Heavy metals pollution indexing, geospatial and statistical approaches of groundwater within Challawa and Sharada industrial areas, Kano City, North-Western Nigeria

Abstract

Abstract The present study focused on pollution status of groundwater in the industrial areas of Challawa and Sharada in Kano city based on pollution indices, statistical and spatial analyses. Twenty groundwater samples representing groundwater of the studied areas (Ten from each area) were analyzed for the presence of Cd, Cr, Ni, Fe, Mn and Zn using atomic absorption spectrophotometer. The result showed 95%, 5%, 60%, 15% and 25% of the analyzed water samples had detectable Cd, Cr, Ni, Fe, and Mn above the drinking water limits of both Nigerian standards for drinking water quality NSDWQ and World Health Organization (WHO) with Cd dominating other analyzed heavy metals in the groundwater. Evaluation of heavy metal pollution revealed a low polluted status based on the contaminant index (Cd), synthetic pollution index, heavy metals evaluation index, and heavy metal pollution index. Metal index categorized the groundwater as seriously polluted. The statistical evaluation gave strong and positive correlations between indices and a moderate one between the metallic ions. Component analysis revealed a strongly positive loading of Fe, Ni and Zn while Cd had a strong negative loading. Cr and Mn were positive and moderately loaded. Statistical analyses suggested both anthropogenic and geogenic sources for the heavy metals mainly from the industrial and agricultural practices and rock weathering processes, respectively. This study is expected to be a useful tool in the planning, monitoring and mitigation of pollution activities in the area. Article Highlights The pollution status of groundwater with respect to heavy metals was investigated in the Challawa and Sharada industrials zones in Kano city Nigeria The concentration of Cd, Fe, Ni, Cr Mn and Zn was determined using the AAS Different Pollution indices of HPI, HEI, SPI, Cd and MI were utilized to categorized the area as low, medium and highly polluted. Spatial and temporal distribution maps demarcated based on the metal concentrations and computed indices in the area. CA, PCA, and HCA were used to identified the geochemistry, relationship, sources and origin of heavy metals in groundwater. The study revealed zones with low to high-risk groundwater in terms of toxic heavy metals and pollution status.