title: Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil.
abstract: Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia. Environ Toxicol Chem 2017;36:1202-1210. © 2016 SETAC.
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Kasun S
authors.initials: KS
authors.lastname: Abeysinghe
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Yang
authors.affiliation: College of Forestry, Guangxi University, Nanning, Guangxi, China.
authors.forename: Eben
authors.initials: E
authors.lastname: Goodale
authors.affiliation: Soil and Earth Sciences, Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand.
authors.forename: Christopher W N
authors.initials: CWN
authors.lastname: Anderson
authors.affiliation: Department of Earth Sciences, Uppsala University, Villavägen, Uppsala, Sweden.|Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelmsväg, Uppsala, Sweden.
authors.forename: Kevin
authors.initials: K
authors.lastname: Bishop
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.|School of Chemistry and Material Sciences, Guizhou Normal University, Guiyang, China.
authors.forename: Axiang
authors.initials: A
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
authors.forename: Xinbin
authors.initials: X
authors.lastname: Feng
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, China.|University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Shengjie
authors.initials: S
authors.lastname: Liu
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, China.
authors.forename: Christos
authors.initials: C
authors.lastname: Mammides
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Meng
authors.affiliation: Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, China.
authors.forename: Rui-Chang
authors.initials: RC
authors.lastname: Quan
authors.affiliation: College of Resources and Environmental Sciences, Nanjing Agricultural University, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China.
authors.forename: Guangle
authors.initials: G
authors.lastname: Qiu
mesh_terms: D000383:Agriculture; D000818:Animals; D004784:Environmental Monitoring; D008628:Mercury / Q000032:analysis*; D008767:Methylmercury Compounds / Q000032:analysis*; D008906:Mining; D009835:Oligochaeta / Q000737:chemistry* / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis*
chemical_list: D008767:Methylmercury Compounds; D012989:Soil Pollutants; D008628:Mercury
keywords: Biomagnification; Earthworms; Ecotoxicology; Mercury biomonitoring; Soil contamination