Presenters: Mark Morley, Tonkin & Taylor
Presentation title: Uncertainty and Risks in Sampling Asbestos in Soils

Asbestos can be found in soil on a property when buildings that contained asbestos were not demolished and disposed of properly or asbestos-contaminated soil was used for topsoil ling or filling. Asbestos is a human health-related contaminant that differs from most other chemical contaminants. It does not have any known environmental effects. The most occurrence of asbestos in New Zealand is in a bonded cement-based form where fragments or intact manufactured products occur discretely in an asbestos contaminated area. However, asbestos fibres can depart from the cement, if physically disturbed. Asbestos fibres are persistent and do not degrade over time to form less harmful materials. Rather, degradation causes greater risk of fibre release from cement matrixes. Fragments of asbestos containing material (ACM) in rubble or soil can be difficult to detect, while fibres are almost impossible to be visibly identified by the naked eye. This is an area of considerable interest and increasing concern in Christchurch, because of the volume of demolition and construction work that is currently occurring. There are currently no NZ guidelines which consider sampling for asbestos fibre in soils. Due to the lack of national guidance, there is significant variation in methods being adopted here in NZ. Guidance is provided by various regulatory authorities and agencies around the world. This paper provides some information on the available guidance. Due to the inherent heterogeneity of asbestos in rubble and soils, these guidelines typically require a large sample size and requirements for on-site processing, significantly increasing the cost of an investigation. This paper discusses the sampling risks and uncertainties, with consideration of natural and other insitu material types. It is followed by a discussion of an approach that could be adopted for New Zealand to achieve national consistency.

Event: WasteMINZ Conference 2014
Date: Wednesday 23 October 2014