Hydrochemical Characteristics and Identification of Groundwater
Pollution Sources in Tropical Savanna
Abstract
Groundwater pollution of the watershed is mainly influenced by the
multifaceted interactions of geogenic and anthropogenic processes. In
this study, classic chemical and multivariate statistical methods were
used to assess the groundwater quality and identify the potential
pollution sources affecting the groundwater quality of Galma
sub-watershed in a tropical savannah. For this purpose, the dataset of
18 groundwater quality variables covering 57 different sampling
boreholes (BH) was used. The order of abundance of the main cations and
anions in the samples are Ca2+ > Na+ > Mg2+
> K+ and HCO3− > Cl− > SO4−2
> NO3− respectively. Piper diagram classified the
groundwater types of the watershed into mixed Ca–Mg–Cl type of water,
which means no cations and anions exceeds 50%. The second dominant
water type was Ca–Cl. The Mg–HCO3 water type was found in BH 9, and
Na–Cl water type in BH 29 respectively. Hierarchical cluster analysis
grouped the sampling boreholes into five statistically significant
clusters based on similarities of groundwater quality characteristics.
Principal component extracted two principal components that explained
around 65% of the total variance, which natural and anthropogenic
processes especially agricultural activities as the dominant factors
affecting the groundwater quality. The findings of this study are useful
to the policy and decision-makers for formulating efficient groundwater
utilization and management plans for the groundwater resources.