Geospatial Distribution of Mercury in Surface Soils Across Ghana

The presence of mercury in soils has become a concern as artisanal gold mining activities in Ghana have increased significantly. This study assessed mercury concentration, spatial distribution, and potential ecological effects in surface soils throughout Ghana. Mercury concentrations were analyzed in 327 soil samples collected at 25 km by 25 km grid intersections using a Lumex Zeeman RA 915M mercury analyzer equipped with the Pyro-915 + attachment. The arithmetic mean and median values for mercury in the current study, 0.024 mg/kg and 0.011 mg/kg, respectively, are low when compared to the global average for permissible levels of 0.07 mg/kg. The pH of the soil ranged from 5.20 to 8.38, with mean and median concentrations of 5.81 ± 0.84 and 5.81, respectively, indicating that it was acidic. The root mean square error of the spatial distribution of mercury in the soil was 0.004, indicating an accurate result, and the map accurately predicted a concentration range of 0–0.075 mg/kg. Spatial distribution analysis using Empirical Bayesian Kriging indicated high mercury concentrations in the Ashanti, Eastern, Western, and Western North regions, exceeding the global standard average. The southwestern region of Ghana exhibited relatively higher mercury pollution levels than other regions. Geo-accumulation and potential ecological risk indices demonstrated that the soil was uncontaminated, and the potential ecological risk was low. These findings provide baseline information on mercury concentrations in surface soils in Ghana that can inform policymaking for sustainable resource management and environmentally friendly solutions for agricultural production, industrialization, and mining activities.