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

Role of the Environmental Professional

GFOA PS3260 Contaminated Sites WorkshopThursday, November 14, 2013

Whitehorse, YT

Role of the Environmental Professional

Process – from screening to determining financial liability

Outline

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?

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 I Investigation – What Do You Do With The Results?

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

Phase II Site Assessment

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

What Standards Should You Use?

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 Complete – Now What?

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

Phase II Assessment continued

Soil and Groundwater Investigation

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?

Rank Sites Following Phase II

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 Methods (Plan of Restoration)

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 Planning

Remediation Options

SOIL

Remove and dispose Excavate and treat onsite Excavate and treat offsite Treat in-situ Manage in-situ

GROUNDWATER

Pump and treat Pump, treat and reinject Natural attenuation Modify groundwater

movement characteristics In-situ biological

treatment In-situ chemical

treatment (oxidize, reduce, immobilize)

SEDIMENT

Dredge and dispose Dredge and cap Cap

In-Situ Remediation Options

Physical

Soil vapour extraction Sparging

Biological

Biological ◦ Amendment with

nutrients◦ Amendment with new

carbon source (food)◦ Modify groundwater

flow conditions (direction, mounding)

Chemical

Oxidizing chemicals Reducing chemicals Oxygen enhancing Chemicals to immobilize

metals

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

Remediation by Risk Management

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

Costs - Investigations

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 Planning

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

Remediation Costs

Thank YouFor further information contact

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

Documents

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