POLLUTION EVALUATION AND HEALTH RISK ASSESSMENT OF HEAVY METALS IN STREAM WATER AT EAST AKIM MUNICIPAL ASSEMBLY, GHANA

Abstract

Water contamination with toxic chemicals such as heavy metals continue to rise globally and particularly in developing countries due to mining, urbanization, and industrialization. In this study, a total of 10 stream water samples were collected from the mining environment. Physicochemical parameters such as pH and heavy metals; arsenic (As), chromium (Cr), nickel (Ni), and lead (Pb) were examined using standard procedures. The study assessed heavy metals concentrations, evaluated the pollution indices, and the health risk (carcinogenic and non-carcinogenic) for the populace (both adult and child) through direct oral intake and dermal contact of stream water in East Akim Municipal Assembly. The results of the concentrations of As (0.114 mg/kg), Cr (0.00000605 mg/kg), Ni (0.025 mg/kg), and Pb (0.257 mg/kg) revealed that they were within acceptable limits prescribed by World Health Organization (WHO) and Water guidelines. Heavy metal evaluation index (HEI) and degree of contamination (Cd) values obtained indicated that all the examined samples were categorized as low (Cd < 1 and HEI < 10). Non-carcinogenic risk indicated that stream water consumption via ingestion and dermal pathways were below the oral reference dose for their respective heavy metals indicating that both age groups may be ingesting safe levels of heavy metals. Furthermore, the non-carcinogenic risk assessment suggest that children are more susceptible to health threats than adults considering both exposure pathways. Also, the hazard quotient and hazard index were < 1 inferring that there is a tolerable degree of non-carcinogenic health risk for both adults and children in the research area. In addition, average values (1.86×10-5 and 7.12×10-5 for adults and children) obtained for the assessment of cancer risk (CR) for CRingestion were within the safe range of 1×10-6 to 1×10-4 while CRdermal contact average values (4.52×10-8 and 2.53×10-7 for adults and children) were above the range recommended by US Environmental Protection Agency. Regardless of the relatively safe indices recorded, precautionary measures are necessary to sustain the aquatic ecosystem and its quality. Efforts must be made to ensure that heavy metals that can pose health risks even in their low concentrations are monitored and kept as low as possible to ensure safety and reduced human health risks.