Those with experience of working on contaminated land will know that Petroleum hydrocarbon and PAH contamination is often encountered on brownfield sites.
The remediation of such sites might involve removal of contaminated soils to landfill or to another site where the contamination criteria are less sensitive.
In either case the soil in question would be defined as a waste, and as such its classification as either hazardous or non-hazardous is important.
Barred
Hazardous waste is significantly more costly to dispose of, and its re-use on another site is currently barred because exemptions from controls under the Environmental Permitting Regulations are not available for such material.
Thus the classification of soils that could become waste can sometimes be key to the viability of regeneration projects.
Incorrect classification can result in unnecessary expense on the one hand, or possible prosecution on the other.
The Environmental Industry Commission's Contaminated Land Working Group has been pushing hard for greater clarity and better guidance on how to classify contaminated soils.
The Environment Agency has responded by changing the guidance, but there are still issues to resolve.
Soils contaminated with petroleum hydrocarbons and/or PAH may be classed as hazardous by H7 if the relevant threshold concentrations (0.1% or 1% depending on category) are exceeded.
The classification process is not straightforward, however, and in England and Wales the Environment Agency has issued specific guidance (HWR08).
Complicated tests
Appendix B of this document defines the rather complicated test methods and assessment criteria preferred by the Agency. The basic premise is that if the ‘oil' component of the waste is carcinogenic, then the whole mass will be classed as hazardous.
Unfortunately the analytical methods specified in HWR08 are peculiar to waste classification and differ from the methods preferred by the Standing Committee of Analysts, which are designed to be used for human health risk assessment.
This means that separate analyses need to be carried out for the two purposes. It would clearly be beneficial if the Environment Agency guidance could be modified so that the results of the SCA type of analysis could be applied to waste classification.
Scotland
In Scotland the classification of hydrocarbon contaminated soils is based on SEPA guidance SWAN04.
This guidance is similar to that used by the Environment Agency prior to the introduction of HWR08, being based on benzo(a)pyrene as a marker. It also lacks commonality with the SCA methods. There is scope for harmonisation here also.
EIC's Contaminated Land Working Group is pushing the Agency to provide guidance to addresses these problems.
Paul Spence is a member of the EIC Contaminated Land Working Group
