Structural equation modeling and GIS application into non-carcinogenic health risk assessment of the phreatic aquifers of the south-western coastal basin-Ghana

Abstract

The World Health Organisation (WHO) advocates the use of risk assessment together with risk management for the control of water safety in drinking water supplies. Groundwater has become important source of water supply for domestic use in Ghana. In the present study, sixty-five (65) constructed wells in the Dixcove Belt Granitoids (DBG) and Sandstone Mudstone Slate Carbonate (SMSC) geological formations of the Sekondi-Takoradi metropolis were investigated for their non-carcinogenic health risk state for children (0–6 years) and adults. The hazard index (HI) method was used as a measure of public health risk. The results indicated the HI values ranged from 4.58 × 10−2 to 111 × 10−2 and 18.5 × 10−2 to 226 × 10−2 for the adult category in the SMSC and DBG respectively. For the children category the HI values were 32.9 × 10−2 to 217 × 10−2 and 39.7 × 10−2 to 403 × 10−2 respectively. On individual well basis, 2.1% and 12.5% of wells have HI > 1 for adults in the SMSC and DBG respectively. In the children category the values were 29.2% and 50% respectively. Using the mean HI values, HI 1 for children (1.01 and 1.18 SMSC and DBG respectively) indicating a potential health risk. At the 95th percentile level, children were 66.79% and 64.28% more at risk than adults in the SMSC and DBG, respectively. Structural Equation Model and Point Pattern Analysis indicated, fluoride content accounted for the greater proportion of the human health risk for both adults and children.