Evaluation of Heavy Metal Pollution in the Suame Industrial Area, Kumasi, Ghana

Abstract

Background. Heavy metal pollution in industrial and residential areas in cities has become a public health issue in Ghana. Anecdotal evidence suggests that most industrial areas have elevated levels of heavy metals in soil. As a result of poor zoning and unregulated activities, large sections of seemingly industrial areas are also used as residential areas. There have been no studies on the levels of heavy metal contamination in such mixed activity locations. Objectives. The study was undertaken to identify possible heavy metals and their concentrations in soil samples collected from the Suame Industrial Area, Kumasi, Ghana. Methods. Soil samples were collected, processed and the concentration of copper (Cu), lead (Pb), zinc (Zn), cobalt (Co) and chromium (Cr) were analyzed using X-ray fluorescence (XRF). Results. The concentration of all metals exceeded the threshold limit values (TLV). They also exceeded the European Soil Bureau Network (ESBN) maximum allowable limits (MAL), and are therefore considered to be pollutants. The results, expressed as mean concentration±standard deviation mg/kg (percent above TLV) were Pb: 414.83±159.38 mg/kg (418.9%), Cr: 264.84±189.15 mg/kg (353.1%), Co: 68.15±34.12 mg/kg (227.2%), Cu: 265.82±80.53 mg/kg (354.4%) and Zn: 3,215.84±4,074.54 mg/kg (1,607.9%). Furthermore, the concentrations of Pb and Co exceeded the United States Environmental Protection Agency (USEPA) residential soil regional screening levels (RSLs). Conclusions. The elevated metal concentrations found in the present study demonstrate that the site is heavily polluted with Pb, Co and Cr. This is attributed to unregulated activities at the site; therefore, measures should be put in place to ameliorate the effects of potential heavy metal toxicity to workers, local residents and the environment. Re-zoning of activities and clear demarcation of residential and industrial areas is advocated.