Transcript Phase I Investigation – What Do You Do With The Results?

GFOA PS3260 Contaminated Sites Workshop
Thursday, November 14, 2013
Whitehorse, YT
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Role of the Environmental
Professional
Process – from screening to
determining financial
liability
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Screening of sites
Initial Assessment
◦ Ranking?
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Confirming contamination
Determining extent
Evaluating remediation strategies
Opinion of cost of remediation
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Inventory all properties
◦ By government body
◦ Screen to select sites that are no longer productive
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Non-productive property list
◦ Is it, or might it, be contaminated?
◦ Initial screening to select potential contaminated
sites
 Owner knowledge of site and adjacent sites
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An assessment of current and historic site
uses and conditions
◦ Historic records:
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Air photographs
City directories
Land use maps
Fire insurance maps
Topographic & geological maps
MOE records (Site Registry)
Local government archives
Fire department records
Newspapers
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◦ Interviews:
 Persons knowledgeable about current and past
property uses and activities
 Current and former employees
◦ Site reconnaissance:
 Visual or olfactory evidence of possible contamination:
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Staining
Distressed vegetation
Aboveground storage tanks
Underground storage tanks - fill or vent pipes
“Patches” in pavement
Oil water separators
Waste material or other storage or disposal
Soil disposal
Etc.
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Can you do part or all of the assessment?
Can the Environmental Professional provide a
template that can be used to enable staff to
undertake?
How much does it cost?
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If a large number, may rank for further
action:
◦ By potential risk:
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Known contamination
Type of contaminant
What “media” is suspect to be contaminated
Potential consequence
Financial constraints
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Phase I identifies only potential for
contamination
Phase II includes collection and analysis of
samples (soil, groundwater, and/or surface
water)
Results compared to standards
Contaminated if exceed standards
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Soil:
◦ Land use dependent
◦ Current land use or future land use
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Groundwater:
◦ What is current and expected future use
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Surface Water – aquatic and other uses
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Create a risk profile?
◦ Set priority for further assessment
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Consider:
 Likelihood of adverse effect
 Consequence of adverse effect
 Receptors affected (human vs. ecological)
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Duty to Act – imminent threat
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To determine the extent of contamination in
all affected media
◦ Vertical and horizontal extent (three dimensions)
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Conceptual Site Model (CSM)
◦ Shows conceptually where contamination may be
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Remediation can be an expensive process and
where there are multiple properties, there may
be a need to rank them
◦ Is there an imminent threat to human health or the
environment?
◦ Is there current or likely contamination migration
to other properties or sensitive environments?
◦ Is there a “business” priority?
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There are dozens of ways to remediate a site
As a rule of thumb, the faster the process,
the more expensive it will be
Costs tend to be higher if the Phase II is not
rigorous
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Client considerations:
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Technical considerations:
◦ Schedule
◦ Cost – capital vs. operating and maintenance or long
timeframe
◦ Public considerations – transparency
◦ Future land use
◦ Contaminant type:
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Metals
Organic
Easy to treat/difficult to treat
Mobility
◦ Media contaminated
◦ Geology and hydrogeology
◦ Access constraints
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SOIL
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Remove and dispose
Excavate and treat onsite
Excavate and treat offsite
Treat in-situ
Manage in-situ
GROUNDWATER
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Pump and treat
Pump, treat and reinject
Natural attenuation
Modify groundwater
movement characteristics
In-situ biological
treatment
In-situ chemical treatment
(oxidize, reduce,
immobilize)
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SEDIMENT
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Dredge and dispose
Dredge and cap
Cap
Physical
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Soil vapour extraction
Sparging
Biological
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Biological
◦ Amendment with
nutrients
◦ Amendment with new
carbon source (food)
◦ Modify groundwater
flow conditions
(direction, mounding)
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Chemical
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Oxidizing chemicals
Reducing chemicals
Oxygen enhancing
Chemicals to immobilize
metals
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Does the contamination present an
unacceptable risk to human health and/or the
environment
Can that risk be reduced by engineered
controls or administrative controls
Contamination remains
Conditions on use based on
controls/assumptions about use in risk
assessment
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Preliminary Site Investigations
◦ Stage 1 about $2,500 or lower when multiple sites
◦ Stage 2 Minimum $10,000 for simple site.
Complex sites can reach many tens of thousands
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Detail Site Investigation
◦ Suggest budget minimum $25,000 per site if
simple
◦ Can be several hundreds of thousands of dollars for
complex multiple contaminant sources and multiple
media
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Simple site budget $10,000
Complex sites with multiple contaminants
and media – planning a preliminary
engineering can be several hundred thousand
dollars
Required to determine opinion of cost of
remediation
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Underground Storage Tank - $10,000 $50,000
Works Yard
◦ Vehicle maintenance - $25,000 - >$100,000
◦ Fueling station $50,000 - >$250,000
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Depends on complexity, extent and media
affected
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