A MYSTERIOUS strand of blue-green algae is growing at unprecedented levels in Mount Isa’s water supply.
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The city is 15 months into what is described by the Mount Isa Water Board as “potentially the largest blue-green algae bloom recorded in a Queensland water supply system”.
The board’s chief executive Stephen Farrelly said the cell count of the non-toxic strand Pseudanabaena “exploded” in Clear Water Lagoon since December 29.
University testing laboratories were receiving test results, but very little research had been done on the strand. “We don’t understand fully how it impacts us,” Mr Farrelly said. “It’s not toxic, it’s just choking us to death.”
A graph provided by the Mount Isa Water Board showed blue-green algae’s cell count levels in Clear Water Lagoon had tripled from late December to January 27.
But the most recent test taken on February 2 showed a decrease from 3.6 million cells a millilitre to 3.178 million, which was “slightly down but not enough data to know the trend.”
The Mount Isa Water Board was having increasing difficulty in filtering water because of the algae.
Previously a toxic algae strand called Cylindrospermopsis raciborskii dominated Lake Moondarra and Lake Julius, but could be controlled by chlorine.
State member for Mount Isa Rob Katter discussed water shortages with the director-general of the Department of Energy and Water Supply Dan Hunt on Wednesday.
Mr Katter was told the new strand could be toxic if there were attempts to treat it with copper sulphate and powdered activate carbon.