Geochemical Assessment of Heavy Metal Contamination in rural and urban wetlands in Akwa Ibom State, Nigeria

Nutrient and waste inputs into wetlands have dire consequences on both soil and water quality and by extension dependent aquatic flora and fauna. Within this purview, heavy metal contamination was assessed in a rural and urban wetland in Akwa Ibom State, Nigeria. Soil samples were analyzed for Pb, Zn, Fe, Ni and Cd using AAS. Results show marked variations of heavy metal concentrations within study area. Mean values of Fe (713.22 ± 59.39), Pb (5.95 ± 0.42), Zn (88.54 ± 8.03) and Cd (1.53 ± 0.65) were higher in the urban site while Ni (9.45 ± 1.56) was
higher in the rural area. Heavy metal contamination status was assessed using four indices; enrichment factor, geoaccumulation index, contamination factor and degree of contamination. The calculated enrichment factor values for the studied metals in both wetland areas were significant for Zn and Pb. The same trend was also true for Geoaccumulation index values and contamination factor in the two wetland sites. Additionally, result for degree of contamination was high for both wetlands; urban (39.08) rural (33.71). Cluster analysis was employed to show the heavy metals source apportionment in the wetlands. The results of this study clearly show that presently, these wetlands are contaminated due to increased anthropogenic activities and as such, adequate measures should be put in place by relevant authorities to checkmate and regulate human activities around wetlands in order to protect them from further deterioration and contamination.