Groundwater Quality Investigation in the Coastal Aquifer of Limbe, South West Cameroon

Abstract

Coastal aquifers are vital fresh water reservoirs that could be affected by seawater intrusion, thereby polluting the water resources. This study investigated the current status of subsurface water in Limbe-Cameroon, focusing on aquifer hydrochemical characteristics. Groundwater samples were obtained from nine boreholes and measurements were conducted on the following physicochemical parameters; pH, electrical conductivity (EC), and total dissolved solids (TDS) and major ions (cations and anions). The results showed that most of the sampled boreholes were in the permissible limits of the World Health Organization (WHO) guidelines, except for a few samples. 11.11% of the pH values, 11.11% of the EC values and 11.11% of the TDS values the WHO recommended limits. Major ion concentrations were below WHO prescribed levels in all analysed samples. The water quality index (WQI) indicated that 44.44% of the samples were of good quality water with water quality values varying from 26-50, 11.11% were classified as poor-quality water and another 11.11% of the samples were unsuitable for drinking purposes. The hydrochemical facies were principally Ca-HCO3 and Ca-Mg-Cl-SO4 water types. Irrigation water quality indices such as sodium adsorption ratio (SAR), Magnesium Hazard (MH), soluble sodium percentage (SSP) indicated that groundwater in Limbe is suitable for irrigation. These higher values signify the possiblity of salt water intrusion in the study area and highlights the critical need for sustainable groundwater management in Limbe to prevent further degradation from seawater intrusion and protect the freshwater resources in the region.