Biochar-impacted sulfur cycling affects methylmercury phytoavailability in soils under different redox conditions
- Authors
- Wang, Yongjie; Zhang, Yue; Ok, Yong Sik; Jiang, Tao; Liu, Peng; Shu, Rui; Wang, Dingyong; Cao, Xinde; Zhong, Huan
- Issue Date
- 5-4월-2021
- Publisher
- ELSEVIER
- Keywords
- Mercury; Rice; Wheat; Bioavailability; Soil remediation
- Citation
- JOURNAL OF HAZARDOUS MATERIALS, v.407
- Indexed
- SCIE
SCOPUS
- Journal Title
- JOURNAL OF HAZARDOUS MATERIALS
- Volume
- 407
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/128261
- DOI
- 10.1016/j.jhazmat.2020.124397
- ISSN
- 0304-3894
- Abstract
- Recently, there has been increasing interest in reducing methylmercury (MeHg) phytoavailability using biochar, although the underlying mechanisms are not fully understood. By combining lab-scale batch incubation with pot and field validations, we demonstrate that biochar-impacted sulfur cycling in soils and MeHg-soil binding play key roles in controlling MeHg phytoavailability. (1) Under anoxic conditions, biochar-associated sulfate and biochar-facilitated microbial sulfate reduction enhanced the production of reduced inorganic sulfur species as acid-volatile sulfide (AVS) in soils by 122%, facilitating MeHg binding with soils and thus reducing MeHg phytoavailability. (2) In contrast, under oxic conditions, the reduced inorganic sulfur was oxidized (resulting in a 68-91% decrease in AVS), which released soil-bound MeHg and increased MeHg phytoavailability. The proposed mechanisms could explain the distinct effects of biochar amendment on MeHg bioaccumulation observed under anoxic (10-88% lower in rice grains) and oxic conditions (48-84% higher in wheat grains). Our results dispute the commonly held assumption that reduced MeHg phytoavailability under biochar amendment can be primarily attributed to MeHg-biochar binding. Therefore, the potential increased risk of MeHg in oxic soils following biochar amendment should be evaluated in more detail.
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Collections - College of Life Sciences and Biotechnology > Division of Environmental Science and Ecological Engineering > 1. Journal Articles
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