Current through Register Vol. 48, No. 38, September 20, 2024
a) Exclusion of Exposure Route
Site information may demonstrate that there is no actual or
potential impact of contaminants of concern to receptors from the indoor
inhalation exposure route. In these instances, a demonstration excluding the
exposure route shall be submitted to the Agency for review and approval. A
submittal under this Section shall include the following information:
1) A description of the site, physical site
characteristics, existing and planned buildings, and existing and planned
man-made pathways; and
2) A
discussion of the possibility of the route becoming active in the
future.
b) Exclusion of
Exposure Route Using Building Control Technologies
Any proposals to use building control technologies as a means
to prevent or mitigate human exposures under the indoor inhalation exposure
route that differ from the requirements of Subpart L shall be submitted to the
Agency for review and approval. A submittal under this Section shall include
the following information:
1) A
description of the site and physical site characteristics;
2) The current extent and modeled migration
of contamination;
3) Geology,
including soil types and parameters;
4) Results and locations of sampling
events;
5) Scaled map of the area,
including all buildings and man-made pathways;
6) A description of building characteristics
and methods of construction, including a description of man-made
pathways;
7) Present and
post-remediation uses of the land that are at issue due to the area of
contamination, including human receptors at risk;
8) A description of any building control
technologies currently in place or proposed for installation that can reduce or
eliminate the potential for completion of the exposure route, including design
and construction specifications;
9)
Information regarding the effectiveness of any building control technologies
currently in place or proposed for installation and a schedule for performance
testing to show the effectiveness of the control technology. For buildings not
yet constructed, an approved building control technology shall be in place and
operational prior to human occupancy;
10) Identification of documents reviewed and
the criteria used in the documents for determining whether building control
technologies are effective and how those criteria compare to existing or
potential buildings or man-made pathways at the site; and
11) A description as to how the effectiveness
of the building control technologies will be operated and maintained for the
life of the buildings and man-made pathways, or until soil gas and groundwater
contaminant concentrations have reached remediation objectives that are
approved by the Agency. This includes provisions for potential extended system
inoperability due to power failure or other disruption.
c) Calculations and Modeling Used to
Establish Soil Gas Remediation Objectives
The calculations and modeling shall account for contaminant
transport through the mechanisms of diffusion and advection. Proposals to use
soil gas data, including sub-slab samples, to establish remediation objectives
for the indoor inhalation exposure route that differ from the requirements of
Section
742.227
shall be submitted to the Agency for review and approval. A submittal under
this Section shall include the following information:
1) Scaled map of the area, showing all
buildings and man-made pathways (current and planned);
2) The current extent and modeled migration
of contamination;
3) Geology,
including soil types and parameters;
4) Depth to groundwater (including seasonal
variation) and flow direction;
5)
Location of soil gas sampling points;
6) A discussion of soil gas sampling
procedures that, at a minimum, addresses the following:
A) sampling equipment;
B) soil gas collection protocol, including
field tests and weather conditions; and
C) laboratory analytical methods.
d) Calculations and
Modeling Used to Establish Soil Remediation Objectives
The calculations and modeling shall account for contaminant
transport through the mechanisms of diffusion and advection. Any proposals to
use soil data in lieu of soil gas data to establish remediation objectives for
the indoor inhalation exposure route shall be submitted to the Agency for
review and approval. A submittal under this Section shall include the following
information:
1) Scaled map of the
area, showing all buildings and man-made pathways (current and
planned);
2) The current extent and
modeled migration of contamination;
3) Geology, including soil types and
parameters;
4) Location of soil
sampling points;
5) A discussion of
soil sampling procedures that, at a minimum, addresses the following:
A) sampling equipment;
B) soil collection protocol, including field
tests and weather conditions; and
C) laboratory analytical methods;
6) Mathematical and technical
justification for the model proposed; and
7) Demonstration that the model was correctly
applied.
e) Calculations
and Modeling Used to Establish Groundwater Remediation Objectives
The calculations and modeling shall account for contaminant
transport through the mechanisms of diffusion and advection. Proposals to use
groundwater data to establish remediation objectives for the indoor inhalation
exposure route that differ from the requirements of Sections
742.805
and
742.812
shall be submitted to the Agency for review and approval. A submittal under
this Section shall include the following information:
1) Scaled map of the area, showing all
buildings and man-made pathways (current and planned);
2) The current extent and modeled migration
of contamination;
3) Geology,
including soil types and parameters and the thickness of the capillary
fringe;
4) Depth to groundwater
(including seasonal variation) and flow direction;
5) Results and locations of groundwater
sampling events;
6) Mathematical
and technical justification for the model proposed; and
7) Demonstration that the model was correctly
applied.
