gram analysis. In August 1991, five composite soil
ing 1991, samples were analyzed for TPH by an
samples were collected at six times and analyzed
infrared method. Soil samples collected during
using radio-respirometric assays and sheen screen
1992 were analyzed for diesel range petroleum
techniques. Field measurements of CO2 evolu-
hydrocarbons (DRPH), gasoline range petroleum
tion were made on seven different occasions.
hydrocarbons (GRPH), and benzene, toluene,
Contaminant degradation rates. Contaminant
ethylbenzene, and xylene (BTEX).
degradation was also estimated by measuring
Organic vapor emissions. Headspace gas con-
dichromate-oxidizable organic carbon and
centrations were measured for samples collected
gravimetric total petroleum hydrocarbon (TPH)
on 18 August 1992, using an organic vapor meter
levels. At approximately monthly sampling
(OVM) calibrated for benzene. On 20 August
intervals, 25 composite samples were collected in
1992, samples were collected for laboratory
a grid pattern and analyzed. Laboratory results
analysis of DRPH concentrations. No detectable
were then examined using geostatistical meth-
DRPHs were measured in these samples (Table
1). These results indicated that material in the
ods. Soil extract hydrocarbon analyses were also
landfarm reached appropriate cleanup levels for
performed by an independent testing laboratory
closure sampling and disposal.
on soil samples collected by FIA personnel. Dur-
Table 1. Landfarm analytical results.
TPH
GRPH
DRPH
B
T
E
X
Date
(mg/kg)
(mg/kg)
(mg/kg)
(mg/kg)
(mg/kg)
(mg/kg)
(mg/kg)
Location 12
21 Aug 91
1100
28 Aug 91
1700
18 Sep 91
770
01 Oct 91
1100
15 Jul 92
29*
2300
0.06
0.15
<DL
0.29
20 Aug 92
<DL*
Location 14
21 Aug 91
4000
28 Aug 91
3500
18 Sep 91
1000
01 Oct 91
900
7†
15 Jul 92
55
0.02
0.07
0.03
0.08
20 Aug 92
<DL
Location 7
20 Aug 92
<DL
Location 16
20 Aug 92
<DL
* Below detection limits.
Location Numbers
† Light deisel.
190 ft
25
20
10
5
15
N
14
24
19
9
4
23
18
13
8
3
230 ft
22
17
12
7
2
21
16
11
6
1
Access Road
9
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