Leachability, availability and bioaccessibility of Cu and Cd in a contaminated soil treated with apatite, lime and charcoal: A five-year field experiment.
This study evaluated the efficiency of apatite, lime and charcoal in regulating Cu and Cd leachability (toxicity characteristic leaching and synthetic precipitation leaching procedures), availability (CaCl2and MgCl2) and bioaccessibility (simplified bioaccessibility extraction test) in a heavy metal-contaminated soil. Both soil pH and soil organic carbon content were investigated during the five-year field study. The results showed that soil pH and soil organic carbon content increased with application of amendments, but decreased with time in both the control and amended plots. Moreover, the leachability, availability and bioaccessibility of Cu and Cd in amended soils all significantly decreased compared with the control, but increased over time. Pearson's correlation analysis showed that soil pH was significantly negatively correlated with the concentrations of available, leachable and bioaccessible Cu and Cd. Bioaccessible Cu and Cd were positively correlated with the concentrations of available and leachable Cu and Cd, but they were not significantly correlated with soil total Cu and total Cd. Stepwise multiple regression analysis indicated that the variability in bioaccessible Cu and Cd was well explained by MgCl2-extractable Cu, CaCl2-extractable Cd and pH, respectively. Although the longevity of amendments decreased with time, apatite was the most effective in decreasing the availability of Cu, compared with lime and charcoal. These findings provide valuable insights for risk management during long-term in situ immobilization of heavy metals in contaminated soils.
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
Hongbiao
H
Cui
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
Yuchao
Y
Fan
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy Sciences, Nanjing 210008, China.
Guodong
G
Fang
College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, China.
Houxi
H
Zhang
School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China.
Binbin
B
Su
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy Sciences, Nanjing 210008, China. Electronic address: zhoujing@issas.ac.cn.
Jing
J
Zhou
Amendment; Availability; Bioaccessibility; Heavy metal; Immobilization; Leachability