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Environmental Assessments, Monitoring, & Modeling Under Subpart X
Environmental Assessments (Characterization of Media)
Monitoring of Air and Groundwater
Modeling Air and Groundwater
Air and Groundwater References
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Environmental Assessments, Monitoring, and Modeling Under Subpart X
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This section discusses approaches to monitoring and
modeling potential releases from Subpart X units.
Some emphasis is placed on OB/OD units because
of the difficulty in monitoring and modeling air
emissions from such units. The chapter consists of
three major sections: environmental assessments,
monitoring, and modeling. The monitoring and
modeling sections include subsections on air and
groundwater. |
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Environmental Assessments (Characterization of Media)
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| Environmental Assessments, Monitoring, and Modeling Under Subpart X |
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Description: This section discusses approaches to monitoring and
modeling potential releases from Subpart X units.
Some emphasis is placed on OB/OD units because
of the difficulty in monitoring and modeling air
emissions from such units. |
| Environmental Assessments (Characterization of Media) |
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Description: Environmental assessments are performed to
characterize the potential effects on each of the
environmental media (air; groundwater and the
subsurface environment; and surface water,
wetlands, and surface soils) caused by releases from
a Subpart X unit. |
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Monitoring of Air and Groundwater
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| Monitoring Air and Groundwater |
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Description: Monitoring focuses on the actual gathering
of data relevant to the operation of a unit. The data
obtained is used in characterizing the risk to human
health and the environment. |
| Air Monitoring |
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Description: When considering releases to the air from a Subpart
X unit, several factors must be examined in
determining the fate and transport of contaminants.
Contaminants released to the air behave very
differently in different atmospheric conditions. |
| Emissions Qualifications |
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Description: Generally, two types of analyses are employed to
quantify emissions from a Subpart X unit: emission
monitoring and emission modeling. The results of
emission quantification analyses are used in
dispersion modeling analyses to determine
downwind impacts and can be used to determine
compliance with emission standards. |
| Meteorological Monitoring |
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Description: A permit applicant should collect on-site
meteorological data, if possible. However, if this is
not possible, representative data may be available
from a nearby facility, a university, or a governmental
agency. |
| Compliance Monitoring |
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Description: Procedures for and frequencies of monitoring,
testing, collection of analytical data, inspections,
response, and reporting must ensure compliance
with 40 CFR §264.601. |
| Groundwater Monitoring |
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Description: A hydrogeologic assessment must be submitted as
part of the Subpart X permit application to
demonstrate compliance with environmental
performance standards related to potential effects on
groundwater and the subsurface environment (EPA
1986; 1992). Specific performance standards that
must be addressed in the hydrogeologic assessment
are set forth in 40 CFR §264.601(a). |
| Soil Monitoring |
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Description: The permit application must address sampling of
surface and subsurface soils in, and around, the
Subpart X unit, specifically OB/OD unit(s). |
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Modeling Air and Groundwater
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| Modeling Air and Groundwater |
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Description: When conducting a detailed media assessment, a
permit applicant may use either monitoring or
modeling, or a combination of the two, to determine
concentrations of contaminants that are the result of
releases from a Subpart X unit. |
| Air Dispersion and Emission Modeling |
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Description: The models that simulate the transport and
dispersion of air contaminants from the point of
release to potential receptors use known data on the
characteristics of a contaminant release and the
atmospheric conditions as input to calculate air
concentrations and deposition values at almost any
location specified by the user. |
| Groundwater Modeling |
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Description: This section provides information regarding
hydrogeological characterization and model selection
to assist permit writers in evaluating modeling results
submitted by Subpart X permit applicants. |
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