Report on Sustainable Construction

 

 

 

 

Introduction

 

Part 2A of the 1990 Environment Protection Act delineates the issue of contaminated land regime and the importance of remediating such lack given that it is of significant risk to the environment and human health (DEFRA 2012). The following report provides an in-depth assessment of the issue of contaminated land in the UK. The report is divided into three key sections. Section one examines the role of local authority in managing contaminated land regime, and assessing the risk of contaminated land to human health via the CLEA UK Guidance. Part two examines the various techniques of remediation and factors taken into account in examining the suitability of a technique. Finally, part three explores the significance of sustainability of remediation with respect to part 2A of the 1990 Environment Protection Act.

 

A. Analyse the role of local authority (LA) on environmental management of contaminated land regime and evaluate how human health risk assessment is carried out using DEFRA/LA and CLEA UK Guidance.

 

Contaminated Land: Definition

Section 78A (2) of the 1990 Environmental Protection Act defines contaminated land as any land whose condition is such that is posses significant harm to both human health and the environment (Department of Energy & Climate Change 2012). During the 19th and 20th centuries, England underwent a spate of industrial developments and changes in urban development, which are to a certain extent influenced by contamination (Environment Agency. 2009).  Furthermore, the changes in volume and type of refuse produced in the urban environment have led to landfilling of our rural and urban landscapes. This, according to Stallworthy (2013), has culminated in a legacy of contaminated land that is hazardous to the environment and human health as well. The contaminated land regime charges local councils with the responsibility of inspecting land within their jurisdiction on a periodic basis so that they can identify contaminated land that is likely to cause “significant harm “to the environment and human health. 

The 1995 Environment Act introduced the Contaminated Land Regulations under Part 2A of the 1990 EPA (Environment Protection Act) to handle the considerable legacy of contaminated land. England implemented Part 2A on 1 April 2000 with the April 2012 Contaminated Land Statutory Guidance acting as the source of regulation.

Role of Local Authorities

It is the responsibility of local authorities to identify contaminated land in their jurisdiction and deal with the matter appropriately. This can be done in any one of the two ways. First, the local authority can adopt a planning process in which redevelopment of contaminated sites takes place, and secondly, via direct action in which local authorities exercise Part 2A of the 1990 Environmental Protection Act (Great Britain: Department for Environment, Food and Rural Affairs 2006). Statutory Guidance demands that an individual Local Authority in England plans, issues and approve a strategy on how it will identify and handle contaminated land within its jurisdiction.  This therefore means that local authorities also act as enforcing authorities in as far as the issue of contaminated land regime as described under Part 2A is concerned.  Another key responsibility of local authorities as described under Part 2A is to establish if specific areas of land have been contaminated in relation to guidance issued by the Secretary of State. Local authorities can also consult English Nature in establishing the ecosystem effects of contaminated land and the Environmental Agency on pollution of land contaminated by radioactive substances or pollution of controlled waters (SuRF UK 2009).  Moreover, local authority should consult the Environment Agency in making a decision if contaminated land needs to be identified as a “Special Site’.

Another key responsibility of the local authorities is to identifier the occupiers and owners of land, the Environmental Agency and other liable entities that the land in question is contaminated and if it qualifies as a designated “Special Site”.  Should local authorities establish that contaminated land poses ‘significant harm’ to both humans and the environment, Part 2A empowers such an authority to embark on urgent remediation action (Scottish Environment Protection Agency 2014). Thereafter, local authorities have to establish entities that could be legally responsible for the cost incurred in remediation action and the percentage of the total cost they are likely to incur. Additionally, local authorities are supposed to see to it that suitable remediation has occurred, by serving responsible parties with a remediation notice where there are no restrictions, and more importantly, by encouraging voluntary action. In case of ineffective remediation or if remediation has not been conducted as directed, then local authorities can take further action on parties involved. Local authorities are also charged with the responsibility of maintaining a public register in which details of regulatory action on contaminated land as spelt out by Part 2A, are contained. Finally, local authorities have to furnish the Environment Agency with information on contaminated land as defined by Part 2A to enable the agency develop [p the State of Contaminated Land Report.  

 

Evaluate how human health risk assessment is carried out using DEFRA/LA and CLEA UK Guidance.

 

            Human health risk assessment with respect to hazardous substances entails classification of the hazard in question to identify the quantities and toxicological properties of substances present, and evaluation of the likely exposure to the hazard. While conducting risk assessment for contaminated land, the process entails an identification of risk-based “assessment criteria” for specific contaminants early in the investigation process (Bardos et al 2010). The levels of contaminant concentrations are thereafter compared with the assessment criteria as a means of establishing if the levels of contamination pose a significant risk to human health.   Site-specific or generic assessment criteria may be employed.  Initial risk assessment is for the most part, desk based ad evaluates the possibility for human exposure to the contaminated soil relative to the previous history of the site in question. The UK has adopted the CLEA (Contaminated Land Exposure Assessment) model in risk assessment of hazardous substances. This software has been developed by DEFRA and the Environment Agency to assess potential risk to human health.  The aim of this model is to offer technical guidance to aid in the assessment of risks to human health quantitatively, from contaminated land at detailed and generic tiers.

 

B. Critically evaluate different techniques of remediation and factors to be considered in

assessing the suitability of a technique

 

Remediation of contaminated land in the UK could be as a result of various drivers. For instance, landowners could willingly remediate land as a means of reducing potential liabilities to land or raising its value. The local authority may also demand land remediation prior to its redevelopment or it could be a regulatory requirement such as in case it is established to be contaminated land as specified under Part 2A of the 1990 Environmental Protection Act (DEFRA & CIEH 2007). Whatever the reason, remediation of contaminated land is notably a technically difficult and expensive process. Accordingly, various remediation techniques have been developed both in the UK and globally, to deal with varying conditions on individual sites and the diverse potential contaminants. So far, two mina treatment profiles have been identified: in situ and ex situ. In situ techniques refer to the methods that occur in the subsurface, thereby overcoming the need to abstract groundwater or excavate the contaminated soil. The identified treatment profiles in situ remediation methods include chemical reduction and oxidation, electro-remediation, and phytoremediation, among others.

According to Department of Energy and Climate Change (2010), chemical oxidation entails injection of gaseous or liquid oxidants (or oxidising agents) to the subsurface with the aim of facilitating speedy degradation of the numerous organic contaminants. Once the organic compounds undergo partial degradation,   other methods of treatment like bioremediation could then be used. Typical oxidants used include ozone, Fenton reagent, and permanganate. In chemical reduction, reductants (reducing agents) are added to the subsurface to neutralise the toxicity of certain metals and degrade chlorinated solvents. Examples of reductants commonly used include polysulphides and zero valent iron (Nathanail et al. 2007).

Electro-remediation involves the removal of radionuclides, organic contaminants and from unsaturated or saturated sludges, sediments, and clay-rich soils via electric-kinetic and electro-chemical processes. It involves the application of direct but low intensity current across pairs of electrode implanted on either side of soil contaminants. While electrodes attract water and ions, the cathode attracts ammonium ions, positively charged organic compounds, and metal ions, thereby removing and separating contaminants (Environment Agency 2010). Contaminants move via soils towards either electrode is through electrophoresis, electromigration, or electrosmosis. Transported contaminants can then be removed and treated accordingly.

Bioremediation entails the application of microorganisms, usually fungi or bacteria, to degrade or transform contaminants eventually to no-toxic by products (CL:AIRE 2009). Incorporation of reagents enhances the process thus creating anaerobic or aerobic conditions that the fungi or bacteria require to biodegrade organic contaminants.

Phytoremediation relies on the natural ability of vegetation in the pulling out, gathering, storage, and breakdown of inorganic and organic substances. Several mechanism are involved in phytoremediaiton, including phytocontainment, phytoextraction, and phytodegradation.

Phytovontainment involves developing a lover layer on contaminated sites using plants to minimise migration of contaminants and also reduce surface runoff, erosion, skin contact, and dust generation, thereby limiting the availability of contaminants to humans (Hou & Al-Tabaa 2014). Phytoextraction involves use of hyoperaccumulators or plants with the capacity to absorb and accumulate contaminants to high concentrations. In this way, plants are removed form the soil via roots and transported to such other parts of the pant as stem and leaves.  On the other hand, phytodegradation entails the absorption and degradation of organic contaminants contained external to and within plants.

Ex Situ Techniques

These are often used in excavated soil or treatments of gaseous emissions or contaminated water occurring on the surface. Ex situ techniques, by virtue of brining contaminants to the surface, facilitates treatment processes (Nathanail et al 2007). Examples of ex situ techniques include: biological treatment, thermal treatment, and solidification/stabilisation (Environment Agency 2010). Biological treatments involves degrading or transforming contaminants in soil using fungi and bacteria to less-toxic or non-toxic by-products. Examples of biological treatment configuration in use include composting, landfarming, and bipile.

Solidification/stabilisation is dependent on the soil matrix-reagents interaction to minimise the mobility of contaminants. In this case, reagents are added into contaminated materials to form chemically stale constituents (stabilisation process), while in solidification reagents are added to a contaminated material with the goal of conveying dimensional/physical stability.   

 

Factors to be considered in assessing the suitability of a technique

 

Before a remediation technique can be adopted, it is important to establish its suitability on the basis of available options.  Factors to consider include the social, economic, and environmental impacts of the technique in question.

Social impacts: a central focus for the remediation should be on minimising the likely risk of adverse effect of the contamination site to the public and its occupants. This can be quantified via direct measurement or risk assessment.  In order that the remediation approach may be deemed successful, it ought to result in a net positive effect. It is important to consider the occupation safety and health of site workers as it might entail negative effects (Environment Agency 2010). Another factor to consider is the acceptability of stakeholder concern regarding the remediation technique. In this case, there is need to ensure stakeholder liaison especially in case of an association between the public and remediation works, as it could prove essential in identifying and meeting concerns raised by the public.

Another key factor of the social dimension is making an allowance for the effect on the surrounding amenity prior to, during, and following remediation. For example, while the construction phase of a remediation technique is likely to result in negative impacts on surrounding community and land, the technique once implemented could result in beneficial utilisation of land.

 

Economic

 

Cost is a key consideration in remediation projects as it determines their feasibility and choice of options. In undertaking the sustainability assessment of a remediation technique, there is need to consider the likely ongoing or future costs of the technique under consideration. Other considerations include the financial risk linked to project uncertainties. It is also important to consider a life-cycle assessment of proposed alternative (Environment Agency 2010). Other considerations include positive economic effects like indirect and direct benefits to employment and the economy.

 

Environmental

 

In considering a remediation technique’s net effect on the environment, we ought to take into account not just the local environment, but also global environments. While the net effect to local environment as a result of remediation is largely positive, we should also consider negative impacts like disturbance of contamination on adjustment land, discharge from by-products, and the effect of assessment activities. Such local impacts should ideally be balance against minimisation in the risk of contamination and restoring land back to its beneficial use. Another net environmental benefit as a reduction of remediation strategy comes in the form of inclusion of ‘green technologies’ (United States Environmental Protection Agency 2008). Since active remediation entails energy and resources the global effects as a result of remediation techniques including carbon dioxide emission and energy use may be negative. Therefore, the goal should be of minimisation of effects.

 

C. Outline the importance of sustainability of remediation and synthesise how sustainable remediation have been addressed in Part IIA of the Environment Protection Act 1990.

 

Importance of sustainability of remediation

 

Historically, remediation exclusively concentrated on minimising the risk of harm from a contaminated site. Nevertheless, according to the Environment Agency (2010), current remediation practices are multi-faceted. Sustainable remediation encompasses risk control as well as the overall impacts and benefits of remediation. For instance SURF-UK notes that the best remediation option “eliminates and/or controls unacceptable risks in a safe and timely manner, and... maximise the overall environmental, social, and economic benefits of the remediation work” (2010). Besides, integrating sustainability in the decision making process is a chance to combine diverse considerations: renewable energy, risk control, water footprint, carbon footprint, and public participation, among others.   SURFUK has identified several key principles linked to remediation, which are important for the sustainability of remediation. First, sustainable remediation results in the protection of the environment and human health. Ideally, remediation ought to eradicate unacceptable risks to the environment and human health, in addition to according due consideration to the benefits, costs, and technical feasibility. Secondly, sustainable remediation should result in safe working practices for the local communities, workers on-site, as well as the environment. Thirdly, sustainable remediation decisions take into account the social, economic, and environmental; factors, as well as the existing and future implications. With sustainable remediation, it is also possible document remediation decisions and all supporting data and assumptions. Besides, making remediation decisions should encompass stakeholder involvement and good governance.

 

How sustainable remediation have been addressed in Part IIA of the Environment Protection Act 1990.

 

In undertaking remediation of contaminated land, it is important to ensure that this is done in a sustainable manner. SuRF (UK) defines sustainable remediation as “the practice of demonstrating, in terms of environmental, economic, and social indicators, that the benefit of undertaking remediation is greater that its impact and that the optimum remediation solution is selected through the use of a balanced decision-making process” (SuRF UK 2010). In other words, the decision to choose a specific remediation solution is only arrived at after a careful assessment of its economic, environmental, and social impact on the contaminated land, the environment, and more importantly, human health. Part 2A of the 1990 Environment Protection Act has also delineated the importance of sustainable remediation by noting the significance of identifying a remediation technique that results in the least harm to the economic, environmental, and social aspects.

 

Conclusion

 

The issue of contaminated land regime has a rich history in England. Part 2A of the 1990 Environment Protection Act has provided a working definition of contaminated land and the significant risk that it posses to human health and the environment. Local authorities play an important role in notifying occupants of land and land owners in case the land in question is contaminated, and to oversee suitable remediation of such land.  The CLEA model has emerged as a widely applied risk assessment technique in England, especially is assessing the likely risk to human health. So far, various in situ and ext situ techniques of remediation have emerged, each of whom has its own benefits and drawbacks. The choice of a given remediation technique shall be determined by diverse social, economic, and environmental impacts. It is important to ensure sustainability of remediation as a means of safeguarding human health and a safe environment. It also ensures that we consider the social, economic, and environmental effects of a remediation technique prior to its adoption, and the likely future implications. 

 

 

 

 

Reference List

 

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