ENVIRONMENTAL IMPACT ASSESSMENT OF LEAD LEGACY MINES

Pollution from abandoned mine sites is a serious environmental issue worldwide. This study examined the impact of two legacy lead mine sites on the concentrations, mobility, and spatial distribution of Pb and twelve chemical elements (Fe, As, Ni, S, P, Zn, Mn, Cu, Al, Cd, Cr, Hg), with the overall goal of examining their fate and transport to the hydrologic systems within the critical zone environment. A total of 28 soil samples (Loudville, MA: 15, Middletown, CT: 13) were collected up to approximately 100 feet away from the mine entrances. Similarly, a total of 14 water samples were collected from the adjacent streams to the mine sites. During sampling, basic physicochemical parameters of the water column that include pH, temperature, TDS, EC, and DO were determined. In the laboratory, water samples were analyzed for both cations and anions, while soil samples were analyzed for both acid and soluble extractables. In addition, soil samples were analyzed for basic soil parameters such as particle size distribution using the hydrometer method, organic matter contents, and soluble salts. Results showed the average order of abundance of elements as: Fe > Al > Pb > P > Mn > Zn > As > S > Cu > Ni > Cr; with a range of 6,590-13,085, 3,400-6,902, 33-1,835, 832-1,035, 5-677, 19-455, 22-297, 32-215, 70-163, 0.03-31, 0.01-6 mg/kg respectively. Furthermore, concentrations were observed to decrease with distance away from the mine site. Multivariate statistical analysis shows a positive correlation between trace elements and fine-grained soil, an indication of a possible partitioning to fine grained sediment sizes, which invariably influenced the overall fate and transport of these elements within the critical zone environments.