Source Apportionment and Human Health Risk Assessment of Potentially Toxic Elements in Soils Impacted by Artisanal Small-Scale Mining.

Abstract

Industrialization and urbanization in developing nations have contributed to the pollution of the biota and the entire ecosystem with potentially toxic elements (PTEs). This study aims to do source apportionment, assess pollution levels, and evaluate the human health risk of PTEs in soil affected by artisanal small-scale mining in the communities of Atwima Mponua District, Ghana. The concentrations of metals and metalloids in 78 soil samples were estimated using a Thermo Scientific field portable Niton X-ray fluorescence analyser. Statistical algorithms, including positive matrix factorization (PMF), principal component analysis (PCA), and various pollution indices, were utilized to apportion the sources, contributions, correlations, and spatial distribution of the PTEs. The mean concentrations of potentially toxic elements (PTEs) in the soil samples were as follows (in mg/kg): mercury (Hg) – 0.304, chromium (Cr) – 2.90, vanadium (V) – 4.47, lead (Pb) – 4.99, arsenic (As) – 9.10, copper (Cu) – 15.47, nickel (Ni) – 26.30, zinc (Zn) – 39.56, titanium (Ti) – 264.00, cobalt (Co) – 121.16, cadmium (Cd) – 204.22, and manganese (Mn) – 361.80. The study found high contamination factors (CF) for Cd (85.10) and Co (2.08). The results of potential ecological risk (PER) for Cd (2553) show very high risk, but that of Co (10.27), and As (3.71) registered low risk. The enrichment factors (Erf) for Cd, Hg, and Co were all > 1.5, indicating significant enrichment in the area. The correlation coefficient analysis showed strong positive correlations between the majority of the PTEs, suggesting common sources. PMF multivariate receptor modelling analysis identified five (5) dominant and sub-dominant source profiles. The results have apportioned source contributions 2,4, and 5 to anthropogenic sources, mainly the artisanal small-scale mining and agricultural activities, and attributed factors 1,3 as both anthropogenic and geogenic sources in the study area. The investigation concludes that the soil in the Atwima Mponua District is at serious risk due to the high levels of PTEs, particularly Cd and Co, which pose significant ecological and human health risks. Hence, policy interventions are necessary to mitigate pollution and protect public health.