A concerning rate of "mutant toads" with extra limbs and missing eyes are being found in the industrial Queensland city of Gladstone.
Scott Wilson from Central Queensland University said up to 20 per cent of cane toads in certain areas in Gladstone were found with "malformations", compared with 1 per cent of the population in non-urban areas.
On average, between 6 and 8 per cent of 10,000 cane toads examined across the Gladstone region have been found with abnormalities in the past three years.
This cane toad caught in Gladstone was found with an extra leg growing from its sternum. Photo: Supplied
Cane toads have been found with a fifth leg growing from their chest, while others have been found with missing limbs.
The toads are caught for environmental research by a council-run team of Gladstone Toadbusters. The group catches as many as 500 toads in an hour.
Gladstone is home to a coal-fired power station, two aluminium refineries, and a developing liquefied natural gas industry.
But Dr Wilson said the city's heavy industry was not necessarily to blame for malformations in the toads.
"In fact I did some preliminary work in Sydney with native frogs and found abnormalities in around 6 to 8 per cent of the population there," Dr Wilson said.
The mutations in Gladstone's cane toads could therefore spell problems for native frogs in the region too.
"Cane toads are to the fresh water environment, what canaries were to coal mines," Mr Wilson said.
High exposure to ultraviolet radiation and parasites, as well as chemical runoff and airborne pollution can contribute to abnormalities in the amphibians.
"There are a multitude of potential causes," Dr Wilson said. "What might be happening at one site could be different to what's happening at another."
He said further funding was crucial for continued analysis.
"Definitely, follow-up studies are needed. We've seen malformations constantly over the past three years, and we need to find out why," Dr Wilson said.
The water quality and health of fish in Gladstone Harbour has been in sharp focus in recent years.
Temporary fishing bans have been imposed on the central Queensland harbour, after fish with skin lesions and cloudy eyes were found.
In 2011, 231 turtles and six dolphins were found dead in Gladstone.
Fishermen have blamed the water in the harbour for causing the problems, suggesting large-scale dredging had stirred up contaminants.