Researchers are calling for urgent action after a study found thousands of unidentified chemicals on the Great Barrier Reef were being absorbed by green sea turtles, seagrass and coral.
Key points:
- A recent study has found 4,000 chemicals in Great Barrier Reef waters which are affecting green sea turtles
- 1,000 green sea turtles had their blood tested as part of the three-year study
- Turtle rescuers say the number of turtles and hatchlings with abnormalities is increasing
The recent report by Queensland’s Griffith University and the World Wide Fund for Nature Australia tested three sites off Townsville in the state’s north and found more than 4,000 chemicals — many of which could not be identified — in seagrass, coral and, alarmingly, in the blood of endangered green sea turtles.
The researchers are now calling for the monitoring and testing of reef contaminants to be expanded, saying urgent action is required.
Researcher and eco-toxicologist Jason van de Merwe said pesticides and herbicides were among the chemicals detected but some of the results were unexpected.
“We also detected a few heavy metals that we don’t normally monitor for,” Dr van de Merwe said.
But Dr van de Merwe is even more alarmed by the thousands of chemicals that could not be identified and the impact they were having on the health of green sea turtles, 1,000 of which had their blood tested as part of the three-year study.
“Using our databases of chemicals, we weren’t able to identify the names of those actual chemicals,” he said.
“This is telling us that turtles are being exposed to chemicals that we haven’t looked at before [and] without knowing what they are, it’s very difficult to work out where they come from.
Worryingly, Dr Jennie Gilbert, co-founder of the Cairns Turtle Rehabilitation Centre, said she was now seeing deformities and abnormalities in turtle hatchlings, not just adult turtles.
“We’re seeing the abnormalities in hatchlings … the ones in the adults you can put down to [being] hit by a boat or they may have been predated on by a crocodile or a shark,” she said.
WWF marine species project manager Christine Madden Hof said in a statement on the WWF website that it was “staggering” turtles could be absorbing more than 4,000 chemical compounds — and warned that turtles were like “the canary in the coal mine”.
“We suspect contaminants are also impacting the health of other reef species from whales, dolphins, dugongs and sharks through to the fish, prawns and mud crabs caught by commercial and recreational fishers,” she said.
‘Corrective action urgent’
The Great Barrier Reef is the world’s largest coral reef system, spanning an area of 344,000 square kilometres and supporting about 5,500 species.
The Great Barrier Reef Marine Park Authority (GBRMPA) monitors for more than 40 pesticides and studies reef water quality, releasing public reports annually.
But Dr van de Merwe said monitoring needed to be expanded to identify chemical hotspots and new contaminants.
“We do have some really great chemical monitoring programs in the Great Barrier Reef, but they generally focus on pesticides and herbicides,” he said.
“We’d like to see that extended to include pharmaceuticals, heavy metals, other chemicals.”
Ms Madden Hof said the fact that the study showed turtles were being exposed to new and emerging contaminants, made “corrective action all the more urgent”.
The GBRMPA said it was aware of the study, and that it would continue its marine monitoring program to help understand how and where the reef was under pressure, so it could identify ways to enhance protection or recovery.
‘Huge’ abnormalities in turtles
Dr Gilbert has made saving sick and injured turtles her life’s work and is deeply concerned about the impact of marine pollution on turtle health.
She said she was seeing an increasing number of mysterious illnesses affecting the endangered green sea turtles that came into her care.
“We had one come in a couple of years ago that actually was missing an eye and was missing a front flipper,” Dr Gilbert said.
Dr Gilbert said she hoped the research would inform a solution to marine pollution, in particular the various medications identified in the study.
“People are taking antibiotics, people are taking heart drugs, people are taking diuretics and it all goes out into the ocean,” she said.
“What we’ve got to look at is, is there any way of filtering it?”
