PARENT SESSION
PM5 - Fate & Effects of Metals in Wetland & Terrestrial Systems
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P257) Fate and Transport of Lead at an Inactive Skeet and Trap Range.
Petron, Stephen*,1, Weier, Jonathon1, Jackson, Rodger2, McFarland, Dale3, Myers, John3, 1 CH2M HILL, Boston, MA, USA2 Naval Facilities Engineering Command, Atlantic Division, Norfolk, VA, USA3 Marine Corps Air Station Cherry Point, NC, USA
ABSTRACT- In an effort to assess the potential for off-site migration, the extent of lead contamination at an inactive skeet and trap range was characterized using a combination of x-ray fluorescence (XRF) technology and traditional off-site laboratory analytical services. Concentrations near 50 ppt were observed in the surface soil (0-6 inches). The sampling scheme, a subset of the grid points on the expected shot fall pattern, clearly showed the lines of maximum shot fall and the influence of the on-site watercourse in transporting lead within the range. There was good concurrence between concentrations of lead detected by the two XRF machines used on-site and duplicate samples sent to the off-site fixed laboratory. Although showing the same general trend, comparison of co-located XRF and laboratory samples confirmed the hypothesis that there could be significant inter-sample variation for samples collected only inches apart. Collection of deeper surface soil (6-12 inches) showed that lead has moved vertically through the soil column. The concentrations of total and dissolved lead in surface water were similar. It is hypothesized that the acidic conditions created by the pine-dominated upland over much of the site has contributed to the decay of the lead shot and its presence in dissolved form within the water column. Alternatives to reduce the potential for off-site migration are reviewed.
Key words: lead, range, XRF