title: Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.
abstract: Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure.
authors.affiliation: Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China. Electronic address: duyanjun@seu.edu.cn.
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Du
authors.affiliation: Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China. Electronic address: weimingli830716@sina.com.
authors.forename: Ming-Li
authors.initials: ML
authors.lastname: Wei
authors.affiliation: Department of Civil & Materials Engineering, University of Illinois at Chicago, USA. Electronic address: kreddy@uic.edu.
authors.forename: Krishna R
authors.initials: KR
authors.lastname: Reddy
authors.affiliation: Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, China.
authors.forename: Zhao-Peng
authors.initials: ZP
authors.lastname: Liu
authors.affiliation: Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK. Electronic address: leonking1987@gmail.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Jin
mesh_terms: D015258:Acid Rain; D002118:Calcium / Q000032:analysis / Q000737:chemistry; D003252:Construction Materials; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000737:chemistry; D007854:Lead / Q000032:analysis / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D018505:Waste Management / Q000379:methods
chemical_list: D015258:Acid Rain; D012989:Soil Pollutants; D007616:Kaolin; D007854:Lead; D002118:Calcium
keywords: Acid rain; Diffusion coefficient; Dynamic leaching; Lead; Solidification/stabilization