Hydro-geochemistry of groundwater and surface water in Dschang town (West Cameroon): Alkali and alkaline-earth elements ascertain lithological and anthropogenic constraints

Abstract

This study focuses on the sources of alkali and alkaline-earth elements based on the geochemistry of groundwater and surface water in Dschang concerning environmental and anthropogenic constraints. A comprehensive set of 50 samples from groundwater and surface water were analyzed by ICP-MS and processed by spatial interpolation in a GIS environment. The results highlight a geochemical anomaly at the center of the densely inhabited area subject to a profusion of open dumps discharges. This anomaly with the highest spatial contents of Be (Cs, Rb, Mg) suggests an anthropogenic source that demarcates with the lowest alkali and alkaline-earth elements on the peripheral area of Dschang. Other findings include lithological constraints with volcanic rocks being the main source compared to granitoid. The study points out good correlations between Be, Cs, Rb and Mg spatial distributions and physico-chemical parameters of waters (K, EC, TDS), and inversely with the lowest pH. pH is established as the most functioning physico-chemical constraint of alkali and alkaline-earth mobility in Dschang. The pH lowest values within the geochemical anomaly also highlight the impact of human activities on water acidity, which later enhance elements mobility and enrichment. Despite low elements contents relative to WHO standards, our findings point out an example of anthropogenic impact on water geochemistry linked to solid waste pollution; it also demonstrates significant anthropogenic changes of environmental physico-chemical parameters of prime importance in the mobility and distribution of elements in the study area. Similar assessments should be extended in major towns in Cameroon.

Keywords

• alkali/alkaline-earth elements
• groundwater and surface water
• geochemical anomaly
• anthropogenic impact
• dschang-cameroon