Presenter: David Dangerfield,  Aecom

Presentation title: Advances in Understanding Asbestos Risk

ASBINS (ASBestos-IN-Soils) has been a significant issue both nationally and throughout the world. New Zealand currently has no nationally-agreed guidelines on ASBINS due, in part, to the absence of reliable and validated data on the relationship of asbestos fibre release from soil to air. In the last five years there have been significant developments in characterising the human health risk of asbestos in soils, chiefly in the published research in the Netherlands, release of the Western Australian (WA) Asbestos in Soils Guidelines by the WA Department of Health (WAHealth) in 2009 which were formally adopted by the National Environmental Protection Council (NEPC) in Australia this year (April 2013).  Recent studies show a relationship between soil humidity and asbestos emissions. Emission models have been developed to estimate the concentration of fibres at any given distance from an emission source based on soil concentration. There are also methods for simulating activities at an ASBINS Site but until recently there has been little that truly incorporates all the variables to attribute an accurate level of human health risk from ASBINS.  Asbestos is one of a relatively small list of known human carcinogens – each with their defined toxicity limits which drives site characterisation and clean-up. For example, human health criteria for benzene, are available for soil, groundwater and vapour all based on a 10-5 to 10-6 cancer risk, however in New Zealand there is no similarly accepted criterion for ASBINS.  Occupational airborne exposure standards are provided for asbestos in New Zealand, however there are no nationally accepted soil criteria. The Department of Labour (DoL) regulates asbestos in the occupational environment but due to the “hazard-based” approach adopted, risk-based principles are not able to be presented as a viable alternative. This means that sustainable clean-up solutions can be excluded, even when the human health risk may be well below internationally accepted cancer risk. This has significant implications on the Canterbury rebuild, placing an unreasonable cost burden on development. 

Event: WasteMINZ Conference 2013

Date: Tuesday 22nd October 213