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Testing Completed on Derwent Algal Bloom

13 January 2011

Sampling and testing of a red slick reported in the Derwent Estuary around the Hobart area has confirmed it as a non-toxic algal bloom, Environment Protection Authority Acting Director John Mollison said today.

Mr Mollison said reports of the red slick had been received from several locations around the city and on the Eastern Shore.

“An EPA officer collected a sample for analysis from Watermans Dock on Sunday evening and analysis has confirmed it as Noctiluca scintillans,” Mr Mollison said.

“We have had ongoing reports of this algae in the Derwent over several years and although the pinkish-red coloured slick may at times look like a contaminant type spill, this type of bloom is not considered harmful.”

Mr Mollison said during the day the blooms resemble pinkish clouds in the water but at night they are known to become luminous which occurred when the sample was collected on Sunday evening.

“It is important that people are aware when there are algal bloom in the water as there are some varieties that can cause the release of toxins which are harmful to people and animals,” he said.

“This variety we are currently seeing however is not known to release toxins.

“If people are concerned, they can avoid swimming where algal blooms are present and of course always follow any guidelines which may be in place by the Department of Health and Human Services, local councils and other authorities.”