Page 182 - Materials Chemistry, Second Edition

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of potential exposure routes and populations potentially at risk from exposures, and
the estimation for various exposure periods (short- and long term).
The air pathways methods of analysis in relation to air pollutant emission find
several specific applications in situations such as the estimation of VOC emissions
rates from landforms — sludge, landfills, etc. (see, e.g., Mackay and Leinonen,
1975; Mackay and Yeun, 1983; Thibodeaux and Hwang, 1982) and particulate
inhalation exposure from fugitive dust (see, e.g., CAPCOA, 1990; U.S. Environ-
mental Protection Agency, 1989).

4.9.3 POTENTIAL RISKS OF CONTAMINANT VAPORS INTO BUILDING

The migration of subsurface contaminant vapors into buildings can become a
very important source of human exposure via the inhalation route. Although the
degree of dilution in the indoor air of a building is generally far less than the
situation outdoors, contaminant vapors entering or infiltrating into a building
structure may represent a significant risk to occupants of the building. An appli-
cation could be a risk characterization scenario involving exposure of populations
to vapor emissions from cracked concrete foundations or floors that can be
determined for this situation, in order to adopt responsible risk management
and/or mitigating measures.

4.9.4 ENVIRONMENTAL ASSESSMENT AND CHARACTERIZATION
Environmental assessments are invariably a primary activity in the general processes
involved in the management of environmental assessment. The main goal of envi-
ronmental assessments is to determine the nature and extent of potential impacts
from the release or threat of emission of hazardous substances.
First, a representative sampling from the potentially contaminated media must
be collected, along with historical data and sufficient details about the likely envi-
ronmental contaminants. Sampling programs can be designed to search for specific
chemical pollutants that become indicator parameters for sample analysis. For
instance, a multimedia approach to environmental characterization can be adopted
for most environmental pollution problems so that the significance of appropriate
field sampling and analysis procedures increases. The activities included are
expected to provide high-quality environmental data needed to support possible
corrective action response decisions. To accomplish this, samples are collected and
analyzed for the pollutants of concern. Proper protocols in field sampling and
laboratory analysis procedures are used to help minimize uncertainties associated
with data collection and evaluation activities.
The results from these activities will be a complete analysis of the pollutants
detected in the environment. Risk assessment techniques and environmental char-
acterization are typically applied to provide the development of effectual environ-
mental characterization programs. Thus, the information obtained is used to evaluate
current and potential future risks to human health and the environment. In addition
to information about the nature and magnitude of potential risks associated with

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