Iowa Administrative Code › Agency 567 - Environmental Protection Commission › Title IX - Spills and Hazardous Conditions › Chapter 137 - Iowa Land Recycling Program and Response Action Standards › Rule 567-137.8 - Site Assessment

Current through Register Vol. 47, No. 3, July 24, 2024
(1)
Purpose.
The purpose of the site assessment is to define the
				nature and extent of contamination, along with identifying likely exposure
				pathways, with the aim of characterizing potential, current and future risks
				and making an informed decision concerning an appropriate response in the
				context of probable future land uses at the site and in the surrounding area.
				Assessment is to be conducted with the recognition that contaminant fate and
				transport may alter the current areal extent and depth of contamination. It is
				recognized that the scope of such an assessment may be appropriately varied
				dependent upon interrelated factors including the nature and severity of the
				contamination, the complexity of specific details of the site and its setting,
				and the nature of the chosen response, if known.
(2)
Site assessment plan.
The participant is encouraged, but not required, to submit for department
				review a site assessment plan, prior to proceeding with the site assessment.
				Participants choosing to initiate site assessment without department review and
				approval of a work plan shall notify the department in writing of their
				intentions. Likewise, participants choosing to proceed to the risk
				evaluation/response action phase in accordance with rule 137.9(455H) without
				seeking review of the site assessment report shall give prior notice to the
				department of their intentions. The notice shall include a schedule for
				implementation and completion, a description of the area to be assessed and the
				scope of the proposed assessment to be undertaken, any planned construction
				activities in the affected area and a proposed date for submission of the site
				assessment report for department review. If the notice includes an intention to
				go directly to the risk evaluation/response action phase, it shall also include
				a general description of the site assessment results, a schedule for submission
				of the risk evaluation/response action document and the reasons for not
				requesting department review and approval of the site assessment report.
The plan is intended to lay out the rationale to be followed
				  in the conduct of the site assessment. The purpose for this optional stage is
				  to provide an opportunity for the participant and the department to reach a
				  consensus regarding the appropriate scope of the site assessment. The
				  development of a consensus should serve to diminish the likelihood that the
				  department will find the final site assessment to be deficient and, for the
				  benefit of the participant, to avoid the expenditures and time associated with
				  the collection of what may ultimately prove to be unnecessary data.
In order to accomplish this, it is suggested that the plan
				  should address relevant, known characteristics related to the site and its
				  history as well as plans for addressing pertinent details spelled out in the
				  subsequent sections on the site assessment and the site assessment report.
				  Departmental review may result in suggestions from the department regarding
				  perceived shortcomings or proposed activities which are deemed to be
				  unnecessary.
The participant may find it desirable to conduct some
				  preliminary investigation in order to develop a site assessment plan.
(3)
Site assessment
				details.
In order to meet the stated purpose of the site assessment,
				it will be necessary to characterize numerous attributes related to the
				enrolled site and its setting. The following objectives are intended to provide
				a framework in which to accomplish this purpose. It is recognized that these
				objectives may exceed the appropriate scope of some site assessments and that
				there may be situations in which it may be necessary to define additional
				objectives. Any such deviation would preferably be addressed in a site
				assessment plan. The department may also develop guidance documents that
				recommend more specific procedures for accomplishing site assessment
				objectives. Such guidance documents will be readily available to the public. In
				general, an acceptable site assessment should address the following items.
a. Identify and address the medium or media
				of concern associated with the contamination situation for which the site is
				enrolled. The regulatory classification or jurisdiction of contaminants shall
				be indicated if applicable and, if known, e.g., the compound is regulated under
				the Resource Conservation and Recovery Act (RCRA), Toxic Substances Control Act
				(TSCA), or Federal Insecticide, Fungicide and Rodenticide Act
				(FIFRA).
b. Characterize the
				nature, extent, and degree of contamination in both horizontal and vertical
				dimensions. This should involve appropriate sample numbers and locations within
				the contaminated area and beyond the area contaminated in excess of the
				background or statewide standard. Analyses should be conducted for the
				contaminants of concern, breakdown products, and other contaminants likely to
				be present at significant levels. The department may also require analyses for
				additional contaminants which are not the focus of enrollment in the program,
				but which may be of special concern. Special concerns might include waste
				handling or treatment problems posed by the additional contaminants, or
				unacceptable risks remaining unaddressed within the affected area, due to the
				presence of the additional contaminants. In the case of groundwater, attention
				should also be given to the possibility of contaminant accumulation in strata
				overlying confining layers and to the possible presence of non-aqueous phase
				liquids (NAPL). In the case of groundwater, more than one round of sampling
				shall be incorporated, appropriately separated in time. In the case of soils,
				particular attention should be given to characterizing shallow soil
				contamination, from zero to six inches in depth.
c. Characterize the nature of the source of
				contamination or propose a conceptual model explaining the presence of the
				contamination of concern.
d.
				Characterize local contamination maxima or hot spots for the purposes of
				evaluation against relevant standards and to identify handling or treatment
				concerns that they may pose.
e.
				Characterize the stratigraphy. This should be done to a depth extending to the
				first significant confining layer below the deepest contamination. Descriptions
				should rely primarily on results gathered in the site assessment, but relevant
				reference materials or geologic logs from other sources may be incorporated as
				a supplement.
f. Characterize the
				hydrologic properties of the site and its vicinity to a distance appropriate to
				the fate, transport and exposure concerns associated with the site. This
				characterization should consider both horizontal and vertical components of
				groundwater movement as well as other influences on groundwater hydrology such
				as pumping wells, injection wells, surface water bodies, effects of seasonal or
				precipitation-driven variability, and possible aquifer interconnections,
				including those related to existing or abandoned wells. Water level
				measurements, related to a common datum, screening of appropriate depth
				intervals, and determination of hydraulic conductivity will generally be
				considered as necessary.
g.
				Characterize physical and chemical properties of the site and its environs
				associated with contaminant fate and transport, e.g., percent organic matter,
				redox potential, soil bulk density, and transmissivity.
h. Characterize topographic and cultural
				features of the site and its immediate vicinity. Cultural features may include,
				but not be limited to, buildings, basements, paved areas, roadways, utilities,
				storage tanks and associated piping, piles, impoundments, wells, and waste
				disposal systems.
i. Evaluate
				concerns related to whether the contamination situation is dynamic or stable;
				if dynamic, address fate and transport and breakdown products
				appropriately.
j. Identify and
				characterize receptor or exposure concerns. This most clearly involves concerns
				for drinking water and exposures to contaminated soils, as suggested by the
				statewide standards, but additional concerns should be identified and addressed
				by the participant or the department, as the situation warrants, e.g., vapors
				to basements, threats to water supply lines, threats to surface waters, or
				environmental threats.
k.
				Characterize current and probable future uses of the site and its surroundings.
				If probable future uses differ significantly from current uses, then
				characterize them separately and conduct the assessment in a fashion which
				addresses concerns arising from the possible change in use.
l.. Evaluate the potential for contaminants
				to migrate from one medium to another. The following subparagraphs prescribe
				requirements for assessing potential migration of contamination from one medium
				to another. Requirements in the following subparagraphs may be waived if it can
				be demonstrated in accordance with procedures established in 567-Chapter 135 or
				the latest version of ASTM Standards related to the Phase II environmental site
				assessment process that migration of contamination from one medium to another
				will not cause a violation of the applicable standard in the receiving medium.
				The assessment activities prescribed in the following subparagraphs are
				intended to determine if significant migration of contamination from one medium
				to another has occurred. If evidence of significant migration of contamination
				from one medium to another (i.e., generally a contaminant concentration in the
				receiving medium in excess of the statewide standard) is discovered, full-scale
				characterization of the receiving medium may be required.
(1) The water from any pond or lake on the
				site or within 300 feet of the site shall be sampled and analyzed for the
				contaminants of concern, if it is reasonably possible that contaminants from
				the site could impact the pond or lake. Any surface stream that runs through
				the site or within 300 feet of the site should be sampled at a location
				downstream of any potential impact from the site and analyzed for the
				contaminants of concern. Depending on the characteristics of the contaminants
				(e.g., solubility), associated sampling and analysis of sediments may be
				required.
(2) Groundwater at the
				location most likely to be impacted by each known substantial area of soil
				contamination shall be sampled and analyzed for the contaminants of concern. If
				the area of soil contamination exceeds 10,000 square feet, additional
				groundwater samples may be required.
(3) Soil vapors in each area that is most
				likely to be impacted by known groundwater or soil contamination shall be
				sampled and analyzed for the volatile organic contaminants of concern. If the
				area of soil or groundwater contamination exceeds 10,000 square feet,
				additional soil vapor samples may be required. If vapors may be impacting an
				existing enclosed space, a soil vapor sample shall be collected from a location
				that is most likely to have vapor contamination adjacent to the enclosed space.
If the potential for the existence of problematic
				  concentrations of the vapors in the enclosed space cannot be dismissed based on
				  soil vapor sampling, sampling and analysis of vapors inside the enclosed space
				  may be conducted to determine whether or not a problem exists. Appropriate
				  measures for distinguishing between contaminant vapors originating from within
				  the enclosed space versus those from the external sources that are under
				  investigation may be made with the approval of the department.
Ambient air sampling may be required if a very large area or
				  extremely high concentrations of highly volatile contaminants exist in shallow
				  soil or evidence of vapor contamination exists, such as odors or a high vapor
				  reading on a vapor-screening instrument.
(4) If a water line exists within the zone of
				known organic contamination of soil, groundwater or soil vapor and the
				potential for significant diffusion of contaminants into the water line cannot
				otherwise be dismissed, a sample from the water line shall be collected at the
				nearest location where any impact may exist and that sample shall be analyzed
				for the organic contaminants of concern. All such samples should be collected
				at times following minimum movement within the water line (e.g., early morning
				following a weekend).
(4)
Site assessment report.
The site assessment report shall
				include the presentation of all information gathered relative to the foregoing
				description of the site assessment, arranged in appropriate sections of the
				report. It shall include a summary of preliminary information on which the site
				assessment is based, e.g., background and site history. The report shall
				discuss the sampling strategy and methods used in the assessment. The
				department encourages the use of innovative or screening techniques to expedite
				investigations and to control costs, provided that such techniques are approved
				by the department and are supported through verification by accepted scientific
				practices. The report shall also include a description of the quality
				assurance/quality control (QA/QC) protocols followed during the investigation.
				QA/QC protocols shall be consistent with accepted scientific practices,
				including those set forth in appropriate EPA or ASTM guidance or otherwise
				approved by the department.
The presentation should be organized so as to facilitate the
				  assimilation of information by the reader. Maps to be presented, as
				  appropriate, might include maps illustrating the location of the site in a
				  larger geographical context; maps showing cultural features associated with the
				  site and its environs; maps illustrating the contamination extent and
				  concentration in three dimensions; maps illustrating the site hydrology in
				  three dimensions; and maps illustrating receptors, potential receptors, and
				  relevant pathways of exposure. Cross-sectional diagrams should be included to
				  illustrate stratigraphy, geological boring information, and hydrologic and
				  contaminant factors with depth. Tables and graphs should be designed for the
				  purpose of summarizing data in a meaningful fashion, including information
				  about successive rounds of sampling. Appendices should include well logs,
				  copies of laboratory analytical reports, and raw data used to ca1culate
				  parameters presented elsewhere in the report. Appended material shall be
				  labeled in a fashion permitting the cross-referencing of appended materials and
				  the body of the report.
(5)
Approval of site assessment report.
The department suggests,
				but does not require, that the site assessment report be approved prior to
				proceeding with the subsequent risk evaluation/response action phase. Unless
				notice has already been given prior to initiation of the site assessment,
				participants choosing to proceed to the risk evaluation/response action phase
				without department review and approval of the site assessment report must
				notify the department in advance as provided in subrule 137.8(2).
(6)
Public notification.
Before or upon completion of the site assessment, the participant shall provide
				the department with the names and addresses of the owners and occupants of all
				property adj acent to the site enrolled in the land recycling program and any
				additional properties where contaminants from the enrolled site have migrated
				or are likely to migrate in the future. The department shall notify by direct
				mailing all such property owners and occupants, the city or county in which the
				property is located, and officials of any potentially impacted public water
				supply of the site's enrollment in the land recycling program and of the scope
				of work described in the participation agreement. The department shall give the
				notified parties the opportunity to obtain updates regarding the status of
				activities relating to the site that is enrolled in the land recycling program.
				The department may also require the participant of a site enrolled in the land
				recycling program to publish public notice in a local newspaper if the
				department determines that widespread interest in the site exists or is likely
				to exist. The department may provide additional opportunities for public
				participation if, after consultation with the participant, the department
				determines such opportunities are warranted.