Mining effluent impact on selected soil physical quality parameters in agricultural land Daba, Kwara State, Nigeria

Abstract

The study examined soils' physical, chemical, and selected soil water transmission properties in an unregistered mining community in Moro Local Government Area, Kwara State, North-Central Nigeria. The assessed agricultural lands based on the reconnaissance survey were 400 m and 800 m away from the mine site, and 1200 m (forested area) away from the mine site. A 25 m x 25 m plot was demarcated and replicated three times in each farmland and mining site. Soil samples were obtained from 0 to 15 cm soil layer at 5 m x 5 m subplot level and analyzed for particle size distribution, pH, organic C, total N, available P, exchangeable Ca²⁺, Mg²⁺, K⁺ and Na⁺, total acidity and selected heavy metals (Zn and Cu). Infiltration tests were run using the double-ring infiltrometer. Sixty soil core samples were collected from the study area to determine the water-holding capacity, bulk density, and hydraulic conductivity. The study showed that soil particles at mining sites were loamier and contained a significantly higher concentration of heavy metals but lesser concentrations of some soil nutrients than in the farmlands and the forested areas. The study also revealed that hydraulic conductivity and bulk density trends vary between 400 and 800 m from the mining site but within the recommended range of the soil-water transmission pathway. As a result, the mining effluent seems to have little impact on the water retention capacity of the soil's water transmission system, and plants growing in that region will not suffer a distorted soil water flow.