COS 81-8
Spatial patterns of modern pollutants in tuna: A global assessment
It has been well documented that the oceans have become a repository for global pollutants, especially for organic compounds known as persistent organic pollutants (POPs). Resistant to environmental degradation, these toxins can be transported over long distances, contaminating seafood throughout the globe. Although many of these pollutants are now monitored and mitigated by the UN’s Stockholm Convention, they can still be found ubiquitously throughout the marine environment. Food consumption is the major pathway to human exposure for these contaminants, particularly seafood consumption. We are investigating selected classes of modern and legacy pollutants, including organochlorine pesticides, polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE) and mercury within yellowfin tuna. This species (Thunnus albacares) was selected due to its commercial importance and its biological and ecological relevance. Yellowfin often exhibit site fidelity, occupying regions (10-100kms) with distinct chemical concentrations for sufficient periods of time to note regional differences within the tissue. Previous analyses of yellowfin are limited to mercury, with no insight into modern chemicals, especially at a global scale
Results/Conclusions
scale. We found strong spatial patterns between industrialization and increased levels of POPs across ocean basins within PCBs, organochlorine pesticides, and mercury. Additionally, data reveal strong correlations between chemical congeners across sites. Strong positive correlations were seen amongst specific PCB congeners as well between PCBs and select pesticides. In regards to human health concerns, all sites were found to have higher mercury concentrations than the EPA recommended limit of 0.1ppm. Similarly, a majority of the sites screened had higher concentrations than the EPA screening value for subsistence fishers, but lower than the recreational screening value. These results show the far-reaching implications of legacy and modern pollutants on important fisheries resources