Green turtles at Upstart Bay, south of Townsville, have among the highest levels of the metal cobalt ever recorded in the blood of an animal and many are now developing a mysterious eye infection.
These are the latest findings from the Rivers to Reef to Turtles research project - led by WWF-Australia and supported by major partner Banrock Station Wines Environmental Trust.
The project was prompted by the mass death of turtles at Upstart Bay in 2012, which remains a mystery.
Researcher C. Alex Villa from the Queensland Alliance for Environmental Health Sciences – a partnership between The University of Queensland and Queensland Health – is lead author of a recent scientific publication based largely on data from Rivers to Reef to Turtles.
“Testing of remote northern Great Barrier Reef turtles from the Howick Group of Islands has revealed, for the first time, the expected metal levels in a healthy turtle population far removed from local human sources of pollution.
“Compared to this baseline, the turtles we tested at Upstart Bay had levels of cobalt in their blood up to 25 times higher.
“For some individuals, cobalt levels were among the highest ever reported in vertebrates to date. At these blood concentrations, we would expect to see debilitating health effects in many animals, including humans,” he said.
Cobalt occurs naturally in soil and rock and can be washed into waterways by rain. It can also enter the environment through mining and ore smelting; and has been used as an additive in livestock feed.
The levels of cobalt, as well as molybdenum and antimony in Upstart Bay turtles were also significantly higher than in populations from the nearby and geologically similar Cleveland Bay, which showed higher levels of other elements such as arsenic.
This suggests the Upstart Bay results could be caused by human activities such as past or present industrial or agricultural runoff. However, the source remains unknown.
Although Cobalt is essential for health, in high concentrations it is toxic to humans and animals alike causing symptoms ranging from nausea and tinnitus through to cardiomyopathy and permanent nerve damage.
Vet-MARTI Director Mark Flint said: “Tests suggest that both coastal populations, but particularly those at Upstart Bay, have compromised health and appear to be impacted by some sort of stressor.
“Of the turtles tested at Upstart Bay, nearly half (44%) had elevated white cell counts – which indicates the prevalence of an active inflammatory response,” he said.
Dr Flint said eye infections were also now emerging as a new problem in Upstart Bay. Of 161 turtles examined in Upstart Bay in 2016, a quarter (42) had mild to severe eye lesions.
“We don’t know why this is occurring. The infection appears to be bacterial and not a virus (like ﬁbropapillomatosis), but we don’t know what caused it in the first place. It could be another indication that this is a population under pressure,” Dr Flint said.
Banrock Station Wetland Manager and Environmental Trust panel member, Dr Christophe Tourenq, praised the project team.
“Banrock is proud to support this project which is breaking new ground in turtle conservation. By providing the first baseline for healthy turtles the project will benefit researchers around the world,” he said.
WWF-Australia marine scientist and spokesperson Christine Hof said: “Existing environmental programs along the Reef coast test for a narrow set of pollutants.
“Turtles are a great biomonitoring tool to check on the health of a marine environment. The results from Rivers to Reef to Turtles show that a wide range of chemicals, including metals, are finding their way into coastal turtles and that governments should be testing for many more pollutants than is currently the case,” she said.
Since 1995, Banrock Station has supported vital conservation efforts across the world, such as the turtle research project with WWF-Australia. To date the Banrock Station Environmental Trust has donated approximately $6million (AUD) to more than 130 projects in 13 countries.
Rivers to Reef to Turtles is supported by major partner Banrock Station Wines Environmental Trust, and involves WWF-Australia, TropWATER (James Cook University), QAEHS/Entox and Vet-MARTI (The University of Queensland), the Queensland Government, the Great Barrier Reef Marine Park Authority (GBRMPA), Griffith University, and other collaborative partners.
Mark Symons, WWF-Australia Senior Media Officer, 0400 985 571, email@example.com