Immobilization of Cu and Cd in a contaminated soil: one- and four-year field effects |
| |
Authors: | Hongbiao Cui Jing Zhou Youbin Si Jingdong Mao Qiguo Zhao Guodong Fang Jiani Liang |
| |
Affiliation: | 1. Institute of Soil Science, Chinese Academy Sciences, 71st East Beijing Road, Nanjing, 210008, China 2. National Engineering Research and Technology Center for Red Soil Improvement, Red Soil Ecological Experiment Station, Chinese Academy of Sciences, Yingtan, 335211, China 3. University of Chinese Academy of Sciences, Beijing, 100049, China 4. School of Resources and Environment, Anhui Agricultural University, Hefei, 230036, China 5. Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA, 23529, USA
|
| |
Abstract: | Purpose Many amendments have been applied to immobilize heavy metals in soil. However, little information is available on the changes of immobilization efficiencies of heavy metals in contaminated soils over time. This work investigated the immobilization efficiencies of copper (Cu) and cadmium (Cd) in contaminated soils in situ remediated with one-time application of three amendments for 1 year and 4 years. Materials and methods Apatite, lime, and charcoal were mixed with the topsoil of each plot with the amounts of 22.3, 4.45, and 66.8 t/ha, respectively. Soil chemical properties and fractions of Cu and Cd were examined after in situ remediation for 1 year and 4 years. Soil sorption and retention capacities and desorption proportions for Cu and Cd were investigated by batch experiments. Results and discussion The addition of amendments significantly increased soil pH, but decreased exchange acid and aluminum (Al). The amendments significantly decreased the CaCl2 extractable Cu and Cd and transformed them from active to inactive fractions. After the application of amendments for 1 year, the maximum sorption capacities ranged from 35.6 to 38.8 mmol/kg for Cu and from 14.4 to 17.0 mmol/kg for Cd, which were markedly higher than those of the application of amendments for 4 years (Cu, 29.6–34.7 mmol/kg; Cd, 10.9–16.4 mmol/kg). Desorption proportions (D) of Cu and Cd using three extractants followed the order of ( {D}_{{mathrm{NaNO}}_3}<{D}_{{mathrm{CaCI}}_2}<{D}_{{mathrm{MgCI}}_2} ) . Moreover, the retention capacities (R) of Cu and Cd both increased and followed the order of R apatite?>?R lime?>?R charcoal, resulting in higher Cu and Cd in the amended soils than the untreated soil. Conclusions Apatite, lime, and charcoal increased the soil sorption and retention capacities of Cu and Cd and resulted in higher immobilization efficiencies in the amended soils than the untreated soil. However, the immobilization efficiencies of Cu and Cd decreased with the decrease of sorption capacities after 4 years. It was concluded that apatite had the best effect on the long-term stability of immobilized Cu and Cd and can be applied to immobilize heavy metals in contaminated soils. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|