2023 September: Crayfish Kill at Hazelbrook (NSW)

EPA Identifies Pollutant Behind Major Crayfish Kill

The NSW Environment Protection Authority (EPA) has identified the pollutant which caused a major crayfish kill in a tributary of Hazelbrook Creek in the Blue Mountains last month.

According to the EPA media statement, released today, initial lab testing has found the insecticide Bifenthrin in water, sediment, and crayfish samples collected from the impacted creek.

“Bifenthrin is commonly used for general pest control, such as for termites, spiders, ants, and cockroaches and is highly toxic to crayfish and other aquatic organisms,” the EPA statement said.

“The EPA investigation into the source of the Bifenthrin pollution is being finalised.

“Herbicides used by Blue Mountains City Council to control weeds, such as Glyphosate, have been ruled out as the cause of the crayfish kill and Council is not a subject of the ongoing investigation.”

Blue Mountains City Council Mayor Cr Mark Greenhill said “I know many of our staff and volunteers were really hurt by fake claims on social media suggesting our people may have somehow been responsible.

“The opposite is true. Apart from assisting the regulator in the current case, our people dedicate themselves to keeping our waterways clean and protecting the wildlife within.

“To those who think it is a source of personal aggrandisement to suggest possible blame without any evidence, this should be both an embarrassment and a salient warning.

“I await the outcome of the EPA’s investigation.”

After hundreds of dead Giant Spiny Crayfish were discovered in a tributary of Hazelbrook Creek by a tour guide in August, Council worked closely with the EPA on an investigation into the incident.

The Giant Spiny Crayfish, a local native species, face many dangers from runoff, pesticides, habitat destruction and illegal use of traps in Blue Mountains swamps and waterways.

Council will continue to monitor the recovery of freshwater crayfish and other aquatic macroinvertebrates at Hazelbrook Creek, as part of ongoing waterway health sampling programs.

EPA investigating insecticide as possible cause of crayfish kill at Hazelbrook

September 12 2023: https://www.bluemountainsgazette.com.au/story/8337913/epa-investigates-insecticide-as-possible-cause-of-crayfish-kill/

The Environment Protection Authority (EPA) believes insecticide pollution may be the cause of a crayfish kill at Hazelbrook.

“The EPA has narrowed its investigation to the immediate vicinity of the Horseshoe Falls catchment and believe the impact on crayfish may have been caused by insecticide pollution,” they said in a statement on September 4, adding that test results are still being finalised.

Blue Mountains mayor Mark Greenhill has ruled out any actions by council staff or bushcare volunteers contributing to the incident following uninformed speculation on social media.

“I can confirm that no actions by BMCC (Blue Mountains City Council) staff, or our dedicated bushcare volunteers, contributed to the water pollution event that precipitated the crayfish deaths in the Horseshoe Falls catchment,” he said on September 6.

“Council and its people had absolutely nothing to do with this event and some recent commentary to the contrary on social media is false, irresponsible and unfair.

“Council staff were devastated by the discovery, and have been working to improve catchment health and water quality for over two decades across the city.”

The EPA is continuing its investigation into the crayfish kill in a tributary of Hazelbrook Creek on Wednesday, August 23.

A tour guide discovered the dead Giant Spiny Crayfish. A later inspection by council staff found up to 1000 of the crayfish either dead or dying, extending at least 600m downstream from Oaklands Road/Hall Parade at Hazelbrook.

Blue Mountains City Council later won an award in 2019 for its efforts to protect Wentworth Falls Lake and Jamison Creek from stormwater pollution and other threats posed by urban runoff.