Quantitative evaluation of the synergistic effect of biochar and plants on immobilization of Pb

Ping Sun; Youyuan Chen; Jiaxin Liu; Shuang Lu; Jiameng Guo; Zhiming Zhang; Xilai Zheng

doi:10.1016/j.jenvman.2022.115200

Quantitative evaluation of the synergistic effect of biochar and plants on immobilization of Pb

J Environ Manage. 2022 Aug 15:316:115200. doi: 10.1016/j.jenvman.2022.115200. Epub 2022 May 6.

Authors

Ping Sun¹, Youyuan Chen², Jiaxin Liu¹, Shuang Lu¹, Jiameng Guo¹, Zhiming Zhang³, Xilai Zheng³

Affiliations

¹ College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China.
² College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Marine Environment and Ecology, Ministry of Education of China, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China. Electronic address: youyuan@ouc.edu.cn.
³ College of Environmental Science and Engineering, Ocean University of China, Qingdao, 266100, China; Key Laboratory of Marine Environment and Ecology, Ministry of Education of China, Ocean University of China, Qingdao, 266100, China; Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering, Ocean University of China, Qingdao, 266100, China.

PMID: 35533595
DOI: 10.1016/j.jenvman.2022.115200

Abstract

Biochar and plant cooperation in remediation of heavy metal contaminated soil is effective and important, but there still have knowledge gaps of synergistic effect between the two and the synergistic pathway has not been clarified. We prepared the Enteromorpha prolifera biochar at 400 °C and 600 °C (denoted as BC400 and BC600). The Pb fractions changes in soil and Pb toxicity in Brassica juncea were investigated by adding 30 g kg^-1 biochar to soil containing 1200 mg kg^-1 Pb in a pot experiment. There was a significant synergistic effect between biochar and plants on Pb immobilization in soil, according to the "E > 0" of Pb fractions in the interaction equation. Pb immobilization rates of biochar-plant treatments (BJBC4 and BJBC6) were 12.47% and 11.38% higher than biochar treatment (BC4, BC6), and 17.66% and 16.28% plant treatment (BJ). BJBC4 had a better immobilization effect than BJBC6. Biochar alleviated the phytotoxicity of Pb by increasing the antioxidant enzymes activities of plants. These results indicated two synergistic pathways: (1) The high pH and oxygen-containing functional groups of biochar could immobilize Pb through ion exchange, precipitation, or complexation. (2) Biochar enhanced the activity of the antioxidant enzyme system in plants thus improving the Pb tolerance of plants. Statistical analysis methods such as the partial least squares path modeling (PLS-PM) also confirmed the pathways. In a word, clear synergistic effects and pathways could guide the application of biochar and plants in Pb-contaminated soil.

Keywords: Antioxidant system; Brassica juncea; Enteromorpha prolifera biochar; Pb immobilization; Pb phytotoxicity.

MeSH terms

Antioxidants
Charcoal
Lead
Plants
Soil
Soil Pollutants* / analysis

Substances

Antioxidants
Soil
Soil Pollutants
biochar
Charcoal
Lead