Water quality testing done by the Environment Protection Authority (EPA) over the past week shows there are traces of E.coli in Victorian floodwaters that can cause illness.
The first lot of results from last Monday show high levels of E.coli in Rochester, Benalla. In Shepparton, readings show four times the amount of pathogens allowed under guidelines.
Professor Mark Taylor is the chief environmental scientist for Victoria and said E.coli, pesticides and pharmaceuticals could cause illness, backing up stories from residents across towns such as Echuca, Rochester and Shepparton.
"During large flood events, septic systems get engorged with floodwater and then sewerage-related materials into the water, hence higher levels of pathogens," Professor Taylor said.
"In terms of sediments, we've undertaken a set of analyses that include pesticides and chlorinated chemicals."
Pathogens can cause illness
Australia's virtual health information service, Health Direct Australia, states E.Coli is a group of bacteria that is found in the gut of nearly all people and animals and that an E. coli infection can be spread through contact with contaminated food or water or with people who are sick.
It said the bacteria could cause diarrhoea and food poisoning or more serious illnesses like pneumonia.
Professor Taylor said, like Maribyrnong in Melbourne when it flooded, tests would also continue to be done on sediment left behind by floodwaters to test it for pathogens.
E.coli guidelines are that E.coli should not exceed 550 MPN (most probable number) per 100 millilitres, and the EPA said the floodwater results should be treated as contaminated.
Four times the amount of bacteria
Results from Shepparton last week show there were most likely 2,000 organisms of E.Coli in every 100ml of water taken from the Goulburn River.
In Benalla, the Broken River most probably had 230 organisms, and Rochester had 280 for every 100ml.
Professor Taylor said the results from testing the floodwater would help inform a flood response.
"We know that the sewerage systems are being inundated in the regional areas, and we anticipate there will be some of these chemicals in the water, and we just need to ensure what the quality of that water is so we can give the best and appropriate advice," he said.
Flooded communities report residents getting ill with gastroenteritis and having symptoms such as diarrhoea.
Water quality testing to continue
The environment watchdog says it will continue to test floodwaters around regional Victoria for the next three weeks with the help of the SES.
It's testing floodwaters at around 20 locations across the state on Monday and Thursday each week, with indicative results from the last week showing Rochester, Benalla and Shepparton as the most contaminated.
The EPA said last week's results do not identify the source of the contaminated floodwater, such as sewage or animal waste.
