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Sampling and analysis play a crucial role in the redevelopment of contaminated sites, but few give proper weight to the importance of effective and rigorous procedures, as Graham Sprigg discovers.

Brownfield redevelopment, land regeneration and recent changes in landfill legislation are changing the commercial and residential property landscape in the UK.

Sites which in the past may have been considered too polluted now play an important role in meeting the demands of the marketplace - due in no small part to technological and scientific advances that are enabling derelict land to be brought back into use.

Key to the effective and profitable redevelopment of sites is the identification and cleanup of contamination. This is not a straightforward task - where the presence of a wide variety of pollutants may frequently involve a timescale of months and even years before it can be redeveloped.

Monitoring and surveillance of a site ranging from a few samples to 10 to 20 years of checking may also be required. The developer must demonstrate to the regulatory authorities that the site is safe for development before work can begin and that they comply with the Contaminated Land Regulations.

Often a specialist consultancy is called in to put together a feasibility study and monitoring programme and this must satisfy the Regulatory Authorities. At every stage of the remediation process - from initial identification of individual contaminants, to ongoing assessment of the effectiveness of clean-up technologies used - sampling and analysis play a crucial role.

Yet it appears to be an area where many planners, developers and consultants alike are still failing to give proper weight to the importance of effective and rigorous procedures.

Unfortunately, underestimating the need to ensure that consistent sampling and analysis are an integral part of the remediation process, or in some instances trying to save money by skimping or cutting corners, can lead to serious financial penalties.

While consultants, developers and landowners are more aware of the chemical, bio-chemical and physical techniques for insitu clean up, many are not so familiar with the need for proper sampling and analysis prior to a project start.

Rob Fuller, laboratory commercial manager, at Southern Water Scientific Services, frequently encounters developers and landowners alike who appear to have no knowledge of potential contamination on their land, despite the obvious financial and legal implications this could have.

'Not all landowners and developers are fully aware of the importance of accurate and affective sampling and many underestimate the importance of taking a proper laboratory regime in to the field. There is a real need for raising awareness levels and education about the crucial role analysis and sampling plays in the process, ' he said.

'Getting it right at the outset can make the difference between the success and failure of a project.'

A robust sampling and analysis regime is critical to the success of the geotechnical and environmental engineers tasked with the practical development and implementation of remediation procedures. Each site is unique in terms of its contaminants so it is important that sampling considers the following factors:

l Has the history of the site been fully considered?

l Is the sample the correct size and volume?

l Was it taken from the correct location and depth?

l How long since the sample has been taken?

l Has the sample been disturbed?

l How will the state of the sample alter in transit?

l How representative is the sample?

It is also important to remember that volatile substances could well migrate before testing in the lab. According to Eric Cooper, head of Geo-environmental at Hyder Consulting: 'The state of samples containing volatile compounds is prone to change between leaving the site and reaching the lab. Contractors normally take samples but, ideally, this should be supervised by the consultant to ensure that the correct sampling regime is adhered to - volume, location, depth - and that decisions can be taken on-site if unexpected problems arise' The sampling and analysis process is becoming more and more closely regulated. The forthcoming MCERTS accreditation will be an EA requirement for laboratories, while changes in the Contaminated Land Regulations are also driving more robust sampling regimes.

Previously the ICRCL guidance spelt out conditions for soil and groundwater, and this still exists to some extent in the Groundwater Regulations. However, for contaminated soils the regulatory authorities now encourage riskbased assessments, based on the source- pathway-receptor relationships that characterise the site. This reinforces the need to get a laboratory involved with the developer and consultant at an early stage.

A growing number of developers and consultants are choosing to work with an accredited lab - both to ensure transparency of the management of the clean-up process and assure the regulatory authorities of the quality of analytical results and inspire confidence in decisions regarding regulatory compliance.

An MCERTS accredited laboratory will have been certified on its methodology for the chemical testing of soils. Southern Water Scientific Services, for example, has over 90% of its determinands UKAS accredited, and imminent MCERTS accreditation for a range of contaminated land analyses.

As Fuller points out: 'Sampling and analysis is actually the most important aspect of a clean up programme. It enables optimal remedial treatment solutions to be designed and measures how the application of the chosen technology is affecting both the contaminants and also previously stable elements in the ground, which might react to the clean up process itself.

'Building on contaminated land often poses significant operational and financial risks and, without doubt, accurate sampling and analysis is crucial in managing and reducing this.'

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