from the tubing used with the bladder pump.
contamination. Given that a hot air drying step is
Based on the results of our previous study (Parker
critical to adequately decontaminate a ground-
and Ranney 1997b), which showed that heating at
water sampling device, then how practical is this
105C was sufficient to reduce residual contami-
approach?
nation of several VOCs from the most sorptive
Clearly this method is feasible for decontami-
polymer tested (PTFE), we believe that the re-
nating smaller devices such as a bailer. However,
sidual contamination could be removed from this
because this method requires 24 hours drying
tubing also. There are several ways this might be
time and a distilled water rinse, decontamination
accomplished: using a higher temperature than
most likely would not be conducted in the field
70C, blowing hot air through both the air line and
but rather at a support station (motel room, mo-
bile laboratory, etc.). Because of the time required
exterior and interior of the tubing by placing the
to oven dry a sampling device, additional sam-
tubing in an oven or some type of heated com-
pling equipment would have to be purchased so
partment. The results from the third TCE study
that some was being decontaminated while the
indicate that there should be more focus on clean-
rest was in use.
ing the outside of all the tubing exposed to the
Our initial studies (Parker and Ranney 1997b)
indicated that, for VOCs, heat (~105C) alone with-
contaminants.
Based on the results of these two studies, we
out any detergent washing was sufficient for re-
feel that the most effective way to decontaminate
moving VOCs from the most sorptive polymer
groundwater sampling devices exposed to trace
tested, PTFE. Although we did not test this, these
levels of organic contaminants is to use a hot
data suggest that perhaps this decontamination
detergent wash, hot water rinse, and DI water
method could be further streamlined as follows:
rinse, followed by hot air drying (~105C) for 24
Wash with ambient temperature detergent
hours. The exact drying protocol would be based
solution (using tap water).
upon information supplied by the manufacturer
Rinse with tap water.
Hot air dry (~105C) for ~24 hours.
on the ability of the materials in the device to
withstand this treatment.
This procedure eliminates having to provide
It should be noted that we did not decontami-
hot water for washing and rinsing and DI water
nate devices that had been exposed either to neat
rinses and thus is logistically less demanding.
organic solvents or to very high concentrations of
Presumably, any residual organic contaminants
those chemicals (approaching their aqueous solu-
would be removed during the hot air drying
bility). At some point this issue should also be
procedure. Small portable drying ovens could
addressed. This would be especially important
be powered by an electric generator or gas driven.
for devices that are made of fluoropolymers, which
This streamlined procedure appears feasible but
would not be destroyed by this environment but
requires additional testing.
could sorb large quantities of these chemicals.
However, there are more issues to work out
Also, we did not address decontamination of the
with respect to decontaminating groundwater
nylon line used with the bailer or decontamina-
sampling pumps. Some pumps have shut-off
tion of groundwater sampling devices with re-
switches for when water temperatures exceed a
spect to inorganic contaminants.
certain limit. To circumvent this problem, it might
be possible to pump ambient temperature rinse
water (as described in the streamlined method)
through the device and then gently heat the de-
FUTURE APPLICATIONS
vice. Ideally, some type of device that heats the
The results from our previous studies (Parker
inside and outside of the pump and tubing and is
and Ranney 1997b) have shown the critical im-
vented to allow air exchange would be best. This
portance of hot air drying for removing organic
could be a drying oven or some type of "heated
contaminants from permeable polymeric materi-
suitcase" that could be produced by the pump's
als, especially VOCs. Those studies also showed
manufacturer. These devices would provide a con-
that rinsing with organic solvents was not effec-
stant temperature for the entire length of the tub-
tive for removing organic contaminants. The re-
ing and for all components of the sample tubing,
sults from the third TCE study also showed that
including the compressed air tubing. However,
air drying a bladder pump for a week at room
the size of some pumps limits the practicality of
temperature was not sufficient to remove TCE
this solution. In addition, it is difficult to coil the
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