Assessment of some heavy metals from municipal wastewater used for irrigation in Nigeria

Abstract

Heavy metal contamination in soil and accumulation in cultivated vegetables is currently a serious and disturbing ecological problem prevalent throughout the world most especially in areas with water scarcity. The study was carried out to assesses the presence of heavy metals from a municipal waste water source used for irrigation in Unguwar kudu, Dutsinma Katsina state Nigeria. This study assessed the quality of irrigation water in terms of pH, electrical conductivity (EC), total dissolved solids (TDS), and heavy metal concentrations (cadmium, lead, nickel, and chromium). The results showed that the water is slightly alkaline (mean pH 7.5) and has medium salinity (mean EC 1.17 dS/m), which may affect sensitive crops. TDS levels were within permissible limits (mean 845 mg/L). However, heavy metal analysis revealed significant contamination: cadmium (mean 0.0226 mg/L) and lead (mean 0.9008 mg/L) levels exceeded WHO/FAO limits by 2-18 times, posing risks to soil, crops, and human health. Chromium levels were also high (mean 1.626 mg/L), more than 16 times the permissible limit, while nickel levels were relatively low (mean 0.0278 mg/L). These findings suggest potential health and environmental risks associated with using this water for irrigation, emphasizing the need for regular monitoring and mitigation strategies.

Keywords: Heavy metals, irrigation water, contamination, savannah