Assessment of the quality of the Densu river using multicriterial analysis and water quality index

Samuel Nii Odai,Samuel Anim Ofosu,Kwaku A. Adjei

doi:10.1007/s13201-021-01516-z

Abstract

The natural resources, especially water in the Densu river basin, play significant roles in the socio-economic development of Ghana. The purpose of this study was to analyse the water quality of the Densu river using water quality index (WQI) and multivariate techniques. In this study, physico-chemical and bacteriological parameters were measured from surface water samples taken from eight (8) sampling stations in the study area. water quality index and multivariate techniques such as hierarchical cluster analysis and principal component analysis were utilized in the analysis of surface water quality data. The results indicated that the average WQI of the Densu river for the two sampling periods was sixty-one (61) which is classified as Medium, based on the Solway WQI index. The pH levels of all the samples were within allowable limits of World Health Organization (WHO) guidelines. All the sampling stations for the two seasonal periods had bacteriological parameters higher than WHO guidelines, making the samples unsuitable for most domestic uses. The study revealed that six (6) principal components accounted for about 97% of the total variance of dataset and three (3) spatial clusters were classified. This research has provided the basis for applying both WQI and multivariate techniques in analysing and classifying water quality in a river basin.

Highlights

Freshwater resources have come under the spotlight due to quantity and quality reasons
PC1 for dry season had strong positive loadings of conductivity (0.991), total dissolved solids (TDS) (0.991), total hardness (0.760), calcium hardness (0.600), chloride (0.816), calcium (0.700), magnesium (0.647), total coliforms (0.857), E. coli (0.873) and heterotrophic bacteria (0.923). These results show that electrical conductivity, TDS and the bacteriological parameters greatly influenced the quality of the river
The results of principal component analysis (PCA) revealed that six (6) factors accounted for about 97% of the dataset variances for both wet and dry sampling seasons

Summary

Introduction

Freshwater resources have come under the spotlight due to quantity and quality reasons. Surface water resources have been noted to be extremely sensitive to changing natural processes such as rainfall, temperature, forest cover and climate change (Li et al 2009; Usman et al 2014; Wang et al 2018). These changes in natural environmental processes are greatly influenced by anthropogenic activities that include growth in urban areas and agricultural activities (Khatri and Tyagi 2015; Bouguerne et al 2017; Verma et al 2019). High concentrations of toxic materials from pollution sources could lead to diverse environmental challenges such as loss of

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Conclusion