Quantification of pollution sources contribution on surface water resources of the Abaya-Chamo Lake Basin, Ethiopia: an integrated multivariate statistical analysis and a receptor model approach

ABSTRACT In this study, a water quality analysis was conducted at 24 surface water monitoring stations for 17 water quality parameters to investigate the spatial variability of the constituents, determine the possible sources of pollution and quantify the contribution of each identified source on individual parameters using multivariate statistical analysis (MSA) and the multivariate receptor model (MRM) conjunctively. Although most of the analysed water quality constituents were in the recommended water quality guideline standard, nutrient concentration at some of the monitoring stations was found above the permissible limit, making the water resources in the river basin prone to eutrophication and leaving the aquatic life completely at risk. On the other hand, based on factor analysis in the basin (which explained 86.9% of the total variance with four principal factors), agricultural (nutrient) waste is the dominant pollution source followed by ground water intrusion and mineral dissolution. Besides, the MRM analysis using the UNMIX model-assigned source contribution to individual parameters with a minimum signal-to-noise ratio (S/N) of 3.38 > 2 and R2 of 0.88 > 0.8. A coordinated land use management and continuous water quality monitoring could be a better approach to managing the increasing pollution level in the catchment.