As more brownfield sites get developed and Part IIA of the Environmental Protection Act (EPA) 1990 encourages local authorities to take contaminated land seriously, knowledge of this issue is becoming increasingly important to ground engineers.
Rising landfill costs are making disposal of contaminated material prohibitively expensive, while the system of tax credits and exemptions is adding complexity to the financial planning of construction projects.
Add to this the legal liabilities involved in remediation and it is clear there has never been a greater need for ground engineers to stay on top of government policy and guidance in this area.
A recent announcement from the Department for Environment Food and Rural Affairs (DEFRA) should be noted carefully (see www.defra.gov.uk/envioronment/land/ contaminated/pdf/clan2-05-sgvs.pdf). It states that, just because a site has contamination in excess of an Environment Agency soil guideline value (SGV), it is not necessarily 'contaminated' in the eyes of the law.
This is important since, whether rightly or wrongly, both practitioners and local authority officials have been using SGVs to decide just this. The announcement goes on to say there is currently no published guidance on what does constitute 'contaminated land', but such guidance will be issued in due course. No time scale is attached, leaving local authority officials and others to discharge their responsibilities in a vacuum.
In legal terms, the DEFRA announcement states SGVs cannot be used to ascertain whether there is a 'significant possibility of significant harm' - the key test under EPA 1990 Part IIA - since they denote essentially 'safe' levels in soil.
The difference between essentially 'safe' soil levels and those posing a 'significant possibility of significant harm' can be large, and can easily make the difference on whether costly remediation is needed at a given site.
The announcement provides official recognition that there is a clear difference between what was required from the SGV related guidance and what it actually delivered. One suggesion for this apparent disconnect is it stemmed from the erroneous view that contaminated land legislation was similar to water quality or food safety legislation. This would have meant it required chemical levels to be set for soil that are 'safe' for site occupants.
This was never the intention of the contaminated land regulations, which were drafted to require regulators to take action only where there was a real danger of adverse effects occurring. Anything else would have been economically unfeasible, given the UK's legacy of industrial activities and widespread high levels of naturally occurring chemicals.
To those with an interest in contaminated land, this is the latest episode in a long running saga which began in the early 1990s. Production of the much-heralded Contaminated Land Exposure Assessment (CLEA) model - designed to produce SGVs and first promised in the mid-1990s - was beset with delays. It was not until the early 2000s that the Environment Agency started to use it for this purpose.
Only a handful of SGVs were produced initially and the rate has since slowed to an average of just two per year. But making sure the new risk-based paradigm was here to stay, DEFRA withdrew the old Inter-departmental Committee on the Reclamation of Contaminated Land (ICRCL) levels in 2002.
Although the cause of the apparent 'mission creep' is not clear, what is clear is the team of experts who have been asked by the Cabinet Office to provide new guidance will have their work cut out. Especially so since they have just a few months to do this, in comparison with the 10 years it took to get things to where they are now.