Emerging POPs-type cocktail signatures in Pusa caspica in quantitative structure-activity relationship of Caspian Sea

摘要

The Caspian seal Pusa caspica is the only endemic mammalian species throughout the Caspian Sea. This is the first report on risk assessment of persistent organic pollutants (POPs) in Caspian seals by age-sex and tissue-specific uptake, and their surrounding environment (seawater, surface sediments, and suspended particulate matters, SPMs) in the Gorgan Bay (Caspian Sea, Iran). Among the quantified 70 POPs (Sigma 35PCBs, Sigma(3)HCHs, Sigma(6)CHLs, Sigma 6DDTs, Sigma 17PCDD/Fs, HCB, dieldrin, and aldrin), Sigma(35)PCBs were dominant in abiotic matrices (48.80% of Sigma(70)POPs), followed by HCHs CHLs DDTs PCDD/Fs other POPs in surface sediments SPMs seawater, while the toxic equivalent quantity (TEQ(WHO)) exceeded the safe value (possible risk in this area). In biota, the highest levels of Sigma(70)POPs were found in males (756.3 ng g(-1) dw, p 0.05), followed by females (419.0 ng g(-1) dw) and pups (191.6 ng g(-1) dw) in liver kidney muscle blubber intestine fur heart spleen brain. The positive age-related POPs declining correlation between mother-pup pairs suggested the possible maternal transfer of POPs to offspring. The cocktail toxicity assessment revealed that Caspian seals can pose a low risk based on their mixed-TEQ values. Self-organizing map (SOM) indicated the non-coplanar PCB-93 as the most over-represented functional congener in tissue-specific POPs bioaccumulation. Quantitative toxicant tissue-profiling is valuable for predicting the state of mixture toxicity in pinniped species.