title: Prediction of methylmercury accumulation in rice grains by chemical extraction methods.
abstract: To explore the possibility of using chemical extraction methods to predict phytoavailability/bioaccumulation of soil-bound MeHg, MeHg extractions by three widely-used extractants (CaCl2, DTPA, and (NH4)2S2O3) were compared with MeHg accumulation in rice grains. Despite of variations in characteristics of different soils, MeHg extracted by (NH4)2S2O3 (highly affinitive to MeHg) correlated well with grain MeHg levels. Thus (NH4)2S2O3 extraction, solubilizing not only weakly-bound and but also strongly-bound MeHg, may provide a measure of 'phytoavailable MeHg pool' for rice plants. Besides, a better prediction of grain MeHg levels was obtained when growing condition of rice plants was also considered. However, MeHg extracted by CaCl2 or DTPA, possibly quantifying 'exchangeable MeHg pool' or 'weakly-complexed MeHg pool' in soils, may not indicate phytoavailable MeHg or predict grain MeHg levels. Our results provided the possibility of predicting MeHg phytoavailability/bioaccumulation by (NH4)2S2O3 extraction, which could be useful in screening soils for rice cultivation in contaminated areas.
authors.affiliation: Nanjing University, School of Environment, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, People's Republic of China.
authors.forename: Dai-Wen
authors.initials: DW
authors.lastname: Zhu
authors.affiliation: Nanjing University, School of Environment, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, People's Republic of China. Electronic address: zhonghuan@nju.edu.cn.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhong
authors.affiliation: Institute of Botany, Jiangsu Province and The Chinese Academy of Sciences, Nanjing, Jiangsu Province, People's Republic of China.
authors.forename: Qi-Long
authors.initials: QL
authors.lastname: Zeng
authors.affiliation: Nanjing University, School of Environment, State Key Laboratory of Pollution Control and Resource Reuse, Nanjing, Jiangsu Province, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yin
mesh_terms: D002523:Edible Grain; D004777:Environment; D004784:Environmental Monitoring; D008767:Methylmercury Compounds / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism*; D018514:Plant Structures; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D008767:Methylmercury Compounds; D012987:Soil; D012989:Soil Pollutants; C004925:methylmercuric chloride
keywords: Ammonium thiosulfate; Bioavailability; Chemical extraction; Methylmercury; Paddy soil