1g) were ground with Na2SO4 and extracted with 20 mL hexane:methylene chloride (1:1). Sera samples were extracted using commercially available disposable C18 columns. The extracts were separated on a micro-Florisil column, and analyzed by HRGC-ECD. Lipid determination in the serum was obtained by colorimetric analysis with 20 microliters samples. Results from the analysis of replicates and standard reference materials showed good recoveries, precision, and accuracy for both the blubber and blood methods.