Environmental Health Criteria 214

HUMAN EXPOSURE ASSESSMENT
A sophisticated vacuum sampling device, called the HVS3, was
designed to make dust collection efficiency from different surface
types as consistent as possible (ASTM, 1993). The HVS3 is a
high-powered vacuum cleaner equipped with a nozzle that can be
adjusted to a specific static pressure and air flow rate to allow for
consistent dust collection. The sampler uses a cyclone to separate
particles greater than about 5 mm from the air stream and collects
them in a 250 ml sample bottle screwed into the bottom of the cyclone.
Smaller particles are not collected. The HVS3 can collect large,
representative samples of settled dust from indoor surfaces, such as
rugs and bare floors, and dust from outdoor surfaces, such as streets,
sidewalks, lawns and bare, packed dirt. However, it cannot be used to
sample from small or uneven areas because of the large size of the
device. The HVS3 has been used in numerous exposure assessment studies
to measure toxic metals and pesticides in settled dust. The sampler is
not made from standard materials and is therefore relatively expensive
to buy. Interested readers should consult the ASTM standard method
(D5438-93) for more information on the specifications and availability
of the HVS3 sampling device (ASTM, 1993).
Farfel et al. (1994) modified the HVS3 by using the same cyclone
as in the HVS3 but with a commercially available handheld vacuum to
make the device smaller and more portable. These authors also used
flexible tubing as the pickup nozzle to allow small surfaces, such as
windowsills, to be sampled. This modification, called the BRM
method, does not allow control of either the sampling flow rate or
the static pressure at the pickup nozzle. The ASTM standard method for
the HVS3 does not apply to the BRM, except for its description of the
cyclone.
Another settled dust vacuum sampling method that has been used in
several research studies, the Sirchee-Spittler method, is a
hand-held, battery-powered vacuum unit (Rinehart & Yanagisawa, 1993;
Weitzman et al., 1993; Aschengrau et al., 1994). The sampler is simple
to use, highly portable and can cover large areas in a short period of
time. Unfortunately, there are not many Sirchee-Spittler sampling
devices in service and its availability to researchers worldwide is
therefore limited.
8.2.2.3 Sedimentation methods
Sedimentation methods involve measuring the amount of dust which
settles on a clean, preweighed surface over a given period of time.
Such procedures can make use of a simple collecting cup (Aurand et
al., 1983) or a flat plate (Pellizzari et al., 1995). After a
specified period of time, the sample is collected and measured, and
the dust is then analysed in a laboratory. Data from the German
Environmental Survey (Schulz et al., 1995) on domestic dust
precipitation is given in Table 30. Sedimentation methods are useful
for collecting samples over a specific period of interest (e.g., a
day, week or month). In contrast, the integration times of settled
dust samples collected using the wipe or vacuum methods described
above are not well characterized.
Page 142 of 284
Table 30. Sedimentation of elements in indoor dust, Germany 1990-1992 (Schu
Element No. of No. of Percentiles Maxim
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