Geometric Mean

2 Standard Deviations

Geometric Mean

1 Standard Deviation

Geometric Mean

+1 Standard Deviation

Geometric

Geometric Mean

Mean

+2 Standard Deviations

Arithmetic

Estimate

Mean

from

Composite

0

100

200

300

400

500

600

700

800

900

1000

HMX Concentration (mg/kg)

trations of HMX in surface soils as a function of

distance from the target are plotted for sampling

location 1-44, along with similar data from CFB-

1000

Valcartier (Fig. 11). With concentrations decreas-

ing as distance from the target increases, a logical

Fort Ord

sampling array would use concentric rings with

900

CFB-Valcartier

the target at the center. Such rings might employ

800

points would be located equidistant from each

other around each ring, which would allow two

700

composite surface samples to be formed for each

ring (Fig. 12). Each discrete sample should con-

tain about a kilogram (200 g) of soil and be ho-

600

mogenized thoroughly prior to subsampling for

formation of composites, as described earlier in

500

the *Experimental Methods *section. Each composite

would contain one-half of the sampling points

400

chosen in an alternating pattern. Results of this

work demonstrate that EOD personnel can effi-

300

ciently collect soil samples for site characteriza-

tion at the same time that they are clearing the site

200

for unexploded ordnance. Since the major portion

of the explosives residues at the inland ranges are

in the surface soils, samples for additional charac-

100

terization should be relatively easy to collect. The

depth of contamination in specific areas can be

0

0

3

6

9

12

15

18

21

determined iteratively after the extent of surface

Distance from Target (m)

contamination is mapped.

The choice of four discrete samples per compos-

ite is a compromise between 1) our desire to

improve the reliability of each analysis (represen-

22