Contaminated Land post 2010. Where
might we be headed? By Cecilia Macleod, Technical Director, Arcadis
The past 2 years have been tough for the contaminated land industry in the UK. The economic downturn saw a dramatic slowdown in Brownfield redevelopment and many industrials cut back on their planned environmental programs. Following the change in government there was further stalling in growth due to the announcement that the government desired to make revisions to the contaminated land legislation and would in particular redefine Contaminated Land.
In December 2010, DEFRA released the consultation document on the proposed changes to the Statutory Guidance for the Contaminated Land Regime under Part 2A of the Environmental Protection Act 1990. The definition of contaminated land is not significantly changed it is strengthened with respect to the contamination of controlled waters :
“Section 78A(2): “contaminated land” is any
land which appears to the local authority in whose area it is situated to be in such a condition, by reason of substances in, on or under the land that – (a) significant harm is being caused or there is a significant possibility of such harm being caused; or (b) significant pollution of controlled waters is being caused, or there is a significant possibility of such pollution being caused;....”
There is discussion of harm and the need for the regulator to show that harm either is being caused or likely to be caused. There is really no softening or hardening of the actual legislation. However, in reading through the guidance, with particular reference to Controlled Waters, it appears that the Local Authority, not the Environment Agency is determining if significant harm to controlled waters is occurring.
This is an important change within the guidance as Local Authorities are unlikely to have hydrogeologists on staff who can make this assessment and they will have to rely on advice from a reduced Environment Agency or seek assistance from outside experts. There is a statement within the guidance that the Local Authority needs to ensure that the experts it uses are suitably qualified but gives no further information on how the Local Authority should determine this.
The guidance points out that the Risk Assessment process should not be taken as giving an absolute answer and that the regulator should understand the uncertainties associated with risk assessment and |96| ENVIRONMENT INDUSTRY MAGAZINE
should use where appropriate an external expert to supply advice and guidance.
Within the accompanying consultation document DEFRA makes it clear that there may have been sites which have been determined under Part 2A which with further investigation and a better understanding of risk assessment may not have required that the whole site be determined.
For environmental consultants and our clients, we should see the requirement for assessing uncertainty as a need to provide within our reports our data quality objectives. We also need to assess the uncertainty within our data and to show the regulator where the uncertainty lies within our assessments. All too often, there is a reliance on stating that samples were analysed at an MCERTs accredited laboratory and little to no analysis of actual uncertainty which should include an assessment of sampling. We need to make sure our clients who may be cash limited local authorities, understand that in undertaking an assessment of uncertainty there may be a need to increase the number of samples in the sampling program.
The new guidance also introduces the use of background data for assessing contamination in areas where a contaminant such as As might occur naturally or such as where PAHs may be elevated in the local environment for factors not associated with any industrial process.
Using Background as an assessment tool can be contentious as defining background is not straight forward and while it is clear that DEFRA is hoping that using Background will assist those sites where the levels of contaminant are above Generic Assessment Criteria but are not due to industrial processes, there could continue to be issues associated with how background is determined and which method is appropriate.
While the BGS has mapped a number of metals and some organic contaminants across the UK to create geochemical maps, there are issues with using them to emphatically define background. Sample spacing may not be fine enough, methods of analysis different from those used in environmental testing labs and sample collection may be limited to specific geologic horizons which do not correlate to environmental sampling programs.
There are a number of methods and tools which are used to assess background. These will require that an appropriate number of samples be collected and analysed in order to be able to assess the population distribution and to separate overlapping populations. Some methods for assessing background of heavy metals require the analysis of certain major elements such as Fe, Al and Si in order to normalise the data to the elements and again assess the distribution and identify background and anomalous populations. It is likely that Local Authorities will desire outside advice on
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