Contaminated Land: Moston Brook, Manchester and Oldham - Case Study Example

Contaminated Land Case Study: Moston Brook, Manchester and Oldham Introduction The United Kingdom’s Government policy concedes that land contamination hampers the institution of sustainable development projects. The previously industrial land has remained unused for many years, and there is a possibility for contamination to be present. Contamination of land has occurred due to many different kinds of human activity, and it is considered to be a legacy of recent industrial history (Sarsby 2004, p. 331). Contaminants appear in solid, liquid or gaseous form, and they adversely affect human beings, rivers, buildings, aquifers and abstraction wells, and the environment. Contaminated land has been defined as land that, because of its former use, it contains substances that present hazards likely to affect its redevelopment (Sarsby 2000, p. 332). It has also been defined as a land that requires an assessment to determine whether redevelopment should proceed without some form of remediation of the site. Fundamental to the UK policy framework is the implementation of the ‘suitable for use’ approach. This approach requires that any unacceptable risks be dealt with and, where practicable, land that is already contaminated should be brought back to a suitable standard, considering the actual or intended use of the land development. The subject area has been subject to investigations by Oldham and Rochdale and is subject to consideration by regulators for further action under PartIIA of the Environmental Protection Act. 1. Study Objectives This study seeks to establish the appropriateness of the subject area for recreational use such as walking, games, picnics, and other leisure activities. The purpose of this study is to describe the context of the site and then define the risk assessment objectives. The objective of this study is to: i. Gather site-specific details including the current and historical information, and future intended use. ii. Establish the contaminants migration sources and pathways iii. Identify the potential health implications of the site to the surrounding inhabitants and environment iv. Provide suitable information and data for designing the field investigation strategy The Aims of this Study are to: i. Identify whether the contaminants on the site pose chronic health risks to the receptors. ii. Identify the representative concentration of contaminants and their hazardous effect on the receptor. iii. Whether the level of concentration is significant enough to pose acute health risks to the receptors. iv. Establish whether the contaminated land on the exposed bank (between the canal and the brook) and the ‘Football Ground’ should be brought back to a suitable standard that will accommodate the proposed projects. The study seeks to meet the requirements laid down in the Contaminated Land (England) Regulation 2006. 2. Preliminary Investigation Strategy Site Description Moston Brook is located in Manchester, North West England. It is located 5 km north-east of the city centre (Oldham and Rochdale 2008, p. 9). The subject of this case study comprises a land site at the Moston Brook, Manchester and Oldham, which has a previous history of both industrial development and waste disposal. The subject is an area lying across two local authorities – Manchester City Council and Oldham Metropolitan Borough Council. The area is a more than 70 hectare corridor of green space along the boundary of Manchester and Oldham, between Failsworth and Moston. A part of Irk Valley Green Space Network contains sites of biological importance. Moston Brook links into the Rochdale Canal corridor which is considered of significant ecological and recreational importance (Oldham and Rochdale 2008). The site also contains nine former landfill sites, and a water course of poor water quality, namely Moston Brook. The local community expresses its desire to see the brook and green corridor improved. Currently, the site is not achieving its full potential as a community amenity or strategic gateway corridor. Ferranti football field is considered to be of intermediate value (3.3), whereas the exposed bank between the canal and the Brook is considered to be of very high value (4.7) because of its natural beauty (Oldham and Rochdale 2008, p. 43). Ferranti Football Field This field is a fairly flat land surrounded by native hedge trees, scrub land and the railway embankment (Oldham and Rochdale 2008, p. 38). The surface is characterised by loose rocks probably linked to past industrial use of the land. Ferranti Football Field is open and exposed in the centre. The eastern end of the area is used as a BMX track whereas the western end is used as a dog training centre. Most of the area is neglected and is characterised by overgrown vegetation along the edges. The area is largely unmanaged, and this gives an unsettling air to it. “White stuff’ path dissects the neglected area. ‘White stuff’ is an industrial waste and is covered with grassland and woodland. However, it is visible on the surface. Site History It has been established that the subject area was an open countryside with farming settlements in the 14th century (Oldham and Rochdale 2008, p. 6). In the 16th century, the main activity in his area was washing and bleaching of linen. Bleaching and washing were the main activities of the area. In the 18th and 19th centuries, the area became an active part of the northern ‘Cottonopolis’ In addition to washing and bleaching activities in the area, Moston Mill Print Works was conducting its activities. Other land uses that were taking place in the area in the past were extraction of sand and clay. Clay has been linked to the brickwork. There is enough evidence of clay works because the landfill site currently known as Hardman Fold was a large clay pit (Oldham and Rochdale 2008, p. 6). There are other sites that were used as clay and sand pits such as a site to the south of William Road and another site to the north of the Lancaster Club. Landfill activities have taken place in almost the entire subject area. The recreation activities that have taken place previously include the Lower Memorial Park in 1930s, tennis ground (1910) and golf driving range (1970s) in Broadway Common. Football matches and dog training have also taken place. Discussion of previous investigative work and assessment of the level and distribution of key contaminants across the site There are several studies conducted previously to assess the level and distribution of key contaminants across the subject site. These studies offer an insight of the potentially contaminative historical land uses and highlight the contaminants potentially present in the subject area. According to the past surveys, the site has been landfill, and there is possible emission of gases by the waste disposed of in the landfill. In addition, if the concentration of these gases exceeds a certain point, there is a risk of explosion. According to studies previously conducted on the site, there are elevated concentrations of heavy metals (Oldham and Rochdale 2008, p. 31). Historically, the area has also been used for brickworks; therefore, there may be a presence of Asbestos, Ph. Preliminary conceptual model with potential pollutant linkages illustration A Conceptual Model (CM) provides all interested parties with a vision of the site (Nathanail and Bardos 2004, p. 49). It presents the possible contaminants, pathways, and receptors. The Government policy that relates to the land affected by historic contamination is based on a ‘suitable for use’ approach (Defra 2006a). This approach enables the contamination areas to be considered in the policy frameworks. For a land to be considered contaminated, it must have a pollutant linkage. For a linkage to be considered valid the following characteristics must be present: i. A contamination source; ii. A receptor that can be easily harmed; and iii. A pathway exposing a receptor to the contaminant. In Moston Brook, there is a presence of a pollutant linkage because all the above characteristics have been fulfilled. The subject area had a rich industrial heritage during the early 1800s; however, over the years, the area has been subjected to contamination from the high concentration of dye works, paper mills, and bleach works operations along the Moston Brook that flows through the subject area. Due to pollution the area was even nicknamed ‘Black Brook’. More recently, the area was subjected to landfill such that it attained the same level as the surrounding land. It was then covered over, became a low-grade area, unattractive and a neglected green space (Forest Research 2008). The pollutant linkage in a “Conceptual Model” of the subject area is presented in Table 1. By considering the sources, pathway, and receptors in the pollutant linkage, this study will conduct an assessment of the significance and degree of risk. Contaminant(s) Pathway(s) Receptor(s) Metals (Cadmium, Barium, Lead, Copper, Nickel, Mercury, Chromium, Zinc, Vanadium) Inhalation, dermal, and ingestion: Contact with landfill material and contaminated soil Windblown dust and landfill material Neighbouring site users (Ferranti football field), future site users, the environment within the site. Grazing animals Wildlife Vertical migration of dissolved and free-phase contaminants Ground water in the aquifer Ground water in made ground Lateral migration of free-phase and aqueous contaminants in shallow groundwater system and surface runoff. The stream in Hardman Fold bottom valley Inorganic chemicals (, ) Inhalation, dermal, and ingestion: Contact with contaminated soil and landfill material Windblown dust and landfill material Neighbouring site users (Ferranti football field), future site users, the environment within the site. Grazing animals Wildlife Vertical migration of dissolved and free-phase contaminants Ground water in aquifer Ground water in made ground The stream in Hardman Fold bottom valley Landfill Gas (Components of carbon dioxide, methane, carbon monoxide and H2S) Inhalation of gas flux Pressure driven flow of gas through Made Ground and underlying geology Neighbouring site users (Ferranti football field), future site users Grazing animals Wildlife Explosive risk Neighbouring current users and the future site users Others (Asbestos, Ph, Phenol, PCBs, Dioxins and furans) Inhalation, dermal, and ingestion: Contact with landfill material and contaminated soil Windblown dust and landfill material Neighbouring site users (Ferranti football field), future site users Grazing animals Wildlife Vertical migration of dissolved and free-phase contaminants Ground water in aquifer Lateral migration of aqueous and free-phase contaminants in shallow groundwater system and surface runoff Ground water in made ground The small stream running east to west Table 1. “Conceptual Model” of the subject area People Flora Site Workers Ingestion, inhalation, direct Plant uptake contact with human beings Water supply pipes Permeation Soil Gas (Carbon dioxide) MADE GROUND Leaching into ground water AQUIFIER Water Table Figure 1: Visual Representation of Conceptual Site Model One particular concern was the occurrence of methane gas. Methane is a dangerous greenhouse gas which is considered to cause global warming 21 times more than carbon dioxide (Mohajan 2011, p. 3). Methane gas is lighter than air, odourless, colourless, and flammable. It is usually present in shallow, organic-rich deposits and deep coal beds as well as other rock units. According to the Department of Environmental Protection (2013, p. 1). Methane migrates from high pressure to low pressure areas through available pathways. Drilling of wells in the residential areas within the subject area may have been affecting the pressure thus, increasing the pathways in the subsurface allowing passage of methane to lower pressure areas such as shallow aquifers and water wells. If methane gas penetrates any enclosed structure, it can accumulate to hazardous levels. Concentration of methane at 5 percent in the air has been found to constitute an explosion hazard (DEP 2013, p. 1). The site visitors are bound to smoke cigarettes or light matches causing the gas to explode. However, no health effects from drinking water that contains methane have been established. The presence of contamination Contamination is present in the subject area. The contamination is in the ground as well as in the underlying groundwater resulting from the historic contamination from dye works, paper mills, and bleach works operations. This contamination is due to wastes and disposal of raw materials from paper and clothes industries. The United Kingdom government encourages the beneficial reuse of contaminated sites such as Moston Brook. In UK, the extent of contamination is not clearly defined. However, it is estimated that approximately 200,000 ha of land in UK is affected by contamination (DETR/Urban Task Force 1999). Environment Agency (2002) further estimates that there are about 5,000 to 20,000 problem sites in the UK. Ground-gas Risk Assessment Previous studies of the subject area have found concentrations of methane, carbon monoxide, carbon dioxide, hydrogen sulphide and VOL in the subject area (Oldham and Rochdale 2008). This study proposes that measures be put in place to manage and control these ground-gases. However, if control measures involve disturbing the landfill material through excavations, a risk assessment and action plan specific to this situation should be implemented. Ground and Surface Water Previous studies have established that surface water quality in the area is being affected by past and current wastes. According to Oldham and Rochdale (2008), the contamination is significant. The Brook rises in North East Manchester / South West Oldham near the Rochdale Canal and discharges into River Irk. However, River Irk is outside the subject area. The Brook has been subjected to contamination (Oldham and Rochdale 2008, p. 9). There is no geological barrier to prevent the migration of contaminants into the major aquifer; therefore, there is possibility that the major aquifer is being contaminated. Ground water within the subject area is highly contaminated (Oldham and Rochdale 2008, p. 9), and further investigation should be conducted prior to establishing any recreational activity in the area. The investigation should be conducted to establish whether the waste material present constitutes an ongoing source of contamination. Drilling methods used in the subject area may contribute to the creation of pathways (Chesnaux 2012, p. 743; Santi et al. 2006, pp. 52). This study recommends the use of appropriate drilling methods and restoration materials to preclude creating pathways. Field Investigation Design On-Site and Off-Site Measurements According to Steeds, J., Slade, N. and Reed, M. (2000, P. 47), on-site measurement incorporates instruments that are portable. These instruments are used to measure parameters such as gas concentrations, and Ph in order to enable the investigator to obtain quantitative information about the study area. Off-Site measurements are carried out in a laboratory away from the site (CIRIA 1993). Ground Gas Monitoring In relation to ground gas monitoring, the investigator should ensure that the ground gas protection measures installed in the site are capable of coping with the investigation process. Several issues that an investigator should consider in selecting the methods of ground gas measurement have been proposed. Monitoring of ground gas will combine both in situ and ex-situ (gas samples will be transported to an analytical laboratory). Ground gas samples will be extracted. Even if there will be field-based measurements, it is important to test these gases in an analytical laboratory. The study will also use meteorological data so as to help in explaining the variations. The investigator should conduct a thorough and up-to-date listing when selecting the equipments. The advantages and disadvantages of all equipments are found in CIRIA Report 659 (2006) (Wilson et al. 2006). Factors Influencing Ground Gas Migration The investigator should put into consideration several conditions that may influence ground gas migration when conducting the study. These conditions include tidal effects, meteorological conditions, geological characteristics, development, and vegetation. The preliminary study and the conceptual site model should be consulted to predict the worst-case temporal conditions that the site may experience. The most reliable results will be achieved only when the above conditions are put into consideration. Cross-Contamination The investigator should ensure that there are enough measures to avoid the cases of cross-contamination during the site investigation work (USEPA 1991). Good decisions about excavation techniques and other working methods should be made prior to the investigation in order to avoid cross-contamination because the processes named above are the major culprits of cross-contamination. All the site investigation workers will be informed of the site specific issues and the reasons for choosing any particular investigation technique or working method. According to Design Manual for Roads and Bridges (1995, p. 23), the techniques that minimise cross-contamination are essential. Therefore, the equipments for investigating a contaminated land should be carefully selected. The investigation will use a combination of intrusive (excavation and trial pits) and non-intrusive (geophysical techniques) methods. Geophysical Techniques These techniques will involve the use of properties of subsurface materials such as electrical resistivity and density to indicate changes in ground conditions. These techniques are effective in locating anomalies in a site for further investigation by drilling and excavation. They are very useful in determining the limits of areas possibly containing hazardous materials. In the present study, geophysical methods will be helpful in determining the limits on the edges of the landfill. Some of the geophysical techniques that will be used are ground penetrating radar, seismic refraction surveys to establish the depth of the ground water table; electrical resistivity measurements to differentiate between saturated and unsaturated soils. Conductivity Surveys can also be used to detect the presence of buried metallic objects. Infra-red thermo-graphic surveys and infra-red photography can be used to detect contaminated ground, particularly landfill sites. Sampling Method Water samples from the boreholes will be taken using a number of sampling techniques such as pumps and balers. The potential for cross-contamination of these samples will be recognised. Ground water will be obtained from standpipes from groundwater sampling wells. Controlled sampling protocols and strict sampling protocols are required to address the conditions of transporting and storing samples including temperature and time. Laboratory Testing The chemical analysis techniques should be fully defined prior to the investigation fieldwork. The investigator should ensure full compatibility of the test method and the assessment method. The choice of chemical analysis will be based on the history of the subject sites. Quality control will be maintained to ensure reliable analysis of results. Legislation The present legislation concerning contaminated land consists of statutes such as The Environmental Protection Act 1990 (EPA) and The Water Resources Act 1991. Other statutes of relevance to this study include Health and Safety at Work Act 1974 and Control of Pollution Act 1974. Concluding Remark Though this study has identified the potential pollutant linkages, it does not indicate that the site cannot be used for the current or proposed projects. However, the study proposes further data collection in the subject area. The area is environmentally sensitive making the land highly sensitive. References Chesnaux, R. 2012. Uncontrolled Drilling: Exposing a Global Threat to Groundwater Sustainability. Journal of Water Resources and Protection, 4, pp. 746-749. CIRIA. 1993. The Measurement of Methane and Other Gases from the Ground. Report 131. Contaminated Land (England) Regulation 2006. Available http://www.ukooaenvironmentallegislation.co.uk/contents/Topic_Files/Onshore/Contaminated%20Land.html DEFRA. Circular 01/2006. Environmental Protection Act 1990: Part 2A Contaminated Land. Department of Environmental Protection. 2013. Methane Migration into Occupied Buildings. DEP. Design Manual for Roads and Bridges. 1995. Site Investigation for Highway Works on Contaminated Land. Geotechnics and Drainage Earthworks, 4 (1), pp. 1-50. DETR/Urban Task Force. 1999. Towards an Urban Renaissance. Environment Agency. 2002. Dealing with Contaminated Land in England. Environment Agency. 2008. Guidance for the Safe Development of Housing on Land Affected by Contamination. Chartered Institute of Environmental Health, 1. Forest Research. 2008. Benefits of Green Infrastructure: Case Study. Forest Research. Mohajan, H. 2011. Dangerous effects of methane gas in atmosphere. International Journal of Economic and Political Integration, 1 (2), pp. 3-10. Nathanail, P. and Bardos, P. 2004. Reclamation of Contaminated Land. West Sussex: John Wiley & Sons O’Riordan, N. and Milloy, C. 1995. CIRIA Report 152: Risk Assessment for Methane and Other Gases from the Ground. CIRIA. Santi, P., McCray, J. and Martens, J. 2006. Investigating Cross-Contamination of Aquifiers. Hydrogeology Journal, 14, pp. 51-68. Sarsby, R. 2000. Environmental Geotechnics. London: Thomas Telford. USEPA. 1991. Handbook of Suggested Practices for the Design and Installation of Ground-Water Monitoring Wells. EPA1600 14-89 1034. Available on http://www.epa.gov/swerust1/cat/wwelldct.pdf Wlson, S., Oliver, S., Mallett, H., Hutchings, H. and Card, G. 2006. CIRIA Report 659. Assessing risks posed by hazardous ground gases in buildings. CIRIA. Read More