The blue line shows the local waterway Stony Creek.
This update includes water quality data from 30 August 2018 to the most recent available test results, collected on 13 September 2019.
EPA has tested water for a range of contaminants from the Stony Creek area and continues to advise not to eat fish taken from Stony Creek. However, based on the results of testing of water quality, there are no concerns regarding fishing and other recreational activities in the Lower Yarra River and Hobsons Bay. We advise avoiding contact with the water and sediment in Stony Creek and to keep pets from swimming or drinking the water.
Past results have shown that a range of industrial solvents, detergents and ash particles were washed into Stony Creek. The key chemicals detected were phenol (an industrial chemical and cleaning product), polycyclic aromatic hydrocarbons (fire and soot by-products), lighter petroleum hydrocarbons called BTEX (benzene, toluene, ethylbenzene and xylene), PFAS (per- and poly-fluoroalkyl substances), and industrial solvents such as acetone and butanone.
Concentrations of these chemicals were very high in Stony Creek on Thursday 30 August 2018 and caused rapid death of fish and aquatic life in Stony Creek and in some cases exceeded human health recreational contact guidelines for several days after the fire. Concentrations of these chemicals have declined significantly over time.
Conditions in Stony Creek have improved considerably since the fire due to dilution by creek flows, chemical degradation and recovery works by Melbourne Water and EPA. Water quality in Stony Creek has met human health water guidelines for recreational contact since late 2018.
To aid rehabilitation of Stony Creek, Melbourne Water has undertaken a program to remove contaminated sediments downstream of the fire site to Paramount Rd by dredging the creek bed from the beginning of April to early September.
The figure below shows Stony Creek mean daily flows (ML/day) measured at the Spotswood gauging station (Bena St, Yarraville) from 26/08/2018 to 13/09/2019. The black horizontal bar indicates that the period of dredging has coincided with increased base flows in Stony Creek and periodic heavy rainfalls and creek flows from May to August 2019. These flows may have contributed to further flushing of contaminants from affected areas within Stony Creek.
Results from regular water quality monitoring at fixed sites in Stony Creek
Concentrations of perfluorooctane sulfonate acid (PFOS) at all downstream sites were below environmental guidelines on 13/09/2019. Concentrations of the herbicide 2,4-D have declined since November 2018. Levels of 2,4-D recorded at Cruickshank Park and Hyde St were similar to background levels recorded upstream at Quarry Rd, but remained above background levels at Cala St on 13/09/2019.
Results for persistent PFOS and the herbicide 2,4-D upstream of the fire site (Quarry Rd) and at three sites downstream of the fire site at Cala St, Cruickshank Park and Hyde St from 30/8/2018 to 13/09/2019 are shown below. The red and green lines indicate recreational water quality and aquatic ecosystem guidelines, respectively. Note, the very high PFOS levels recorded on 30/08/2018 downstream of the fire site are not displayed on this figure to aid interpretation.
Chemicals presented in previous updates of water quality occurred below detectable levels and are not presented (e.g. BTEX chemicals benzene, ethylene, toluene and xylene, acetone, methylethylketone, and phenol). Note, that although these chemicals are no longer presented in these reports, EPA will continue to measure and assess these chemicals to ensure they remain below relevant guidelines.
This update includes sediment quality data from 11 September 2018 to the most recent available test results collected on 13 September 2019. This update reports on how sediment conditions have changed over time since the fire.
We have tested sediment at fixed locations for a range of pollutants from the Stony Creek area since 11 September 2018. Although in most cases contaminant levels in the sediment have declined, disturbing the sediments would mobilise contaminants and increase the risk of harm to the environment and human health. We advise avoiding contact with creek sediments in Cruickshank Park until further notice.
Concentrations of C16-C34 hydrocarbons in the sediments of Stony Creek were below human health guidelines for recreational contact at all downstream sites on 13/09/2019. Concentrations of C10-C40 hydrocarbons in sediments exceeded environmental guidelines at all downstream sites but were similar to background levels of hydrocarbon contamination recorded upstream at Quarry St on 13/09/2019. Concentrations of copper in sediments were below environmental guidelines at all downstream sites on 13/09/2019. High variation in sediment contaminant levels over time at Cala St may reflect the movement of contaminated sediments downstream during high flow events and/or the spatially patchy distribution of contaminants within the sediments of Stony Creek.
Results from regular sediment quality monitoring at fixed sites in Stony Creek
Results for the C16-C34 and C10-C40 hydrocarbon fractions and copper in sediments sampled upstream of the fire site (Quarry Rd) and downstream of the fire site at Cala St, Cruickshank Park and Hyde St from 11/09/2018 to 13/09/2019 are shown in the figures below. The red line indicates human health guidelines for recreational contact with sediments. The green lines indicate aquatic ecosystem guidelines for sediments. Other chemicals presented in previous updates occurred below relevant guidelines and are not presented here (e.g. C6-C10 hydrocarbons and PFOS). Note that although these chemicals will no longer be presented in these reports, EPA will continue to measure and assess these chemicals to ensure they remain below relevant guidelines.