Persistent organic pollutants in rough-toothed dolphins ( Steno bredanensis) sampled during an unusual mass stranding event

Blubber, kidney, and liver samples were collected from 19 of 62 rough-toothed dolphins Steno bredanensis that stranded in December 1997 near Apalachicola, FL, and concentrations of persistent organic pollutants were measured by dual capillary column gas chromatography with dual micro-electron capture detection. The sum of PCBs in females and males averaged 25,900 and 47,600 ng/g, respectively, with congener 153 contributing the most to the PCB load. Among organochlorine pesticides, DDTs were present in the highest concentrations, with average sums of 14,100 and 22,100 ng/g in females and males, respectively. The next highest concentrations were found for the chlordane groups, with concentrations averaging 3700 and 4050 ng/g in females and males, respectively. Females contained an average mirex concentration of 376 ng/g, while the concentration in males was 710 ng/g. Dieldrin was detected in all samples at mean concentrations of 467 and 318 ng/g, respectively, in females and males, while hexachlorocyclohexanes were detected at relatively low levels, and hexachlorobenzne concentrations were among the lowest of all persistent organic compounds detected. The extensive concentration data are tabulated.