concentrations of copper, zinc, lead, chromium, and
has developed a Risk-Based Concentration Table that
antimony above most of the other samples we collected
may be used to screen sites not on the National Priority
(Fig. 24 and 25). Because these samples were collected
List. Tables 18 and 19 give levels for explosives residues
adjacent to target tanks, source of the metal could have
and metals in industrial and residential soils.
been either the missiles or the tank or both.
Only one sample had RDX and TNT concentrations
above the Risk-Based Concentrations for soil in a
Comparison with current cleanup guidance
residential area, and that soil sample was in direct
contact with unexploded Composition B from a low-
Action levels
order detonation. For some chemicals, the Risk-Based
Cleanup or action levels for contaminants in soil are
Concentration Table also gives soil screening levels for
the protection of groundwater. Although values are not
site-specific and depend on several factors, including
given for RDX and TNT, there are values for 2,4-DNT
the characteristics of the soil, the mix of contaminants,
and 2,6-DNT (an impurity in military-grade TNT and
potential receptors and exposure pathways, and
2,4-DNT). These values are 0.029 g/g and 0.012 g/g
potential for migration to groundwater. EPA Region III
300
TOW
250
TOW
200
TOW
150
TOW
TOW
40-mm
TOW
100
SADARM
TOW
TOW
50
TOW
Lampkin Range FP
40-mm
TOW
0
Lead
Zinc
Figure 25. Box plots of lead and zinc concentrations showing which
events resulted in increased metal concentrations. Each box encloses
50% of the data with the median value represented as a line in the
box, the upper quartile as the top of the box and the lower quartile as
the bottom of the box. The circles represent outliers, which are val-
ues greater than the sum of the upper quartile plus one and one-half
times the difference between the upper and lower quartile.
31
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