Environmental Health Criteria 214

HUMAN EXPOSURE ASSESSMENT
predesigned depth of the auger. Alternatively, a predetermined amount
of surface soil may be scooped with a small trowel, with less precise
definition of sampler depth. In either case, the sample is stored in a
clean, inert container and transferred to the laboratory for analysis.
8.2.1.2 Soil contact and intake measurements
Skin contact has been measured by methods similar to those used
for settled dust (e.g., self-adhesive labels, hand wipes), and
controlled application followed by recovery of the fraction of
deposited soil on the skin (Lepow et al., 1975; Roels et al., 1980;
Que Hee et al., 1985). The amount of soil that adheres to the skin
depends on a number of variables including soil properties (e.g.,
water content, particle size, carbon content), region of the body and
activity (Kissel et al., 1996). A number of studies have attempted to
estimate soil ingestion based on hand adherence estimates and
scenarios of activities, as well as analyses of soil tracers (e.g.,
concentrations of aluminium, silicon or titanium) (e.g., Calabrese et
al., 1989, 1990).
8.2.2 Settled dust
Although indoor dust is becoming recognized as a reservoir for
many toxic substances and a potentially significant source of human
exposure, there is no uniform standard for sampling settled dust. More
than 15 methods have been described in the literature to date.
Scientists do not yet agree either on the definition of settled dust
or on the methods to measure it. This issue is further complicated by
the fact that results from one settled dust sampling method may not be
directly comparable to results from others. Even with these
limitations, settled dust sampling methods have been used effectively
and provided valuable insights into the total human exposure paradigm.
Selected sampling methods are described below to give the reader
an indication of the diversity of techniques available. The list is by
no means exhaustive. Several of the methods described are simple to
use and readily available to researchers worldwide. Brief descriptions
of how to use the simpler methods are provided. Other methods require
specialized equipment that is relatively expensive and may be
difficult to obtain in some regions of the world. The methods are
distinct from one another, but most fall into three categories: wipe,
vacuum sampling and sedimentation methods. These methods are widely
used for sampling settled dust indoors; however, in principle they may
be applicable for outdoor settled dust as well. Bulk sample collection
methods, such as sweeping, are not covered here. Key features of the
various methods for collecting settled dust samples described in this
chapter are summarized in Table 29.
Page 139 of 284
Table 29. Comparison of features of different methods for collected settled
Feature Common HUD Preweighed Commercial DVM Rota
wipe wipe sample vacuum vacuum vacu
Widely available Yes Yes Yes Yes No No
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