Advanced Geotechnical Engineering
ES4D8
Contaminated Land
Dr Mohaddeseh Mousavi-Nezhad
Room:D211
Email:m.mousavi-nezhad@warwick.ac.uk
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Outline of the course & assessment
Lectures 2 hour per week
• Lecture 1
Introduction: Course outline and assessment, reading, and tutorial structure.
Introduction to contaminated land concepts.
• Lecture 2
Contaminated land legislation: Contaminated land concepts, definitions and relevant
legislations ; Planning advice in UK.
• Lecture 3
Risk assessment for contaminated land and groundwater: Source-pathway-target
framework, risk assessment definitions.
• Lecture 4
Site Investigation and Sampling/Analysis: Site description, conceptual modelling, risk
detections, ground investigation.
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Outline of the course & assessment
• Lecture 5
Contaminated fate - Basic concepts I: Characteristics and sources of contaminated
land and groundwater pollution, pollutant properties. Basic concepts and mechanisms
including porous media transport, diffusion and dispersion and reactions.
• Lecture 6
Contaminated fate - Basic concepts II: Governing equations including sources and
sinks, adsorption and desorption. Mathematical models and concepts including
retardation coefficients and the effect of organic matter, analytical and numerical
modelling approaches.
• Lecture 7
Contaminated land remediation methods I: Covering systems, Pump & Treat
Technology, In-situ air-sparging
• Lecture 8
Contaminated land remediation methods II: Continue remediation methods
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Outline of the course & assessment
• Tutorial
Contaminant fate
• Feedback Opportunities
Verbal feedback on tutorials
• Reading
25% of module credit (i.e 3.75 credits)
Each student 37.5 hours (10 hours per credit)
 Contaminated land:
Edited by T.Cairney
ISBN-13: 978-0419230908
 Ecological risk assessment for contaminated site:
ISBN-13: 978-1566705257
•
Assessment
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25% of final exam
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Introduction: Topics to be covered
• Why is Contaminated Land important to YOU?
• Basics & definitions & legislation
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Why is Contaminated Land important to YOU?
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
Example: Landfill site is a site
for the disposal of waste
material.
It is covered by special cover
systems to prevent physical
contact and exposure of waste
material.
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Migration of gases
• Migration of methane and carbon dioxide is
now recognised as a major hazard regarding
developments on, or near, historic landfills.
• Natural migration pathways include pore
spaces in granular sands and gravels.
• Pathways in impermeable strata include fault
and bedding planes, fractures, joints.
Cavity walls
Openings of service pipes/cavities
Cracks in concrete floor slabs
Joints/openings at
the interface
between weight
bearing walls and
concrete floor slabs
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Gaps, openings or cavities present in
suspended wood/ concrete floors and ceilings
Cracks present in below ground
walls due to shrinkage/curing
and prolonged soil pressures
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A number of incidents
involving methane related
explosions were reported in
houses developed on, near,
historic landfills.
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Sandford Farm , Reading
Regional location map (scale 1:50 000)
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Location map on large scale (scale 1:10 000)
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Sandford Farm , Reading
Proposed redevelopment plan:
• Redevelopment to comprise 250
residential properties with private
gardens,
• accommodating approximately 600
new residents
• The proposed redevelopment will
also include several large areas of
public open space
Layout plan for redevelopment of the area
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Historic Landfill Site in Woodley, Reading
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Hungary 2010 - Dam Burst
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Do all Contaminated sites look like this?
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Downtown Tannery
Repeating processes of soaking raw
hides and wringing them out, the
tanning process create large amounts of
wastewater contaminated with
chromium compounds, sulfuric acid
sodium chlorate.
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Conclusion-All contaminated sites do Not look like this?
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Example: Presence of lead (Pb) in soils
Chemical reaction
Flocculated
components
Dispersed chemical
components
• Decrease of soil strength
• Increase of soil permeability
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Stress vs. strain of lead contaminated samples (Resmi, et al., 2011).
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Stress vs. strain of lead contaminated samples (Resmi, et al., 2011).
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Significant reductions in
strength with increasing
lead concentrations.
Stress vs. strain of lead contaminated samples (Resmi, et al., 2011).
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Significant reductions in
strength with increasing
lead concentrations.
Stress vs. strain of lead contaminated samples (Resmi, et al., 2011).
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Significant reductions in
strength with increasing
lead concentrations.
Stress vs. strain of lead contaminated samples (Resmi, et al., 2011).
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Significant reductions in
strength with increasing
lead concentrations.
Stress vs. strain of lead contaminated samples (Resmi, et al., 2011).
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Why is Contaminated Land important to YOU?
• Risk of hazard to human health & environment
• Contaminants in the ground can change the mechanical
properties of soil
Example: land heavily polluted with crude oil
Reduction in
soil strength
Uniaxial compressive strength vs. Oil content % (Khamehchiyan, 2007).
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Why is Contaminated Land important to YOU?
List the issues that you fear as a property developer.
work in a group
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Why is Contaminated Land important to YOU?
List the issues that you fear as a property owner.
work in a group
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Why is Contaminated Land important to YOU?
• Many Civil Engineering projects require it to be investigated.
•
All planning permissions, new developments, most likely to require
it to be investigated.
• It is a topic that will be with you for the rest of your career.
• You’ll be involved with it to a greater or lesser extent depending
you specialism.
• It’s constantly changing, still relatively new; mid 1980’s !!!
• Connected with sustainability – your generation’s ongoing
responsibility!!
• Clients aware of it, but some / many don’t fully understand it!
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Basics & Terminology
Classification of Lands
Use
Location
Condition
Status
Agricultural
Coastal
Polluted
Vacant
Industrial
Upland
Damaged
Under-used
Residential
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Contaminated
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Basics & Terminology
Classification of Lands
B
Use
Location
Condition
A
Status
Agricultural
Coastal
Polluted
Vacant
Industrial
Upland
Damaged
Under-used
Residential
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Basics & Terminology
Classification of Lands
Status
Vacant
Under-used
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Historical status
 Brownfield Land
 Greenfield Land
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Basics & Terminology
What is Brownfield Land?
Previously developed land.
 Can be in current active
use or derelict, redundant,
not used.
 The soil & groundwater
beneath may or may not
be contaminated.
Brownfield
is
not necessarily contaminated.
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Basics & Terminology
What is Greenfield Land?
Previously un-developed land.
 Greenfield not necessarily
un-contaminated,
it could be contaminated.
Don’t confuse with the “greenbelt”, a planning term for land on
the edges of urban developments where development should be
limited in order to
restrict urban sprawl and protect the countryside.
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Basics & Terminology
As a decision maker you are faced with two options:
1. Develop existing Brownfield sites
2. Develop new Greenfield sites
Government encouraging redevelopment of Brownfield sites. They want to
bring damaged land back into beneficial use.
 3 million new homes by 2020, 240,000 homes/annum.
 Many (or most) of our project are on “brownfield” land.
 Preference given to brownfield developments over greenfield
developments.
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Basics & Terminology
Why bother with brownfield land? Why bother to develop it?
• Sustainability; It’s a resource, not to be wasted, to be recycled, re-used.
The Environment Agency estimates that there are some 300,000ha (not
accurate).
• An ideal tool to limit encroachment into rural areas – i.e. greenbelt.
• Encouraged development / regeneration in urban, inner city areas,
avoids blight. So the area will improve and things like crime rates will
improve.
• An ideal opportunity to “clean up” historical contamination
• Make the most use of infrastructures which already exists in urban
areas- in Greenfield sites new drainage, electricity, roads etc. would all
have to be produced.
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Basics & Terminology
The six principles of the National Brownfield Strategy are:
1. Redevelop or reuse first: When considering the allocation of land for
future uses, the principle of ‘redevelop or reuse first’ shall be used
alongside the Planning Policy Statement 25: Development and flood risk
(PPS25) sequential test.
1. Reuse of urban land in towns and cities: consider before rural &
greenbelt.
1. Environmental impact: consider it.
1. Sensible cost – Remove blight: Where the cost of full remediation
unsustainable (too high), do sufficient to safeguard the local
environment and to remove visual blight.
1. Highest standards compatible with economic limitations
1. Consultation: Consult with local communities.
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Why is Contaminated Land important to YOU?
Why do we need to consult with local communities?
work in a group
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Basics & Terminology
Legal definition
Pollution, Contamination and Contaminated Land
Based on The Royal Commission on Environmental Pollution (RCEP)
in 1984
“Pollution can be defined as the introduction by man into the environment of substances
or energy liable to cause hazards to human health, harm to living resources and
ecological systems, damage to structures or amenity, or interference with legitimate
uses of the environment. Substances introduced into the environment become
pollutants only when their distribution, concentration or physical behaviour are such as
to have undesirable or deleterious consequences.”
“Contamination can be defined as the introduction or presence in the environment of
alien substances or energy, on which we do not wish or are unable to pass judgment on
whether they cause, or are liable to cause, damage or harm. Contamination is therefore
a necessary, but not sufficient condition for pollution.”
Basics & Terminology
Legal definition
What is “Contaminated Land”?
Two complimentary regimes:
• Environmental Protection Act (1990)
• Planning and development regime
NB
Contaminated land is not just one thing;
ranges from natural to very heavily polluted.
Mostly man made so even less “ordered” than geology.
Terminology:
“Contaminated Land” vs “Land Affected by Contamination”
We’ll discuss later.
Basics & Terminology
Part IIA – Legislation, states:
www.legislation.gov.uk/ukpga/1995/25/contents
• “Contaminated land” [ under part IIA ] is any land which appears
to the local authority in whose area it is situated to be in such a
condition, by reason of substances in, on or under the land, that:
(a) significant harm is being caused or there is a significant possibility of such
harm being caused; [ to living organisms, ecological systems property ] or
(b) pollution of controlled waters is being, or is likely to be, caused;
Basics & Terminology
Part IIA Responsibilities:
• Local authorities responsible for identifying potentially
contaminated sites in their area and investigating to determine if
“contaminated land” as defined in Part IIA. There is a public
“record” / “register”.
• LA to prove land in contaminated. cf next slides
• Local authorities can then serve a remediation notice.
• Mechanisms in legislation for forcing polluters to remediate or
• Local authorities may undertake remediation themselves and
recoup costs later.
• Environment Agency (EA) responsible for severely contaminated
sites i.e. “special sites”.
Basics & Terminology
Most contamination is dealt with by the planning process.
Most planning permissions have a condition to investigate
contaminated land.
A typical example:
“No development shall commence on site until a risk based contaminated land assessment
has been submitted to and approved in writing by the Local Planning Authority. The
assessment should be carried out in accordance with BS 10175: 2001 “Investigation of
Potentially Contaminated Sites Code of Practice” and CLR 11 “Model Procedures for the
Management of Land Contamination” issued by the Environment Agency. Thereafter, the
development shall be implemented in accordance with the approved details and retained
in perpetuity, unless otherwise agreed in writing by the Local Planning Authority.”
Reason: To ensure the land is fit for purpose and to accord with the
aims and objectives of PPS 23.”
Basics & Terminology
Developers’ responsibility
 to demonstrate the site is NOT contaminated
 or demonstrate that significant harm is NOT being caused or there is
NO significant possibility of such harm being caused and that pollution
of controlled waters is NOT being, or un-likely to be, caused.
If this cannot be demonstrated, developer has to remediate the site.
This may be necessary even on greenfield sites.