EVALUATION OF ARSENIC CONCENTRATION IN SOIL AND ROCK UNITS ACROSS LEBANON, CT

High arsenic concentration within the bedrock of New England area has been a major concern because rock weathering and soil formation are important geological processes associated with the release of trace elements into the environment. The release of trace elements could provide sources of essential nutrients for plants as well as toxic trace elements into the ecosystem, and hydrologic systems. Two years after Lebanon Elementary School was shut down due to high levels of arsenic concentration in the drinking water, the source of the arsenic to well water is still unknown. This project examined lithogenic concentrations of arsenic and other elements (trace and major) in soil and bedrock of Lebanon, CT with the view of correlating concentrations between soil and different rock formations. Eleven rock samples were collected from different rock units that include Hebron gneiss, Scotland schist, Brimsfield schist, and Lebanon gabbro across the entire Lebanon, CT. In addition, soil sample around each rock unit were collected. The sahemples were pulverized and analyzed for arsenic as well as other major and trace elements using PW2400 XRF machine at the Geosciences department, University of Massachusetts. Results showed: i) concentrations of arsenic and other elements in rock and soil of Lebanon, CT, ii) ratio of elements in soil to that of the bedrock units, iii) extent of rock weathering rate, and iv) loss of element in soil ions to hydrologic systems. Overall, results provide contribution of bedrock and topsoil chemistry to the concentrations of trace and major elements in Lebanon hydrologic systems.