ReviewLiterature review of baseline study for risk analysis — The landfill leachate case
Introduction
The main driver for improved and increasingly comprehensive environmental legislation in the UK and other European nations is undoubtedly European legislation (see Table 1). From the signing of the Treaty of Rome in 1957, until the signing of the Maastricht Treaty in 1992, the European Community was essentially an economic common market and had no mandate for environmental regulation. Any directive with an environmental element rested on the principles of either ‘public health protection’ or ‘harmonisation’ of environmental rules to avoid market distortion. The Maastricht Treaty officially adopted the objective of sustainable development as community policy, advocating a high level of protection of the environment, based on the precautionary principles including the principle of “pollution prevention at source” and the “polluter pays principle” (Calleja et al., 2004, Luken, 2009, Pearce and Turner, 1992, Tadhg and Dermot, 2003).
European waste and water management policies were originally developed to control pollution and protect the environment, which stimulated infrastructure investment in the waste and wastewater treatments sectors. Although criticised for its high cost, this succeeded in reducing concentrations of regulated point-source pollutants. It was however found that Member States were exploiting inconsistencies in the legislative text, and that standards set out in the Dangerous Substances Directive were not being achieved in many instances. Additionally, evidence of increasing pollution of waters (especially groundwater), and the recognition of the need to safeguard the ‘ecological quality’ of waters led to the revision and integration of the existing fragmented waste- and water-related legislation (listed in Table 1) into integrated management frameworks taking an ecosystem-based approach (Kallis and Buder, 2001). The Landfill Directive and the Water Framework Directive were published in the Official Journal of the European Community in 1999 and 2000, respectively. Both of these became European, and hence national law, in 2003.
In order to protect public health and the environment, risk assessment has become a dominant public policy tool for making choices based on limited resources. Having realised the significance and effectiveness of risk assessment in environmental management, environmental legislation has started to impose risk analysis as a tool for meeting legal requirements associated with waste hazards (Butt et al., 2009, Environment Agency, 2003a). For instance, to protect groundwater from landfill leachate contamination, risk assessment has been legislatively introduced into the UK since 1st May 1994, through “Regulation 15 of the Waste Management Licensing Regulations” (SI, 1994a) and the “Groundwater Regulations” (SI, 1998). The Landfill Directive is implemented in England and Wales through the “Landfill Regulations” (SI, 2002), made under the “Pollution Prevention and Control (PPC) Act” (England and Wales) 1999. The equivalent legislation, which is called Landfill (Scotland) Regulations, has come out in Scotland as well (SEPA (Scottish Environment Protection Agency), 2005a, SEPA (Scottish Environment Protection Agency), 2005b, SSI (Scottish Statuary Instrument), 2000, SSI (Scottish Statuary Instrument), 2003). It can be inferred from the introduction of all these legislative instruments that the ‘out of sight, out of mind’ concept regarding wastes is no longer possible or permissible. To achieve the maximum protection of the environment against the hazards associated with landfill sites, all potential hazards must be identified and risks associated with them must be assessed.
Landfill is the most widely employed method for disposal of waste around the world. The majority of municipal solid waste landfills, including those that previously co-disposed hazardous materials, continue to receive a significant proportion of bioreactive wastes which produce mainly greenhouse gases and wastewater known as leachate. Landfill leachate contains organic and inorganic pollutants including ammonia, heavy metals, humic-acids, persistent synthetic organic pollutants and inorganic salts of high concentration. If landfill leachate is not collected, treated and discharged safely, it shall become a potential pollution source which threatens soil, surface water and groundwater (Butt et al., 2009, Fatta et al., 1999). Therefore, landfill leachate is recognised as an important environmental problem and its risk assessment and management is thereby considered essential.
Risk assessment, however, is a relatively new and fast developing science, both in terms of its adoption as a formalised analytical process applied to environmental issues, and also as a policy tool to assist regulators in the decision making process (Butt et al., 2009, Eduljee, 2000). This is not just in relation to landfill and other environmental sectors but also in relation to other areas including ecology, epidemiology, health and safety, radiation, earthquakes, finance, construction management, building contract selection, insurance, economics, fire, landslides, ship navigation, the food industry, and the oil industry (Butt and Oduyemi, 2003, Butt et al., 2006, Butt et al., 2009, CIWEM (the Chartered Institution of Water and Environmental Management), 1999). Regardless of the type of risk assessment needed and the specific environmental area of its application, a baseline study is the most important component of a risk analysis system (Asante-Duah, 1996, Blight and Fourie, 1998, CIRIA (Construction Industry Research and Information Association), 2001, Environment Agency, 2003a, ICE (Institution of Civil Engineers), 1994). In this paper it is this baseline study which is the core focus.
The main aim of the paper is to establish knowledge gaps in baseline study specifically regarding landfill leachate risk assessment, thereby paving a way for researchers to further research and develop in this particular area. Hence this paper identifies and critiques the limitations of existing research literature in this area while simultaneously establishing the ‘state-of-the-art’ of baseline studies. Further aims in this work include developing some new insights in how to bridge the identified knowledge gaps, and the significance of why these gaps need to be closed. However, as the focus of the paper is primarily to both review the existing ‘knowledge’ and ‘knowledge shortfalls’ regarding this subject matter, any new insights are only indicatively addressed for the sake of brevity, and in order to simply present a way forward for future research work in this area.
The basic methodology used to carry out this review study included the following elements:
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The systematic selection of specific material used in the literature review process.
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The criteria that are set and used to bench-mark the selected literature against.
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A review of the relevant environmental legislation.
Initially as a background to the review process, this paper sets the environmental legislative scene dating as far back as 1957. From that point onward, the paper describes how the environmental legislation came into being and has been steadily growing ever since then, both in terms of becoming more stringent and holistic. The paper next considers the links between the environmental legislation with risk assessment, and the significance of baseline studies in risk assessments. In addition, the paper commences the review of literature from a broad prospective covering various business fields, both environment-related and non-environment-related (e.g. insurance and construction management sectors). Then the paper narrows the review down to contaminated land in which landfills are deemed as a specific type of land contamination. After this, the paper then further narrows down the focus on to the main issue in this study which is landfill leachate.
Following on from the above, a brief but clear list of a wide range of features that can make a baseline study more holistic are discussed (for a more integrated and unified risk assessment of landfill leachate). The literature review work is then bench-marked against these features. It must be noted that this literature review considers not only recent studies but studies going as far back as the 1970s and 1980s. Thus the wide period considered under this study ensures that no appropriate studies, past or present, around the subject matter are missed out from the review process. Further, this paper does not consider one specific type of literature, but examines a diverse range of literature types including ones that cover the academic, public, private, consultancy, and industrial sectors respectively e.g. government documents (such as from the Environment Agency, SEPA, EPA US), as well as non-government documents, peer review academic research articles, reports, magazines, websites, and computer models. Some relevant case studies are also mentioned briefly and in-line with the scope of the paper as explained later in Section 2.0. It is worth noting that as part of this review process, the guidance in the form of anecdotal conversations with professionals and academics in the field was also used to find more appropriate literature in this area.
Section snippets
Definitions and scope
From the perspective of landfill risk analysis, the authors describe a baseline study process as that fundamental and initial stage of a risk assessment exercise of landfill leachate in which all basic information and/or data are collected, organised, and analysed. Specifically, in the case of landfills, the baseline study needs to take account of a wide range of multi- and inter-disciplinary issues that the authors categorise into eight groups including: geology, hydrology, hydrogeology,
Risk assessment — connection with baseline study in the holism context
The review of environment-related literature clearly shows that a baseline study is a crucial and primary factor in an environmental risk analysis. Moreover, the investigation (contained Table 2) led to the conclusion that a comprehensive, robust, detailed, and sound risk assessment methodology, incorporating a number of essential features (including that of baseline study) does not exist in an integrated manner. Examples of essential features are:
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Encompassing various types of landfill systems
Concluding discussion
While the current and forthcoming legislation pushes forward to reduce both the quantity of disposed wastes and the environmental impacts of landfill sites, there is still need to manage the current landfill sites and find solutions to remediate and control environmental pollution from these sites. Furthermore according to the sustainable Waste Hierarchy, although waste amounts are to be reduced that are disposed of at landfills, it is still not possible to have a ‘no-landfill’ society for a
Acknowledgements
The authors acknowledge the financial support of Dundee City Council which made this research study possible. We are additionally grateful for the discussion and help received from Mr Peter Goldie of the Environment & Consumer Protection Department, Dundee City Council. The support from Mr Stephen T. Washburn (CEO, ENVIRON, New Jersey, US), Dr I. M. Spence (Consultant Environmental Geologist, Scotland), and colleagues at the University of Abertay Dundee, including Dr Olisanwendu Ogwuda, Dr
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