Common seafood pollutants inhibit a crucial cellular defense protein.

Background:Fish are a source of persistent organic pollutants (POPs) in the human diet. Although species, trophic level, and means of production are typically considered in predicting fish pollutant load, and thus recommendations of consumption, capture location is usually not accounted for.Objectives:Yellowfin tuna (Thunnus albacares) are harvested from across the world’s oceans and are widely consumed. Here, we determined geographic variation in the overall mass, concentration, and composition of POPs in yellowfin and examined the differences in levels of several POP congeners of potential relevance to human health.Methods:We sampled dorsal muscle of 117 yellowfin tuna from 12 locations worldwide, and measured POP levels using combined liquid or gas chromatography and mass spectrometry according to U.S. Environmental Protection Agency standard procedures.Results:POP levels varied significantly among sites, more than 36-fold on a mass basis. Individual fish levels ranged from 0.16 to 138.29ng/g wet weight and lipid-normalized concentrations from 0.1 to 12.7μM. Levels of 10 congeners that interfere with the cellular defense protein P-glycoprotein, termed transporter interfering compounds (TICs), ranged from 0.05 to 35.03ng/g wet weight and from 0.03 to 3.32μM in tuna lipid. Levels of TICs, and their individual congeners, were strongly associated with the overall POP load. Risk-based analysis of several carcinogenic POPs indicated that the fish with the highest levels of these potentially harmful compounds were clustered at specific geographic locations.Conclusions:Capture location is an important consideration when assessing the level and risk of human exposure to POPs through ingestion of wild fish. https://doi.org/10.1289/EHP518

Mercury is a toxic compound to which humans are exposed by consumption of fish. Current fish consumption advisories focus on minimizing the risk posed by the species that are most likely to have high levels of mercury. Less accounted for is the variation within species, and the potential role of the geographic origin of a fish in determining its mercury level. Here we surveyed the mercury levels in 117 yellowfin tuna caught from 12 different locations worldwide. Our results indicated significant variation in yellowfin tuna methylmercury load, with levels that ranged from 0.03 to 0.82 μg/g wet weight across individual fish. Mean mercury levels were only weakly associated with fish size (R < 0.1461) or lipid content (R < 0.00007) but varied significantly, by a factor of 8, between sites. The results indicate that the geographic origin of fish can govern mercury load, and argue for better traceability of fish to improve the accuracy of exposure risk predictions.

Although persistent, bioaccumulative and toxic pollutants (PBTs) are well-studied individually, their distribution and variability on a global scale are largely unknown, particularly in marine fish. Using 2,662 measurements collected from peer-reviewed literature spanning 1969–2012, we examined variability of five classes of PBTs, considering effects of geography, habitat, and trophic level on observed concentrations. While we see large-scale spatial patterning in some PBTs (chlordanes, polychlorinated biphenyls), habitat type and trophic level did not contribute to significant patterning, with the exception of mercury. We further examined patterns of change in PBT concentration as a function of sampling year. All PBTs showed significant declines in concentration levels through time, ranging from 15–30% reduction per decade across PBT groups. Despite consistent evidence of reductions, variation in pollutant concentration remains high, indicating ongoing consumer risk of exposure to fish with pollutant levels exceeding EPA screening values. The temporal trends indicate that mitigation programs are effective, but that global levels decline slowly. In order for monitoring efforts to provide more targeted assessments of risk to PBT exposure, these data highlight an urgent need for improved replication and standardization of pollutant monitoring protocols for marine finfish.

xi down" approaches and western from "bottom-up". Finally, we found that management region, applicant type, fishery, and size of project were positively associated with success in EFP projects, with Alaska and West Coast regions accounting for the highest proportion of successful projects.

Multidrug resistance (MDR) transporters, from the ATP binding cassette (ABC) superfamily, are thought to act as determinants of chemical accumulation in cells. Despite a long history of research on the interactions of MDR proteins with pharmaceuticals, little is known about the molecular basis of their interactions with environmental compounds such as persistent organic pollutants (POPs). This research is urgently needed to further understanding of substrate recognition by the transporters and to test the hypothesis that pollutant persistence relates to predictable patterns of interaction with the major MDR transporter ABCB1. We use purified recombinant P‐glycoprotein (ABCB1) from mouse and yellowfin tuna to measure pollutant‐transporter interaction kinetics via ATPase stimulation and fluorophore knock‐off experiments. These kinetic will be compared to what is observed with ABCB1 overexpressed in whole cells. Previously analyzed data on “real‐world” pollutant levels in the cosmopolitan and widely consumed fish species of yellowfin tuna (Thunnus albacares) was used to guide the selection of persistent pollutants. The preliminary results of this study show that the majority of the selected persistent pollutants found in tuna are inhibitors of mouse ABCB1 efflux pump. Thereby, isomeric forms of the same pollutant can differ in their IC50 values up to an order of magnitude while reaching inhibition coefficients in the range of the model inhibitor cyclosporine A. These studies aim at determining the conservation of pollutant‐transporter interactions across marine and mammalian ABCB1 transporters. In addition, we want to investigate whether common structural features of ABC transporters and pollutants govern their interactions. These results will shed light on the question of how transporters can direct pollutant movement through the environment and will lead to new avenues for design of more potent pharmaceuticals and safer industrial chemicals. Grant Funding Source: Supported by NIH and the WAITT Foundation