Using mass balance analyses for heavy metal pollution assessment in some wetlands at Obuasi, Ghana

Mass balance estimates take into account every component of the environment under consideration, offering the most straightforward approach and enhancing assessments of heavy metals pollutions. This study estimates environmental pollution using mass balance values of Cd, As, Pb, Hg, and Fe in some wetlands at Obuasi, Ghana. The specific objectives are to (i) determine the concentrations of the elements in the wetlands, (ii) assess the mass balance ratio (B_R) for each of the elements in the wetlands, and (iii) integrate the B_R of the elements for the wetlands. The metal concentrations were determined by Atomic Absorption Spectrometry procedure. Reference crustal average values for Cd, As, Pb, Hg, and Fe were used to calculate the B_R for the elements. The B_R values were integrated to generate geochemical mass balance ratio index (B_RI). The element concentrations are above WHO/FAO permissible limits. Cd, As, and Hg B_Rs are > 1.3 at all sites indicating enrichment from mining, Pb B_R of 1.090 show near equilibrium, while Fe B_R of 0.06 indicate depletion. Average B_RI values for the basins are 30.89, 67.68, and 42.83 for site-A, site-B, and site-C, respectively, dominated by Cd, As, and Hg. This indicates extra source of Cd, As, and Hg from human activities accumulate into the wetlands. In conclusion, the wetlands are not conducive for consumable livelihood venture, enrichment of Cd, As, and Hg is due to mining operations, and B_RI provides strong synergistic and effective metric tool to monitor heavy metal pollution levels in wetland environment.