Impact of the Illegal Gold Mining Activities on Pra River of Ghana on the Distribution of Potentially Toxic Metals and Naturally Occurring Radioactive Elements in Agricultural Land Soils

Abstract

Mining sectors in the developing world are located in villages, where farming is the prime source of income. This generates the likelihood of adverse spillovers to agriculturalists through rivalry for main inputs (i.e. land, labor, water, and environmental pollution). To explore this concern, gold mining sites on the Pra River of Ghana and nearby farmland soils were sampled and analyzed to evaluate the levels of potentially toxic metals (PTM) and naturally occurring radioactive elements (NORE) and appraise the potential ecological risk of PTM in soil samples. Cold vapor atomic fluorescence spectrometer was used to analyze the contents of total mercury (THg) while inductively coupled plasma-optical emission spectroscopy was used to determine the total concentrations of Ni, Cr, Pb, Co, Cu, Cd, Zn, and As. Instrumental Neutron Activation Analysis technique was used to detect the NORE concentrations in the soil samples. Geochemical indices were used to help evaluate the environmental risks. Toxic metals and radioactive elements concentrations in mining soil samples varied in the range: THg (0.37-0.59 mg/kg d.w.), As (4.68-19.69 mg/kg d.w.), Pb (6.67-23.02 mg/kg d.w.), Cd (0.103-0.315 mg/kg d.w.), Co (5.06-15.03 mg/kg d.w.), 97 mg/kg d.w.), Cu (15.43-38.05 mg/kg d.w.), mg/kg d.w.), Zn (20.27-97.64 mg/kg d.w.), Al (34,739.33-51,037.07 mg/kg d.w.), Th (77.97-136.10 mg/kg d.w.), and U (< 34.14-102.31 mg/ kg d.w.). The levels of PTM and NORE in farmland soil samples ranged from THg (0.09-0.49 mg/kg d.w.), As(0.45-7.01 mg/ kg d.w.), Pb (3.01-7.01 mg/kg d.w.), Cd (0.01-0.10 mg/kg d.w.), Co (3.12-8.65 mg/kg d.w.), mg/kg d.w.), Cu (8.83-18.07 mg/kg d.w.), Ni (8.12-16.08 mg/kg d.w.), Zn (9.63-42.33 mg/kg d.w.), Al (23,110.71 mg/kg d.w.), Th (< 47.17-57.061 mg/kg d.w.), and U (< 34.14-42.99 mg/kg d.w.). High levels of NORE, THg, and As were detected in some of the farmland sites. Radioactive elements were enriched in all the soil samples detected, while THg, As, Co and Zn were enriched in some of the soil samples analyzed. Mercury exhibited a moderate level of monomial ecological risk in some farmland soil samples while the other PTMs showed low risk in all farmland soil samples. This study has proved that farmland soils contain concentrations of U, Th, THg, and As that can harm the eco-agrosystem and these hazardous elements can be transferred to humans and animals through the food chain process. It is believed that mining activities on the river and phosphate fertilizer applications on farmlands are the major influence.

Distribution and Contamination of Arsenic in Fish, Gastropods and Bivalves in the Aby and Tendo Lagoons in East of Ivory Coast

“…Arsenic is released when rocks are crushed or chemicals are used to dissolve gold. Arsenic contaminates surface and groundwater, as well as soils [24] [25].…”

Eco-toxic risk assessment and source distribution of trace metals in surface sediments of the coastal and in four rivers estuary of Sarawak

“…The high level of Zn concentration in the surface sediments could be attributed to the fuel station, vehicle emissions, and commercial discharges [19,48]. (13) Fi = Ci/Cb…”

“…As an essential constituent in riverine and estuarine environments, sediments are a source and a sink of trace metals [11,12]. Trace metals entering rivers and estuaries rapidly deposit into the sediment and are much more concentrated than in the water body of riverine, estuarine, or coastal systems [13,14]. When there is an alteration of the hydrological or the physicochemical 2 Methods…”

Trace Metals Assessment in Soils and Sediments near the Abandoned Mine of “El Abed” Pb-Zn deposit – Northwestern Algeria

“…Similar studies of African sites at the level of active gold mining areas in the Bra River in Ghana showed heavy metal concentrations, including lead (Pb), zinc (Zn) and arsenic (As) with high levels of pollution harmful to the ecosystem. The heavy metals can be transmitted to humans and animals (Asare, 2021). For several studies of contaminated sediment and soil samples, evidence has been provided that human interventions are the only source of trace metal transport (Jaffé et al, 2003) considered an environmental disaster (Ali et al, 2019).…”