Investigation of Geochemical Characterization and Groundwater Quality with Special Emphasis on Health Risk Assessment in Alluvial Aquifers, South Africa

The Maputaland coastal plain of KwaZulu-Natal is one of the popular tourist areas in South Africa. Groundwater is the major source for drinking and irrigation purposes which is abstracted from unconsolidated aquifers having higher infiltration rate possibly increases the risk of aquifer contamination. Comprehensive study was conducted in 53 groundwater monitoring wells to identify the characteristic of water quality and processes controlling groundwater chemistry using multiple methods. Rock-water interaction and Na/Ca ion exchange are the dominant processes. Water quality index (WQI) varies from 18.9 to 157.1 with an average value of 45.55. Majority of the samples are classified as good, 22% as poor, 2% as very poor and 7% under unsuitable category, which are spatially distributed towards southern and western part of the study area. Health risk assessment of trace elements via ingestion and dermal absorption pathways was carried out. Hazard quotient through dermal absorption (HQ(dermal)) and hazard index (HI) for Co and Mn are above 1 in adults, children and infants. HQ(dermal) and HI for Cd are greater than 1 in children and infants. HQ(dermal) and HI for As and Pb are greater than 1 in infants. This implies that these metals pose serious to adverse health risk on people while infants are more vulnerable than children and adults. This study provides the baseline data on hydro geochemistry that can be utilised for further studies in future. This study recommends that groundwater in this region should be treated before utilisation and suggest that further extended studies should be conducted to explore more on groundwater resources in this area.

Automated summary

The Maputaland coastal plain of KwaZulu-Natal in South Africa is a popular tourist area, with groundwater being the major source for drinking and irrigation purposes. A comprehensive study was conducted in 53 groundwater monitoring wells, identifying dominant processes such as rock-water interaction and Na/Ca ion exchange. Water quality index (WQI) ranges from 18.9 to 157.1, with most samples classified as good but with spatial distribution variations. Health risk assessment of trace elements indicates potential adverse effects, especially on infants, suggesting the need for treatment before utilization and further extended studies on groundwater resources.