An analysis of tissues for total PCB and planar PCB concentrations in marine mammals stranded along the Gulf of Mexico

Abstract

New methods developed in this study based upon extracting blubber by the maceration of the tissue in methylene chloride and subjecting the resulting extract to gel-permeation chromatography, provided a quick, reliable alternative to classical extraction and separation methods used for analysis of organochlorine residues in marine mammal tissues. Due to the lipophilic nature of PCBS, tissues high in lipid content, such as blubber and melon, give the best estimation of total body burden for the contaminants analyzed. Toxic Equivalents (TEQS) and baseline concentrations of total and planar PCBs in Atlantic bottlenose dolphins (Tursiops truncatus) which stranded along the Gulf of Mexico were determined in this study. The data suggests that concentrations of total PCBs and planar PCBs are not correlated, hence samples must be analyzed for both compounds in comprehensive studies. In the present study, PCB levels were statistically similar in 3 marine mammal species investigated (T. truncates, Stenella sp. , and Peponocephala electra). There appeared to be little correlation between PCB concentrations and stranding condition, stranding location or stranding year; however, a strong correlation was observed between the levels of PCBS, and the maturity and gender of the specimens analyzed. Male bottlenose dolphins accumulate PCBs throughout their lives as they mature, while females dolphins, once sexually mature, offload much of their body burdens of PCBs to their calves both transplacentally and through lactation. This trend would suggest that PCBs can be used as a chemical tracer in evaluating some biological and reproductive parameters of this species. Finally, preferential distribution of PCBs in different body blubber areas of T. truncatus was not observed in this study. This observation is possibly due to the homogeneous distribution of lipids in the thin blubber layer of these animals.