Concentration of Heavy Metals in Playground Soils Near Schools and Auto Mechanic Sites Along Busy Roads in Kaduna State, Nigeria

Abstract

 This study assessed the concentrations and interrelationships of heavy metals in soil samples collected from Kaduna North, Central, and South zones to evaluate potential contamination levels and implications for environmental health. A total of nine heavy metals—chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), tantalum (Ta), and lead (Pb)—were analyzed using standard procedures. Results indicated that Zn had the highest concentration across all zones, with a peak value of 327.50 mg/kg in Kaduna North, while the lowest recorded value was for Ni at 1.95 mg/kg in Kaduna Central. Pearson correlation analyses revealed strong positive correlations among several metals, particularly between Cu and Zn (r = 0.99), As and Zn (r = 1.00), and Pb and Zn (r = 0.99) in Kaduna North. In Kaduna Central, significant positive correlations were observed between Cr and As (r = 0.93), Cu and Pb (r = 0.90), and As and Zn (r = 0.95), while Ni showed a strong negative correlation with Pb (r = -1.00). In Kaduna South, nearly perfect correlations were found between Cr and Cu (r = 0.99), Zn and Cu (r = 0.98), and Fe and As (r = 0.99), indicating possible common anthropogenic sources. These results suggest widespread heavy metal contamination, potentially from industrial, vehicular, and agricultural activities. The presence of toxic metals like Pb, As, and Cr in elevated concentrations raises environmental health concerns and highlights the urgent need for regulatory interventions, continuous monitoring, and remediation strategies to protect both ecological systems and public health.