MONITORING OF SOIL, ASH AND WATER
In addition to air quality monitoring and testing, the EPA established a comprehensive program to test soil, ash and water for contaminants produced by the Hazelwood mine fire.
Soil and Ash
Surface and subsurface soil from within the immediate and surrounding areas of the mine fire were sampled and analysed from 24 February 2014 (see Figure 4.37).93 Mr Merritt notes that these samples were consistent and within the normal variation that would be expected for soil.94
The EPA reported that appropriate testing of surface and subsurface soil samples to distinguish between the natural versus the impacted environment was difficult. The amount of ash deposited on soil was also limited, which made it difficult to test.95
Ash samples were collected from 24 February 2014.96 The EPA reported that ash deposits were not significant enough in many places to conduct sufficient testing. Ash was only found in protected areas where it had been blown and accumulated. This made it challenging for the EPA to distinguish mine fire ash from bushfire ash, which was also present in the area. Some samples were collected from the garages and sheds of Latrobe Valley residents, where ash had been protected from rain and wind.97 Once results were received, it was evident to the EPA that the ash from the mine fire was different.98
Mr Merritt told the Board that ash samples will be further analysed by the EPA to determine whether the ash contains contaminants that could end up in waterways and soil.99 The results of that analysis will inform the long-term health study announced by the Department of Health.100
Figure 4.37 Latrobe Valley monitoring sites – soil101
The EPA collected water samples from waterways (wetlands, streams, rivers and drains) near Morwell (see Figure 4.38) and tested for toxic elements that may have come from the smoke and ash emitted by the Hazelwood mine fire. Toxic elements impacting on water can include heavy metals like zinc and mercury, complex organic compounds such as benzene, surfactants (found in firefighting products), and various other compounds.102
The EPA conducted testing before and after rain to capture any contaminants that may have been washed from land into water.103 Water testing in residential areas in Morwell and surrounding areas was conducted weekly from 18 February 2014.104
The EPA reported that appropriate testing of ‘background sites’ was initially difficult. Finding background sites allows for a comparison of the natural versus impacted environment. Such sites needed to be close by, but not directly impacted by the fire.105
Water was sampled and tested in one water tank located in Willis Crescent, Morwell on four occasions from 23 February – 17 March 2014. The results were compared to standards for drinking water, although the EPA had no evidence this tank was used for drinking water.106 The EPA stopped this particular water sampling after receiving advice from the Department of Health that it was not necessary.107 The water results provided to the Board showed a small percentage of exceedences compared to relevant standards.108
The EPA also sampled and tested water in three dams that supplied water for firefighting. These dams were sampled from 15 February 2014 and the data provided to the CFA.109
Water and carbon monoxide monitoring for workplace air and water quality standards, as they apply to firefighters, is dealt with in Chapter 4.4 Firefighter health.