Characterization of Heavy Metals from a Contaminated Industrial Site

Abstract

Soil contamination due to heavy metals has become a global problem. The knowledge of heavy metal speciation in soils must be understood for the rational investigation of risk and remediation of contaminated soils. This study presents a systematic investigation of an industrial site soil, known as Jarosite, which is obtained from a zinc smelter. The soil was found to be clayey soil with low to medium consistency, with organic content of 2.13% and pH of 5.59. The total heavy metals in the soil were determined using acid digestion procedure, and TCLP (toxicity characteristic leaching procedure) tests were also conducted for understanding the leachable metals from the soil. The total concentrations of heavy metals were found to be: zinc (Zn) = 13653 mg/kg, lead (Pb) = 6871 mg/kg, cadmium (Cd) = 1371 mg/kg, copper (Cu) = 128 mg/kg, nickel (Ni) = 37 mg/kg, arsenic (As) = 19 mg/kg, and cobalt (Co) = 13 mg/kg. TCLP concentrations were found to be: Zn = 1263 mg/kg, Pb = 503 mg/kg, and Cd = 251 mg/kg. The total heavy metals and TCLP metals are found to exceed the allowable limits, hence remediation action is required. Stabilization/solidification is considered to be promising technology to use for the site conditions.