Distribution and partitioning of lead related to soil characteristics in a former gun range

Abstract

Lead shot is commonly used in shooting ranges throughout the world. When introduced into the environment, several factors such as wind and precipitation will aid in the breakdown of the lead (Pb) compound, as well as the transportation of the Pb throughout the soil in which it lands. Weathering and other environmental factors will cause the Pb to oxidize, potentially turning it into hydroxide, sulfate, carbonate, or a phosphate species. The amount of precipitation that falls annually in a Pb shot contaminated range contributes to lead distribution within the soil profile. Acid precipitation and acidic soils can solubilize the Pb making it more mobile. Conversely, organic matter, clays, and other mineral components can inhibit the mobility of soluble Pb because of sorption onto soil particles. Therefore, it is important to identify the type of soil, the permeability, porosity, pH, and organic matter content which will influence how much the Pb will migrate through the soil. It will also give insight to the future leaching potential. When Pb is subject to dissolution and erosion, it can leach into soil and groundwater, possibly causing health problems for humans and animals. Because of the potential impacts, this research examines the spatial distribution of Pb from munitions used at the Grand Valley Hunting Ranch in Orwell, Ohio, a property now owned and under ecological restoration plans by the Western Reserve Land Conservancy. A preliminary assessment of elevated Pb concentration in soils was determined using an X-ray Fluorescence Spectrometer (XRF). Four sample locations were established and were cored to further and more accurately analyze Pb concentrations in the soil. The four locations were located within the fall zone of the Pb shot. A fifth location outside of the fall zone was cored and designated as the reference. Each core was 60-90 cm in total length and divided into 2-5 cm segments and halved, resulting in 148 total samples. This depth provided a good illustration of how the Pb leached through the