Sulfur-driven methylmercury production in paddies continues following soil oxidation  

作　　者：Wenli Tang Chao Tang Pei Lei 

机构地区：[1]School of the Environment,State Key Laboratory of Pollution Control and Resource Reuse,Nanjing University,Nanjing 210023,China [2]School of Environment,Nanjing Normal University,Nanjing 210023,China

出　　处：《Journal of Environmental Sciences》2022年第9期166-174,共9页环境科学学报（英文版）

基　　金：the financial support from the Natural Science Foundation of Jiangsu Province (Nos. BK 20190319 , BK20200322 );the National Natural Science Foundation of China (No. U2032201 )。

摘　　要：Methylmercury(MeHg) production in paddy soils and its accumulation in rice raise global concerns since rice consumption has been identified as an important pathway of human exposure to MeHg. Sulfur(S) amendment via fertilization has been reported to facilitate Hg methylation in paddy soils under anaerobic conditions, while the dynamic of S-amendment induced MeHg production in soils with increasing redox potential remains unclear. This critical gap hinders a comprehensive understanding of Hg biogeochemistry in rice paddy system which is characterized by the fluctuation of redox potential. Here, we conducted soil incubation experiments to explore MeHg production in slow-oxidizing paddy soils amended with different species of S and doses of sulfate. Results show that the elevated redox potential(1) increased MeHg concentrations by 10.9%-35.2%, which were mainly attributed to the re-oxidation of other S species to sulfate and thus the elevated abundance of sulfatereducing bacteria, and(2) increased MeHg phytoavailability by up to 75% due to the reductions in acid volatile sulfide(AVS) that strongly binds MeHg in soils. Results obtained from this study call for attention to the increased MeHg production and phytoavailability in paddy soils under elevated redox potentials due to water management, which might aggravate the MeHg production induced by S fertilization and thus enhance MeHg accumulation in rice.

关 键 词：MERCURY SULFUR AVAILABILITY Mercury methylation RICE 

分 类 号：X71[环境科学与工程—环境工程]