Assessment of Groundwater Quality and Health Risk of Heavy Metals: A study from the Tarkwa Mining Area, Ghana
Identification of water types and classification of natural waters has varied between researches in the world. This study seeks to evaluate the hydrogeochemical characteristics of water in the Tarkwa mining area using the Piper and Chadha plots and to carry out a health risk assessment using the USEPA health risk assessment model. A total of 39 groundwater sample points were used for this study. Results from the Piper and Chadha diagrams show that the dominant water types in the study area are Ca-HCO3 and Mixed Ca-Mg-Cl water types which indicates that groundwater in the area can be classified as fresh water. The hazard quotient (HQ) value for heavy metals estimated, suggested an acceptable level of noncarcinogenic inimical health risk. In relation to the HQ value, the Hazard Index (HQ) calculated was less than 1 suggesting that inhabitants will not be exposed to a potential health risk for the injection of heavy metals. Carcinogenic risk estimated for As (1.80×10-4) was higher than the acceptable risk. The carcinogenic risk estimated therefore indicated that, drinking of groundwater over a long period will increase the probability of cancer. It can be concluded that currently the groundwater in the Tarkwa area is safe for domestic purposes.