Floodwaters can wash away cars or people with their strong currents, but what exactly is in floodwater? A new partnership between the Environment Protection Authority in Victoria (EPA), the Victoria State Emergency Service (VICSES) and Natural Hazards Research Australia is being undertaken in rivers across Victoria to better understand possible contamination.
In October and November VICSES members collected samples of floodwaters to further understand the level of risk to human health and the environment.
EPA are testing the floodwater samples for bacteria (E. coli, an indicator for faecal contamination) and a range of trace elements (such as metals and metalloids) and contaminants - organic chemicals such as artificial sweeteners, endocrine disrupting chemicals, pesticides, perfluoroalkyl and polyfluoroalkyl substances (PFAS), petroleum hydrocarbons, pharmaceuticals and personal care products, phthalates and volatile organic compounds.
Initial results indicate that E. coli levels and other contaminants such as trace metals, volatile organic compounds, pesticides, phthalates and per-and polyfluoroalkyl substances (PFAS) are generally below levels of concern.
“We found that detected levels for perfluoro-octane sulfonic acid (PFOS), are consistent to levels detected in agricultural sites in previous EPA studies,” said EPA Chief Environmental Scientist, Prof Mark Taylor.
“Concentrations of pesticides were below human health and environmental guidelines. All volatile organic compounds were below the level of detection, and no exceedances of recreational water guidelines were detected for trace elements, such as copper, lead and zinc.
“Phthalates, which are used as plasticisers in various industrial commodities, were detected at most testing sites at concentrations below current guidelines.
“This is a unique program and one that will help agencies in other flood affected parts of the country to monitor and report on contamination issues in their floodwaters,” Prof Taylor explained.
In mid-November, floodwaters tested in the Broken and Snowy rivers showed very high levels of E. coli. The Broken River at Benalla tested E. coli at 6,400 Most Probable Number per 100 ml (MPN/100ml). The guideline for E. coli is around 550 MPN/100ml. Most samples were below the E. coli short-term guideline number.
Floodwater should always be treated as contaminated explained VICSES Chief Officer Tim Wiebusch.
“It is vital communities understand the many different risks associated with floodwater. As well as the immediate physical dangers, floodwater can also carry pollution into waterways. The advice to community remains unchanged. Never enter floodwater. These initial results show that you can never be certain what is in floodwater.”
Andrew Gissing, CEO of Natural Hazards Research Australia, said that partnerships like this with EPA and VICSES are vital. “This research in partnership with EPA and VICSES is essential to understand the broader harms associated with floodwater and will be shared nationally to inform communities and emergency services of the many dangers of entering floodwater. Partnerships like this between scientists and practitioners are vital to improve knowledge for the benefit of our communities.”
Testing locations are:
- Broken River, Benalla and Shepparton
- Campaspe River, Echuca, Kyneton and Rochester (upstream and downstream)
- Coliban River, Eppalock
- Goulburn River, Echuca and Shepparton
- Lake Nagambie, Nagambie
- Little Murray River, Swan Hill
- Murray River, Echuca and Swan Hill
- Snowy River at Bete Bolong, Orbost and Marlo
For more information see the EPA website.