Physico-chemical properties of borehole water and heavy metal contamination in soil near an open dumpsite in Giwo District, Bauchi, Nigeria.

Abstract

This study investigates the physico-chemical properties of borehole water and heavy metal contamination in soil near an open dumpsite in Giwo District, Bauchi. Environmental pollution from industrialization, urbanization, and inadequate waste management has contaminated soil and water with organic and inorganic matter, posing significant health risks. Water samples were analyzed using standardized APHA methods, including pH, temperature, colour, electrical conductivity, turbidity, total dissolved solids, dissolved oxygen, biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Most parameters met World Health Organization (WHO) and Nigerian Standard for Drinking Water Quality (NSDWQ) standards. However, BOD levels exceeded the WHO guideline of 5 mg/l, ranging from 12.20 ± 0.004 mg/l to 13.56 ± 0.005 mg/l, and COD levels surpassed the recommended limit of 200 mg/l, ranging from 251.60 ± 0.030 mg/l to 298.20 ± 0.003 mg/l, indicating significant organic pollution near the dumpsite. Soil samples were analyzed for eight heavy metals—Zinc (Zn), Iron (Fe), Copper (Cu), Cadmium (Cd), Chromium (Cr), Lead (Pb), Arsenic (As), and Manganese (Mn)—using Atomic Absorption Spectroscopy. The results showed low concentrations of heavy metals, with Index of Geo-accumulation (I_geo) values ranging from -1.6 to -17.0 and Contamination Factor (CF) values from 0.00 to 0.01, indicating minimal contamination. The Pollution Load Index (PLI) values were 0.0028, 0.0031, 0.0026, and 0.0025 for Giwo 01, Giwo 02, Giwo 03, and Giwo 04, respectively. These findings highlight the need for improved waste management practices to prevent further water contamination and elevated heavy metal levels in the Giwo District.