Rice straw returning enhances cadmium activation by accelerating iron cycling thus hydroxyl radical production in paddy soils during drainage

Hui Huang; Zhuoqi Tian; Di Guo; Zhixian Tang; Ronghua Li; Amjad Ali; Zhengxian Cao; Haiying Lu; Yu Shen; Yongli Zhu; Jiangang Han

doi:10.1016/j.scitotenv.2024.171543

Rice straw returning enhances cadmium activation by accelerating iron cycling thus hydroxyl radical production in paddy soils during drainage

Sci Total Environ. 2024 May 1:923:171543. doi: 10.1016/j.scitotenv.2024.171543. Epub 2024 Mar 6.

Authors

Hui Huang¹, Zhuoqi Tian², Di Guo³, Zhixian Tang⁴, Ronghua Li⁵, Amjad Ali⁶, Zhengxian Cao², Haiying Lu⁷, Yu Shen², Yongli Zhu², Jiangang Han⁸

Affiliations

¹ College of Ecology and Environment and Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, China. Electronic address: [email protected].
² College of Ecology and Environment and Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, China.
³ School of Petroleumn Engineering and Environmental Engineering, Yan'an University, Yan'an, Shaanxi 716000, China.
⁴ College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China. Electronic address: [email protected].
⁵ College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712100, China. Electronic address: [email protected].
⁶ School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, China. Electronic address: [email protected].
⁷ College of Ecology and Environment and Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, China. Electronic address: [email protected].
⁸ College of Ecology and Environment and Co-Innovation Center for the Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, Jiangsu 210037, China; School of Chemical Engineering and Materials, Changzhou Institute of Technology, Changzhou, Jiangsu 213032, China. Electronic address: [email protected].

PMID: 38453068
DOI: 10.1016/j.scitotenv.2024.171543

Abstract

Straw returning is widely found elevating the bioavailability of cadmium (Cd) in paddy soils with unclear biogeochemical mechanisms. Here, a series of microcosm incubation experiments were conducted and spectroscopic and microscopic analyses were employed. The results showed that returning rice straw (RS) efficiently increased amorphous Fe and low crystalline Fe (II) to promote the production of hydroxyl radicals (OH) thus Cd availability in paddy soils during drainage. On the whole, RS increased OH and extractable Cd by 0.2-1.4 and 0.1-3.3 times, respectively. While the addition of RS effectively improved the oxidation rate of structural Fe (II) mineral (i.e., FeS) to enhance soil Cd activation (up to 38.5 %) induced by the increased OH (up to 69.2 %). Additionally, the existence of CO₃^2- significantly increased the efficiency level on OH production and Cd activation, which was attributed to the improved reactivity of Fe (II) by CO₃^2- in paddy soils. Conclusively, this study emphasizes risks of activating soil Cd induced by RS returning-derived OH, providing a new insight into evaluating the safety of straw recycling.

Keywords: Bioavailability; Cd; Food safety; Free radical; Straw returning.

MeSH terms

Cadmium / analysis
Hydroxyl Radical
Iron / analysis
Oryza* / chemistry
Soil / chemistry
Soil Pollutants* / analysis

Substances

Cadmium
Soil
Iron
Hydroxyl Radical
Soil Pollutants