tubing and oven drying for the Teflon. In this in-
EFFECTIVENESS OF VARIOUS
stance, it is not clear why they eliminated the de-
DECONTAMINATION METHODS
tergent wash.
In fact, very little scientific evidence could be
When the literature was reviewed, only five
found to justify any of the recommended proto-
studies (Dunbar et al. 1985, Bryden et al. 1986,
cols. Mickam et al. (1989) concluded that the base
Matteoli and Noonan 1987, Fink et al. 1989, Schuh
of research information is insufficient to permit
et al. 1993) were found that compared the effec-
an adequate assessment of these methods. Appar-
tiveness of various decontamination protocols. Of
ently, decontamination methods are either based
these five studies, only two (Dunbar et al. 1985,
on unpublished observations or best guesses.
Bryden et al. 1986) were in peer-reviewed jour-
nals. Bryden et al. (1986) reported having excel-
lent results decontaminating purging and sam-
Special instructions
pling equipment in the field using a small portable
for cleaning pumps
Cleaning a sampling pump is much more in-
steam-cleaning machine followed with a rinse
volved than cleaning a bailer. With a pump, there
with distilled water or "type II" water (to remove
are more surfaces and crevices and often there are
any contaminants coming from the steam cleaner
several different types of materials. Only three
or water supply). They did not elaborate on the
methods that dealt specifically with cleaning
types of contaminants they encountered, but re-
pumps were found in the literature. These meth-
ported that the pressure was sufficient to dislodge
ods recommended either circulating or recircu-
particulate matter. They also warned that Teflon
lating a series of cleaning fluids through the pump
could warp if steam-cleaned too vigorously.
system. Classen (1982) recommended pumping an
Dunbar et al. (1985) found that rinsing a stain-
acid-wash solution (100200 L) through the sys-
less steel bailer and nylon rope with clean water
tem and rinsing with deionized water in a similar
was not sufficient to prevent carryover of con-
fashion. However, he did not supply any data to
taminants (chloroform and benzene) from well to
prove the effectiveness of this method. Keely and
well. They recommended decontaminating the
Boateng (1987) recommended recirculating three
bailer by using steam cleaning, washing with de-
cleaning solutions: 1) detergent in water (the out-
tergent, and rinsing with deionized water, and
side surfaces would be scrubbed), 2) 10% (vol/
using new lengths of nylon rope in each well.
vol) acetone in clean water (again the outside
However, they did not present any data that sub-
would be scrubbed), and 3) rinse with distilled
stantiates this recommendation. Presumably, the
water, followed by air drying. For high concentra-
bailer would be much easier to decontaminate
tions of nonvolatile organics and pesticides, they
than the nylon rope.
recommended a second distilled water rinse. They
The next three studies (Matteoli and Noonan
claimed that this method was effective for decon-
1987, Fink et al. 1989, Schuh et al. 1993) actually
taminating a positive-displacement (Johnson
compare the effectiveness of various decontami-
Keck) submersible pump that had been used to
nation protocols. Unfortunately none of these
sample VOCs, but they did not offer any proof of
studies was peer reviewed. However, because
this. They also claimed that this series of cleaning
there were no other peer-reviewed studies avail-
solutions was effective for cleaning a stainless
able and because they do provide us with more
steel bailer exposed to similar contaminants.
complete data, they were included in this dis-
ASTM Method D 5088-90 (ASTM 1990) for de-
cussion.
contaminating sampling devices (used at nonra-
Matteoli and Noonan (1987) conducted several
dioactive sites) recommends circulating 1) a de-
field tests to study decontamination of sampling
tergent solution, 2) a rinse of known quality
tubings. They tested two types of tubing: rubber
water, 3) a rinse with 10% nitric acid or hydro-
hose (neoprene lined with ethylene propylene-
chloric acid (this step is deleted if samples are not
diene monomer) and fluorinated ethylene pro-
analyzed for inorganic contaminants), 4) a rinse
pylene (FEP, another type of Teflon). In their first
with known-quality water, 5) a rinse with an or-
two field tests, they used a stainless steel sub-
ganic desorbing agent (isopropanol, acetone, or
mersible pump with the rubber hose. They
methanol), 6) a rinse with deionized water, and
pumped well water contaminated with TCE, at
following all of this with air drying. Again, this
concentrations of approximately 860 to 1100 ppb,
method did not provide any scientific studies
for 2 hours. They then steam cleaned the exterior
that justify using this procedure.
of the pump and hose and pumped clean water
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