| 其他摘要 | Per- and polyfluoroalkyl substances (PFAS) have been widely used in various fields of domestic and industrial products due to their excellent hydrophobic, lipophobic, acid- and alkali-resistant, and antioxidative properties, as well as surfactant characteristics. Among them, perfluorooctanoic acid (PFOA) and others have been listed as persistent organic pollutants (POPs) due to their impacts on ecosystems and human health. Perfluoroether carboxylic acids (PFECAs) have emerged as alternatives to PFOA and are now produced and used. Laizhou Bay is one of the marine areas in China with the highest concentration of PFOA, but the distribution characteristics of PFOA and PFECAs in the marine ecosystems of the Laizhou Bay region still unclear. As one type of PFECAs, although the concentration of perfluoro-2-methoxyacetic acid (PFMOAA) in water and sediments of Xiaoqing River and Laizhou Bay is relatively low, it exhibits the highest level among PFAS in sea snails. Sea snails are popular seafood among coastal residents. However, the differences in PFAS concentrations in sea snails from different habitats and the distribution variations of PFAS among different tissues within sea snails are still unclear. In this study, the marine ecosystems samples of the Laizhou Bay and its surrounding areas (including Laizhou, Longkou, and Changdao Island) and the veined rapa whelk (Rapana venosa) of the typical Bohai Sea areas (including Tianjin, Dongying, Xiaoqing River Estuary, Penglai, and Daqin Island) were investigated. The distribution characteristics of PFAS in environmental media and organisms in different habitats of the Laizhou Bay and its surrounding areas were analyzed at the individual level, while the tissue distribution patterns of PFAS in the veined rapa whelk (Rapana venosa) from the typical Bohai Sea areas were studied at the organ level. Furthermore, a systematic assessment of health risks associated with PFAS exposure was conducted. The research results are of great significance for understanding the environmental behavior and migration patterns of PFAS. The main findings of this study include:
(1) The contamination level of PFAS in the marine ecosystem of the Laizhou Bay region was related to the distance from Xiaoqing River Estuary, with areas closer to the estuary experiencing more severe pollution. In seawater, sediments, and marine organisms, ΣPFAS followed the pattern of Laizhou > Longkou > Changdao Island in general. PFOA was the predominant PFAS in water, sediments, and planktonic organisms across all regions. However, besides PFOA, high concentrations of short-chain PFMOAA were also found in invertebrates, while fish exhibited high levels of long-chain PFAS (C8-C12 PFCAs). Overall, the bioaccumulation factor (BAF) of long-chain PFAS was higher than that of short-chain PFAS (with PFUnDA having the highest BAF value). However, the high concentration of PFMOAA in invertebrates contributed to its relatively high BAF value. The results of the PFAS human dietary risk assessment indicated potential health risks associated with consuming seafood from the Laizhou Bay and surrounding areas to varying degrees.
(2) In various tissue samples of the veined rapa whelk (Rapana venosa) from different regions of the Bohai Sea, PFMOAA consistently remained the predominant PFAS (ranging from 20.7% to 3.7% of total PFAS). The concentration order of PFAS in different tissues was approximately as follows: kidney > gill > Lebrin's gland ≈ digestive tract ≈ liver > foot ≈ gonad ≈ mixed tissues ≈ adductor muscle. The ΣPFAS levels in the whelks from Xiaoqing River Estuary were significantly higher than in other regions, which may be attributed to the background concentration in the whelk's habitat. Additionally, the PFAS levels in the whelk from Penglai and Daqin Island were higher than those from Tianjin and Dongying, possibly due to the longer lifespan of the whelks in the former two regions. Different types of PFAS exhibited varying enrichment patterns in different tissues. Short-chain PFAS (such as PFMOAA and PFBA) showed the highest absolute concentrations in the kidney. Medium to long-chain PFAS (such as PFOA and HFPO-TrA) exhibited high absolute concentrations in Lebrin's gland, particularly PFOA. Sulfonic acid PFAS (such as PFOS and PFHxS) had significant absolute concentrations and contributed to a large proportion of the overall concentration in the liver. This may be related to the whelk's digestion, metabolism, circulation, and the content of lipid and protein in various tissues. Preliminary risk assessment indicated that consuming whelks alone posed relatively low health risks, but this result may underestimate the actual risks. |
修改评论