Pump study. After removing the pump from
Working standards were made each sampling day
the standpipe, the exterior of the pump and the 5
by serially diluting the combined standard in hex-
ft of tubing that contact the test solution were
ane (600, 400, 200, 100, 20, and 4 ng/mL). The
sprayed with hot water from the pressure washer,
MDL was obtained according to the EPA protocol
scrubbed with a brush using a hot detergent solu-
as described in the Federal Register (1984).
tion, and rinsed with hot water. The pump was
then washed using the EPA protocol outlined in
Munitions study
the TCE studies. Samples were taken at one, three,
six, and nine volumes.
Experimental methods
A barrel containing water contaminated with
Sample handling and analysis
munitions was obtained from Louisiana Army
Samples were collected in 40-mL glass vials
Ammunition Plant. A barrel pump was used to
with Teflon-lined plastic caps. For each sample
fill the standpipe with this solution.
collected there were five replicate vials. Ten mL
Bailer study. The procedure for contaminating
was removed from the vials and discarded. The
and decontaminating the bailer was the same as
pesticides in the remaining 30 mL were extracted
that used in the pesticide study.
according to modified EPA Method #505 (US EPA
Pump study. The procedure for this study was
1991) as follows: nine grams of reagent sodium
the same as that used to contaminate and decon-
chloride was added to the vials, which were then
taminate the pump in the pesticide study.
shaken to dissolve the salt. Three mL of pesticide-
grade hexane was added, the vials were recapped
Sample handling and analysis
and placed horizontally on a shaking table, and
Samples were collected in 500-mL glass jars
shaken for three hours. The vials were allowed to
with Teflon-lined plastic screw caps. There were
stand vertically for approximately 10 minutes to
three replicates (jars) for each sample taken.
allow separation of the two phases. Enough hex-
Analysis of the munitions-contaminated water
ane was carefully drawn off with a Pasteur pipet
was made by using a modified HPLC method
to fill a 1.8-mL amber glass, autosampler vial. The
(Thorne and Leggett in press) using a modular
autosampler vials were stored in a refrigerator
system consisting of a Waters 717 autosampler,
(4C) until analyzed.
616 pump, 600S controller, 996 photodiode array
Analyses were performed on a Hewlett-Packard
detector, and Millenium workstation. A Pheno-
(HP) 5890 series II gas chromatograph (GC) with
menex (Torrance, California, USA) Ultracarb 5
ODS (20) (4.6 mm 250 mm, 5 m) reverse-phase
an electron capture detector (ECD) equipped with
an HP 6890 series autosampler-injector, all under
column with an Alltech C-18 guard cartridge was
the control of HP-Chemstation software. The GC
used for the analytical separations. The aqueous/
was operated in splitless mode with 1-L injec-
methanol (V%/V%) gradient elution time steps
tions. Nitrogen was used as carrier and makeup
were as follows: start at 85/15, ramp to 65/35 at
gas. The instrument was set with the following
eight minutes, ramp to 42/58 at 10 minutes and
operating parameters: an injector temperature of
hold for 13 minutes, ramp to 0/100 at 28 minutes
250C; initial oven temperature of 150C and hold
and hold for seven minutes, ramp down to 85/15
time of two minutes, ramp at 10 /minute to 250C
at 40 minutes and hold for 10 minutes before the
and hold eight minutes; detector temperature of
next injection. The flow rate was 0.8 mL/minute.
300C; purge time 1.0 minute. The column was a
Quantification was performed at 254 nm. Peak
J&W DB-5.625, 30-m 0.25-mm-i.d., 0.50-m film.
identities were determined by comparing sample
Gas flows were as follows: 1.0 mL/minute for the
and standard peak spectra and retention times.
column, 2.5 mL/minute for the purge gas, and 60
In order to work at lower detection levels in
mL/minute for the makeup gas.
the analyses of the munitions desorbed into the
Primary certified pesticide standards were pur-
DI water, the munitions were extracted by pass-
chased from Ultra Scientific (100 g/mL in hex-
ing 500 mL of water through Sep-Pak Vac, Poropak
ane) and each was diluted with pesticide-grade
Rdx cartridges and eluting with 4 mL acetonitrile.
hexane to yield 10 g/mL. A combined standard
The extract was stored in a freezer until analyzed
was made by pipeting 1 mL of each of the diluted
by GC/ECD according to a method being devel-
pesticide standards into a 10-mL volumetric flask
oped by Walsh and Ranney (in prep.). A modular
and filling to volume with hexane (1 g/mL). All
system consisting of a Hewlett-Packard (HP) 5890
these standards were kept in the dark in a freezer.
series II GC with an ECD and equipped with an
8
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