Key Laboratory of Estuarine Ecological Security and Environmental Health, Education Department of Fujian, Tan Kah Kee College, Xiamen University, Zhangzhou, 363105, China.
Key Laboratory of the Coastal and Wetland Ecosystems, Ministry of Education, Xiamen University, Xiamen, 361105, China.
Biol Trace Elem Res. 2022 Feb;200(2):855-867. doi: 10.1007/s12011-021-02695-1. Epub 2021 Apr 1.
Wild-caught seafood contains significant amounts of mercury. Investigating the mercury accumulation levels in wild-caught seafood and analyzing its migration and transformation are of great value for assessing the health risks of mercury intake and for the tracking of mercury sources. We determined the concentrations and stable mercury isotopic compositions (δHg, ΔHg, ΔHg, and ΔHg) of 104 muscle samples collected from 38 species of seafood typically harvested from the Taiwan Shallow Fishing Ground (TSFG), Southern Taiwan Strait. Overall, the concentrations of total mercury (THg) and methylmercury (MeHg) ranged from 11 to 479 ng/g (dry weight, dw) and 10 to 363 ng/g (dw), respectively, and were below the threshold value established by the USEPA and the Chinese government. Demersal and near-benthic species accumulated more mercury than pelagic or mesopelagic species. The characteristics of mercury isotopes in wild-caught marine species differed in terms of vertical and horizontal distribution. Considering the known peripheral land sources of mercury (ΔHg ≈ 0), the mercury in seafood from the TSFG (ΔHg > 0) did not originate from anthropogenic emissions. The ratio of ΔHg and ΔHg (1.18 ± 0.03) suggested that the photoreduction of Hg (II) and the photo-degradation of MeHg equally contributed to mass-independent fractionation. Based on the values of ΔHg/δHg (1.18 ± 0.03), about 67% of the mercury in seawater had undergone microbial demethylation prior to methylation and entering the seafood. Additionally, the vertical distribution of ΔHg in seafood from different water depths implies that mercury input was in part caused by atmospheric deposition. Our results provide detailed information on the sources of mercury and its transfer in the food web in offshore fishing grounds.
野生捕捞的海鲜中含有大量的汞。调查野生捕捞海鲜中的汞积累水平，并分析其迁移和转化，对于评估汞摄入的健康风险和追踪汞的来源具有重要价值。我们测定了从台湾浅海渔场（TSFG）捕捞的 38 种海鲜的 104 个肌肉样本中的总汞（THg）和甲基汞（MeHg）浓度以及稳定汞同位素组成（δHg、ΔHg、ΔHg 和 ΔHg）。总的来说，THg 和 MeHg 的浓度范围分别为 11-479ng/g（干重，dw）和 10-363ng/g（dw），均低于美国环保署和中国政府规定的阈值。底栖和近海底物种比洄游或中层鱼类积累了更多的汞。野生捕捞海洋物种的汞同位素特征在垂直和水平分布上存在差异。考虑到已知的汞的外围陆地来源（ΔHg≈0），来自 TSFG 的海鲜中的汞（ΔHg>0）并非来自人为排放。ΔHg 和 ΔHg 的比值（1.18±0.03）表明 Hg（II）的光还原和 MeHg 的光降解同等程度地促成了质量独立分馏。根据 ΔHg/δHg 的值（1.18±0.03），大约 67%的海水中的汞在进入海鲜之前已经经历了微生物的脱甲基作用和甲基化作用。此外，不同水深的海鲜中 ΔHg 的垂直分布表明，汞的输入部分是由大气沉降引起的。我们的研究结果提供了关于近海渔场中汞的来源及其在食物网中的迁移的详细信息。
