Environmental Health Criteria 214

HUMAN EXPOSURE ASSESSMENT
downwind of potential sources of toxins. The toxins were found to be
below regulatory levels, with the exception of hydrogen fluoride and
hydrogen chloride.
Fifty-six VOCs and 8 airborne trace metals were sampled at
residences, office, cars and recreation areas. Each personal exposure
study had a 24-h exposure profile prepared using the concentrations in
each environment and the time spent in that environment. It was found
that the period of highest exposure to VOCs was during the commute,
with outdoors the lowest. The highest exposure to heavy metals was
inside the home.
Heavy metal concentrations in garden produce and soil were below
regulatory limits, but cadmium and mercury levels were higher in the
Windsor area than in rural areas. Indoor air exposure had
disproportionately higher health risk than did outside air. Inhalation
was found to be more important than dermal absorption and ingestion
for these compounds.
The exposures to dioxins and furans were each less than one
quarter of the tolerable daily dose. Mercury was 60% of the tolerable
daily dose, and could be a health risk because of its persistence in
the environment and bioaccumulation. The additive risks for all of the
studied air pollutants were approximately 1 × 10- 5 .
12.7.4 Pesticide exposure study
The Non-Occupational Pesticide Exposure Study (NOPES) was
designed to examine human exposure to 32 pesticides and pesticide
degradation products in two cities in the USA: Springfield,
Massachusetts and Jacksonville, Florida (Whitemore et al., 1994). The
two goals of the project were to develop instrumentation, laboratory
procedures and surveys needed for a study of non-occupational exposure
to pesticides and to determine non-occupational exposure to
pesticides.
The NOPES study used TEAM in determining exposure levels. A
probability sampling design was used to make statistical conclusions
on the health risks of the pesticides. More participants were chosen
from high-exposure groups in order to facilitate estimation of risk
levels. Jacksonville was chosen as the high-use region and Springfield
as the low-use area. The two sites were studied during the summer of
1986 (Jacksonville only), the spring of 1987 and the winter of 1988.
The study population varied between 49 and 72 people. The study
examined skin, food and water as routes of exposure, but focused on
air as the primary route of exposure. Twenty-four-hour personal,
indoor and outdoor samples were collected on polyurethane foam and
analysed by gas chromatography/mass spectrometry and gas
chromatography/electron capture detection. Personal samples were used
as well as fixed monitors inside and outside the home. A questionnaire
was administered after the end of the 24-h period to determine the
activities of the subjects.
The lowest concentrations were found in the winter and the
highest concentrations in the summer, with the spring levels
intermediate. Readings from the indoor monitors were correlated with
personal monitors, but neither was comparable to the lower
measurements from the outdoor monitors. The relative importance of
dietary and respiratory routes of exposure varied between pesticides:
most of the chemicals had the diet as the main routes of uptake, but
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