title: Bioaccumulation of methylmercury versus inorganic mercury in rice (Oryza sativa L.) grain.
abstract: Mercury (Hg) bioaccumulation in aquatic food webs has been much studied, motivated from high Hg levels found in many fish species important for human consumption. Hg bioaccumulation in terrestrial food chains have received little attention and assumed to be of minor importance. However, recent studies showed that rice can be an important pathway of methylmercury (MeHg) exposure to inhabitants in Hg mining areas in China. In this study, 59 sampling sites (including 32 sites from "heavily polluted area", 19 from "less-impacted area" and 8 from "control sites") were selected in a Hg mining area in China and both inorganic Hg (IHg) and MeHg were determined in rice grain (brown rice) and soil samples to evaluate Hg bioaccumulation in rice grain. Bio-Accumulation Factors (BAFs) for IHg ranged from 0.00014 to 0.51 and from 0.71 to 50 for MeHg. BAFs for MeHg were on average more than 800 times higher than those for IHg (maximum: 40,000 times). This study, for the first time, showed that rice grain is an intensive bioaccumulator of MeHg, but not of IHg, which may be trapped by the roots.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Xinbin
authors.initials: X
authors.lastname: Feng
authors.forename: Thorjørn
authors.initials: T
authors.lastname: Larssen
authors.forename: Lihai
authors.initials: L
authors.lastname: Shang
authors.forename: Ping
authors.initials: P
authors.lastname: Li
mesh_terms: D000383:Agriculture; D002681:China; D008628:Mercury / Q000378:metabolism*; D008767:Methylmercury Compounds / Q000378:metabolism*; D008906:Mining; D012275:Oryza / Q000378:metabolism*; D018570:Risk Assessment; D012639:Seeds / Q000378:metabolism*; D012987:Soil / Q000032:analysis
chemical_list: D008767:Methylmercury Compounds; D012987:Soil; D008628:Mercury