IT’S not actually the blue-green algae in our waterways that poses concern for health and water authorities – but the bacteria it produces.
TAFE NSW Riverina Institute freshwater ecologist Alison Mitchell cleared up the science behind what is scientifically termed cyanobacteria in a information session for residents on Tuesday.
Dr Mitchell said the bloom’s cause was due to an imbalance in the types of algae in waterways – blue-green, green and diatoms.
“What we’re seeing at the moment with the bloom means the algae are out competing and it’s a really complicated system out there,” she said.
“What’s happening in the system at the moment is, something is out of balance in the biodiversity.
“For some reason at the moment the blue-green algae has knocked out the greens and the diatoms – science doesn’t know why.
“We still don’t really know what causes a bloom to produce toxins.”
Dr Mitchell said toxins possibly produced by the bloom – hepatotoxin, neurotoxins and dermatoxins – could cause serious health risks.
“Someone who has had hepatitis would know that hepatotoxin can attack the liver and someone who has had dermatitis would know that dermatoxins can give you itchy skin,” she said.
“Neurotoxins can actually attack your nervous system.
“It doesn’t happen often that we have large-scale deaths, or any deaths at all.
“There were reports in the late 19th century of livestock killed at the Murray mouth.
“Personally I wouldn’t take the risk, but if people want to, that’s up to them.”
Dr Mitchell said there were a number of control measures and carbon filtration was used commonly.
“If you’re a water provider, you’re going to use something like UV, ultrasound and chlorine,” she said.
“Albury for example uses the charcoal process, it’s absorbing it and filtered so you’re getting clean water.”
Dr Mitchell said foreseeing the bloom’s end was as difficult as determining its cause.
“If it’s nutrient levels that keep it going, once it’s run out of nutrients it will die off pretty quickly,” she said.
“If it’s a temperature thing, as we’re getting cooler weather it may die off quite slowly.”
Dr Mitchell said monitoring was crucial as climate scientists predicted the conditions facilitating algal blooms were likely to become more frequent.
“That’s why funding is so important … there’s been a reduction for the CSIRO.
“We need this research, we all have questions, but who’s going to answer them if it’s not our scientists?”