ANALYSIS OF GROUNDWATER AND SURFACE WATER LEAD CONTAMINATION: MOSS KNOB SHOOTING RANGE, WESTERN NORTH CAROLINA

According the USEPA, an estimated 80,000 tons of lead is annually shot as bullets, with a large amount ending up at outdoor shooting ranges. The effects of lead exposure on humans has been well documented; nervous system and brain damage, reproductive problems, high blood pressure, and developmental retardation have all been reported, among numerous other adverse effects. Lead poisoning has also been linked to the impairment and death of various wildlife species. After being shot at an outdoor shooting range, metallic lead can be weathered and dissolved, which allows it to bind with other elements in the soil to form compounds such as sulfates, carbonates, and organic complexes. The compounds formed, as well as their solubility, depend partially on eH and pH conditions within the soil. Lead dissolved in water can remain in the vadose zone, or make its way into groundwater and/or stream water, all of which have the potential to become bioavailable. Because of this, regions that have acidic soils and large amounts of precipitation, including much of the southeastern US, are especially prone to bioavailable lead contamination.

This study focuses on Moss Knob Shooting Range, a public range near Franklin, NC, operated by the US Forest Service since 2004. Franklin has a temperate climate, with an average temperature of 12.8°C, and an average annual rainfall of 1372 mm. Some preventative measures against contamination are being taken, including applying lime (CaCO₃), and the addition of silt fencing and small settling ponds downslope of the range to catch sediment and runoff before it enters a small stream.

The primary objectives of this study are: (1) to determine the concentrations of lead in the shooting range sediment, groundwater, and surface water compared to natural background levels, and (2) provide the US Forest Service with information regarding preventative measures. Seven groundwater monitoring wells and piezometers have been installed in and around the shooting range. Head levels have been, and are being recorded to determine flow patterns. This presentation focuses on lead concentrations within sediments, surface waters, and groundwater at Moss Knob shooting range, analyzed via ICP-OES.