Kaolinite reduced Cd accumulation in peanut and remediate soil contaminated with both microplastics and cadmium

Xin Song; Jianpeng Jin; Haiyun Li; Fangli Wang; Jun Liu; Xuexia Wang; Xiaoli Huang; Chao Chai; Ningning Song; Haiying Zong

doi:10.1016/j.ecoenv.2023.115580

Kaolinite reduced Cd accumulation in peanut and remediate soil contaminated with both microplastics and cadmium

Ecotoxicol Environ Saf. 2023 Nov 1:266:115580. doi: 10.1016/j.ecoenv.2023.115580. Epub 2023 Oct 19.

Authors

Xin Song¹, Jianpeng Jin¹, Haiyun Li², Fangli Wang¹, Jun Liu¹, Xuexia Wang³, Xiaoli Huang⁴, Chao Chai¹, Ningning Song⁵, Haiying Zong⁶

Affiliations

¹ Qingdao Engineering Research Center for Rural Environment/School of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, PR China.
² Jingtanggang Branch of Technology Center of Shijiazhuang Customs District, Shijiazhuang 050011, PR China.
³ Institute of plant nutrition and resources, Beijing Agricultural Forestry Academy Sciences, Beijing 100097, PR China.
⁴ Central Laboratory, Qingdao Agricultural University, Qingdao 266109, PR China.
⁵ Qingdao Engineering Research Center for Rural Environment/School of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, PR China. Electronic address: snn05@163.com.
⁶ Qingdao Engineering Research Center for Rural Environment/School of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, PR China. Electronic address: u571zhy@126.com.

PMID: 37864965
DOI: 10.1016/j.ecoenv.2023.115580

Abstract

Microplastics (MPs) increase the effective state of heavy metals (HMs) in soil and seriously threaten the yield and quality of peanuts (Arachis Hypogea L.). Kaolinite (KL) has the potential to ameliorate MP- and HM- contaminated soils, but the mechanism of action between them is not well understood. Therefore, 60-day experiments were conducted, where KL (1 %, 2 %) and MPs (0.1 %, 1 %) were individually or jointly mixed into soils with different cadmium (Cd) concentrations (0.5, 2.5, and 5.0 mg·kg^-1) to cultivate peanuts in a greenhouse. Finally, soil-bioavailable Cd, peanut dry weight, peanut Cd concentrations, the pH, cation exchange capacity (CEC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) were determined. It was shown that MPs negatively affected the peanut dry weight and increased the content of soil-bioavailable Cd and Cd concentration in peanut. In the MP- and Cd-contaminated soils, KL mitigated the negative influence of MPs by increasing the dry weight of peanuts by 8.40 %-40.59 %, decreasing the soil-bioavailable Cd by 23.70-35.74 %, and significantly decreasing peanut Cd concentrations by 9.65-30.86 %. The presence of MPs decreased soil pH (7.69-7.87) and the CEC (20.96-23.95 cmol·L^-1) and increased the soil DOC (1.84-2.26 mg·kg^-1). KL significantly increased soil pH (7.79-8.03) and the CEC (24.96-28.28 cmol·L^-1) and mitigated the adverse influence of MPs on the pH and CEC of Cd-contaminated soils. A regression path analysis (RPA) evidenced that KL decreased Cd accumulation in plants by changing the properties of soil contaminated with MPs and Cd. The research results revealed the mechanism of KL on peanut growth and Cd absorption in MP- and Cd-contaminated soil. The results of this study provide a foundation to improve the quality of MP- and HM-contaminated soils and realize safe peanut production.

Keywords: Cadmium accumulation; Heavy metals; Kaolinite; Microplastics; Peanut; Soil quality.

MeSH terms

Arachis / chemistry
Cadmium* / analysis
Kaolin
Microplastics
Plastics
Soil / chemistry
Soil Pollutants* / analysis

Substances

Cadmium
Soil
Microplastics
Plastics
Kaolin
Soil Pollutants