General EHS Guidelines [Complete version] at: www.ifc.org/ehsguidelines
Environmental, Health, and Safety (EHS) Guidelines
GENERAL EHS GUIDELINES: ENVIRONMENTAL
CONTAMINATED LANDWORLD BANK GROUP

1.8 Contaminated Land
•The liability that it may pose to the polluter/businessowners (e.g., cost of remediation, damage of business

Applicability and Approach .............................................54
Risk Screening ..............................................................55
Interim Risk Management ..............................................56
Detailed Risk Assessment..............................................56
Permanent Risk Reduction Measures.............................57
Occupational Health and Safety Considerations..............59

reputation and/or business-community relations) or
affected parties (e.g. workers at the site, nearby propertyowners).
Contamination of land should be avoided by preventing or

Applicability and ApproachThis section provides a summary of management
approaches for land contamination due to anthropogenic
releases of hazardous materials, wastes, or oil, including
naturally occurring substances. Releases of these materials

controlling the release of hazardous materials, hazardous
wastes, or oil to the environment. When contamination of land issuspected or confirmed during any project phase, the cause of
the uncontrolled release should be identified and corrected to
avoid further releases and associated adverse impacts.

may be the result of historic or current site activities,

Contaminated lands should be managed to avoid the risk toincluding, but not limited to, accidents during their handlinghuman health and ecological receptors. The preferred strategy

and storage, or due to their poor management or disposal.

for land decontamination is to reduce the level of contamination

Land is considered contaminated when it contains hazardous
materials or oil concentrations above background or naturally
occurring levels.
Contaminated lands may involve surficial soils or subsurface
soils that, through leaching and transport, may affectgroundwater, surface water, and adjacent sites. Where
subsurface contaminant sources include volatile substances,soil vapor may also become a transport and exposure
medium, and create potential for contaminant infiltration ofat the site while preventing the human exposure tocontamination.
To determine whether risk management actions are warranted,
the following assessment approach should be applied toestablish whether the three risk factors of ‘Contaminants’,‘Receptors’, and ‘Exposure Pathways’ co-exist, or are likely toco-exist, at the project site under current or possible future landuse:•Contaminant(s): Presence of hazardous materials, waste,or oil in any environmental media at potentially hazardous

indoor air spaces of buildings.

concentrations
Contaminated land is a concern because of:••plants, and other living organisms with the contaminants of

The potential risks to human health and ecology (e.g.
risk of cancer or other human health effects, loss ofecology);

Receptor(s): Actual or likely contact of humans, wildlife,concern•

Exposure pathway(s): A combination of the route ofmigration of the contaminant from its point of release (e.g.,leaching into potable groundwater) and exposure routes

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Environmental, Health, and Safety (EHS) Guidelines
GENERAL EHS GUIDELINES: ENVIRONMENTAL
CONTAMINATED LAND
(e.g., ingestion, transdermal absorption), which wouldWORLD BANK GROUP•

Identification of the location of suspected highest level ofallow receptor(s) to come into actual contact withcontamination through a combination of visual andcontaminants

historical operational information;•Sampling and testing of the contaminated media (soils orwater) according to established technical methods
applicable to suspected type of contaminant57,58;•Evaluation of the analytical results against the local andnational contaminated sites regulations. In the absence ofsuch regulations or environmental standards, other sourcesof risk-based standards or guidelines should be consulted
to obtain comprehensive criteria for screening soilconcentrations of pollutants.59•Verification of the potential human and/or ecological
receptors and exposure pathways relevant to the site inquestion

FIGURE 1.8.1: Inter-Relationship of Contaminant
Risk Factors

The outcome of risk-screening may reveal that there is nooverlap between the three risk-factors as the contaminant levels
identified are below those considered to pose a risk to human

When the three risk factors are considered to be present (inhealth or the environment. Alternatively, interim or permanent

spite of limited data) under current or foreseeable futureconditions, the following steps should be followed (asdescribed in the remaining parts of this section):1)

Risk screening;

2)

Interim risk management;

3)

Detailed quantitative risk assessment; and4)

Permanent risk reduction measures.

Risk Screening
This step is also known as “problem formulation” forenvironmental risk assessment. Where there is potential
evidence of contamination at a site, the following steps arerecommended:

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57 BC MOE. http://www.env.gov.bc.ca/epd/epdpa/contam_sites/guidance
58 Massachusetts Department of Environment.

http://www.mass.gov/dep/cleanup

59 These may include the USEPA Region 3 Risk-Based Concentrations (RBCs).

http://www.epa.gov/reg3hwmd/risk/human/index.htm. These RBCs are
considered acceptable for specific land use and contaminant exposure
scenarios as they have been developed by governments using risk assessment
techniques for use as general targets in the site remediation. Separate PRGs
have been developed or adopted for soil, sediment or groundwater, and often adistinction is made between land uses (as noted earlier) because of the need formore stringent guidelines for residential and agricultural versus
commercial/industrial landuse. The RBC Tables contains Reference Doses(RfDs) and Cancer Slope Factors (CSFs) for about 400 chemicals. These
toxicity factors have been combined with “standard” exposure scenarios tocalculate RBCs--chemical concentrations corresponding to fixed levels of risk
(i.e., a Hazard Quotient (HQ) of 1, or lifetime cancer risk of 1E-6, whicheveroccurs at a lower concentration) in water, air, fish tissue, and soil for individual
chemical substances. The primary use of RBCs is for chemical screening duringbaseline risk assessment (see EPA Regional Guidance EPA/903/R-93-001,“Selecting Exposure Routes and Contaminants of Concern by Risk-BasedScreening”). Additional useful soil quality guidelines can also be obtained fromLijzen et al. 2001.

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GENERAL EHS GUIDELINES: ENVIRONMENTAL
CONTAMINATED LANDWORLD BANK GROUP

risk reduction measures may need to be taken with, or

strategies that yield acceptable health risks, while achieving lowwithout, more detailed risk assessment activities, aslevel contamination on-site. An assessment of contaminant

described below.

risks needs to be considered in the context of current and future
land use, and development scenarios (e.g., residential,

Interim Risk Management

commercial, industrial, and urban parkland or wilderness use).

Interim risk management actions should be implemented at

A detailed quantitative risk assessment builds on risk screening

any phase of the project life cycle if the presence of land

(problem formulation). It involves first, a detailed site

contamination poses an “imminent hazard”, i.e., representinginvestigation to identify the scope of contamination.61 Site

an immediate risk to human health and the environment if

investigation programs should apply quality assurance/quality

contamination were allowed to continue, even a short period

control (QA/QC) measures to ensure that data quality isof time. Examples of situations considered to involve

adequate for the intended data use (e.g., method detection

imminent hazards include, but are not restricted to:limits are below levels of concern). The site investigation in turn•Presence of an explosive atmosphere caused byshould be used to develop a conceptual site model of how andcontaminated land

where contaminants exist, how they are transported, and whereAccessible and excessive contamination for which short-routes of exposure occur to organisms and humans. The risk

term exposure and potency of contaminants could result

factors and conceptual site model provide a framework forin acute toxicity, irreversible long term effects,

assessing contaminant risks.

•sensitization, or accumulation of persistentbiocumulative and toxic substances•

Concentrations of pollutants at concentrations above theRisk Based Concentrations (RBCs60) or drinking water
standards in potable water at the point of abstraction

Appropriate risk reduction should be implemented as soon aspracticable to remove the condition posing the imminent

Human or ecological risk assessments facilitate risk
management decisions at contaminated sites. Specific risk
assessment objectives include:•(e.g., children, adults, fish, wildlife)•As an alternative to complying with numerical standards or
preliminary remediation goals, and depending on local
regulatory requirements, a detailed site-specific,
environmental risk assessment may be used to develop

60 For example, USEPA Region 3 Risk-Based Concentrations (RBCs).

http://www.epa.gov/reg3hwmd/risk/human/index.htm.

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Determining if contaminants are present at levels that pose
potential human health and/or ecological concerns (e.g.,hazard.

Detailed Risk Assessment

Identifying relevant human and ecological receptors

levels above applicable regulatory criteria based on healthor environmental risk considerations)•Determining how human or ecological receptors areexposed to the contaminants (e.g., ingestions of soil,
dermal contact, inhalation of dust)

61 Examples include processes defined by the American Society of Testing andMaterials (ASTM) Phase II ESA Process; the British Columbia Ministry ofEnvironment Canada (BC MOE)
http://www.env.gov.bc.ca/epd/epdpa/contam_sites/guidance); and theMassachusetts Department of Environment http://www.mass.gov/dep/cleanup.

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GENERAL EHS GUIDELINES: ENVIRONMENTAL
CONTAMINATED LAND
•Identifying the types of adverse effects that might result•

Identifying the preferred technologies (includingfrom exposure to the contaminants (e.g., effect on target

engineering controls) needed to implement the conceptualorgan, cancer, impaired growth or reproduction) in therisk reduction measuresabsence of regulatory standards•

WORLD BANK GROUP•

reduction measures are effective

Quantifying the magnitude of health risks to human andecological receptors based on a quantitative analysis ofDeveloping a monitoring plan to ascertain whether risk•

Considering the need and appropriateness for institutional

contaminant exposure and toxicity (e.g. calculatecontrols (e.g. deed restriction, land use restrictions) as part

lifetime cancer risk or ratios of estimated exposure rates

of a comprehensive approachcompared to safe exposure rates)•••

Determining how current and proposed future land use

Permanent Risk Reduction Measures

influence the predicted risks (e.g. change of land use

The risk factors and conceptual site model within thefrom industrial to residential with more sensitive

contaminant risk approach described also provide a basis toreceptors such as children)

manage and mitigate environmental contaminant health risks.

Quantifying the potential environmental and/or human

The underlying principle is to reduce, eliminate, or control any or

health risks from off-site contaminant migration (e.g.,

all of the three risk factors illustrated in Figure 1.8.1. A short list

consider if leaching and groundwater transport, orof examples of risk mitigation strategies is provided below,

surface water transport results in exposure at adjacentalthough actual strategies should be developed based on site-lands/receptors)

specific conditions, and the practicality of prevailing factors andDetermining if the risk is likely to remain stable,site constraints. Regardless of the management options

increase, or decrease with time in the absence of any

selected, the action plan should include, whenever possible,

remediation (e.g., consider if the contaminant iscontaminant source reduction (i.e., net improvement of the site)

reasonably degradable and likely to remain in place, oras part of the overall strategy towards managing health risks at

be transported to other media)62

contaminated sites, as this alone provides for improved

Addressing these objectives provides a basis to develop andenvironmental quality.

implement risk reduction measures (e.g., clean-up, on-site

Figure 1.8.2 presents a schematic of the inter-relationship of riskcontrols) at the site. If such a need exists, the following

factors and example strategies to mitigate contaminant healthadditional objectives become relevant:risk by modifying the conditions of one or more risk factors to•

Determining where, and in what conceptual manner, risk

ultimately reduce contaminant exposure to the receptor. The

reduction measures should be implemented

selected approach should take into consideration the technicaland financial feasibility (e.g. operability of a selected technology
given the local availability of technical expertise and equipment

62 An example of a simplified quantitative risk assessment method is theASTM E1739-95(2002) Standard Guide for Risk-Based Corrective Action
Applied at Petroleum Release Sites and the ASTM E2081-00(2004)e1
Standard Guide for Risk-Based Corrective Action (at chemical release sites).

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and its associated costs).
Example risk mitigation strategies for contaminant source andexposure concentrations include:57

Environmental, Health, and Safety (EHS) Guidelines
GENERAL EHS GUIDELINES: ENVIRONMENTAL
CONTAMINATED LAND
•Soil, sediment, and sludge:

Installation (during building construction) of an

In situ biological treatment (aerobic or anaerobic)

impermeable barrier below the building and/or ano

In situ physical/chemical treatment (e.g., soil vapor

alternative flow pathway for soil vapor beneathextraction with off-gas treatment, chemicalbuilding foundations (e.g., porous media andoxidation)

ventilation to shunt vapors away from building)ooo

In situ thermal treatment (e.g., steam injection, 6-Example risk mitigation strategies for receptors include:phase heating)•Limiting or preventing access to contaminant by receptors

Ex situ biological treatment (e.g., excavation and(actions targeted at the receptor may include signage withcomposting)

instructions, fencing, or site security)

Ex situ physical/chemical treatment (e.g.,•Imposing health advisory or prohibiting certain practices

excavation and stabilization)

leading to exposure such as fishing, crab trapping, shellfish

Ex situ thermal treatment (e.g., excavation andcollection

thermal desorption or incineration)•

Educating receptors (people) to modify behavior in order too

Containment (e.g. landfill)

reduce exposure (e.g., improved work practices, and use ofoNatural attenuation

protective clothing and equipment)oOther treatment processes

Groundwater, surface water, and leachate:oIn situ biological treatment (aerobic and/or aerobic)oIn situ physical/chemical treatment (e.g., airsparging, zero-valent iron permeable reactivebarrier)otreatment)oContainment (e.g., slurry wall or sheet pile barrier)oNatural attenuation

oOther treatment processes

Soil vapor intrusion:ooExample risk mitigation strategies for exposure pathways
include:•Providing an alternative water supply to replace, forexample, a contaminated groundwater supply well•

Capping contaminated soil with at least 1m of clean soil toprevent human contact, as well as plant root or small

Ex situ biological, physical, and or chemicaltreatment (i.e., groundwater extraction and•ooo•

WORLD BANK GROUP

mammal penetration into contaminated soils•

Paving over contaminated soil as an interim measure tonegate the pathway of direct contact or dust generationand inhalation•

Using an interception trench and pump, and treat
technologies to prevent contaminated groundwater fromdischarging into fish streams

Soil vapor extraction to reduce VOC contaminant

The above-reference containment measures should also be

source in soil

considered for immediate implementation in situations whereInstallation of a sub-slab depressurization systemsource reduction measures are expected to take time.

to prevent migration of soil vapor into the building
oCreating a positive pressure condition in buildings

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Environmental, Health, and Safety (EHS) Guidelines
GENERAL EHS GUIDELINES: ENVIRONMENTAL
CONTAMINATED LANDWORLD BANK GROUP

Occupational Health and SafetyConsiderations
Investigation and remediation of contaminated lands requiresthat workers be mindful of the occupational exposures that
could arise from working in close contact with contaminatedsoil or other environmental media (e.g., groundwater,wastewater, sediments, and soil vapor). Occupational healthand safety precautions should be exercised to minimize
exposure, as described in Section 2 on Occupational Healthand Safety. In addition, workers on contaminated sites
should receive special health and safety training specific tocontaminated site investigation and remediation activities.63

FIGURE 1.8.2: Inter-Relationship of Risk Factors
and Management Options

63 For example, US Occupational Safety and Health Agency (OSHA)

regulations found at 40 CFR 1910.120.
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STAN
DARDS&p_id=9765

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