MONITORING reports released by the Environment Protection Authority have shown no evidence that the Hazelwood mine fire has had an ongoing impact on the Latrobe Valley environment.
The two reports looking at air quality, water, soil and ash in Morwell and surrounds contained the results of a 12-month, ramped-up monitoring program by the EPA in response to the fire.
The air quality report concluded “all of the compounds tested during the incident returned to background, or low, stable concentrations shortly after emissions from the fire ceased”.
“This has remained the case for the duration of the recovery phase,” the report stated. Air quality monitoring was conducted at stations in Morwell’s south, east, Kernot Hall, Morwell Bowling Club, Maryvale Crescent Preschool and St Luke’s Uniting Church, along with a Traralgon station, Churchill and Moe.
Pollutants measured included breathable airborne particles PM10 and PM2.5, carbon monoxide, sulphur dioxide, nitrogen, volatile organic compounds and polycyclic aromatic hydrocarbons.
Not all of the sites measured for all types of pollutants, but most were able to measure for fine particulate matter known as PM2.5. This was the cause of major concern during the mine fire when it was recorded well above the National Environment Protection Measure guidelines and exceeded the 24-hour guideline on 21 days in Morwell’s south.
The report found levels dropped off sharply as the fire was brought under control. Since the fire, PM2.5 exceeded the NEPM daily advisory guideline of 25 micrograms per cubic metre during two periods: the first measurements were 31 and 34 at Traralgon in mid-May 2014 and 35 and 33 at Traralgon and Morwell east respectively on 1 April this year.
“These guideline breaches are associated with elevated smoke levels that may have originated from landholder burning off, forest regeneration burns and planned burning at the time,” the report stated.
“Smoke is often persistent in the Latrobe Valley in autumn due to the stable atmospheric conditions at that time of year.”
In relation to carbon monoxide, the report found there were no breaches of the eight-hour rolling average guideline of nine parts per million during the fire recovery phase and the average eight-hour CO level was 0.2 parts per million, 0.1ppm and 0.1ppm at Traralgon, Morwell’s south and Morwell’s east, respectively.
During the month of the fire, the CO guideline was exceeded on three days at Morwell’s south.
The water, soil and ash assessment found ash deposits on soil were not sufficient to change the soil composition and no chemical evidence of ash was found in waterways in the Morwell region at any stage during the sampling period.
Twelve ash samples were collected during the fire, predominantly from areas where it had built up in sheds, driveways and eaves.
Waterways were sampled weekly from late February to 7 April 2014, while in the recovery phase, quarterly sampling of water and soil from the Morwell area was undertaken.
Sites sampled were Waterhole Creek, the Hazelwood Pondage boat ramp, Thons Bridge on the Latrobe Rover, the main drain to Morwell Wetlands and the Morwell River.
The technical reports are available on the EPA’s website.