Heavy Metal Concentrations in Stream Sediments Adjacent to the Greenfield Sanitary Landfill, Dade County, Missouri

Missouri passed Senate Bill 197 (S.C.S.S.B. 197) in 1955 licensing county and township governments to operate sanitary landfills. According to records provided by the Missouri Department of Natural Resources (MDNR) the Greenfield Sanitary Landfill located in Dade County, Missouri was opened in early 1968 and closed in April of 1973. Many substances placed in sanitary landfills contain heavy metals believed to be toxic or cause environmental degradation. The purpose of this study is to determine if heavy metals are entering Wetzel Branch, a stream running adjacent to the closed landfill. The very fine sand fraction of sixty sediment samples was analyzed for silver (Ag), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) using Inductively Coupled Plasma-Atomic Emission Spectrophotometry (ICP-AES) and a single nitric acid extraction. A t-test was used to compare each of the statistical mean metal concentrations in the control, samples collected upstream from the landfill, with that in test samples collected adjacent to and downstream from the landfill. A significant difference was indicated for Ni, Zn, Cr, and Cd at 99.9% confidence; for Ag at 99.7%; for Cu at 98.9% and Pb at 97.5% confidence. The statistical values show that the landfill is releasing these metals into Wetzel Branch, at levels which may affect the aquatic environment