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)
Fluoride across regional airsheds [A Indicator 4.7]
Fluoride compounds, which occur as both gases and aerosol, cause damage to plants at concentrations about 1000 times lower than those that cause detectable human health effects. Certain plants, such as grapevines, are particularly sensitive. Aluminium smelters, power stations and brick and ceramics works can be major sources of fluoride. The Australia and New Zealand Environment Conservation Council has recommended environmental guidelines (based on damage to plants) for fluorides (ANZECC 1990) (Table 33).
| 12-hour | 24-hour | 7-day | 30-day | 90-day | |
|---|---|---|---|---|---|
| General land use | 3.7 | 2.9 | 1.7 | 0.84 | 0.50 |
| Special land use | 1.8 | 1.5 | 0.8 | 0.40 | 0.25 |
Source: ANZECC (1990).
The NPI (2001) presently reports inventory data on fluoride emissions from the six primary aluminium smelters in Australia (Table 34), but for a complete picture, it is necessary to await inclusion of emissions from the major coal-fired power stations and other lesser sources. For example, the power stations in the upper Hunter Valley (NSW) have reported to the NPI (2001): their total emission of fluoride was 636 t for 2000. The NPI Trial for Kalgoorlie (DEP 1999) established an industrial fluoride emission total of 284 t. These greatly exceed or are comparable with, respectively, the higher emitting smelters (Table 34).
| Location | 1999 Al capacity (kt/y) | 1999-2000 F emissions (t/y) |
|---|---|---|
| Kurri Kurri (NSW) | 150 | 160 |
| Tomago (NSW) | 440 | 250 |
| Point Henry (Vic.) | 180 | 220 |
| Portland (Vic.) | 320 | 120 |
| Boyne Island (Qld) | 490 | 370 |
| Bell Bay (Tas.) | 137 | 250 |
| Total | 1 717 | 1 370 |
Source: AAC (1999) for capacities, NPI (2001) for emissions.
The aluminium industry collects a lot of ambient monitoring data on fluoride and reports these to EPAs across Australia. However, these data are rarely reported to the public.
Several aluminium smelters employ buffer zones of up to 1 km or so, in which concentrations of hydrogen fluoride are likely to be high enough to cause plant damage or fluorosis of the teeth of grazing cattle. In general, brick and ceramics works are said to have a more limited area of effect (EPAN 1997), but power station emissions are dispersed widely at low concentrations.
In the Hunter Valley (NSW), results of ambient fluoride monitoring around the smelters show that within the buffer zone the desired goals are regularly exceeded, but beyond this area, levels generally meet the goals. At sensitive vineyard sites, data from 1990 to 1995 show annual maximums of 0.1-0.3 g/m3 , indicating that levels remain well below the guideline for sensitive vegetation of 0.8 g/m3 (EPAN 1997).
The Boyne Island smelter near Gladstone (Qld) is said to comply with the guideline in nearby residential areas but not in the strip surrounding the plant (Qld SoE 1999) set aside to separate the industry from other activities (the buffer zone).
Near the Bell Bay (Tas.) refinery, current fluoride levels in the ambient air are said to be well below acceptable limits. Fluoride levels in the bones of some cattle near the aluminium refinery have been above desirable concentrations. The problem may be compounded by fluoride present in some fertilisers used in the region. Significant reductions in fluoride emissions from the refinery have been achieved recently through modifications to refining methods and improved pollution controls (see Figure 155). Ongoing investigations will establish the significance of air emissions and appropriate controls introduced through permit conditions (DPIWE 2000).
There have been consistently low atmospheric fluoride concentrations near the Alcoa smelters in Victoria (Figure 154).
Figure 154: Ten years of 90-day rolling averages measurements of fluoride near Portland Aluminium Smelter (1.3 km away) and Point Henry Aluminium Smelter (1.5 km away) in southern Victoria.
Source: courtesy of Alcoa Australia
Major reductions in emissions of fluoride from the older smelters operated by Comalco Ltd have occurred in Australia since 1995. The improved performance means that the Comalco Ltd smelters (Figure 155) are now comparable with Tomago and Portland (Table 34).
Figure 155: Aggregate reduction in fluoride emissions from Comalco Ltd smelters (Boyne Island, Qld, Bell Bay, Tas., Tiwai Point, New Zealand).
Source: Comalco (1999)
Implications
Fluoride concentrations are not a cause for concern in any of the locations where they are monitored. However, it would be more reassuring and preferable that the responsible agencies made public the results of the monitoring data that they routinely obtain as part of licence requirements.
Once comprehensive emissions inventories are available from the National Pollutant Inventory, it is likely that there will be calls for a review of the cumulative effects of fluoride emissions from sources other than aluminium smelters.