Cinderella of remediation and clean-up
Dr Rob Fuller, Laboratory Commercial Manager, at the UK's Southern Water Scientific Services explores the importance of selecting the right kind of samples from contaminated sites in order to achieve accurate analyses.A remediation programme is only as good as the information available on the the contaminant present. However many developers and remediation consultants rely too heavily on scant or inappropriate analytical results to samples taken in-situ. Here we look at the increasing need for good practice in field sampling and laboratory analysis.
The development of brownfield (old industrial and/or contaminated) sites, particularly for housing, is a major issue for developers and contractors in the UK where the government has clearly stated its intentions for increasing housing stock and the focus is very much on re-use of existing or derelict sites.
Brownfield development not only satisfies the Government's aims to increase housing stock while maintaining greenbelt; it could easily be argued that it provides a more sustainable approach to building.
Building on contaminated land can however, pose both an operational and financial risk and, without doubt, accurate sampling and analysis is crucial in managing and reducing this. It is imperative that consultants and developers know exactly what they're dealing with in terms of contamination, in order to implement an effective and good value clean up programme and to secure regulatory approval.
Unfortunately 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.
Without the complete knowledge, developers and consultants are in the dark when it comes to selecting the best remediation programme. An inappropriate clean up regime, based on a scant analysis of the site, will inevitably mean higher costs for the developer. One step forward in achieving a quick answer through cutting corners with sampling, will mean two steps back when the site fails to comply with regulatory requirements.
A clear indication of the type, volume, distribution and combination of contaminants on a site is crucial in selecting the most appropriate tools to clean up. Far from their perception as the 'bloke with a spade', contractors, working together with the analysis laboratory from the first stages of site investigation, hold the key to the bigger picture - and getting it right first time.
Brownfield development requires a thorough knowledge of the nature and extent of the contamination present. Each site is unique in terms of its contaminants so it is important that a sampling regime is implemented, which considers the following factors: Has the history of the site been fully considered? Is the sample the correct size and volume? Was it taken from the correct location and depth? Has the sample been disturbed? How will the state of the sample alter in transit? How representative is the sample?
Consider a developer who wants to build five new houses on a plot of land previously used by industry. These homes will need to be connected to the mains water supply. To rule out the potential for the contamination of drinking water, the developer must prove to the water supplier that the soil through which the pipes will run is not contaminated.
Unfortunately, there is currently some uncertainty over exactly what has to be tested for. Previously the UK's ICRCL (Interdepartmental Committee for the Redevelopment of Contaminated Land) guidance spelt out conditions for soil and groundwater that were acceptable to the regulatory authorities. This still exists to some extent in the Groundwater Regulations. However, it is no longer an acceptable path for contaminated soils where ICRCL has been withdrawn.
The regulatory authorities now encourage risk-based assessments, based on the source- pathway -receptor relationships that characterise the site. If the water company and the lab communicate from an early stage and set the parameters for which substances must be identified, it is clear what must be achieved to satisfy the water company first time round.
The key to keeping one step ahead of the game is to know your site history. If the site used to home a paint factory, it is likely to be contaminated with volatile compounds, whereas hydrocarbons are likely to be present if fuel was used on the site. It's all about sharing information: From landowner, to developer to consultant to the labs and back again. A simple note taken at the time of sample extraction: 'It smells of diesel', for example, can give the analysis lab an idea of substances to test for, which might otherwise only be discovered at a later stage.
There are various things to consider when selecting an analytical laboratory. A consultant will look for speed and accuracy of results on which to work out the risks associated with the site. The developer, on the other hand may be more concerned with value for money. The cost of analysing a site and developing a clean up strategy is after all risk money, and payback is only guaranteed once the site has satisfied the regulatory authorities and planning permission is granted.
An holistic approach
To ensure transparency of the management of the clean-up process, I would advise developer and consultants to work with an accredited lab. An MCERTS (UK Monitoring Certification Scheme) accredited laboratory will have been certified on its methodology for the chemical testing of soils. By using an accredited lab, you can assure the EA of the quality of your analytical results and inspire confidence in decisions regarding regulatory compliance.
In my role at Southern Water Scientific Services, I am amazed by the number of enquiries which ask, 'Is my land contaminated?' and come armed with no indication of potential contaminants, and a spade full of earth in a bag. With such a broad range of potential contaminants, this can make our job very demanding and also very costly for the developer.
By taking an holistic approach to developing brownfield land and involving
consulting, sampling and analytical parties from the outset, developers can
make an informed decision on the most effective way to minimise their risks,
and get the most out of brownfield land.