Double-edged effects of elevating temperature on the aging of exogenous arsenic in flooded paddy soils

Xiayun Zang; Xingxiang Wang; Zhengfu Yue; Zhigao Zhou; Taolin Zhang; Changfeng Ding

doi:10.1016/j.jenvman.2022.115336

Double-edged effects of elevating temperature on the aging of exogenous arsenic in flooded paddy soils

J Environ Manage. 2022 Aug 15:316:115336. doi: 10.1016/j.jenvman.2022.115336. Epub 2022 May 21.

Authors

Xiayun Zang¹, Xingxiang Wang², Zhengfu Yue³, Zhigao Zhou⁴, Taolin Zhang³, Changfeng Ding⁵

Affiliations

¹ CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; Soil Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
² CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Ecological Experimental Station of Red Soil, Chinese Academy of Sciences, Yingtan, 335211, China.
³ CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
⁴ CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
⁵ CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address: cfding@issas.ac.cn.

PMID: 35658266
DOI: 10.1016/j.jenvman.2022.115336

Abstract

Temperature variation can have a significant impact on arsenic (As) bioavailability in paddy soils. However, details regarding the transformation of exogenous As during the aging process in paddy soils at various temperatures remain unclear. This work investigated the effects of temperature on the As extractability and As species transformation of three paddy soils spiked with exogenous arsenate at 60 mg kg^-1 under flooded aging and explored the related chemical and microbial mechanisms. The results showed that 0.05 M NH₄H₂PO₄-extractable As decreased over time during flooded aging for 192 days, and it decreased by approximately one-third at 35 °C compared with 15 °C and 25 °C at the same aging time, indicating that higher temperatures facilitated the decrease in As extractability. As(V) reduction mainly occurred at 35 °C because the abundance and As(V)-reducing capacity of the predominant indigenous bacteria, the Bacillus sp strains, and the abundance of the arrA gene were significantly higher than those at 15 °C and 25 °C. The reduction of As(V) to As(III) and aging occurred simultaneously. The kinetic models were established, and the rate constants of the reduction and aging processes were obtained. Soil properties significantly affected the aging and reduction processes of extractable As(V). Our study indicated that elevating temperature had dual effects on the environmental risk of As in the flooded aging process. The previous definition of "aging" based on cationic metals needs to be updated according to the transformation characteristics of As species in flooded conditions. Our results addressed the necessity of impeding the reduction of As(V) in paddy soils under global warming.

Keywords: Aging and reduction kinetics; As availability; Microbial reduction; Paddy soil; Temperature.

MeSH terms

Arsenic* / chemistry
Oryza*
Soil / chemistry
Soil Pollutants* / analysis
Temperature

Substances

Soil
Soil Pollutants
Arsenic