SOURCES AND SPATIAL DISTRIBUTION OF HEAVY METALS IN AGRICULTURAL SOILS OF LEBANON, CT

Accumulation of certain metals in agricultural soils threatens the safety of the ecosystem, and humans through adverse effects. The bioavailabilty and mobility of these metals are strongly dependent on a number of factors such as the presence of the input sources, as well as soil properties such as pH, organic matter fractions (OM), cation exchange capacity (CEC), and the type and amount of available colloids. This study examined possible sources, concentrations and spatial distribution of fourteen trace and major elements (As, Al, Cd, Cr, Cu, Fe, K, Ca, Mg, Mn, Ni, Pb, S, and Zn) within agricultural soils of Lebanon, a predominant agricultural town. A total of eighty eight (88) soil samples were collected throughout the entire town of Lebanon, and analyzed for acid and soluble extractable elements, and basic soil parameters such as particle size distribution, organic matter contents and soluble salts. Results shows spatial variability in trace and major elements concentration due to the amount of clay and organic matter content in each soil sample. Using GIS maps with overlays of hydrology and land use activity, correlations between elements and agricultural activities within Lebanon were examined. Calculation of Principal Component Analysis (PCA), Enrichment factor (EF) and Geoaccumulation Indices (GI) on sediment geochemical data showed degree and distribution of trace element enrichment as well as contribution from both geogenic and anthropogenic sources.