Assessment of the environmental impact of gemstone mining on vegetation and soil in the Egbeda mine site, Saki, Nigeria

Abstract

Gemstone mining, though economically valuable, poses environmental risks by altering soil properties and introducing heavy metals into ecosystems. In Egbeda, Saki, Nigeria, pollutants like zinc, copper, lead, and arsenic accumulate in soil and plants, negatively affecting plant health and soil fertility. This study investigates the extent of heavy metal contamination at the Egbeda mining site to inform ecological remediation and ensure sustainability. Random samples of soil and plants (Scleria depressa) were collected from the mining and control sites for analysis. The study evaluated physical and chemical soil properties (pH, conductivity, porosity, bulk density, organic carbon, nitrogen, cation exchange capacity) as well as heavy metal concentrations, including zinc, copper, arsenic, lead, chromium, cadmium, and nickel. Atomic Absorption Spectroscopy (AAS) Buck Technique, involving incineration and wet digestion was used to determine metal concentrations. Results, assessed via an independent Student's T test, revealed that Zinc showed the highest concentration in the soil (1.3870 mg/kg at the mining site and 1.2090 mg/kg at the control), while cadmium had the lowest (0.5000 mg/kg at the mining site and 0.0010 mg/kg at the control). Although heavy metal concentrations were elevated at the mining site, they remained within World Health Organization (WHO) permissible limits for both plants and soils. The findings suggest that heavy metal levels are safe for agricultural use, but continued monitoring is necessary to prevent potential ecological risks.