Contaminated land test gets 'glowing' report

Local authorities can improve their economic and environmental sustainability by adopting recent advances in industrial biotechnology developed and supported as part of the DTI's BIO-WISE programme. Dr Paul Fisher of BIO-WISE outlines how one such application is helping LAs manage contaminated land characterisation.

Glow-in-the-dark bacteria are helping Vale Royal Borough Council meet contaminated land obligations and reduce consultancy bills, says the borough's Principal Environmental Health Officer, Rupert Adams, who claims that this novel approach also improves the risk assessment process.

There are as many as 100,000 contaminated sites across England and Wales according to Environment Agency estimates. Local authorities have a statutory responsibility to inspect and review such sites on a prioritised basis, under PartIIA of the Environmental Protection Act (1990).

Cheshire-based local authority, Vale Royal, has potentially in excess of 800 contaminated sites, including 300 closed waste sites within its boundaries, the majority produced as a result of backfilling sand and salt excavation works, making the characterisation of contaminated sites an important as well as a costly issue.

Managing liabilities

"Aside from the legal requirement, identifying contaminated land also plays an important part of the borough's planning process, and as a landowner in its own right the Council needs to assess potentially hazardous sites so it can manage its own liabilities," Mr Adams explains.

He points out that PartIIA states that contaminated land characterisation requires an overall risk-based approach. This is true of Vale Royal, which uses a range of sources including English Nature and Environment Agency reports, OS maps and various other specific data to identify and risk-assess sites.

Desk-based assessment can only go so far, identifying the sites that are most likely to present a real concern. These sites undergo physical investigation to clarify their status, something that can cost upwards of £10,000 per site, according to Mr Adams. "Traditionally, environmental consultants are engaged to survey and sample the site, and perform a range of laboratory-based chemical analyses to evaluate the extent of the contamination and guide potential remediation options."

However, Vale Royal has teamed up with biotechnology company Cybersense Biosystems Ltd (www.cysense.com), a spin-off firm of Surrey University, to use an alternative approach. Cybersense has developed a patented field test known as the Rapid On-site Toxicity Auditing System (ROTAS") with funding from the DTI's flagship industrial biotechnology programme, BIO-WISE (www.dti.gov.uk/biowise).

ROTAS" is an indicative screening tool that provides same day results in relation to levels of soil contamination. This simplifies site assessment by providing a measure of overall soil toxicity.

The system is based on naturally-occurring, light-emitting (bioluminescent) bacteria. This is a well-established technology, currently used in a number of pollution monitoring fields, including wastewater analysis, notes Dr Tim Hart of Cybersense.

He explains that light output from these bacteria is directly proportional to the level of toxic contamination in the environment. "In essence, the more toxic the environment the less the bacteria glow. It is this drop in light that can be quantified and used to measure overall toxicity."

Measuring light output

At the heart of the technology is a rugged portable instrument (called a luminometer), which measures changes in light output from a number of samples simultaneously. All the equipment necessary to extract the toxic material from the solid sample and to perform the test with luminescent bacteria is supplied as packs of consumables. Large numbers of samples can be run in parallel which means that many more samples can be analysed faster than by conventional methods. The speed and cost-effectiveness of data generation means that this is a true management tool to increase the efficiency of project management.

The system requires little expertise, equipping councils with the ability to survey sites using in-house human resource, thereby considerably minimising consultancy fees, Mr Adams claims. The system is more or less fool-proof in his opinion, providing a traffic light indication of the level of contamination at a site - a red light if there is an issue that requires further analysis or green if contaminant levels are below those of concern. "It also adds an extra level of risk-assessment which can dramatically lower the cost of the eventual clean up job." The system can also be used as an effective screening system for checking the quality of imported "clean" cover material which is an increasingly common method of tackling contamination issues.

At around £6 per sample, ROTAS" costs approximately one-fifth of comparable laboratory analysis. This lower cost per sample means that the sampling resolution can be increased, with more samples taken per unit area. "This enables us to identify contamination 'hotspots' within a site. "In essence, ROTAS" is a valuable starting point that complements and targets the activity of external consultants and guides land remediation efforts more accurately," says Mr Adams.

In addition to fulfilling statutory responsibilities the system could have a rapid knock on effect on the economics of "brownfield" development in Mr Adams' and Dr Hart's opinion. Vale Royal has, for example, acquired an area of land which was a redundant part of a chemical plant site.

An initial survey suggested that remediation costs would have made any purchase unviable due to the expected liabilities. The Cybersense system however, enabled the site to be rapidly and accurately characterised with negligible investment, revealing that the extent of the contamination was significantly lower, enabling Vale Royal to acquire the site at a favourable cost.

The bottom line is that where contaminated land issues are serious, their investigation and resolution can be expensive and time consuming. Even small time savings, or improvements to site assessments, can make a big financial difference, enabling the budget to go further and reducing liabilities.

To view a video clip of the ROTAS" system in action and learn how other industrial biotechnologies can assist with contaminated land remediation visit www.dti.gov.uk/biowise.

The BIO-WISE programme (www.dti.gov.uk/biowise) supports the development of industrial biotechnology in a range of areas affecting local authorities including the sustainable management of solid waste and air emissions.


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