TOXIC FISH: Your health questions answered
THE DISCOVERY of a hazardous chemical in the flesh of seven fish caught in a Mackay creek has caused many residents to fear they have been unwittingly exposed to a dangerous toxin.
Last week, the government owned corporation Airservices Australia revealed testing had found potentially dangerous levels of perfluorinated substances in fish caught in Shellgrit Creek.
On Thursday, Mackay Hospital and Health Services director of public health Brigid Fenech attended a community drop-in session at Mackay Airport to answer questions from concerned members of the public.
These were the top concerns of Mackay residents over the Shellgrit Creek contamination:
Is it safe to eat seafood in Shellgrit Creek?
After the discovery of the contaminated fish, Queensland Health recommended that no one should eat fish caught in the creek.
Ms Fenech said this was a precaution until further testing was conducted.
She said the contaminated area also included a canal on Bridge Creek, north of the airport, and the eastern branch of the creek south of Petrie St.
However, she added that "potentially all tidal areas of the system may be affected due to the movement of water and fish throughout it".
While crustaceans, like crabs bugs and prawns, were not tested, Ms Fenech said they were likely to be contaminated.
"Consumption of crustacea is likely to be a lower risk than fish because people generally eat lesser amounts of crustacea than fish," she said.
I have eaten fish from Shellgrit. Am I at risk?
Ms Fenech said if residents had only occasionally consumed fish from Shellgrit Creek there should be no health risk.
She said the health system's main concern was for people who regularly ate fish from Shellgrit Creek.
Adults who ate more than 150g of Shellgrit Creek fish a week, or children who ate one serving, or 75g of fish, per week could have health concerns
Given the level of toxins detected, Ms Fenech said eating that amount of fish "would place a person above their tolerable weekly intake of PFAS... that can safely be consumed over a lifetime".
She said anyone concerned about their health, or their family's health, could contact their GP or call 13 HEALTH (13 43 25 84).
Can I still swim or fish in Shellgrit Creek?
Ms Fenech said recreational activities posed a low contamination risk.
But, she added "activities that result in the ingestion of water should be minimised".
Ms Fenech said fishing could continue only on a catch and release basis.
She also suggested any cuts be covered and the skin rinsed with tap water after swimming in the creek.
Will fish that migrate up and down stream also be contaminated?
Ms Fenech said the highest concentrations of PFAS were likely to be near Mackay Airport "because it directly received run-off from the airport".
"It's too early to say if fish outside the investigation are are also contaminated and to what extent," she said.
Due to the risk of contamination, she said "consumption of fish caught from areas outside the investigation area should be limited to three serves per week."
Although Ms Fenech added this limit was in line with the existing recommended total dietary intake of fish to prevent an unhealthy consumption of mercury.
What are the symptoms of PFAS contamination?
Ms Fenech admitted the symptoms of PFAS exposure were difficult to tell, as only preliminary research had been conducted on the chemical.
A Queensland Health information sheet said limited research into the chemical had revealed consistent health risks.
PFAS contamination is associated with increases in cholesterol and uric acid in the blood, reduced kidney function, changes to immune function, altered levels of thyroid and sex hormones, a later age for starting menstruation in girls and earlier menopause.
Studies have also shown PFAS exposure was linked to a lower birth weight in babies.
The main concern is that PFAS accumulates over years in the body Ms Fenech said.
"It's not deemed as a very toxic substance but it doesn't break down easily," she said.
"They tend to accumulate in the food chain and in human tissue"
"So the best course of action is to minimise exposure"
Queensland Health said the chemical could take between two to nine years to leave the body.
How common is PFAS contamination?
Queensland Health said the chemical's widespread use means PFAS was found at very low levels in the blood of the general population all over the world.
"The general public are exposed to small amounts of PFAS in everyday life through exposure to dust, indoor and outdoor air, food, water and contact with consumer products that contain these chemicals," Queensland Health said.
Incidents of high exposure, such as at Shellgrit Creek, have been recorded across the State, with some councils launching legal action against the Federal Government for damages relating to PFAS contamination.
"There has been a lot of incidents state wide - and nationally," Ms Fenech said.