Contribution, absorption mode, and model prediction of atmospheric deposition to copper and lead accumulation in soybean

Min Li; Haotian Wang; Ziqi Chen; Hailong Liu; Huan Zhao; Xiuting Rong; Ruizhi Xia; Xiaozhi Wang; Jun Zhou

doi:10.1016/j.scitotenv.2024.177448

Contribution, absorption mode, and model prediction of atmospheric deposition to copper and lead accumulation in soybean

Sci Total Environ. 2024 Nov 11:957:177448. doi: 10.1016/j.scitotenv.2024.177448. Online ahead of print.

Authors

Min Li¹, Haotian Wang¹, Ziqi Chen¹, Hailong Liu², Huan Zhao¹, Xiuting Rong¹, Ruizhi Xia³, Xiaozhi Wang¹, Jun Zhou⁴

Affiliations

¹ College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225000, PR China.
² College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225000, PR China; State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China. Electronic address: liuhailong@yzu.edu.cn.
³ State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China.
⁴ State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China. Electronic address: zhoujun@issas.ac.cn.

PMID: 39521081
DOI: 10.1016/j.scitotenv.2024.177448

Abstract

Atmospheric deposition plays a significant role in the introduction of trace metals into agricultural ecosystems; however, accurately determining its impact on the accumulation of metals in crops remains a challenge. Here, the contribution, absorption mode, and model prediction of atmospheric deposition to trace metal accumulation in soybean were investigated by a three-year full factorial atmospheric and soil exposure experiment near a large copper (Cu) smelter. The results showed that newly deposited (one-year atmospheric deposition) metals only accounted for 0.2 %-14 % of total soil pools, while they contributed 8 %-77 % of Cu and 14 %-84 % of lead (Pb) in soybean plants. Meanwhile, the extension of soil exposure time to atmospheric deposition (two- and three-year atmospheric deposition) did not lead to significant increase in the bioavailable fraction of Cu and Pb in soil plough horizon and the bioaccumulation in soybean tissues. This suggested that the newly atmospheric deposition during the growth period was the key source of Cu and Pb in soybean plants. Furthermore, foliar absorption was an important pathway for metal accumulation in aboveground tissues as evidenced by its relative high contributions in metal bioaccumulation, i.e., 17 %-62 %, 26 %-70 %, 19 %-75 %, and 20 %-46 % of Cu and Pb in stem, leaf, hull, and seed, respectively. Besides, two models were developed to predict the Cu and Pb concentrations in soybean seeds using multiple regression analysis with atmospherically deposited metals and soil metals as variables. Compared with models based on a single variable, these models significantly improved the prediction accuracy of Cu and Pb concentrations in soybean seeds (adjusted R² = 0.936 and 0.995). The model prediction results suggested that the threshold value of atmospherically deposited Pb to ensure the safe production of soybean was 17.7 mg/m²/year. This study offers new insights into the effective management of metal pollution in soybeans, focusing on atmospheric deposition and foliar absorption.

Keywords: Atmospheric deposition; Factorial exposure experiment; Foliar absorption; Model prediction; Trace metals.