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Role of the Environmental Professional. GFOA PS3260 Contaminated Sites Workshop Thursday, November 14, 2013 Whitehorse, YT. Outline. Role of the Environmental Professional Process – from screening to determining financial liability. Page 2. Role – To Participate in All Or Part Of:.
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Role of the Environmental Professional GFOA PS3260 Contaminated Sites Workshop Thursday, November 14, 2013 Whitehorse, YT
Outline Role of the Environmental Professional Process – from screening to determining financial liability Page 2
Role – To Participate in All Or Part Of: • Screening of sites • Initial Assessment • Ranking? • Confirming contamination • Determining extent • Evaluating remediation strategies • Opinion of cost of remediation
Screening of Sites • Inventory all properties • By government body • Screen to select sites that are no longer productive • 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
Phase I Investigation • An assessment of current and historic site uses and conditions • Historic records: • Air photographs • City directories • Land use maps • Fire insurance maps • Topographic & geological maps • MOE records (Site Registry) • Local government archives • Fire department records • Newspapers
Phase I Investigation • Interviews: • Persons knowledgeable about current and past property uses and activities • Current and former employees • Site reconnaissance: • Visual or olfactory evidence of possible contamination: • 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.
Phase 1 Investigation– Internal or External Process or Split 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?
Phase I Investigation – What Do You Do With The Results? • If a large number, may rank for further action: • By potential risk: • Known contamination • Type of contaminant • What “media” is suspect to be contaminated • Potential consequence • Financial constraints
Phase II Site Assessment Phase I identifies onlypotential for contamination Phase II includes collection and analysis of samples (soil, groundwater, and/or surface water) Results compared to standards Contaminated if exceed standards
What Standards Should You Use? • Soil: • Land use dependent • Current land use or future land use • Groundwater: • What is current and expected future use • Surface Water – aquatic and other uses
Phase II Assessment Complete – Now What? • Create a risk profile? • Set priority for further assessment • Consider: • Likelihood of adverse effect • Consequence of adverse effect • Receptors affected (human vs. ecological) • Duty to Act – imminent threat
Phase II Assessment continued • To determine the extent of contamination in all affected media • Vertical and horizontal extent (three dimensions) • Conceptual Site Model (CSM) • Shows conceptually where contamination may be
Rank Sites Following Phase II 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?
Remediation Methods (Plan of Restoration) 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
Remediation Planning • Client considerations: • Schedule • Cost – capital vs. operating and maintenance or long timeframe • Public considerations – transparency • Future land use • Technical considerations: • Contaminant type: • Metals • Organic • Easy to treat/difficult to treat • Mobility • Media contaminated • Geology and hydrogeology • Access constraints
Remediation Options SOIL GROUNDWATER SEDIMENT • Pump and treat • Pump, treat and reinject • Natural attenuation • Modify groundwater movement characteristics • In-situ biological treatment • In-situ chemical treatment (oxidize, reduce, immobilize) • Dredge and dispose • Dredge and cap • Cap Remove and dispose Excavate and treat onsite Excavate and treat offsite Treat in-situ Manage in-situ
In-Situ Remediation Options Physical Biological Chemical • Biological • Amendment with nutrients • Amendment with new carbon source (food) • Modify groundwater flow conditions (direction, mounding) • Oxidizing chemicals • Reducing chemicals • Oxygen enhancing • Chemicals to immobilize metals Soil vapour extraction Sparging
Remediation by Risk Management 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
Costs - Investigations • 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 • 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
Remediation Planning 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
Remediation Costs • Underground Storage Tank - $10,000 - $50,000 • Works Yard • Vehicle maintenance - $25,000 - >$100,000 • Fueling station $50,000 - >$250,000 • Depends on complexity, extent and media affected
Thank You For further information contact