Multidimensional Analysis of the Contamination Status, Corrosivity and Hydrogeochemistry of Groundwater from Parts of the Anambra Basin, Nigeria

Abstract

Groundwater samples from five rural agricultural villages within the Anambra basin of southeastern Nigeria were selected for the determination of their drinking quality, hydrogeochemical characteristics, corrosivity and scaling potentials. The groundwater temperature ranged from 10 to 31 °C. The pH measurements revealed that the samples are acidic. Parameters such as total dissolved solids, electrical conductivity, magnesium, calcium, sodium, chloride, bicarbonate, sulfate and nitrate recorded scores within their respective standard limits. However, potassium and phosphate pollution was observed in some samples. Synthetic pollution index was used to summarize the drinking water quality of the samples. The results showed that 88% of the samples were moderately polluted while 12% were highly polluted. Thus, the results show that they have questionable drinking water quality. Several indices used for corrosivity and scaling analyses indicated that, although the samples pose low risk of scaling (encrustation), they are severely aggressive. Hence, they are likely to deteriorate metallic water storage and distribution facilities in the study area. The predominant water facies are Cl·SO4–Ca·Mg and Cl·SO4–Na·K. Multiple hydrogeochemical and chemometric analytical models were integrated to better unravel and understand the geochemical history, processes and evolution of the groundwater. All of the models used jointly indicated that mixed, multiple processes, namely mineral-rock weathering, ionic exchange processes and anthropogenic inputs, are responsible for the predominant hydrogeochemistry observed in the study area. However, in this regard, natural, geogenic processes were identified as more important factors than those from anthropogenic activities.