修正案
环境化学
土壤水分
稻草
水田
化学
生物利用度
Mercury(编程语言)
甲基汞
环境科学
环境工程
土壤科学
农学
生物累积
法学
无机化学
生物
程序设计语言
生物信息学
计算机科学
政治学
作者
Xu Yang,Zihao Li,Tantan Wang,Zhongzhu Yang,Xin Wen,Kun Yang,Yicai Huang,Wenhao Chen,Yubo He,Xiaohong Shi,Chang Zhang,Zhigang Yu
标识
DOI:10.1016/j.envres.2023.116127
摘要
Mercury (Hg) poses a significant risk in paddy fields, particularly when it is converted to methylmercury (MeHg) and accumulates in rice. However, the bioavailability and resupply kinetics of Hg in the paddy soil-water environment are not well understood. In this study, the diffusive gradients in thin films (DGT) and the 'DGT-induced fluxes in sediments' model (DIFS) were first adopted to investigate the Hg resupply kinetics, diffusion fluxes and bioavailability in a paddy environment subjected to flood-drain-reflood treatment and straw amendment. Our results show that although the straw amendment limited the bioavailability of Hg (38.2%-47.9% lower than control) in porewater by decreasing its resupply capacity, especially with smaller straw particles, the net production of MeHg in paddy fields was significantly increased after straw amendment (73.5%-77.9% higher than control). The results of microbial sequencing indicate that enhanced methylators (e.g., family Geobacter) and non-Hg methylators (e.g., Methanosarcinaceae) played a crucial role in MeHg production following straw amendment. Moreover, Hg-containing paddy soils generally tend to release Hg into the overlying water, while drain-reflood treatment changes the direction of Hg diffusion fluxes in the paddy soil-water interface. The drainage-reflooded treatment decreases the Hg reactive and resupply capacity of the paddy soil, thereby hindering the release of Hg from soil into overlying water during the early stages of reflooding. Overall, this study provides novel insights into the behavior of Hg in paddy soil-water surface microlayers.
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