Risk Assessment Contaminated Land • Objectives – to know the characteristics of soil and chemical contaminants affecting risk assessments of contaminated land. – to know the practical steps involved in identifying and quantifying the pollutant hazards – to know the risk assessment tools and frameworks used to manage contaminated land • References • Nathanail, Paul.: Reclamation of contaminated land / Paul Nathanail, Colin Ferguson and Paul Bardos 2003 • BURA Breaking old ground: BURA guide to contaminated land assessment and development 2001 • Petts, Judith. Risk-based contaminated land investigation and assessment 1999 • Nathanail, C. P Introduction to contaminated land management 1999 • Risk assessment for contaminated sites in Europe Nottingham : LQM Press, 1998 • Vol. 1. Scientific basis -- Vol. 2. Policy frameworks 628.5094 RIS • Cairney, T. The re-use of contaminated land : 1995 • Environment Agency and DEFRA Websites –
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Risk Assessment Contaminated Land
• Objectives– to know the characteristics of soil and chemical
contaminants affecting risk assessments of contaminated land.
– to know the practical steps involved in identifying and quantifying the pollutant hazards
– to know the risk assessment tools and frameworks used to manage contaminated land
• References• Nathanail, Paul.: Reclamation of contaminated land / Paul Nathanail, Colin
Ferguson and Paul Bardos 2003• BURA Breaking old ground: BURA guide to contaminated land assessment and
development 2001• Petts, Judith. Risk-based contaminated land investigation and assessment 1999• Nathanail, C. P Introduction to contaminated land management 1999• Risk assessment for contaminated sites in Europe Nottingham : LQM Press, 1998 • Vol. 1. Scientific basis -- Vol. 2. Policy frameworks 628.5094 RIS• Cairney, T. The re-use of contaminated land : 1995• Environment Agency and DEFRA Websites –
Risk Management of Contaminated Land
1. Introduction
• Subsurface Characteristics - Soils and Contaminants
2. Site Investigation (Hazard Assessment)
3. Interpretation of data (Risk Assessment)
4. Regulatory Frameworks (Risk Management)
5. Remediation (Risk Management)
Course Structure
The Contaminated Land Legacy
Parliamentary Office of
Science and Technology
1993
Expert Estimates:-• 50,000 to 100,000
potentially contaminated sites in UK
• 100,000 to 300,000 hectares
• (significantly less which pose risk to human health)
Type of contaminant Industry/Activity Principal hazards
Toxic metals e.g. Metal mines, iron and Harmful to health cadmium, lead, arsenic, steel works, foundries, of humans or animals mercury. smelters. Electroplating, if ingested directly anodising and galvanising. or indirectly. Other metals e.g. copper, Engineering works, May restrict or nickel, zinc. e.g. shipbuilding. Scrap prevent the growth yards and ship breaking of plants. sites. Combustible substances, Gasworks, power stations, Underground fires. e.g. coal/coke dust. railway land. Flammable gases Landfill sites, filled Explosions within or e.g. methane. dock basins. beneath buildings. “Aggressive” substances “Made ground” including Chemical attack on e.g. sulphates, chlorides, slags from blast furnaces. building materials acids. e.g concrete foundations. Oily and tarry substances, Chemical works, refineries, Contamination of phenols. by-products plants, tar water supplies by distilleries. deterioration of service mains. Asbestos. Industrial buildings. Dangerous if Waste disposal sites. inhaled. (Source: ICRCL Guidance Note 59/83)
Potentially Contaminating Industries
Landfill and other waste disposal sites.
Gas works, coal-carbonization plants and ancillary by-product works.
Sewage works and farms.
Scrapyards.
Railway land, especially large sidings, depots and breaking yards.
Roads, airports and abandoned wartime airfields.
Docks, canals and abandoned or infilled port ancillaries, shipbreaking yards.
Oil refineries, petroleum storage and distribution sites.
Metal mines,, foundries, steelworks, metal finishing works.
Mineral extraction sites not yet infilled (quarries, coal)
Glass works.
Chemical works.
Munitions production and testing sites, wartime installations.
Asbestos works and building incorporating asbestos.
Tanneries and fellmongeries.
Paper and printing works.
Industries making or using wood preservatives, herbicides and pesticides.
Cotton and other textile mills and bleach works.
Metal plating works and yards.
Brickworks, potteries and ceramic works.
Nuclear power stations, radioactive storage/disposal installations .
Law & Legislation
•Common Law (Civil Law)•case law, not specific to CL
•Statutory Law•new regulations specific to CL
Common Law (Civil liability )
Law of Tort (breach of legal duty) i.e. Case Law• Rylands v. Fletcher 1866
– A person bringing a dangerous item or substance onto his own land does so at their own risk
– strictly liable for the consequences of any escape onto another’s land
– substance must be ‘unnatural’ or ‘unnaturally there’– damage must be reasonably foreseeable– conduct of the defendant is irrelevant
• Trespass
– direct, unauthorised interference with another’s property– could cover spillage or deposit of pollutants– not yet tested in the courts
Common Law (Civil liability )• Negligence
• fault based - failure to take care in situations in which damage is reasonably foreseeable
• “care” extends to ‘future users’
• liability is variable depending on the amount of care taken
• does not cover purely economic losses
• Nuisance (interpretation of degree of harm)
• activity that interferes with another’s enjoyment of land
• On-going interference - can obtain an injunction
• Concluded interference - can obtain damages
• foreseeable “omission to do what a reasonable person would do”
• Time Limit - 6 Years
– (begins from time of discovery)
Cambridge Water (CW) v.Eastern Counties Leather (ECL) Ltd
• Perchloroethylene solvent escaped from tannery
• Contamination of groundwater
• Water company failed new EC standards
1. CW failed in High Court
– case of negligence, nuisance, Rylands v. Fletcher dismissed as tanning was not unnatural
2. Prosecution upheld in Court of Appeal
– ECL deemed liable, £1m damages (focused on Nuisance)
3. House of Lords Decision (in favour of ECL)
– reversed the Court of Appeal decision
– no liability under Rylands v. Fletcher as “not foreseeable”
Contaminated land - Disasters
• Love Canal, USA (1978)– Hooker Chemical Company 1942 - 1953
– Building in 1950’s (despite caveat in deeds)
– illness, genetic disorders, residents evacuated
• Lekkerkerk, Netherlands (1978)– building on reclaimed site
– 1600 illegally dumped drums
– drinking water polluted, residents evacuated
• Eastern Counties Leather vs Cambridge Water Co (UK 1993)
Nature of the Pollution
• Some important factors which determine the fate of chemicals in soil.– Organic or Inorganic
– Hydrophobic character, interaction with soil colloids
– Quantity or Concentration
– Toxicity and Biodegradability
– Density (Specific Gravity), Viscosity
Soil Structure and Hydrology
• Soil Depth and Horizons
• Organic Matter content– Plant Residues
– Humic Acids, Fulvic Acids, Humin.
• Particle size distribution– Sand, Silt and Clay Fractions
• Soil Permeability
• Groundwater, Water-table– Vadose (unsaturated) zone
– saturated zone
Movement in the Soil
Liquids• Gravity
– vertical movement until sorption by soil matrix dominates.– LNAPL - as far as Capillary Zone or Water Table– DNAPL - through water table, stops at Impermeable Layer
• Advection– transported by the flow of the bulk liquid (water) if dissolved
Vapours• Diffusion
– random molecular movement
• Advection– transported by bulk flow of soil vapour
Movement of Contaminants within an Aquifer
Vadose Zone
Saturated Zone(Aquifer)
Soil Surface
Capillary Zone
LNAPL
Spill
DNAPL
Plume of solublecomponents
Spill
Spill
Potential Outcomes for Contamination in Soil
• Hazard stays fixed in soil matrix = MINIMAL RISK
• Hazard stays fixed in soil matrix but site has receptors = RISK
• Hazard moves into groundwater and is transported towards receptor. = RISK
• Dust and Volatilisation give rise to subsequent Air Contamination. = RISK
Which Are relevant to the site?
REMEDIATION eliminates or minimises RISKS
Typical effects of Hazards
Toxicity to Human Health
– Uptake of contaminants by crops
– Ingestion
– Inhalation
– Skin Contact
• Contamination of water resources (Groundwater)
• Toxicity to Ecosystems / Wildlife
• Fire and Explosion
• Chemical attack on buildings, materials and property
For a contamination to present a risk there must be:
• a potentially harmful Source• a Pathway along which the contaminant can travel.• a Receptor• a plausible Pollution Linkage.
SOURCE RECEPTOR
PATHWAY
Risk Management
Technical Approach to Risk Management of Contaminated Land
What are the key stages in the process?
• Identify and assess Hazards
– Collection of Data
– Conceptual model (source-pathway-receptor linkages)
• Evaluate and Quantify Risks posed by Hazards– Professional judgement– Generic Guidelines or screening values– Models (site-specific characteristics)
• Prioritize sites (Local Authority)– fair and transparent process – Consider consequences of a change in use– force remediation of sites with “Risk”
• Deal with unacceptable risks to human health and the environment (Environmental)
• Bring contaminated land back into beneficial use(Economic)
• to limit cost burdens to proportionate, manageable and economically sustainable levels (Social)
(Sustainable Development)
Contaminated Land Regime
Environment Act 1995• Section 57 (EA 1995) inserts Part IIA into
the Environmental Protection Act 1990• Local Authority responsible• LA to formulate Strategy by mid-2002• LA actively identify contaminated sites &
cause them to be remediated
Definition of Contaminated land
• “Contaminated land is any land which appears to the regulatory authority, 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; or
b) pollution of controlled water is being, or is likely to be caused” (Environment Act 1995)
“harm to the health of living organisms or other interference with the ecological systems of which they form part, and in the case of man, includes {harm to} his property”.
EA 1995 Enforcement Responsibilities
Duties Tasks
• Cause their area to be inspected to identify Contaminated Land
• To determine whether a particular site is “contaminated”
• To Act as enforcing authority for contaminated sites (other than Special Sites)
• Establish responsibility for remediation.
• Determine what remediation is required and to ensure that it takes place.
• Arbitrate on the who bears what proportion of consequent liability.
• Record and maintain prescribed information in a Public Register.
Powers of Inspectors
Section 108 Environment Act 1995 :-• enter at any reasonable time• make any examination or investigation
necessary• take photographs or samples• require the giving of information• order that premises or parts be left undisturbed
EA 1995 Information and Inspection
L.A’s may derive information form a number of
sources to enable an assessment to be made
• Other Statutory Bodies
• Its own Land Use records
• Public Complaint
• Land Owners
Prioritisation/Categorisation
• Part I AssessmentPreliminary prioritisation of sites
into groups for Part II Assessment
under the following headings.
• Development
• Surface Waters
• Groundwater
(This will comprise a desk top study
and can be carried out by
non- specialist personnel)
• Part II AssessmentSites in each group will be
categorised using individual risk
assessment• Priority given first to
“Development Group A”• Site information examined• Site Visit• Establish contaminants, pathway
and risk• Detailed exploratory survey where
indicated
(Expert help will be required)
Part I Assessment
Residential development, school playground or allotment within 50 m
Industrial, commercial development within 50 m or residential within 250 m
Site in agricultural or amenity use including Parks and playgrounds
GROUP AYES
Not KnownNO
GROUP B
NO
YES
Not Known
YES Not Known
NO GROUP C
Appropriate Person
• CLASS “A”
Any person who
causes or knowingly
permitted contaminating
substances to be IN, ON
or UNDER the site
• CLASS “B”
Where reasonable enquiry
has failed to identify a
person fitting the definition
of “Class A”, the owner or
occupier of the land
If no Class A or Class B then site is an Orphan Site (ownership passes to LA)
Appropriate Persons - Exclusions
• Class A – for abandoned mines
• Class B - where pollution is to controlled water
• Class B – for contaminants escaping to adjacent land
• Class B - when they act in official capacity e.g. ‘insolvency practitioners’, ‘official receiver’
• Class A – where land was sold with ‘information’ regarding level of contamination
Apportionment of Liability
Inherited Problems
• “Person A” causes contamination of “Contaminated Land X”
• Innocent “Person B” becomes owner/occupier of “Contaminated Land X”
• “Person B” not liable to remediate “Adjoining Land Y” unless they had knowledge of the contamination at purchase (Caveat emptor)
migration
Adjoining LandContaminated land
X Y
Contaminant
Special Sites
Environment Agency becomes the enforcing authority after LA designates a site as a Special Site on the basis of:
• Water Pollution Cases– Controlled water used for Drinking Water abstraction– Ecologically important sites (SSSI, reserves)– Major Aquifers
• Industrial Cases– Pollution from sites involving Acid tar, Oil, Explosives, and
Nuclear (excludes coal processing)• Defence Cases
– Army, Navy, Airforce, Weapons Testing sites
Extends to contaminated sites adjacent to above cases
EA 1995 Remediation Notices
Where Pollution Linkage is confirmedRemediation Notice served on each “appropriate person”
• Can cover assessing site condition (detailed intrusive Site Investigation), preventative works, remediation and monitoring
• Must be “reasonable” having regard to cost and seriousness of harm/pollution
• Must be preceded by consultation (an opportunity for voluntary action)
Attributing Costsfor Remediation Actions
• Single-Linkage Action• Shared-Action (when more than than one pollution-linkage)• Single Liability Group• Multiple Liability Groups
Complex Variable Attribution of Responsibility. The costs may be shared:– Equally– In proportion to capital assets in the land (multiple Group B)– In proportion to costs relating the contamination caused be each member (multiple Group A)– As the enforcing authority sees as just and fair
Non-Compliance withRemediation Notice
• Enforcing Authority can carry out the remediation and recover costs.
• Non-compliance is a criminal offence, punishable by imposition of a fine of up to £20,000 plus £2,000 a day.
Recovery of Costs
Local Authorities must take into account:
• HARDSHIP
LA must consider any hardship that may be caused.
• BUSINESS CLOSURE OR INSOLVENCY
Where remediation costs would make a business insolvent, the authority should consider a reduction in costs. The main aim is to recover as much cost as possible without causing insolvency.
EA 1995 Public Registers
Will be maintained to include:
• Remediation notices and appeals.
• Remediation work carried out following a remediation notice.
• Conviction for offences.
EA 1995 Conclusion
• CL Regime brought into force 2000.
• Local Authorities published Strategy 2002
• New regime extremely complex and bureaucratic
• Lack of significant new resources
• Responsibility for “orphan sites”
Pollution Prevention & Control (PPC) Regulations 2000
• IPPC Directive (96/61/EC)
– enacted in UK as “The Pollution Prevention and Control (England and Wales) Regulations 2000”
– Contaminated land covered under requirements for ‘Site Reports’
– Regulator is ‘Environment Agency’
Pollution Prevention & Control (PPC) Regulations 2000
Principle of PPC
• Specific Industrial Sectors are regulated
• Aim to preserve land quality rather than deal with Historic pollution (I.e. stop
future pollution)
• Linked to Permit Application
– authorises the site (or installation) to conduct specified industrial activity
• Process requires ‘Site Report’
– a detailed investigation of current state of the land that acts as a ‘baseline’
• Closure of Site (or Change of Use)
– Cessation Site Report compared with Original Site Report
– Site must be remediated to ORIGINAL CONDITION and not ‘Suitable for use’
Pollution Prevention & Control (PPC) Regulations 2000
• Purpose of a Site Report
– To document the condition of the site with particular reference to substances in, on or under the land that may constitute a pollution risk
– All land of the installation is covered
• Phased approach
– 1a Desk Study (Conceptual Model)
– 1b Further Desk Study and Exploratory Investigations
– 2 Main Intrusive Investigation
– Complex activities may be zoned
– Technical Content• presentation of lateral and vertical distribution of contaminants
• Site Report sent to LA (as statutory consultee)
– Data can be used by LA under Part IIA EA 1995 legislation
5. Site Remediation
(Risk Management)
Risk Management Remediation Strategy
• Source– permanent reduction of risks
– numerous technical approaches
• Pathway– risks managed in short to medium term
– several different engineering approaches
• Target– not usually applicable or practicable
Remediation of Contaminant Source
• Removal– excavation and landfill (dig and dump)
• Degradation– Bioremediation, Chemical and Thermal destruction
– Natural Attenuation
• Extraction– Soil washing, Vapour Extraction
Remediation - Contaminant Pathway
• Engineering Methods– In-ground Barriers
– Surface Covers• hard cover
• vegetation
– Solidification and Stabilization
– Groundwater pumping
Contaminated land Remediation
• Multifunctionality Approach– always apply highest technical level of clean-up
• Suitable For Use – clean-up level determined by land use– favoured approach based on the “risk-environmental benefit”
residential with gardens residential without gardens parks and recreational areas agricultural industrial and commercial
Risk Based Corrective Action (RBCA)
• The "formal" definition of RBCA is as follows:
“A streamlined approach in which exposure and risk assessment practices are integrated with traditional components of the corrective action process to ensure that appropriate and cost-effective remedies are selected, and that limited resources are properly allocated.”
• The goals of a RBCA process are: – Protection of human health and environment
– Practical and cost-effective application of risk-based decision-making
Natural Attenuation• Spontaneous process
– mostly biological– BTEX half life (chemical =108 yr , biological = <1 yr)
• Long Term
• Risk Based Corrective Action (RBCA)– Environmental benefit v. Cost– may be better to address consequences than to treat the source (e.g.
borehole contaminants)– Lines of Evidence
• Primary
(concentration v. time, concentration v. distance)
• Secondary (supportive)
(DO level, pH, electron acceptors, active microbes)
Monitored Natural Attenuation
• Not a “Do-Nothing” Option– quantify the natural breakdown process