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.
