Assessment Of Health Risks Due To Toxic Metals And Naturally Occurring Radioactive Materials In The Birim River In East Akim Municipality Of The Eastern Region Ghana

Abstract

A detailed study has been carried out to determine the health risk associated with the level of trace metals and naturally occurring radioactive materials in the Birim River in East Akim Municipality of the Eastern Region of Ghana. The river runs through several communities in the municipality and serves as the main source of drinking water, irrigation and for domestic purposes. However, small-scale mining activities in the area are deteriorating the quality of the river water. Results of the study show that water from the Birim River is polluted with respect to Hg, As and Fe. The most polluted sampling points were Adadientem and Kibi. Turbidity levels in water samples were between 2 – 708 NTU. Results from Principal Component Analysis/Factors Analysis (PCA/FA) analyses in November suggest high loading of phosphate (0.934) and chloride (0.802). High level of Hg was recorded in sediment samples from Adadietem (Ad-1) (0.4 mg/kg), KTC-6, (0.775 mg/kg), Kyebi Training College (KDS-5), (0.55 mg/kg), Bonsu-Accra Road (B-AR-10) (0.575 mg/kg) and Bonsu Bridge (BB-8) (0.4 mg/ kg) while at all the sampling points, high levels of As and Fe were recorded. As levels ranged between 8.40 mg/kg and 16.25 mg/kg while mean Fe levels were 821.62 – 837.81 mg/kg. Health risk assessment shows that Fe, Mn, As, Zn and Hg metals were the main contributors for ingestion and dermal exposures to the human environment in the river. The levels of Hazard Quotient (HQing) for As was greater than one, indicating that it could have harmful effects on human health. This is an indication that risk may occur via the ingestion of contaminated water in the municipality. As, Fe, Hg, Mn and Cr were found to be the main contributors to non-carcinogenic risk (HI) from the Birim River in Kibi Municipality. Carcinogenic risk (CRing) was found to be associated with the slight elevated value of As. The calculated average activity concentration of 232Th was higher than WHO guidance level of 1.0 Bq/L in water. The mean annual effective doses of the two periods in the various communities had values lower than the WHO recommended value of 0.10 mSv/year. Cancer risk to adult in water for November and February is 2.25×10-6 and hereditary effect is 4.41×10-7. Estimated results of the lifetime risk among adult member of the Kibi Municipality are within the range of acceptable risk values recommended by USEPA.