Groundwater quality assessment in the catchment area of Kadey (East-Cameroon): water quality index approach

Groundwater is considered an important water source for agricultural, drinking and domestic uses in many regions of the world including Cameroon. A study was conducted in 72 deep groundwater samples in the catchment area of Kadey, East-Cameroon to assess the quality of groundwater’s resources in this area through the water quality index (WQI). A water quality index summarizes the information from multiple water quality parameters into a single value that is understandable and usable by the public. This information can be used to assess spatial and temporal variations in overall water quality. The groundwater samples were randomly collected during 24 months between January 2019 and December 2020. Physicochemical characteristics such as pH, electrical conductivity, and some heavy metals were evaluated to estimate the groundwater quality for drinking water. It was found that the pH value ranges from 5.4 to 6.4, these values were below the recommendations of WHO drinking-water quality guidelines (6.5–8.5). Electrical Conductivity range from 92 to 1715 μS/cm and ORP range from 161 to 135 m/V. It was also found that the groundwater in the area is vulnerable to drink due to presence of arsenic, iron and manganese. The concentrations of arsenic were in the range between 0.003 and 0.137 mg/L. Iron was in the range 0.1–1.75 mg/L, and manganese was in the 0.35–1.75 mg/L. Arsenic, iron and manganese concentrations were, respectively, exceeded permissible WHO guideline value for drinking water. These high concentrations are mainly due to the semi-mechanized mining activities that are developing throughout most of the East-Cameroon region. Based on WQI values, the groundwater quality is unsafe for drinking, barring the elevated arsenic, iron and manganese content in certain areas. The high value of WQI is because of elevated concentration of iron and arsenic. The majority of the area is occupied by poor water in pre-monsoon and in post-monsoon period.