Different circulation history of mercury in aquatic biota from King George Island of the Antarctic. (July 2019)

• Record Type: Journal Article
• Authors: Liu, Hongwei; Yu, Ben; Fu, Jianjie; Li, Yingming; Yang, Ruiqiang; Zhang, Qinghua; Liang, Yong; Yin, Yongguang; Hu, Ligang; Shi, Jianbo; Jiang, Guibin
• Is Part Of: Environmental pollution. Volume 250(2019)
• Page Start: 892
• Page End: 897
• Publication Date: 2019-07
• Subjects: Mercury isotope -- Antarctic -- Methylmercury source -- Photo-degradation; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2019.04.113
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: To trace the circulation history of aquatic bioavailable Hg in the Antarctic, the species and isotopic compositions of Hg in sediment, Archaeogastropoda (Agas), Neogastropoda (Ngas), and fish collected from King George Island were studied in detail. Positive mass independent fractionation (MIF) was observed and positively correlated with the percentages of methylmercury (MeHg%) in Agas and Ngas, suggesting an effect of MeHg accumulation during trophic transfer on MIF signatures. However, both the ratios of Δ 199 Hg/δ 202 Hg and Δ 199 Hg/Δ 201 Hg indicated different circulation histories of Hg in Agas, Ngas, and fish. The microbial methylation in sediment was the primary source of MeHg in Agas and Ngas (Δ 199 Hg/δ 202 Hg ∼0, Δ 199 Hg/Δ 201 Hg ∼1.00). In contrast, the MeHg in fish (Δ 199 Hg/δ 202 Hg = 0.55 ± 0.06, Δ 199 Hg/Δ 201 Hg = 1.19 ± 0.17) came from the combined sources of residual MeHg which had sunk from the surface water and microbial-methylated MeHg in sediments, and the bioavailable Hg in the sediments contributed to approximately 44% of the total Hg in fish. Subsequently, the Δ 199 Hg values of bioavailable MeHg and IHg in sediments were quantitatively calculated, which provided key end-member information for future source apportionment in the Antarctic and other pelagic regions. It was also found that the Hg accumulated in Agas and Ngas had no history of MeHg photo-degradation, indicating that the methylated Hg in benthic zones suffered little photo-degradation and thus presented high bioavailability and environmental risk. Graphical abstract: Image 1 Highlights: The biogeochemical cycles of Hg in mollusks and fish were different. There was no history of MeHg photo-degradation for Hg in mollusks. Contributions of sediment and the water column to the Hg in fish were calculated. Abstract : This work found that there was no history of MeHg photo-degradation for Hg in mollusks and calculated the contributions of sediment and the water column to the Hg in fish.