Environmental Health Criteria 214

HUMAN EXPOSURE ASSESSMENT
Cost Low Low Low Medium High High
Simple method Yes Yes Yes Yes Yes Yes
Loading Yes Yes Yes No Yes Yes
Concentration No No Yes Yes Yes Yes
Sieving possible No No No Yes No No
Portable Yes Yes Yes No Yes Yes
Samples small areas Yes Yes Yes Yes Yes Yes
AC powered No No No Yes Yes Yes
Size selective No No No No Yes No
8.2.2.1 Wipe sampling methods
A common wipe sampling method uses premoistened towelettes to
wipe a measured area defined inside a template placed on the sampling
surface (Vostal et al., 1974; US HUD, 1995). Typical sampling areas
are in the range of 0.1 m 2 and masking tape is commonly used as a
template. The actual surface area inside the template is not critical
as long as it is measured and recorded. However, sampling areas
greater than 0.2 m 2 are not recommended because larger areas cannot
be wiped effectively with one towelette. This method has been used
extensively in the USA to measure lead amounts in settled dust, but
has also been used to ascertain levels of cadmium, chromium and
arsenic, as well as many other metals and organic compounds.
With the HUD method, the person collecting the sample should
wear a clean disposable glove on the hand that will come in contact
with the towelette. To collect a sample, the surface inside the
template is wiped with a towelette back and forth in vertical
S-strokes. The exposed side of the towelette is then folded inward,
exposing a clean portion, and the same area is wiped with horizontal
S-strokes. The towelette is folded once more, again exposing a clean
portion, and the area is wiped a final time with additional vertical
S-strokes. The towelette is then folded, exposed side in, placed into
a clean sealable plastic bag or container, and sent to a laboratory
for analysis.
Several researchers have used preweighed wipe material, such as
cotton gauze or filter paper, in order to determine the quantity of
settled dust collected (Lepow et al., 1974; Stark et al., 1982;
Rabinowitz et al., 1985; Levallois et al., 1991). The sampling
material is then reweighed in a laboratory after sample collection.
Theoretically, the weight of total dust collected can be calculated by
subtraction, and toxicant concentration could be determined after
analysis on a mass basis.
An important issue that needs to be addressed when using the
preweighed wipe methods is the potential loss of sampling material or
dust during handling in the field or laboratory. Furthermore,
Chavalitnitikul & Levin (1984) noted that filter paper tends to fall
apart when rough surfaces are wiped. Loss of sampling material in the
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