major peaks in the Kovats Index 1500 to 2300
the major constituents would be truncated at 100%
range (between n-C15 and n-C23 in the diesel stan-
full scale [at an increased instrument sensitivity (at-
tenuation 64 10)], thereby facilitating detection of
dard; von Kovats 1958). The exact identification
of these constituents is not known, but they could
the smaller peaks. The results of these analyses are
be aldrin, dieldrin, and endrin based on the ex-
shown in Figure 3 along with the two RESTEK Co.
ceedingly high concentrations of these materials
pesticide standards for reference. In this case, al-
in the sample (see the ECD GC discussion below).
drin, dieldrin, and endrin can now also be observed
The FID GC profiles for two of the "below the
in the wet, saturated gray clay/silt sludge from
liner" samples (41238 and 41249) are very similar
below the liner (sample 24093), along with numer-
to each other, but different (both quantitatively
ous other constituents common to all four samples.
and qualitatively) from the soil-amended sludge
Unfortunately, given the lack of adequate stand-
(sample 24216). The third below-the-liner sample
ards, it is impossible to identify most of these un-
(24093) was a wet, saturated gray clay/silt sludge,
known compounds. They are probably chlorinated
and although it had a light petroleum hydrocar-
organics; given their sensitivity to the electron cap-
bon smell, the FID GC showed only two very
ture detector, however, they do not correspond to
small resolved peaks with retention times similar
any of the components in the standards available at
to the larger constituents in sample 24216. Clearly
the time of these analyses. Compound identifica-
there is no evidence of significant petroleum hy-
tion by GC/MS might be possible, but it too would
drocarbon-type contamination (i.e., diesel or other
be difficult due to the low (pg) quantities involved.
distillate product) in any of the samples.
These analyses show the general qualitative
Figure 2 presents the chromatograms obtained
similarity among the samples, and based on these
on two RESTEK Co. pesticide standards and the
chromatographic observations and the data in
hexane extracts from the four RMA soil samples.
Table 1, it was not difficult to select the soil-
Each of the four RMA sample chromatograms
amended Basin F sludge as the worst-case mate-
was obtained under identical instrument condi-
rial for DCR treatability testing. In addition, it
tions (attenuation 512 10) on the same "nominal
was known that the majority of the contamina-
concentration" of sample extract. That is, a con-
tion originated in the Basin F liquid (Table 2), and
stant nominal weight (20 g) of each sample was
for this reason as well, sample 24216 was se-
extracted/diluted with a constant volume (5,000
lected. In addition to significant levels of pesti-
mL) of solvent so that the relative concentrations
cides, the Basin F liquid (later mixed with clean
of individual pesticides would be readily discern-
soil to yield the soil-amended Basin F sludge)
ible from the peak size. Here again, the soil-
contained very high concentrations of inorganic
amended Basin F sludge from above the liner is
salts [e.g., NaCl, NH4Cl, and (NH4)2SO4] as well
as 14% urea (Table 2).
clearly the most contaminated, with 3,270 mg/kg
dry weight total pesticides resolved. Comparison
of retention times with those from individual con-
Table 2. Descriptive chemical characterization
stituents in the two RESTEK pesticide standards
of RMA Basin F liquid* (highest historical data).
allows aldrin, dieldrin, and endrin to be identi-
fied in three out of the four RMA samples. As
Constituent
mg/L
with the FID GC results discussed above, two of
Water
620,000
the below-the-liner samples (41238 and 24093) are
Major metals
qualitatively very similar with one unique com-
Sodium (Na)
65,000
ponent [retention time (RT) 15.6] that is not pres-
Copper (Cu)
5,860
ent in the above-the-liner soil-amended sludge
Potassium (K)
2,900
(sample 24216). The other peaks in these two
Major inorganics
samples are common with sample 24216 (although
Chloride (Cl)
159,000
at much lower levels). At these "nominal" extract
Ammonia (NH3)
60,900
concentrations, there are only traces of aldrin and
Sulfate (SO4=)
27,000
Total phosphorus
16,200
essentially no other resolved compounds in the
Nitrate (NO3)
1,300
wet, saturated gray clay/silt sludge from below
the liner (sample 24093).
Additional components
Urea
143,000
To allow better comparison of the common con-
Dimethylmethylphosphonate
2,000
stituents in all of the RMA samples, the extracts
were concentrated so that the peaks from each of
* From R.F. Weston document 1212WG.APA (12/17/90)
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