title: Variations in the isotopic composition of stable mercury isotopes in typical mangrove plants of the Jiulong estuary, SE China.
abstract: Variations in the composition of stable isotopes of mercury contained in tissues (root, stem, leaf, and hypocotyl or flower) of three typical mangrove plants (Kandelia candel, Aegiceras corniculata, and Bruguiera gymnorhiza), collected from the mangrove wetland of Jiulong estuary, SE China, were used to investigate the sources and transformation of mercury in the mangrove plants. Tissue samples from the plants were digested and mercury in the solution was pre-concentrated with purge-trap method and then analyzed by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The results showed that the mass dependent fractionation (MDF) of mercury ranged from -2.67 to -0.87 ‰ for δ202Hg while the mass independent fractionation (MIF) of mercury isotopes ranged from -0.16 to 0.09 and -0.19 to 0.05 ‰ for Δ199Hg and Δ201Hg, respectively, relative to the standard NIST SRM 3133. The ratio of Δ199Hg/Δ201Hg was 0.991, indicating that the mercury had been photo-reduced before being accumulated in mangrove plants. Analyses of the data from MIF studies revealed that the major portion of the mercury measured in leaves (∼90 %) originated from the atmosphere while the source of over half of the mercury present in roots was the surficial sediment. This study, the first of its kind investigating the variations in isotopic composition of mercury in the tissues of mangrove plants, could be helpful to identify the source of mercury contamination in mangroves and understand the biogeochemical cycle of mercury in the estuarine mangrove wetlands.
authors: Key Laboratory of Estuarine Ecological Security and Environmental Health, Fujian Province University, Tan Kah Kee College, Xiamen University, Zhangzhou, 363105, China. susun98@outlook.com.|Key Laboratory of the Coastal and Wetland Ecosystems, Ministry of Education, Xiamen University, Xiamen, 361102, China. susun98@outlook.com.
authors: Lumin
authors: http://orcid.org/0000-0003-1539-2847
authors: L
authors: Sun
authors: Key Laboratory of the Coastal and Wetland Ecosystems, Ministry of Education, Xiamen University, Xiamen, 361102, China.
authors: Bingyan
authors: B
authors: Lu
authors: Key Laboratory of the Coastal and Wetland Ecosystems, Ministry of Education, Xiamen University, Xiamen, 361102, China.
authors: Dongxing
authors: D
authors: Yuan
authors: Key Laboratory of Estuarine Ecological Security and Environmental Health, Fujian Province University, Tan Kah Kee College, Xiamen University, Zhangzhou, 363105, China.
authors: Wenbo
authors: W
authors: Hao
authors: Key Laboratory of Estuarine Ecological Security and Environmental Health, Fujian Province University, Tan Kah Kee College, Xiamen University, Zhangzhou, 363105, China.
authors: Ying
authors: Y
authors: Zheng
mesh_terms: D005591:Chemical Fractionation; D002681:China; D063366:Estuaries; D008629:Mercury Isotopes / Q000737:chemistry*; D043982:Rhizophoraceae / Q000737:chemistry; D053833:Wetlands
chemical_list: D008629:Mercury Isotopes
keywords: Mangrove plants; Mass dependent fractionation; Mass independent fractionation; Mercury isotope