Bioaccessibility of arsenic, lead, and cadmium in contaminated mining/smelting soils: Assessment, modeling, and application for soil environment criteria derivation

• Published in: Journal of hazardous materials Vol. 443; p. 130321
• Main Authors: Xie, Kunting, Xie, Nangeng, Liao, Zhiyang, Luo, Xiaoshan, Peng, Weijie, Yuan, Yong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.02.2023
• Subjects: Mining/smelting soil; Potentially hazardous trace elements; Random forest model; Soil environment criteria; Random forest model; Potentially hazardous trace elements; Soil environment criteria; Mining/smelting soil
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.130321

Soil environment criteria (SEC) are commonly derived from the total concentration of pollutants in soils, resulting in overly stringent values. Herein, we examined the feasibility of deriving the SEC by using the bioaccessibility of pollutants. In this regard, soil samples from 33 locations at 12 mining/smelting sites in China were collected and examined in terms of soil properties, chemical fraction distributions, and bioaccessibilities of cadmium (Cd), lead (Pb), and arsenic (As). The gastric (GP) and intestinal phases (IP) of the potentially hazardous trace elements (PHEs) were measured by in vitro assays, showing that these values varied from 11 % to 72 %, 1–79 %, and 2–27 % for Cd, Pb and As, respectively. Pearson analysis showed that the GP and IP bioaccessibilities of these PHEs were mainly influenced by soil pH, CEC, and clay fraction and positively correlated with the sequential extraction form. The random forest regression (RF) model showed excellent performance in predicting the gastric phase (GP) bioaccessibilities of Cd, Pb, and As, with a mean R2 and RMSE of 0.86 and 0.31, respectively. Both the measured and predicted bioaccessibilities were feasible to be used to derive SEC. This work will contribute to the development of regional soil environmental standards based on bioaccessibility for Cd-, Pb-, and As-contaminated mining/smelting soils. [Display omitted] •The bioaccessibilities of Cd, Pb and As in 33 soils were determined with in vitro methods.•Random forest models were developed to predict the bioaccessibility of potentially hazardous trace elements.•The predicted potentially hazardous trace elements bioaccessibilities were suitable to induce soil environment criteria.