The importance of IBA in characterizing source-sink relationships in Australian aeolian dust research: examples from case studies

Richard Greene 1, Keith Scott (Deceased)2, Craig Strong1, Eduard Stelcer3, David Cohen3
1Fenner School of Environment and Society, Australian National University, Canberra, ACT, 0200, Australia, 2CSIRO, Sydney, Australia, 3ANSTO Institute for Environmental Research, Locked Bag, 2001, Kirrawee DC, NSW, 2232, Australia

In aeolian dust research an understanding of source-sink relationships is critical. For example in pedological studies into the possible role of aeolian materials in soil-landscape formation, we need to be able to locate source areas. Also in environmental studies where contaminants such as salts and pollutants are bound to dust particles and transported by aeolian processes, we need to define source areas. To do this we need to characterize the properties of the aeolian materials.

However, accurately characterizing the properties of dust to determine the sources' fingerprints and source areas is frequently difficult. While techniques such as particle size analysis and XRD analysis provide some insight, detailed chemical data from ion beam analysis (IBA) provides a very powerful and comprehensive means of characterizing dust and both fingerprinting and identifying sources. IBA methods have been used for many year to characterise dust in both Europe, North and South America and Australia.

At ANSTO it is possible to use four IBA techniques (PIXE, PIGE, RBS and PESA) together simultaneously to provide a full suite of elements from H to U with µg/g detection limits. Typically around 25 different elements in dust and soil samples can be detected which enables soil and dust fingerprints to be obtained for different regions and to trace dust movements. Because IBA analysis is very fast and efficient hundreds of samples can be analysed in a few days of accelerator time. In addition IBA is non-destructive technique and after IBA samples can be also analysed with some other technique for obtaining additional information.

This paper will describe how IBA techniques, in combination with other analytical techniques, have been used in several different aeolian dust studies by ANU students to characterize the chemistry of dust particles and hence progress our understanding of Australian aeolian dust, particularly source/sink relationships. These studies have been  AINSE student projects carried out in collaboration with ANSTO staff. The case studies are as follows:

(i) The recognition of terrestrially-derived salt (NaCl) in SE Australian dust-a study where the NaCl components in dust samples from SE Australia were calculated from elemental IBA data.

(ii) The characterization of aeolian dust across NW Australia-a study where IBA was used in combination with PSA to indicate that the collected dust was sourced both from central Australian as well as being locally derived.

(iii) The assessment of aeolian dust properties in the Port Hedland area-a study where dust generated in the region was analysed by both IBA and ICPAES to determine source areas and possible causes of the dust.

The benefits of these collaborative ANU-AINSE student projects in training young researchers are also outlined.