Journal of Earth Science & Climatic Change
Open Access

Abstract

Mine tailing pH play important role in controlling trace metal solubility and mobility, with most metals (in free ionic form) being most mobile in acidic mine tailings. The purpose of this experiment was to evaluate the sorption of lead (Pb) in an acid sulfide mine tailing (SMT) (pHCaCl2 2.8) amended with chicken eggshell residue (CES) or concrete cement (0, 20, 40, 60, 80 and 100 g kg-1 tailing). Tailing samples were equilibrated with 0 and 50 mg Pb L-1 in 0.01 M CaCl2 for seven days at room temperature. Afterwards, they were centrifuged and decanted. The supernatant solution was analyzed for Pb and calcium (Ca) by atomic absorption spectrophotometry and pH (pH e ). The cement application introduced high amount of Ca compounds and resulted in a great increase of the aqueous tailing pH (pH t ). On a weight basis CES has lower alkalizing power than cement in terms of its ability to neutralize acid or elevate pH t . The amount of Pb sorbed was positively correlated (P<0.01) with pH t , pH e and soluble Ca. The relationship between Pb sorbed and pHt was better described by a polynomial equation of degree 3 (R2 = 0.994). The differences in Pb sorption between mine tailing treatments were attributed to the pH t induced by calcareous amendment application. These results suggest that pH has a major effect on the sorption of Pb. Consequently, the SMT can sorb significant quantities of toxic metals from the mine drainage and surrounding environment, depending upon pH conditions.

Biography

Antoine Karam is a Professor of Environmental Soil Sciences and Head of the Department of Soils and Agrifood Engineering (2011-2019) at Laval University. He received his PhD (1986) in Soil Chemistry from Laval University, Québec, Canada. He is also the Director of graduate programs (soils and environment). In response to the years of dedicated to advancing the field of soil science in the province of Quebec, he was the recipient of the AQSSS Award (2007). He is currently conducting research on the development of bio-geowastes as soil amendments or sorbent materials for toxic metals in aqueous solution.