title: Fumigant methyl iodide can methylate inorganic mercury species in natural waters.
abstract: Methyl iodide or iodomethane (CH3I) has recently been registered as a fumigant in many countries, although its environmental impacts are not well understood. Here we report the results of a study on the methylation of mercury by CH3I in natural water by incubation experiments using both Hg ((199)HgCl2 and CH3(201)Hg(+))- and hydrogen (CD3I)-stable isotope addition techniques. We find that methylation of Hg(0), Hg2(2+) and Hg(2+) by CH3I can occur in natural water under sunlight, while only Hg(0) and Hg2(2+) can be methylated in deionized water. We propose that the methylation of Hg by CH3I in natural waters is mediated by sunlight and involves two steps, the reduction of Hg(2+) to Hg(0)/Hg2(2+) and the subsequent methylation of Hg(0)/Hg2(2+) by CH3I. Further quantitative assessment suggests that CH3I-involved methylation of inorganic Hg could be an important source of CH3Hg(+) in an environment where CH3I has been used in large amounts as a fumigant.
authors.affiliation: 1] State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, No. 18, Shuangqing Road, Haidian, Beijing 100085, China [2] Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, Florida 33199, USA [3] Southeast Environmental Research Center, Florida International University, University Park, Miami, Florida 33199, USA.
authors.forename: Yongguang
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao 266100, China.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Li
authors.affiliation: 1] Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, Florida 33199, USA [2] Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo 454000, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Tai
authors.affiliation: 1] Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, Florida 33199, USA [2] Southeast Environmental Research Center, Florida International University, University Park, Miami, Florida 33199, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cai
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, No. 18, Shuangqing Road, Haidian, Beijing 100085, China.
authors.forename: Guibin
authors.initials: G
authors.lastname: Jiang
mesh_terms: D005844:Geology; D006812:Humic Substances; D006847:Hydrocarbons, Iodinated / Q000737:chemistry*; D007287:Inorganic Chemicals / Q000737:chemistry*; D008628:Mercury / Q000737:chemistry*; D008745:Methylation; D010575:Pesticides / Q000737:chemistry*; D055668:Photochemical Processes; D045483:Rivers; D013059:Spectrum Analysis, Raman; D013472:Sunlight; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D006812:Humic Substances; D006847:Hydrocarbons, Iodinated; D007287:Inorganic Chemicals; D010575:Pesticides; D014874:Water Pollutants, Chemical; D014867:Water; C014055:methyl iodide; D008628:Mercury