Assessment of Heavy Metal Concentrations and Textural Properties of Soils in The Southern Part of Kebbi State, Nigeria

Agricultural soils are increasingly vulnerable to heavy metal contamination, which may threaten food security, ecosystem quality and human health. This study assessed heavy metal concentrations and soil textural properties in the southern part of Kebbi State, Nigeria. A multistage sampling technique was used to collect 48 composite soil samples from four Local Government Areas (LGAs): Zuru, Danko Wasagu, Yauri and Shanga. Particle-size distribution was determined using the hydrometer method. Cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), lead (Pb) and zinc (Zn) concentrations were determined using atomic absorption spectrophotometry (AAS). The data were subjected to analysis of variance (ANOVA), and means were separated using Duncan’s New Multiple Range Test (DMRT). The soils were generally sandy loam in texture. The overall mean concentrations of the analysed metals were 3.2375 mg/kg for Cd, 0.0597 mg/kg for Cu, 15.435 mg/kg for Fe, 2.8463 mg/kg for Mn, 0.1808 mg/kg for Pb and 0.3056 mg/kg for Zn. The mean Cd concentration exceeded the NESREA limit of 3.00 mg/kg reported in the study, whereas the other reported metal concentrations were below the comparison limits presented. Most of the measured heavy metals were below the comparison limits used in this study. However, the overall mean Cd concentration exceeded the stated NESREA limit, indicating the need for further investigation and regular monitoring. The soils were predominantly sandy loam, although the textural classification reported for Shanga LGA differed from that of the other LGAs.