GFOA PS3260 Contaminated Sites Workshop Thursday, November 14, 2013 Whitehorse, YT

 Role of the Environmental Professional  Process – from screening to determining financial liability Page 2

 Screening of sites  Initial Assessment ◦ Ranking?  Confirming contamination  Determining extent  Evaluating remediation strategies  Opinion of cost of remediation Page 3

 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 Page 4

 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 Page 5

Page 6 ◦ 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.

 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? Page 7

 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 Page 8

 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 Page 9

 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 Page 10

 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 Page 11

 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 Page 12

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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? Page 14

 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 Page 15

 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 Page 16

SOILSOIL  Remove and dispose  Excavate and treat onsite  Excavate and treat offsite  Treat in-situ  Manage in-situ GROUNDWATERGROUNDWATER  Pump and treat  Pump, treat and reinject  Natural attenuation  Modify groundwater movement characteristics  In-situ biological treatment  In-situ chemical treatment (oxidize, reduce, immobilize) SEDIMENTSEDIMENT  Dredge and dispose  Dredge and cap  Cap Page 17

PhysicalPhysical  Soil vapour extraction  Sparging BiologicalBiological  Biological ◦ Amendment with nutrients ◦ Amendment with new carbon source (food) ◦ Modify groundwater flow conditions (direction, mounding) ChemicalChemical  Oxidizing chemicals  Reducing chemicals  Oxygen enhancing  Chemicals to immobilize metals Page 18

 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 Page 19

 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 Page 20

 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 Page 21

 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 Page 22

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