Effects of fulvic acid and humic acid from different sources on Hg methylation in soil and accumulation in rice

作     者：Shu Ran Tianrong He Xian Zhou Deliang Yin Shu Ran;Tianrong He;Xian Zhou;Deliang Yin

作者机构：Key Laboratory of Karst Georesources and Environment(Guizhou University)Ministry of EducationGuiyang 550025China College of Resources and Environmental EngineeringGuizhou UniversityGuiyang 550025China Guizhou Karst Environmental Ecosystems Observation and Research StationMinistry of EducationGuiyang 550025China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2022年第34卷第9期

页      面：93-105页

核心收录：

学科分类：0710[理学-生物学] 082803[工学-农业生物环境与能源工程] 07[理学] 08[工学] 0828[工学-农业工程] 0818[工学-地质资源与地质工程] 0903[农学-农业资源与环境] 0703[理学-化学] 0901[农学-作物学] 0713[理学-生态学] 

基　　金：supported by Science and Technology Project of Guizhou Province (Nos. QKHZC4Y031 QKHJC1Y187 ) the Natural Science Foundation of China (Nos. 41763017 42007305 ) the Program Foundation of Institute for Scientific Research of Karst Area of NSFC-GZGOV (No. U1612442 )。 

主　　题：Humic acid Fulvic acid Methylmercury Accumulation Rice 

摘      要：Humus is often used as an organic modifier to reduce the bioaccumulation of heavy metals in plants, but the effects of different humus components from different sources on the fate of mercury(Hg) in paddy fields are still unclear. Here, fulvic acid(FA) and humic acid(HA) extracted from composted straw(CS), composted cow dung(CCD), peat soil(PM) and lignite coal(LC) were used to understand their effects on the methylation and bioaccumulation of Hg in paddy soil by pot experiments. Amendments of both FA and HA largely increased the abundance of Hg-methylating microbes and low-molecular-weight organic matters(e.g, cysteine) in paddy soil. They were also found to change the aromaticity, molecular size and Chromophoric DOM concentration of DOM, and resulted in heterogeneous effects on migration and transformation of Hg. All the FA-amended treatments increased the mobility and methylation of Hg in soil and its absorption in roots. Nevertheless, FA from different sources have heterogeneous effects on transport of Hg between rice tissues. FA-CCD and FA-PM promoted the translocation of Me Hg from roots to rice grains by 32.95% and 41.12%, while FA-CS and FA-LC significantly inhibited the translocation of inorganic Hg(IHg) by 52.65% and 66.06% and of Me Hg by 46.65% and 36.23%, respectively. In contrast, all HA-amended treatments reduced the mobility of soil Hg, but promoted Hg methylation in soil. Among which, HA-CCD and HA-PM promoted the translocation of Me Hg in rice tissues by 88.95% and 64.10%, while its accumulation in rice grains by 28.43% and 28.69%, respectively. In general, the application of some FA and HA as organic modifiers to reduce Hg bioaccumulation in rice is not feasible.