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The last round of water results were from samples taken on 26 May and 10 June 2015 at sites around Morwell in the Latrobe Valley. Sample sites flow through a mixture of rural, industrial and urban areas.
Although some sites recorded elevated levels of substances such as aluminium and zinc, none of the results were considered unusual for creeks and waterways in an urban environment.
The results from June 2015 water testing were consistent with sampling done since March 2014. The results of 14 months of sampling showed that the water in the Latrobe Valley has not been changed by the Hazelwood mine fire. As a result, this part of the environmental monitoring program has now ceased. EPA continues to sample water quality in response to suspected and confirmed cases of pollution events, in addition to the water sampling being conducted as part of the Latrobe Valley Citizen Science program.
The water sampling results from March 2014 to March 2015 are presented in EPA Hazelwood Recovery Program water, soil and ash assessment – Morwell and surrounds (publication 1600).
Why did we sample the water?
Due to the ash that fell in and around Morwell from the Hazelwood mine fire, EPA sampled water to see whether the presence of ash impacted the quality of nearby waterways. The ash may have either fallen directly into waterways; or have been washed into streams and wetlands, either by rain or from washing down streets and footpaths.
From this sampling, we were able to detect if the ash had any impacts on the waterways in the region.
What did we sample for?
EPA tested the water for chemicals that may have come from the smoke and ash from the fire.
The chemicals found in ash, although naturally occurring, can cause problems in waterways if their concentrations get too high.
These chemicals can include heavy metals (such as mercury and lead), organic compounds (such as benzene and toluene), surfactants (which are in firefighting products) and many other compounds.
Some of these chemicals, particularly metals such as zinc and aluminium, are among the more common pollutants found in waterways in urban environments. This is usually due to run-off from houses, roads and industry.
When the concentration of these chemicals becomes too high, it can reduce water quality and potentially have a negative impact on aquatic life.
What did we find from our water sampling?
The last water samples were taken from sites in the Latrobe Valley on 26 May and 10 June 2015.
Water samples taken from creeks and waterways in May–June had a number of metals (such as aluminium and zinc) that exceeded the water quality criteria. These pollutants were detected in most samples taken since February 2014. These results are typical of a waterway in or near an urban area like Morwell, and were most likely caused by urban run-off.
In the May–June 2015 sampling, none of the organic compounds usually associated with coal mine fires (such as benzo[a]pyrene) were detected in the water samples.
What do the results mean?
The results from June 2015 from the water sampled in the zones most affected by the mine fire confirm that waterways in the area were unchanged by the fire.
Results also showed that the water quality in the affected areas was very similar to water quality in the zone that was further away from the mine fire. From this, we concluded that the ash that fell did not cause significant changes to the natural environment.
The May–June 2015 water results showed that the creeks and rivers in the affected areas were typical of those found in areas that receive urban run-off. This indicated that the pollution in the waterways had probably come from a source such as urban run-off rather than from the Hazelwood mine fire.
Overall, the water quality issues in the creeks and waterways tested in the Latrobe Valley are comparable to those in most urban waterways in Victoria.