Assessment of Soil, Surface Water, and Food Crop Quality around Municipal Waste Dumpsites in Abakaliki, Southeastern Nigeria

Abstract

Uncontrolled waste dumpsites can contribute to environmental degradation, particularly in rapidly urbanizing areas where waste management practices are inadequate. This study assessed the physicochemical characteristics and elemental concentrations of soil, surface water, and selected food crops around municipal waste dumpsites in Abakaliki, southeastern Nigeria. Soil, surface water, and food crop samples were collected from selected locations around the Umuoghara, Rice Mill, and Mechanic Village dumpsites and analysed using standard laboratory procedures. Physicochemical parameters were determined using standard analytical methods, while elemental concentrations were quantified using Atomic Absorption Spectrophotometry (AAS). Descriptive statistics and Pollution Index (PI) assessment were used to characterize the measured concentrations and compare elements with applicable environmental benchmarks. The soils were slightly acidic (pH 5.98–6.10) and generally non-saline, while surface water pH ranged from 6.47 to 6.67, with relatively low electrical conductivity and total dissolved solids. Several elements, including Fe, Hg, Cd, Ni, Pb, and Cu, exceeded applicable Nigerian surface water criteria at one or more sampling locations, whereas the measured soil elemental concentrations were below the selected Canadian Council of Ministers of the Environment (CCME, 2007) agricultural soil guideline values for elements with applicable benchmarks. Food crop samples contained measurable concentrations of the analysed elements; however, the limited number of composite crop samples and absence of field replication restricted broader interpretation of crop variability and food safety implications. The PI results indicated exceedances for several individual elements in surface water, while soil values were comparatively lower for elements with available benchmark criteria.  The findings suggest that the investigated dumpsite environments warrant continued environmental monitoring and improved waste management, including appropriate disposal practices and effective leachate management. Further spatially replicated and seasonal investigations are recommended to better establish contaminant sources, transport pathways, and potential human-health implications.