Evaluation of the levels of selected heavy metals in mangrove ecosystem and roadside topsoil in Ghana

Abstract

Trace metals were determined in the soil and water of four lagoons, two estuaries, and four heavy-traffic roads in Greater Accra along the Atlantic coast of Ghana. The results showed that water samples from all of the water bodies studied were polluted with mercury (Hg) and less polluted with arsenic (As), nickel (Ni), and cadmium (Cd). The pollution status of water samples was confirmed by contamination degree (CD) analysis, which yielded values of >1 of Hg and <1 of As, Ni, and Cd. Evaluation of the data from the soil sample was enhanced by the application of pollution quantification tools—the pollution load index (PLI) and the index of geoaccumulation (IGEO)—which showed that the mangrove swamp soil studied is progressively degrading with Hg, As, Ni, and Cd. It was also revealed that vehicular emissions were a potential source of lead (Pb), Ni, and manganese (Mn) in the roadside soils monitored. From the results of this study, it is clear that the mangroves are gradually degrading and that measures should established to control release of these metals into the environment