The signs went up on Thursday, January 10 advising against swimming along the northern end of the beach, in addition to existing warnings at Blackmans Bay south.
They were then removed from the northern end the next day after further testing revealed the water quality was safe for swimming.
For some time, frustrated residents have been circulating flyers calling for action on the water quality of the beach urging people to contact Kingborough Council and TasWater to voice their concerns.
Kingborough Council is calling on the State Government to take the lead role in investigating and dealing with pollution after the publication of the latest Derwent River Estuary water sampling last week.
The council is concerned about the unusually high faecal contamination for beaches across the Derwent, but particularly at Blackmans Bay.
The usual preconditions for poor water samples such as high rainfall, were not present during this testing, and Mayor of Kingborough, Cr Dean Winter, said council had been working with TasWater to resolve the stormwater pollution issues and was pleased to have
achieved an extremely low pollution result for its stormwater outflow at central Blackmans Bay Beach earlier last week.
“Getting people back in the water at southern Blackmans Bay Beach has been my number one priority in my first couple of months as Mayor.
“While we’ve made excellent progress in resolving the stormwater issues, the readings last week appear to suggest contamination is coming from other sources apart from stormwater.
“The readings at Blackmans Bay Beach are astronomical and totally unacceptable”.
“Kingborough Council tested its stormwater outflow at the same location, on the same day and found an extremely low reading.
“This points to external factors and these need to be investigated immediately.
“This issue requires the full attention of the State Government at the time of year when Hobart residents and visitors want to get out in the water.
“For a state that prides itself on its clean, green image, we must do more to identify the cause of these issues, and it must be done urgently”, Mayor, Cr Dean Winter said.
TasWater was pleased that the Blackmans Bay Beach test results came back safe for swimming and will continue to investigate a range of factors which may have led to the high readings of enterococci bacteria in the first place.
TasWater CEO Michael Brewster says part of this investigation will involve DNA fingerprinting of the enterococci bacteria to determine a source.
Enterococci are an indicator of the presence of faecal material in seawater.
There are many potential sources including warm-blooded animals like seabirds, native animals and household pets.
It can also be found in seaweed and beach vegetation.
“While the DNA tests may not give us a definitive answer it is part of working through the process to identify what happened and what we can do about it," said Mr Brewster.
To date, TasWater has identified no sewage blockages, pipe breaks or any abnormal discharge from sewage treatment facilities or pumping stations, which may have contributed to the unusually high reading of enterococci which resulted in the beach closure.
“We acknowledge the concern of the community and TasWater will keep working with councils, Derwent Estuary Program and the State Government who is fulfilling its responsibilities through the Environment Protection Authority in maintaining the water quality of beaches on the Derwent.
“In the meantime, I encourage beachgoers to always take note of advice from councils and the Department of Health, and we will keep you informed when our findings become available,” Mr Brewster said.
But Mayor, Cr Dean Winter said, “the fact remains, there has been a major environmental incident here."
Kingborough Council will extend its intensive testing regime for the remainder of summer on top of the work already done with the Derwent Estuary Program.
The Council will publish the data as soon as it is available so that people can see exactly what is going on at Blackmans Bay and Kingston Beaches and feel safe to swim.
“I understand that some people in the community will have lost confidence in the water quality at Blackmans Bay Beach.
We will do everything we can to restore confidence, but to do that we need to urgently find the cause of last week’s incident”, said Mayor, Cr Dean Winter.
Residents should heed any warnings as they pose a health risk.