Biochar affects methylmercury production and bioaccumulation in paddy soils: Insights from soil-derived dissolved organic matter  

作　　者：Siqi Zhang Mingxing Wang Jiang Liu Shanyi Tian Xueling Yang Guangquan Xiao Guomin Xu Tao Jiang Dingyong Wang 

机构地区：[1]Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin,Department of Environmental Sciences and Engineering,College of Resources and Environment,Southwest University,Chongqing 400716,China [2]State Key Laboratory of Environmental Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550002,China [3]Soil Ecology Laboratory,College of Resources and Environmental Sciences,Nanjing Agricultural University,Nanjing 210095,China [4]National Engineering Research Center for Compounding and Modification of Polymer Materials,Guiyang 550014,China [5]Guizhou Material Industrial Technology Institute,Guiyang 550014,China [6]Institute of Environment and Health,Jianghan University,Wuhan 430056,China

出　　处：《Journal of Environmental Sciences》2022年第9期68-77,共10页环境科学学报（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 41671469 and 41977275);the open funding (No. PTS2020-01) from PTS Key Laboratory of Hubei Province of Institute of Environment and Health, Jianghan University;the State Key Laboratory of Environmental Chemistry and Ecotoxicology (SKLECE) of Research Center for Eco-Environmental Sciences, Chinese Academy of Science (CAS), for the generous support of the open grant (No. KF2020-08);partially financially supported by the State Key Laboratory of Environmental Geochemistry open grant (No. SKLEG2021201) from the Institute of Geochemistry, Chinese Academy of Sciences (CAS);the Science and Technology Support Plan Project of Guizhou Province (No. 2019-2836)。

摘　　要：Biochar has been used increasingly as a soil additive to control mercury(Hg) pollution in paddy rice fields. As the most active component of soil organic matter, soil dissolved organic matter(DOM) plays a vital role in the environmental fate of contaminants. However, there are very few studies to determine the impact of biochar on the Hg cycle in rice paddies using insights from DOM. This study used original and modified biochar to investigate their effect on DOM dynamics and their potential impact on methylmercury(MeHg) production and bioaccumulation in rice plants. Porewater DOM was collected to analyze the variations in soil-derived DOM in paddy soils. The results showed that the addition of biochar, whether in original or modified form, significantly reduced the bioaccumulation of MeHg in rice plants, especially in hulls and grains( p < 0.05). However, MeHg production in soils was only inhibited by the modified biochar. Biochar addition induced a significant increase in DOM’s aromaticity and molecular weight( p < 0.05), which decreased Hg bioavailability. Furthermore, enhanced microbial activity was also observed in DOM( p < 0.05), further increasing MeHg production in the soil. Thus, the effect of biochar on the fate of Hg cycle involves competition between the two different roles of DOM. This study identified a specific mechanism by which biochar affects Hg behavior in rice paddy soil and contributes to understanding the more general influence of biochar in agriculture and contaminant remediation.

关 键 词：Dissolved organic matter Mercury METHYLMERCURY BIOCHAR Rice 

分 类 号：X144[环境科学与工程—环境科学]