Land Contamination Report Nick Woolcott-Brown 110225665 LSC 305- Land Contamination, Restoration and Revegetation
LSC 305 - Land Contamination Content
Content
1. Introduction.....................................................................................................................................Page 2
1.1- Introduction
1.2- Background information and site history
2. Baseline Information.....................................................................................................................Page 3-4
2.1- Location 2.2- Geology 2.3- Topography
3. Conceptual Model..........................................................................................................................Page 5
3.1- Definition and purpose of conceptual model
3.2- Conceptual model
4. Contaminants on site....................................................................................................................Page 6-8
4.1- Heavy metals: arsenic, lead and copper
4.2- Vosaile Organic Compounds (VOC’s)
4.3- Asbestos
5. Tabulated Conceptual Model........................................................................................................Page 9
5.1- Summary table of contaminants interferring pathways and receptors
6. Remediation.....................................................................................................................................Page 10-11
6.1- What is Remediation?
6.2- Remediation for Heavy Metals
6.3- Remediation for VOC’s
6.4- Remediation for Asbestos
7. Conclusion.........................................................................................................................................Page 12
8. Bibliography......................................................................................................................................Page 13
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LSC 305 - Land Contamination Introduction
1.0. Introduction 1.1- Introduction • The aim of this assignment consists of important information regarding the future development of the Croda site, as it is heavily contaminated, thus having to produce a tabulated and pictorial conceptual model of the contaminants of the Croda site. • Furthermore, the report will include relevant information gathered from research and 2 site visits concerning the potential contaminants, possibly pathways and potential receptors which could be affected. • In spite of this, the report will include remediation and mitigation methods that will break source, pathway and receptor linkages prior to site development.
1.2- Background information and History • In terms of the historical information of the site, back in the day during the industrial revolution, the Croda site was heavily used for industrial purposes, thus contaminating the land in various ways, even up till today. • Mitchell and Ellison produced a coal distillation and processing facility during the 1880’s. This resulted in contaminating the area with a chemical substance called coke. ‘The solid residue of impure carbon obtained from bituminous coal and other carbonaceous materials after removal of volatile material by destructive distillation. It is used as a fuel and in making steel.’ • Furthermore, in the 1920’s the area was used for storage of the remains from the distillation process, known as Yorkshire Tar Distillers. A chemical substance called creosote was produced for preserving timber. However, in the 1970’s tar production was replaced by longer chained hydrocarbons of petroleum, resulting to be less detrimental. • Lastly, in 1975 it was named Croda, and tar production was finished by 1981 and the production of Bitumen was influenced until demolition of the works and clearance of buildings and the infastructure which occured in 1988.
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LSC 305 - Land Contamination Baseline Information
2.0. Baseline Information 2.1- Location • The Croda site is located in Kilnhurst, near Rotherham on the edge of Swinton. The site is also seperated by Carlisle Street and is based along the South Yorkshire Canal on its east perimeter. • The Croda site is heavily contaminated and lies adjacent to housing areas and in close proximity to surface water courses. It contains remnants of a range of built structures, and also contains areas with habitat value and potential. • In the southern part of the Croda Site, the tar distillation works was situated there and used the northern part of the site as a ‘waste’ area, hence it being ‘heaviy contaminated’. • The northern and southern parts of the site are enclosed by industrial development, whereas the west side consists of residential area and a rail way line. • Furthermore, the vegetation on site has been highly affected due to its contamination from develpoment in the past, resulting in poor soil, therefore tree growth seems impossible. However, the vegetation surrounding the site grows relatively well considering the pollution and contaminants in the soil and elsewhere.
Surrounding land use map Industrial Development
Residential Area
Croda Site
Agricultural Land
Industrial Development
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LSC 305 - Land Contamination Baseline Information 2.2- Geology • The British Geological Survey map of the area (Sheet 87, Barnsley) and information from previous site investigation indicates that ground conditions of the site consist of between 0.5 and 2.0m of Made Ground. • The materials consists variously of silt, sand, gravel and general demolition rubble. The figure on the right indicates the site in diagonal red strips- which is a geological map from digimap indicating that the site consists of artificial ground (Made Ground). • Made Ground is considered by the Environment Agency to be a non aquifer. Made Ground overlies between 1.0m and 5.0m of alluvial deposits. Alluvium at the site consists predominantely of fine to coarse sand and fine to coarse gravels. According to the Environment Agency, alluvium deposits are considered to be a minor aquifer of variable permeability. • The geological map indicates that Upper Carboniferous Middle Coal is present underneath the alluvial deposits, which consist of layers of mudstone, siltstone, seat earth and coal in sequenes up to 1500m in depth. • Lastly, at the Croda site, the Coal Measures outcrop at the surface as weathered sandstones and mudstones. Coal Measures are considered by the Environment Agency to represent a minor aquifer of variable permeability. Groundwater has been identified beneath the site predominantly within the alluvial deposits at a depth of approximately 4.5m below ground level.
2.3-Topography • The site remains relatively flat in the topographical sense, although some areas are raised due to the industrial remains on site, that are made up of past building materials and rubble. • The site lies approximately 18m above sea level, and closer to the north part of the site is raised due to the replacement of fill materials. However the southern part of the site climbs 6m higher due to sandstone outcrop. • In terms of the vegetation on site, it remains very low in biodiversity and ecology. For the reason being poor soil nutrient and contaminants on site. Although, in the north part of the site, vegetation seems to be more established with trees and shrubery being present. This is interesting because the north part of the site was used for waste and storage tanks, thus containing various toxic contaminants with tar and bitumen lying at ground level.
Panorama
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LSC 305 - Land Contamination Concept Model
3.0. Conceptual Model 3.1- Definition and Purpose • Conceptual models is a simple way to exemplify certain aspects on site, providing enough detail about potential sources of contaminants on site, potential pathways and receptors in the area. • The Conceptual model will include various aspects which take into account Contaminant Sources, Pathways and Receptors and lastly, Linkages. These considerations will be expressed through a pictorial model and tabulated model, thus providing a strong understanding of the site. • Conceptual models will help in finalising mitigation and remediation methods as it is an easy way in understanding the site from a different persepective and will help create a plan in order for the final part of the project.
Potential Sources Potential Pathways Potential Receptors
Remains of old buildings could potentially contain metals and asbestos People walking near the site or passing through could inhale dust particles and chemicles realsed into the air
3.2- Concept Model
Evaporated VOC’s and dust particles in the air
People planting in their gardens or cropping could come into contact with contaminated soils
Wildlife could come into contact with contaminants on site Railway The trains can transport contaminants into other areas Made Ground Alluvial Deposits Soil could be Ground Water contaminated Upper Carboniferous Middle Coal Measures
South Yorkshire Canal River Don
Residential Area Water run off into the Local Residents could easily come into contact with contaminants canal and the river around the site, through inhalation
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LSC 305 - Land Contamination Contaminants of Croda Site
4.0. Contaminants of Croda Site 4.1- Heavy Metals: Arsenic, Lead and Copper Arsenic Description: It is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals. ‘The three most common arsenic allotropes are metallic gray, yellow and black arsenic, with gray being the most common.’
Location/Source: In the north part of the site arsenic traces can be found in the made ground due to the disposal dumping that it once was before. Also by the canal where storage tanks were used before, and could be in contact with the ground water below the surface.
Threats: Arsenic contamination of groundwater is a problem that affects millions of people across the world. It is extremely toxic to humans and can be cancerous of the liver, skin, prostate and more.
Lead Description: It is very soft, highly malleable, and a relatively poor conductor of electricity. It is a chemical element in the carbon group with symbol Pb and atomic number 82.
Location/Source: In the north part of the site lead traces can be found in the made ground due to the disposal dumping that it once was before. Also by the canal where storage tanks were used before, and could be in contact with the ground water below the surface.
Threats: Lead is a highly poisonous metal (regardless if inhaled or swallowed), affecting almost every organ and system in the body. The nervous system is most effective both in adults and children.
Copper Description: Copper is a chemical element with the symbol Cu and atomic number 29. Pure copper is soft and malleable. It is also used as a conductor of heat and electricity, building materials, etc.
Location/Source: -Near transport routes- railway, canal -In the north part of the site copper traces can be found in the made ground due to the disposal dumping that it once was before. Also by the canal where storage tanks were used before, and could be in contact with the ground water below the surface.
Threats: Not as toxic as the above heavy metals.
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LSC 305 - Land Contamination Contaminants on Croda site 4.2- Volatile Organic Compounds- Benzene, Ethylbenzene and Xylene Benzene Description: Benzene is an organic chemical compound with the molecular formula C6H6. Benzene is a natural constituent of crude oil, and is one of the most elementary petrochemicals.
Location/Source: Trace amounts of benzene may result whenever carbon-rich materials undergo incomplete combustion. In the past there was a tar distillery on the Croda Site, therefore benzene is around. It will be in areas such as where coke was produced, and in made ground, soil and shallow ground water.
Threats: Benzene is highly toxic to humans- benzene increases the risk of cancer and other illnesses. It is highly volatile, therefore being easily mobile in soils and groundwater.
Ethylbenzene Description: Ethylbenzene is an organic compound with the formula C6H5CH2CH3. It is a highly flammable, colorless liquid with an odor similar to that of gasoline.
Location/Source: Spillages from refinery operations, into the made ground, ground water, soil and underground storage tanks.
Threats: Ethylbenzene is highly toxic to humans- It is highly volatile, therefore being easily mobile in soils and groundwater. Ethylbenzene is found mostly as a vapor in the air since it can easily move from water and soil.
Xylene Description: ‘a volatile liquid hydrocarbon obtained by distilling wood, coal tar, or petroleum, used in fuels and solvents and in chemical synthesis.’
Location/Source: Made ground, ground water, soil, spillages from past operations
Threats: Similar to ethylbenzene, it is a volatile organic compound and is very toxic to humans and flammable. Xylene is also water soluble thus being dissolved in some ground water or in the air as evaporated particles.
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LSC 305 - Land Contamination Contaminants on Croda Site 4.3- Asbestos Asbestos Description: a highly heat-resistant fibrous silicate mineral that can be woven into fabrics, and is used in brake linings and in fire-resistant and insulating materials.
Location/Source: There will be traces of asbestos in the waste area, north part of the site. In the nade ground and soil layer.
Threats: Asbestos can be carcinogenic once evaporated in the air.
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LSC 305 - Land Contamination Tabulated Conceptual Model
5.0. Tabulated Conceptual Model 5.1- Summary  table of contaminants interfering pathways and receptors Contaminants
Pathways and Receptors
Arsenic
Lead
Copper
Benzene
Ethylbenzene
Xylene
Asbestos
Human Health Dermal Contact Inhalation Water Ground Water Ground Soils Vegetation Plants
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LSC 305 - Land Contamination Remediation and Mitigation
6.0. Remediation and Mitigation 6.1- What is Remediation? • By definition, remediation is the action of remedying something, in particular of reversing or stopping environmental damage. • In this case, remediation and mitigation methods will be suggested for Croda site in order to break source, pathway and receptor linkages prior to site development. • Various techniques regarding remediation and mitigation will help break down any contaminated materials on site so that for the future, health and safety is taken consideration for. • The national planning policy framework suggests: The role of the planning system is to control future development and land use. The assessment of risk arising from contamination and remediation requirements should be considered on the basis of both the current and proposed use. • Remediation technologies are many and varied but can be categorised into ex-situ and in-situ methods. Ex-situ methods involve excavation of affected soils and subsequent treatment at the surface, In-situ methods seek to treat the contamination without removing the soils.
6.2- Remediation for Heavy Metals • In situ remediation -one of the 2 types of remediation techniques, which also treats it in place. • Permeable Reactive Barriers (PRB’s)- water remediation (groundwater)
-also referred to as a permeable reactive treatment zone (PRTZ), is a developing technology that has been recognized as being a cost-effective technology for in situ (at the site) groundwater remediation.
-Reactive zones installed across a groundwater plume flow path to remove or degrade contaminants
-PRB’s will help prevent contaminants entering rivers and canals
• Another Water remediation technique is to Pump and Treat
-Pump and treat involves pumping out contaminated groundwater with the use of a submersible or vacuum pump, and allowing the extracted groundwater to be purified by slowly proceeding through a series of vessels that contain materi- als designed to adsorb the contaminants from the groundwater.
-This method is for treating water soluble contaminants -The disadvantage of the pump and treat method is that contaminants can still leak and enter at ground level surface water since it is in situ remediation, thus it is treated in place on site.
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LSC 305 - Land Contamination Remediation and Mitigation
6.3- Remediation for VOC’s • In situ oxidation
-In situ chemical oxidation (ISCO) is the most rapidly growing remedial technol- ogy applied at EPA hazardous waste sites. According to the U.S. Environmental Protection Agency.
-New in situ oxidation technologies have become popular, for remediation of a wide range of soil and groundwater contaminants. Remediation by chemical oxidation involves the injection of strong oxidants such as hydrogen peroxide, ozone gas, potassium permanganate or persulfates.
-’ ISCO is specifically used to reduce contaminant mass and concentrations in soil and groundwater, contaminant mass flux from source areas to downgra dient pump-and-treat systems, and to reduce anticipated cleanup times required for natural attenuation and other remedial options.’
• Soil vapour extraction
-Soil vapour extraction (SVE) is an effective remediation technology for soil.
-SVE utilize different technologies to treat the volatile organic compounds (VOCs) generated after vacuum removal of air and vapours from the subsur face and include granular activated carbon, thermal and/or catalytic oxidation and vapor condensation.
6.4- Remediation for Asbestos • Ex situ remediation- involve excavation of affected soils and subsequent treatment at the surface • solidification- stabilisation • --> mix soil with added reagent to reduce contaminant mobility by one or more of: 1. Enhanced sorption, precipitation or chemical binding 2. Physical encapsulation 3. Reduced permeability Solidification/stabilisation work has a reasonably good track record but also a set off serious deficiencies related to durability of solutions and potential longterm effects. In addition CO2 emissions due to the use of cement are also becoming a major obstacle to its use in projects. Stabilisation/solidification (S/S) is a remediation technology that relies on the reaction between a binder and soil to stop/prevent or reduce the mobility of contaminants. • Stabilization - involves the addition of reagents to a contaminated material (e.g. soil or sludge) to produce more chemically stable constituents • Solidification - involves the addition of reagents to a contaminated material to impart physical/dimensional stability to contain contaminants in a solid product and reduce access by external agents (e.g. air, rainfall).
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LSC 305 - Land Contamination Conclusion
7.0. Conclusion Conclusion • The Croda Site is highly contaminated and will undergo remediation methods to break source, pathway and receptor linkages prior to site development. The redevelopment strategy will consist of some techniques mentioned in the remediation chapter in order to fight against the contaminants and get rid of most of the toxic chemicals if not all for future use. • Croda will aim to follow policies issued by the government from the National Planning Policy Framework (NPPF). • In order for the site to be of use, there will need to be a range of professionals with expertise in construction, engineering, planning, etc. • Through analysing and researching about the various methods of environmental remediation for restoring the site for public use, housing, improving the local wildlife... A series of approaches should be considered: -Revegetation Strategy- Planting Reed Beds, and Bioswales will help with improving the local wildlife -Soil Remediation- In situ chemical oxidation and soil vapour extraction to treat VOC’s -Water Remediation- PRB’s to treat the heavy metals, and reduce the impact of contaminated groundwater on the Croda Site. To conclude, this land contamination report provides an overview of the sites history/context, contaminants, sources, pathways, receptors and lastly remediation methods which help remove the chemicals from the site, thus providing some use for the future.
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LSC 305 - Land Contamination Bibliography
8.0. Bibliography Bibliography • Lsc 305 Lecture Series • Environment Agency (2002). Guidance on the use of permeable reactive barriers for remediating contaminated groundwater. [online] Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/290423/scho0902bitm-e-e.pdf [Accessed 25th April 2014] • Environment Agency (2004). Guidance on the use of stabilisation/solidification for the treatment of contaminated soil. [online] Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/290978/scho0904bifo-e-e.pdf [Accessed 22nd April 2014] • NPPF Communities and Local Government (2012) National Planning Policy Framework. [online] Available at: https://www.gov.uk/ government/uploads/system/uploads/attachment_data/file/6077/2116950.pdf [Accessed 20th April 2014] • Environment Agency (2012) National Planning Policy Framework – planning and contaminated land. [online] Available at: https:// www.gov.uk/government/uploads/system/uploads/attachment_data/file/297014/geho0512bupg-e-e.pdf [Accessed 27th April 2014]. • Norman, Nicholas C (1998). Chemistry of Arsenic, Antimony and Bismuth. Springer. p. 50. [Accessed 23rd April 2014]. • mecx. (2006). In-Situ Chemical Oxidation. Available: http://mecx.net/links/in-situ_chemical_oxidation.html. Last accessed 22nd April 2014.
Images • Arsenic: http://eochemistry.wikispaces.com/Arsenic • Lead: http://www.connectpositronic.com/finding-an-alternative-to-lead-in-electronics/ • Copper: http://en.wikipedia.org/wiki/Copper • Benzene: http://commons.wikimedia.org/wiki/File:Benzene-aromatic-3D-balls.png • Ethylbenzene: http://commons.wikimedia.org/wiki/File:Ethylbenzene-3D-balls.png • Xylene: http://en.wikipedia.org/wiki/Xylene • PRB’s: http://www.geoengineer.org/education/web-based-class-projects/geoenvironmental-remediation-technologies/permeablereactive-barriers?showall=1&limitstart= • Pump and Treat: http://oceanworld.tamu.edu/resources/environment-book/groundwaterremediation.html • Chemical Oxidation: http://www.epa.gov/ada/gw/isco.html
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Land Contamination Report LSC 305- Land Contamination, Restoration and Revegetation Nick Woolcott-Brown