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PHASE II ESAINVESTIGATING IDENTIFIED CONCERNS
PHASE II ESA
Why do we do it? To provide information relevant to:＞ Assessing whether there has been a release
＞ Meeting continuing obligations of landowner under CERCLA liability defenses
＞ Qualifying for a brownfields remediation grant
＞ Identifying, defining and evaluating property conditions associated with target
analytes that could present a risk to human health or the environment and
therefore result in potential liability
＞ Allocating business environmental risk
＞ Supporting liability disclosures
PHASE II ESA
How do we do it?
＞ ASTM E 1903-11 for most initial investigations
＞ Can also be informed by multiple agency and regulatory program
standards, e.g.:
• OEPA Voluntary Action Program (VAP)
• RCRA Corrective Action
• CERCLA Site Assessment
PHASE II ESA: CONCEPTUAL SITE MODEL
ASTM Definition:
＞ A representation of hypothesized current site conditions, which
describes the physical setting characteristics of a site and the
likely distribution of target analytes that might have resulted from
a known or likely release, and which is based on all reasonably
ascertainable information relevant to the objectives of the
investigation and the professional judgment of the Phase II
Assessor.
PHASE II ESA: CONCEPTUAL SITE MODEL
What do we know or suspect through our observations and
data sources?
＞ Site buildings, site and nearby soils, groundwater and bedrock
＞ Suspected or known releases
And what do we need to investigate as a result?
＞ Confirm presence or absence of releases
＞ Define risks to human health and the environment
Goal: Redevelop Site for Senior Housing
Existing building – former auto dealer, became F.O.E hall
Site visit concerns, including workshop across street
Drums behind building showed signs of leaking
1928 Sanborn: auto-related uses and buried canal nearby
PHASE II ESA: CONCEPTUAL SITE MODEL
What do we know or suspect?
＞ Historical filling station, southwest corner
＞ Historical underground tanks north of northeast buildings
＞ Historical auto-related uses
＞ Damaged drums near surface drain on northwest building corner
＞ Possible solvent and/or petroleum use in workshop across street
＞ There also were additional garages and filling stations in the
surrounding area
PHASE II ESA: CONCEPTUAL SITE MODEL
More of what we know or suspect
＞ Groundwater projected to flow toward the Tuscarawas River,
located approximately 1,000 feet west of the site, BUT
＞ Former Miami & Erie Canal located under 1st Street SW – could
complicate near-surface flow patterns
＞ Hydrogeological sources predict sandy loam surface soils over
sand and gravel aquifer, but surface soils were likely altered by
the past development and subsequent demolition
PHASE II ESA: CONCEPTUAL SITE MODEL
What do we need to investigate as a result?
＞ Are tanks or tank piping still present?
＞ Did the drums near the surface drain cause a release into soils
around the underground drain piping?
＞ Did the auto-related activities on the site and in the area result in
contamination at the site?
＞ Where (depth, formation) is groundwater and which way is it
moving?
PHASE II ESA: CONCEPTUAL SITE MODEL
Always check for existing data!
＞ OEPA files
＞ BUSTR files
＞ Health Department records of wells, septic systems, etc.
Why spend the money to repeat investigations someone
else has already done? Use existing data to refine the site
conceptual model.
Questions?
PHASE II ESA: INVESTIGATIVE METHODS
Investigation methods can be divided into:
＞ Direct observation and sampling vs. remote sensing
＞ Aboveground vs. subsurface
In general, lower disturbance (of soil or building materials)
and simpler technology equals lower cost
PHASE II ESA: INVESTIGATIVE METHODS
Aboveground, direct observation and sampling:
＞ Surface soils, surface water, sediments
＞ Indoor air
＞ Outdoor air (much less commonly used)
Target analytes (suspected contaminants) drive analytical
methods, which are the main cost driver
PHASE II ESA: INVESTIGATIVE METHODS
Aboveground, remote sensing
METHOD DETECTS LIMITATIONS
Magnetometer Buried metal (tanks, drums, piping)
Depth, surface metal or rebar interference
Ground-penetrating radar (GPR)
Changes in density, texture (buried
materials, voids)
Clay soils, damp soils, high subsurface
variability
Seismic reflection Changes in density Natural & man-made noise (traffic, etc.)
PHASE II ESA: INVESTIGATIVE METHODS
Subsurface, remote sensing
＞ Many instruments have modified versions that can be used in a
soil boring or monitoring well:
• Dissolved oxygen, temperature, pH, conductivity
• Flow (groundwater can flow up and down in an aquifer as
well as sideways)
• Seismic reflection/penetration
PHASE II ESA: INVESTIGATIVE METHODS
Subsurface, direct observation and sampling:
＞ Test pits
＞ Soil borings – hydraulic push, hollow-stem auger, air rotary,
hydrosonic, cable tool
＞ Groundwater wells – temporary vs. permanent, bailers vs. pumps
vs. passive samplers
＞ Soil gas
PHASE II ESA: INVESTIGATIVE METHODS
Remember: the driller’s and sampler’s technique will have
a large effect on the usefulness of the information collected
and the validity of the samples.
PHASE II ESA: FIELD INVESTIGATIONS
Questions to remember in talking to the consultant:
＞ What will we know if the tests are positive?
＞ What will we know if the tests are negative?
＞ Will we have defined the site and the concerns well enough to
meet our objectives? (Make sure objectives are clear!)
Field investigation may require multiple phases to meet the
objectives, depending on what they are.
Consider the main concerns
Magnetic survey for tanks
Soil borings and temporary wells in areas of concern
Permanent wells for confirmation and groundwater flow
Questions?And now for a reminder…
“PHASE III” ESARISK AND REMEDIATION
“PHASE III ESA” – RISK AND REMEDIATION
To address concerns identified for a site:
＞ Know the properties of the contaminants
＞ Understand the ways in which those contaminants might affect
property users, the environment and continuing obligations under
CERCLA defenses or other regulatory programs
＞ Limit exposure by removing, treating in place or blocking/
redirecting the contaminants
“PHASE III ESA” – RISK AND REMEDIATION
Exposure＞ Humans exposed through:
• Ingestion
• Inhalation
• Absorption (and skin injury)
＞ Impacts to ecological resources
• Plants
• Animals/birds/insects
• Fish/aquatic species
Media＞ Contamination can be found in:
• Soil
• Groundwater
• Surface water, sediments
• Indoor/outdoor air
• Building materials
• Consumer goods
• Plant matter/living tissue
“PHASE III ESA” – RISK AND REMEDIATION
Migration
＞ Solids can be blown, tracked, deposited and hauled, and can
dissolve, float or sink or be suspended in liquids
＞ Liquids can flow, float, sink, percolate through, be absorbed by
and evaporate
＞ Gases can diffuse in open air and through cracks and porous
materials, including soil, and can dissolve into liquids
“PHASE III ESA” – RISK AND REMEDIATION
At the case study site: magnetic survey found former filling
station piping; possible tanks under sidewalk addressed
during demolition/construction
＞ Soil and groundwater sampling in the vicinity of piping did not
show contaminants, so no remediation was needed
＞ No tanks or contaminants were found beneath the sidewalk north
of the F.O.E. building during demolition
“PHASE III ESA” – RISK AND REMEDIATION
At the case study site: semi-volatile organic compounds
and buried building materials found in former garage
location＞ Building materials removed to prepare site for redevelopment
＞ Contaminants detected at low levels and well below the ground
surface – no significant vapors expected and with the building
over the area, the soils will not be excavated and rainwater will
not percolate through. No other mitigation was needed.
“PHASE III ESA” – RISK AND REMEDIATION
Risk assessment
＞ Define concentrations of contaminants
＞ Evaluate exposure pathways to determine which are complete
• For example, volatile contaminant in soil travels as gas
through soil formation and building foundation to indoor air
＞ Could the known contaminant concentrations cause an
unacceptable risk to human health or the environment?
• 1 in 1,000,000 vs. 1 in 100,000
“PHASE III ESA” – RISK AND REMEDIATION
Screening levels and action levels
＞ Developed by making assumptions about typical conditions, then
calculating the concentration of a contaminant that is the
threshold for risk
＞ If exceed screening levels, either move to more site-specific
evaluation or take remedial action
＞ Action levels are specific to regulatory programs; exceeding them
results in prescribed actions
“PHASE III ESA” – RISK AND REMEDIATION
At the case study site: groundwater contaminated with
volatile organic compounds (solvents)
＞ Not drinking water, no plans to use for irrigation
＞ Concern over vapor diffusion through ground and into building
addressed through passive sub-slab vapor removal system
(“radon system”) and post-construction indoor air sampling to
confirm that active removal was not needed
“PHASE III ESA” – RISK AND REMEDIATION
At the case study site: Arsenic was detected in two soil
samples on the north part of the site at unacceptable levels
＞ Surface soils removed and replaced; adequate removal
confirmed by sampling the edges of the excavation
＞ Some soils allowed to remain in place under building and
pavement; a maintenance plan and deed restriction were put in
place to ensure future maintenance of these controls
Soil arsenic discovered as a result of the soil borings and removed
or covered with clean soils during construction
“PHASE III ESA” – RISK AND REMEDIATION
Arsenic and naturally occurring chemicals of concern
＞ Arsenic is naturally occurring mineral, but can cause cancer at
low levels and is a poison at much higher concentrations
＞ If levels are naturally occurring, then remediation is not required
＞ Natural levels are location-specific; determine through sampling
an undisturbed nearby location
＞ Alternative: published area-specific surveys or the USGS
National Geochemical Survey, which provides county-level data
“PHASE III ESA” – RISK AND REMEDIATION
Recap: remediation and mitigation
＞ Basically three options: remove, prevent contact or treat in place
＞ Always have:
• Scientifically supportable and measurable endpoint
• Means of verifying that the approach is working
＞ If preventing contact, also have a plan to ensure maintenance of
the solution: deed restriction, O&M plan, tenant notification, etc.
Questions?
