HEALTH RISK ASSESSMENT OF SOME HEAVY METALS AND PHYSICO-CHEMICAL QUALITY OF SURFACE WATER IN BIBIANI A MINING ENCLAVE IN GHANA

The quality of water is a powerful environmental determinant of health, increased productivity and enhanced economic development. Levels of As, Fe, Pb, Zn, and Cu were determined in both water and sediment samples within ten communities in Bibiani and its environs using the Atomic Absorption Spectroscopy. The results for most of the physiochemical parameters determined were below the WHO permissible limits with the exception of colour and turbidity. Cd, Pb, and Zn in water were below detection whereas As were in the range of 0.006 to 0.047 mg/l and Fe below detection to 2.00 mg/l. Pamuso had the highest As the level of 0.480 mg/l whilst Pataboso recorded the least value of 0.006 mg/l. Fe in two communities were above the limit but Cu was within the WHO limit. The mean levels of heavy metals in sediment obtained were in the range of: As (1.451 to 4.220); Cd (below detection to 1.104 mg/kg); Cu (below detection to 3.951 mg/kg); Fe (46.215 to 549.450 mg/kg); Zn (0.351 to 2.350 mg/kg) whilst Pb was below detection. The HI results in six communities were above the guidance value of 1.0 for adults and in all samples for children which is likely to pose risk to human health. Moreover, the CRing for As was above the USEPA guidance value of 1 x 10-6 in all the communities which imply consumers are likely to be exposed to cancer risk. The concentrations of As, Cd, Cu and Zn in the sediments were lower than the corresponding effect range low (ERL) values in the sediment quality guidelines and could have no adverse effects on aquatic organisms.