Land contamination report

Land Contamination, Remediation and Mitigation Lsc 305 Student No. 100182268

Contents: Introduction - p.1 Background and History - p.1 Baseline Information - p.3 Geology - p.4 Topography - p.5 Conceptual Model - p.5 Remediation - p.9 Remediation Summary - p.11 Mitigation - p.11 Conclusion - p.12 Bibliography - p.13

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Introduction The aim of this report is to employ a series of techniques coupled with information from a site visit to better understand the contaminants, their possible pathways and the potential receptors which could be affected. This information will be used to formulate remediation techniques to mitigate potential ill effects. Methods for remediation and mitigation will also be explored giving the site potential for future development.

Background and History It is imperative to understand the background information and the historical uses of the site so to understand what contaminants the site has been exposed to, where they might be located, how they might behave in the context of the site and how long they have been present.

The site’s industrial history dates back to the 1880’s processing coal to produce coke for Sheffield’s steel industry. This procedure has a number of toxic by-products including ammonia, coal tar, and gaseous compounds.

The site had expanded by the 1920’s to include numerous storage tanks to accommodate the chemical compounds of the destructive distillation process.

During the 1940’s the site began treating wood with creosote, a by-product of the distillation on site but would include further chemicals such as chromated copper.

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1970’s saw the market’s demands change and the predominant export becoming the longer chained hydrocarbons of petroleum.

Distillation of tar was stopped in 1981 when the solitary export from the then Croda site was bitumen which was again treated with different chemicals to improve the quality and versatility of bitumen, for instance sulphuric acid which had its own complications of being stored in lead lined tanks, and needing neutralising with lime (calcium oxide).

The extensive operational period and variety of chemicals the site has been exposed to allows the conclusion to be drawn that the site is contaminated on a wide scale, especially when considering the mobility of a number of contaminants associated with the industrial processes.

Baseline Information

Location map - Google Earth

Character area map - Google Earth

The site, located in Northern England, is on the periphery of Swinton, Rotherham, dissected

by Carlisle Street dissecting the site, separating it into the north and south. These two areas of the site have been treated differently over the last century and may exhibit different features. Running north south on the eastern boundary of the site is the South Yorkshire Navigation Canal and the River Don, beyond that is largely agricultural fields Site at present whereas the site is between two industrial areas to the north and south and to the west lies one of Rotherham’s suburban residential areas.

Although there is little build structures remaining on site there is evidence that the south site was home to the primary distillery and the north site was utilised as a dumpsite, significantly for used lime but has also been privy to spillages and industrial remnants such as pitch and tar.

The widespread contamination and degradation of soil has led too poor vegetation establishment and stress to be placed on the stunted plants and trees which do grow.

However the remaining vegetation surrounding the site and in the northern area in locations less heavily polluted has established better.

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The contaminants which this report is looking more closely at are the volatile organic compounds (VOCs) benzene, ethylbenzene and xylene, heavy metals Arsenic, lead and copper and asbestos. The VOCs and behave similarly and will be treated as a group in the conceptual model table and likewise for the heavy metals.

According to the European Environment Agency these VOCs are ‘colourless liquids, immiscible with water but miscible with organic solvents. They have a characteristic strong odour and are highly flammable.’ (L. Gurtz, 2010) ‘Heavy metals are commonly defined as those having a specific density of more than 5 g/ cm3. The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic’ (L. Jarup, 2013) Asbestos is a naturally occurring fibre and when in soil it is a ‘risk to health if fibres can become airborne so they may be inhaled. The risk may be increased depending on the type and amount of asbestos material in the soil, and if there is potential for it to become disturbed or airborne.’ (W. Victoria, 2010) The current measures undertaken to block receptors from the contaminated site is most significantly a fence to keep receptors out, a pumping station to clean the water before it enters further watercourses and a spray to prevent gases and odours reaching the residential areas. The fence is regularly vandalised and fails to fulfil its function.

The site is currently destined for housing development but will have to conform with the Environment Agency’s regulations since it falls within the Department of Energy’s industry profiles under both ‘railway land’ and ‘gas works, coke works and other coal carbonisation plants’ (The Environment Agency, 2013)

Geology The site is largely covered by a thin layer of poor quality soil supporting a small degree of vegetation. However surrounding the river there is an improved quality of soil due to the supply of sediment.

The bed rock is predominantly Upper Carboniferous Middle Coal Measures comprising of sandstone, mudstone, silt stone, and coal down to 1.5km and the different faults in this give rise to the site’s topographic features to the north west and south east of the site.

The alluvial deposits of the River Don consist a mixture of particle sizes from clay and silt through to sand and gravel although, principally it is particles between sized on the upper end of this spectrum, between sand and gravel.

The predominant surface geological feature of the site is made ground although it has a range of depths and by the nature of its creation has a varying composition of materials. It falls within Environmental Agency’s description of a secondary aquifer – ‘These include a wide range of rock layers or drift deposits with an equally wide range of water permeability and storage.’ The ‘permeable layers capable of supporting water supplies at a local rather than strategic scale, and in some cases forming an important source of base flow to rivers.

These are generally aquifers formerly classified as minor aquifers’ (The Environment Agency, 2013)

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Topography The topography of the area is predominantly flat. This is largely due to the control over the made ground present, but with exceptions of sandstone outcrops which protrude causing some gentle slopes to the north and south and the hill running parallel to the west of the site.

Conceptual Model Definition and purpose of a concept model: ‘A Conceptual Model is a representation of its site and surrounding area. It is a simplified description of the environmental conditions and its purpose to identify potential sources of contamination, receptors which may be affected by contamination (for example, human health, water courses, the environment) and pathways which may link the two (for example the food chain, drinking water supply, inhalation of dust).’ (The Moray Council, 2013) ‘A conceptual model represents the characteristics of the site in diagrammatic or written form that shows the possible relationships between contaminants, pathways and receptors ‘(C. Stanger, 2004)

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Contaminated Land Risk Assessment Matrix

In accordance with Environment Agency publication CLR 11 ‘Model Procedures for the Management of Land Contamination’, a preliminary contaminated land risk assessment has been developed for the Site and is summarised in Appendix B. The risk assessment has been carried out using the risk model defined and outlined in the table below. Potential sources have been identified from the desk study information and the guidance provided in EA publication CLR 8 ‘Potential Contaminants for the Assessment of Land’.

Hazard Linkages have been determined by the ground investigation and the risk re-assessed on the basis of the viability of the linkage. If the hazard linkage is confirmed then remediation or management solutions will be proposed to ensure that no unacceptable risk remains following development. (Advantage West Midlands, 2009)

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Remediation The remediation is ‘the doing of any works, the carrying out of any operations or the taking of an steps in relation to any.. land or waters for the purpose of avoiding harm to people or water or restoring the lad or waters to their former state.’(A. Grant, 2013) It could take the form of: - Removing the pollutant - Breaking the pathway - Protecting or removing the receptor Remediation methods are not universally applicable and need fine tuning to be site specific if they are to be successful without being inefficient. According to Defra’s Contaminated Land Remediation report (Defra, 2010) these are some of the potential advantages and limitations of remediation techniques.

For VOCs - Chemical oxidation

Potential advantages:

reactions are fast and can result in complete degradation;

Applicable to a wide range of organic contaminants;

Uses reagents that are considered low cost and easily delivered to the

subsurface.

Limitations:

May require large volumes of reagent;

Environmental considerations as using aggressive reagents;

Toxic intermediate breakdown products may be formed;

Groundwater may be coloured by reagents (e.g. permanganate is purple in

solution);

Precipitation reactions may be reversible with changes in redox conditions

over time;

May be difficult to facilitate contact between contaminants and reagents in

the treatment zone.

For VOCs - Enhanced bioremediation using redox amendments

Potential advantages:

Can be used to treat soil and groundwater;

Minimal site disturbance;

Lower monitoring costs in comparison with monitored natural attenuation

due to accelerated remediation;

Relatively simple technique.

Limitations:

Difficult to apply to a heterogeneous subsurface;

Uncertain supply of quantity of amendments;

Toxic intermediate breakdown products may be formed.

When these two forms of remediation, both targeting VOCs, are compared it is apparent that they both have potential to be used in different scenarios. For the site It wouldappropriate to suggest that the chemical oxidation technique be used in areas of high concentration of contaminants and bioremediation in lower concentrated areas as part of a multiphase approach p.9 Land Contamination Report

For VOCs & heavy metals - Permeable reactive barriers (groundwater)

Potential advantages:

Solution for inaccessible or dispersed source;

Relatively easy to maintain and monitor;

Minimal above-ground disturbance

Limitations:

Loss of reactive capacity over time, requiring replacement of reactive media;

Loss of permeability due to precipitation of metal salts or biofilm production;

May have to dispose of reactive media as a hazardous waste;

Requires significant depth of understanding of local geology and hydrogeology;

May be limited by the depth of the contamination below ground.

As the VOCs are very mobile it is imperative to prevent them entering other watercourses and spreading the problem and this, if well executed, maintained and situated appropriately around the river and similar pathways, could prevent this from happening and while the contamination is high the water pumping treatment should continue.

For Asbestos - Stabilisation and Solidification Ex-situ

Potential advantages:

Can be used to treat recalcitrant contaminants (e.g. heavy metals, PCBs,

dioxins);

Process equipment occupies a relatively small footprint;

The physical properties of the soil are often improved by

treatment (e.g. increased strength, lower permeability);

Treated material can be reused on site or be re-classified for less expensive

disposal, both subject to regulatory approval.

Limitations:

Does not destroy or remove the contaminants;

May be difficult to predict long-term behaviour;

May result in an overall increase in volume of material;

May require long-term maintenance of protection systems and/or long-term

monitoring;

Reagent delivery and effective mixing can be difficult to achieve.

It is more desirable to keep remediation on site but since asbestos is difficult to destroy without vitrification or other drastic measures, especially for such wide spread contamination it may be more effective to remove it and treat off site.

Preliminary phases of stabilisation and solidification in situ methods may need to be employed in areas of lime dumping since it may react more with the remediation process than the more hazardous chemicals.

To avoid excavating and relocation of the contaminated land a precaution to take is to cap the contaminated soil and break the linkage and add clean topsoil. This way it will not force the development to wait for the soil to be proven clean. It also is a good insurance that the end receptors (especially considering the proposed development) will not be exposed directly. If this were to take place further protection in the form of impermeable liners would be needed for residencies on site since some VOCs retard the concrete’s ability to set and which could then allow toxic fumes of the volatile liquids into the houses.

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Remediation Summary Preliminary phases: - - - -

Stabilisation and solidification of lime dump sites to make later phases more effective Continuing water pumping treatment removal and off site tratment of high concentrations of asbestos Start bioremediation of low concentrated areas of VOCs

Phase One: -

-

Install a permeable reactive barrier around river and watercourses to stop mobile VOCs and soluable heavy metals (begin to phase out pumping treatments) Chemical oxidation treatment for higher concentrations of VOCs

Phase Two: - -

Cap the site to keep low mobility contaminants away from receptors Install impermeable barriers in buildings to prevent vapour inhalaition of receptors in exposed locations.

Mitigation During the remediation process measures can be undertaken to lessen the negative impacts of the contaminated land or remediation processes themselves.

Firstly those employed currently, such as the spray to reduce odours, should be maintained until deemed unnecessary. Other features could be employed such as the establishment of trees or hedges to prevent unwanted views, reduce noise and contain dust and smells.

Landform, temporary or not, could be shaped to act in much the same way, shielding, particularly the residents, but also other receptors from unpleasant experiences. An alternate route for industrial vehicles could be conceived so to lessen the noise pollution witnessed by the residents. If the process takes a significant period of time or gets halted bare earth could be seeded so to lessen the visual impact and encourage the areas ecology.

The established mitigation to ensure remediation is undertaken successfully is the Guidance for Safe Development of Housing on Land Affected by Contamination (Fordyce, G. et al, 2008) which considers: - - - - -

Costs and benefits Effectiveness of meeting remediation objectives Wider environmental effects Regulatory requirements Practical operational issues and aftercare issues

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Conclusion To conclude, firstly, the project should adhere to the NPPF. In the Core planning principles it says to ‘encourage the effective use of land by reusing land that has been previously developed (brownfield land), provided that it is not of high environmental value’ and when talking about contaminated land it continues to say advise that ‘after remediation, as a minimum, land should not be capable of being determined as contaminated land under Part IIA of the Environmental Protection Act 1990; and adequate site investigation information, prepared by a competent person, is presented.’ (Department For Communities And Local Government, 2013).

Finally the project should seek to be efficient and effective at returning the land to a noncontaminated state but without unnecessary expenditure of: - Energy i.e. where possible not simply excavating and relocating the contamination,

so the project is more sustainable and less energy intensive.

- Time, for the benefit of would-be site users.

- Environmental quality by poorly choosing techniques which damage the integrity of

the ecological function of the site.

- Money so the project is most likely to stay buoyant and reach completion.

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Bibliography Advantage West Midlands (2009) Contaminated Land Risk Assessment Matrix. [e-book] Waterman Civils Limited. p.1-3. Available through: Contaminated Land Risk Matrix.docx http://www. planningportal.rugby.gov.uk/fastweb_upload/Planning%20Scanned%20Applications/R09-0035/ R09-0035%20fig%2014.4.pdf [Accessed: 17 Apr 2013].

Bmb.oxfordjournals.org (2013) Hazards of heavy metal contamination. [online] Available at: http:// bmb.oxfordjournals.org/content/68/1/167.full [Accessed: 17 Apr 2013].

Defra (2010) Contaminated Land Remediation. [e-book] London: Defra. p.35-70. Available through: http://www.claire.co.uk/index.php?option=com_content&view=article&id=431&catid=1&Item id=93 http://www.claire.co.uk/index.php?option=com_phocadownload&view=file&id=207:Extern al-Documents&Itemid=61 [Accessed: 17 Apr 2013].

Department For Communities And Local Government National Planning Policy Framework Department For Communities And Local Government (2013) National Planning Policy Framework. [e-book] London. p.6, 29. Available through: https://www.gov.uk/government/policies https://www. gov.uk/government/uploads/system/uploads/attachment_data/file/6077/2116950.pdf [Accessed: 17 Apr 2013].

Environment-agency.gov.uk (2013) Environment Agency - DoE Industry Profiles. [online] Available at: http://www.environment-agency.gov.uk/research/planning/33708.aspx [Accessed: 17 Apr 2013].

Environment-agency.gov.uk (2010) Environment Agency - Aquifers. [online] Available at: http:// www.environment-agency.gov.uk/homeandleisure/117020.aspx [Accessed: 17 Apr 2013].

Fordyce, G. et al. (2008) Guidance for the Safe Development of Housing on Land Affected by Contamination. [e-book] NHBC and Environment Agency. p.64-65. Available through: http:// a0768b4a8a31e106d8b0-50dc802554eb38a24458b98ff72d550b.r19.cf3.rackcdn.com/sr-dpub66e-e.pdf http://a0768b4a8a31e106d8b0-50dc802554eb38a24458b98ff72d550b.r19.cf3.rackcdn. com/sr-dpub66-e-e.pdf [Accessed: 17 Apr 2013].

Grant, A. (2013) Untitled paper, paper presented at Land Contamination Lecture, Sheffield, 12th March. ECUS. Gurtz, L. (2010) BTEX Definition Page. [online] Available at: http://toxics.usgs.gov/definitions/btex. html [Accessed: 17 Apr 2013].

Jeffries, J. (2009) Using science to create a better place. [e-book] Bristol: The Environment Agency. p.3-4. Available through: http://www.environment-agency.gov.uk http://www.environment-agency. gov.uk/static/documents/Research/SCHO0309BPQI-e-e.pdf [Accessed: 17 Apr 2013].

Moray.gov.uk (2013) Contaminated Land - The Moray Council. [online] Available at: http://www. moray.gov.uk/moray_standard/page_40163.html [Accessed: 17 Apr 2013].

Stanger, C. (2004) Model Procedures for the Management of Land Contamination. [e-book] Birmingham: The Environment Agency. p.13-14. Available through: http://www.environment-agency.gov. uk http://www.environment-agency.gov.uk/static/documents/model_procedures_881483.pdf [Accessed: 17 Apr 2013].

Victoria, W. (2010) Asbestos-contaminated soil. [e-book] Victoria: p.1-2. http://www.worksafe.vic. gov.au/__data/assets/pdf_file/0007/9871/101029_GN_Asbestos-contaminated_soil_WEB_FINAL. pdf [Accessed: 17 Apr 2013]. p.13 Land Contamination Report