Trace metals in the topsoil of Kandahar region, Afghanistan and their associated health and ecological risk

In urban regions, surface dust and topsoil can be used as indicators of metal pollution. Numerous studies have been conducted in different locations throughout the world to assess metal pollution and associated environmental and human health risks, but none have been conducted in Afghanistan's Kandahar region. The purpose of this study is to examine the environmental and health risks of metal concentrations (As, Cd, Co, Cr, Cu, Ni, Pb, V, and Zn) in topsoil samples of sampling site. The average metal concentrations in the topsoil slightly exceeded their corresponding background values in Upper Continental Crust (UCC). Top soil samples showed low contamination for Cd, Co, Cr, Cu, Ni, Pb, V, Zn and considerable to very high contamination for As. Pollution load indices (PLI) demonstrated that all sampling sites are at a high load of metal pollution (PLI >1) indicating deterioration of soil quality.  

According to Geo-accumulation Index (Igeo), topsoil samples fall under uncontaminated category for Co, Cr, Cu, Ni, Pb, V, Zn and moderately to heavily contaminated for Cd and heavily to extremely contaminated for As. Ecological risk values suggested that study area had low risk for Co, Cr, Cu, Ni, Pb, V, Zn while considerable to high risk for Cd and high to very high risk for As. According to the health risk assessment, ingestion is the major pathway for non-carcinogenic risk and children are at more risk as compared to adults. Fall outs of high ammunition usage, wear and tear of heavy duty vehicles and fossil fuel consumption seems to be responsible for the high levels of metals in topsoil of Kandahar region. More such studies need to be conducted with more spatial coverage to identify contaminated areas and subsequent remediation to safeguard human health and ecosystem.