Table 1. Concentration (g/g) of TCE determined for soil samples collected around and within core liners

Table 1. Concentration (g/g) of TCE determined

aggregate micropores (Sawhney and Gent 1990,

for soil samples collected around and within core

Pavlostathis and Mathavan 1992).

liners.

Core liners are devices designed to prevent VOC

volatilization losses from intact soil samples so

Reference soil samples

that the soil can be shipped from the field to an

Core liner/exposure

Within core

from around the

period (min.)

liner

core liner

off-site laboratory prior to sampling for analysis.

During transportation and storage this device is

9.71.0*

(1,2,5,6)†

I/60

0.27

covered with either sheets of TFE or aluminum foil

110.7

II/40

0.99

(2,3,6,7)

121.0

(ASTM, D 4547-91). Ideally, when using core lin-

III/30

2.1

(3,4,7,8)

110.5

IV/20

4.7

(5,6,8,10)

ers, sample exposure would be limited to two short

100.9

V/10

6.5

(6,7,10,11)

periods: when the sample is first retrieved and

121.0

VI/1

(7,8,11,12)

covered, and when it is opened in the laboratory

to prepare a sample for analysis. For this approach

* Mean and standard deviation, n = 4

† Sample positions exterior to core liner (Fig. 1)

to be useful, VOC concentrations must be main-

tained for at least several days to allow time for

sonable to assume that these samples, which had

samples to be shipped to the analytical laboratory.

been removed from the middle of the core liners

Table 2 shows results of field samples stored in

(1.2 cm below/above the exposed surfaces), had

core liners and covered with either TFE or alumi-

experienced large volatilization losses, due to gas-

num foil. As in Table 1, samples taken from core

eous diffusion. The observed faster rate of desorp-

liners immediately after they were removed from

tion has been attributed to processes occurring at

the hole showed TCE concentration estimates com-

the mineral surfaces (macropores), whereas the

parable to the means obtained for adjacent

slower rate may result from diffusion from intra-

samples. However, regardless of the covering or

Table 2. Concentration (g/g) of TCE determined for soil samples collected around

and within core liners. Core liners covered with either TFE sheets or aluminum foil

were stored at 4C.

Reference soil samples

Core liner no.

Storage period**

from around the

covering

Day 0

Day 5

Day 10

core liner

Second experiment

3.20.4†

I/None

2.9

(1,2,5,6)

3.40.7

II/Aluminum

0.15

(2,3,6,7)

3.60.5

III/TFE

0.18

(3,4,7,8)

3.40.8

IV/TFE

0.049

(5,6,8,10)

3.30.6

V/Aluminum

0.16

(6,7,10,11)

3.50.4

VI/None

2.5

(7,8,11,12)

Third experiment

0.790.17

I/None

0.63

(1,2,5,6)

0.700.28

II/Aluminum

0.018

(2,3,6,7)

2.42.5

III/TFE

0.018

(3,4,7,8)

0.620.25

IV/Aluminum

0.017

(5,6,8,10)

0.700.33

V/TFE

0.006

(6,7,10,11)

1.20.7

VI/None

0.82

(7,8,11,12)

Fourth experiment

0.860.01*

1.20.4

I/None

(1,2,5,6)

0.140.08

1.60.8

II/Aluminum

(2,3,6,7)

0.0690.014

1.60.8

III/TFE

(3,4,7,8)

0.0590.016

0.860.18

IV/TFE

(5,6,8,10)

0.0720.001

1.40.9

V/Aluminum

(6,7,10,11)

0.640.21

1.40.9

VI/None

(7,8,11,12)

* Mean and standard deviation, n = 3

† Mean and standard deviation, n = 4

** Samples taken from within core liner.