DD 175 (1988) is dead; long live BS 10175:2001.Ten years after its first release, the much misused draft 'Code of practice for the investigation of potentially contaminated sites' has been formally withdrawn by the British Standards Institute.
The standard's recognition of the importance of the conceptual site model is most welcome.
It gives examples of what models should include after a desk study and walkover survey and at the end of an intrusive investigation.
Indeed, the requirement for a conceptual model may go a long way to resolving the 'how many samples' debate because the answer is 'enough to reduce unacceptable uncertainty in the conceptual model' The integration of geotechnical and contamination investigations is the subject of the Association of Geotechnical and Geoenvironmental Specialists (AGS) report 'Guidelines for combined geoenvironmental and geotechnical investigation'(www.ags.org.uk).
The AGS warns that an integrated investigation should not compromise the requirements of the geotechnical or the contamination aspects. This may mean deploying teams comprising ground specialists and contamination specialists, ensuring that logging is detailed enough for both purposes and of course that the investigation creates no new pathways.
A workshop on 24 January considered the results of a DETR audit of contaminated land research in the UK carried out by AEA Technology. Perhaps surprisingly, one of the Contaminated Land Rehabilitation Network (Clarinet) working groups has found the UK spend on contaminated land research to be higher than anywhere else in Europe.
The workshop concluded that there was still a need for further research despite several thematic research council programmes and work funded by bodies such as the DETR, the Environment Agency, the Scottish Environment Protection Agency, the Scotland and Northern Ireland Forum for Environmental Research, CIRIA and ex Site, which is funded by the landfill tax and in turn funds research into ex-situ remediation.
The rationale for this research was to contribute to the fledgling contaminated land industry's ability to deliver on issues such as environmental protection and sustainable development in a more effective manner. This rationale should be used to derive a national research strategy that in turn would develop research programme strategies and should be regularly reviewed.
The audit also identified the problem of end users not being aware of research outputs, not being able easily to access those outputs, or outputs being in an inappropriate form.
The workshop felt these were largely issues of training, education and continued professional development which were only partly being addressed. The DETR, Environment Agency and CIRIA publications were found to be particularly accessible and relevant.
The workshop also considered specific research requirements. It was felt that site investigation needed validated on-site testing kits, improved methods of VOC sampling, better guidance on what parameters should be collected for a tier 3 risk assessment and better non-intrusive techniques.
For risk assessment the main needs, apart from current research to be published, were in areas such as ecotoxicological testing, uncertainty characterisation, control of financial risk (particularly for private organisations acquiring formerly contaminated land) and calibration of exposure assessment models. Better awareness of what was already published within risk assessment was also needed.
Within remediation, research into how to manage specific substances such as heavy metals and PCBs is still needed. However emerging issues such as the remediation of mixtures and the issue of co-contaminants also required study.
There was still a need for new demonstration projects and case studies, but the habit of rehashing case studies was criticised. Insitu remediation techniques were felt to require particular research effort, even if only to ensure they would work in the UK geological conditions.
Overall, there was a need for a better understanding of the timescales of various remediation options and the likely end points they could achieve.The final report will be drafted to take on board the workshop findings and should be published in spring.
Paul Nathanail is course director of the MSc in contaminated land management at the University of Nottingham, email: ground. email@example.com