Atmosphere Theme Report
Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Dr Peter Manins, Environmental Consulting and Research Unit, CSIRO Atmospheric Research, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06746 9
Regional Air Quality (continued)
Deposition of dust across regional airsheds [A Indicator 4.8]
Management of dust (TSP) emissions, suspension and deposition is a major preoccupation of environmental management plans for all mining and minerals industries across Australia. The effect of the Australian Minerals Industry Code for Environmental Management (see AMI 2000 | a | b | ; AMEEF 2000) is clearly evident. Greatly increased attention to environmental issues and their reporting have occurred in the minerals industry since the inception of the Code (launched in December 1996). Other industries such as cement, coke and steel works, and agriculture, are also responsible for dust emissions and their mitigation. In particular, the factors that lead to dust storms and wind erosion are discussed in the Land Theme Report.
Given the heightened awareness by industry (see Case study), dust deposition levels are likely to decrease.
In New South Wales, a value of 4 g/m2 per month (annual average) of dust deposition is used for assessing the effect on amenity of dust in coal mining areas. Up to 1996, dust deposits in Wollongong remained only just below this level and occasionally above it. In the Port Kembla area, rates of dust deposition were generally higher (EPAN 1997).
The region worst affected by dust in South Australia is the far north of the State, with about 60 dusty days per year, followed by Port Pirie with 19, Lincoln, the West Coast and Whyalla with 17, the Riverland and Murray Mallee with 12 and Adelaide, the Barossa and Yorke Peninsula with eight. More common is dust due to wind erosion of fields. Downwind consequences include increased prevalence of asthma, with possibly as many as 20% of the State's asthma problems resulting from windborne dust (Williams and Young 1999).
BHP's operations at Port Hedland, WA (BPEM 1998), identified the sources of dust (81% attributable to materials handling, 6% to vehicle movements, 5% to mobile plant and 4% to each of windblown and other sources), set about reducing each, and assessed the success by a monitoring program started in 1994 and run over three years. A dust suppression operation is shown in the photograph and Figure 156 illustrates the substantial success of the program, even as tonnages of ore shipped from the Port have increased (WA SoE 1998, p. 51).
Dust suppression of iron ore stockpiles at BHP Port Hedland using water sprays.
Source: BPEM (1998)
Figure 156: Annual average total suspended particulates (TSP) monitoring results from 1994 to 1996.
Source: from BPEM (1998)
The deleterious health effects of dust are adequately covered by environmental Indicators such as PM10 and haze. As a separate environmental Indicator, dust deposition is more a measure of whether, and how well, good practice is being followed.
Anecdotally, there has been a major reduction in deposition of dust in regional airsheds. Increased awareness of the need for its management in several industries, particularly mining, has led to this improvement. However, more needs to be done, especially in rural areas where episodic wind erosion of soil continues to be a problem.