Environmental Engineering Reference
In-Depth Information
Table 5.1a Natural Attenuation Parameters and Criteria Points (Continued)
Criteria
Points
Awarded
Concentration
Criteria
Analyte
Interpretation
Vinyl chloride
Material released or daughter
product of dichloroethenes
2
Ethene/ethane
Daughter product of vinyl
chloride/ethene
>0.01 = 2;
>0.1 = 3
Chloroethane
Daughter product of vinyl
chloride under reducing
conditions
2
1,1,1-Trichloroethane
Material released
1,1-Dichloroethene
Daughter product of
trichloroethene or chemical
reaction of 1,1,1-trichloroethane
Table 5.1b Interpretation of Natural Attenuation Scores
Score
Interpretation
0 to 5
Inadequate evidence for biodegradation of chlorinated compounds
6 to 14
Limited evidence for biodegradation of chlorinated compounds
15 to 20
Adequate evidence for biodegradation of chlorinated compounds
>20
Strong evidence for biodegradation of chlorinated compounds
were installed with a 25-cm-diameter hollow-stem auger. A sand pack was
used in the screened interval and a bentonite plug was placed immediately
above the screened zone. The three IWs were screened from 7.6 to 9.9 m bgs,
and the six RWs were screened from 7.9 to 9.6 m bgs.
Monitoring wells (MWs) that were 5-cm-diameter PVC were also
installed with a hollow-stem augor as described above and screened from
7.9 to 9.6 m bgs. A series of 2.5-cm PVC wells (C-wells) were installed with
a cone penetrometer truck and screened from 8.3 to 9.1 m bgs. All wells were
used for groundwater monitoring, and their locations are shown in Figure
5.5.
A fully screened well (MW-516) was installed outside the contaminated
area utilized for conducting flowmeter and aquifer pumping tests. The well
was constructed of 5-cm schedule 40 PVC casing with machine 0.025-cm-slot-
ted screen from approximately 3 to 10.7 m bgs. This well was installed with
a sonic drilling rig, which pushed the casing into the subsurface.
Seven multilevel samplers (MLSs) were installed within the source zone
and the ring of RWs. The five sampling depths at each MLS location were
8.1, 8.7, 9.1, 9.4, and 9.9 m bgs for a total of 35 sampling locations. These
locations were sampled by the University of Florida (UF), and data are
reported elsewhere (Jawitz et al., 2000).
 
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