For any consideration of wider environmental effects to be a useful tool in refining a shortlist of potential remedial options, it must have a well defined scope agreed by all stakeholders. Three issues are important:
· Components: the individual environmental effects that may be combined into a single assessment of wider environmental value. Examples might include impact on soil function, impacts on water, legacy and others.
· Boundaries: the limits set on the assessment, for example in terms of time periods, geographical extent or the scope of the project; and
· Method of determination.
Bardos et al (2000) identified a large number of possible environmental effects that could be considered within an assessment. These effects were grouped into the following themes;
Aggravation factors: considers environmental impacts which could have a direct and noticeable effect on some stakeholders. In some cases this effect may be more perceived than actual.
Air and atmosphere: considers those impacts on air quality and atmosphere function of emission due to operating the remediation process.
Water function: considers the effects of remediation emissions to surface and groundwaters, although for coastal locations, impacts to estuarine waters should also be considered.
Ground function: considers impacts on the solid subsurface, including impacts on soil water content. Impacts considered include toxic effects, mechanical impacts and changes in soil/ground function.
Legacy: explores how remediation processes vary in their ability to offer a permanent solution to contamination removal and improvement of land quality and to evaluate their long term impact on the site and the surrounding ecosystems.
Resource and energy use: considers the “costs of production” in non monetary terms of a remediation scheme. It is separate from other themes, e.g. legacy, both to make its consideration intuitively clearer, and also because the UK Government approach to sustainable development considers resource utilisation as a discrete issue.
Conservation: explores the impact of remediation work on ecosystems and features of the environment valued by the community.
In this context an effect is an environmental consequence which may be positive (benefit) or negative (impact).
Defining the goals of a wider environmental effects assessment may appear to be simple at the outset, but it is important to ensure that like is being compared with like. The difficulty is in agreeing the scope of the processes or project under consideration, and its the constituent parts. Whether the assessment of wider environmental effects is qualitative or quantitative, the approach provided by life cycle analysis, may be useful in defining boundaries such as the practicality of the assessment; defining the environmental system under study; the environment; and other inter-related systems.
For example, a comparison of the wider environmental effects of a remediation based on excavating and disposing of materials to landfill with, say, soil washing might be significantly affected, depending on whether or not the impact of the soil washing operation on the overall site management was considered. Consider a case where 50% of the excavated material could be dealt with by a specified treatment. If the comparison focuses only on the 50% treated in the treatment plant it will ignore the wider impacts of the treatment component on the broader project, such as management of stockpiles, excavation and transport. These wider impacts may themselves have significant environmental effects and be substantially different for the removal only, and removal plus soil washing options.
Perhaps the most obvious way of ensuring that such questions are addressed equally for each option is to consider the remediation works as an integrated solution for each option. In this case the comparison would be made on all processes required for treating 100% of the contaminated material rather than comparing options which treat differing proportions of the total material.
Contaminated land sustainability assessment tools or appraisal tools are instruments to assess the economic, environmental and/or social effects of contaminated land problems and their management. Click here for further information:
Bardos, R.P., Nathanail, C.P., and Weenk, A. (2000)
Assessing the Wider Environmental Value of Remediating
Land Contamination. Environment Agency R&D
Technical Report P238. Available from:
Environment Agency R&D Dissemination Centre, c/o WRC,