Basic Principal: The apparatus is designed to produce a representative respirable dust concentration of the material under test in the elutriator for subsequent isokinetic sampling of PM10 and asbestos. Volumetric air flow within the various components of the dust generator are controlled so that the flow within the vertical elutriator will properly separate and only contain respirable particles (aerodynamic diameter of 10 ?m and unit density) of dust and asbestos structures.

1. The current "Modified Elutriator Method for the Determination of Asbestos in Soils and Bulk materials" is a modification of Berman's "Superfund Method for the Determination of Releasable Asbestos in Soils and Bulk materials (1997).
   

2. The elutriator is specifically designed to provide measurements that can be related to exposure and risk.
   

3. This Method measures an intrinsic property of the material under test expressed as Structures of Asbestos (within size range of interest)/unit mass of respirable dust, S/g pm10. It should be noted that this parameter has been observed to be independent of respirable dust concentration over a wide range of concentrations.
   

4. Measurements derived using this method can be combined directly with appropriately selected dust emission and dispersion models to predict respirable concentrations of asbestos structures in units of S/m3. Model must be selected to simulate actual site conditions and scenarios of interest
   

5. The operational parameters of the tumbler/dust generator are not intended to simulate any specific field condition. Rather, the releaseability of respirable materials under specified conditions is represented by modeling parameters that are combined with the results from the Method .The operational parameters of the dust generator are intended to develop a representative respirable dust concentration of the material under test in the elutriator.
   

6. The cost to build an elutriator apparatus is approximately $10,000. This apparatus can be built from readily available materials based on the design drawings provided in the Method.

Method Advantages

• Minimizes sample preparation subjectivity
  

• Large sample size promotes representativeness (1 kg sample, 40 70 g
  sub-sample for analysis)
  

• Accurate and precise analysis of biologically relevant asbestos
  structures by TEM
  

• Overall sensitivity more than adequate to evaluate human health
  risk assessment.

Method Disadvantages

• Cost* ($600/sample, but coming down with acceptance)
  

• Minimal operational experience (number of sites)
  

• Few laboratories (none locally) have equipment

* Highly amenable to compositing field samples .... a key to efficient and cost-effective site characterization.