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The Sydney Morning Herald ran with an interesting article this morning on pesticide contamination on the GBR. The impacts of herbicides upon coral has been well documented – severely impacting upon developmental stages of coral larvae and actively impairing photosynthesis, resulting in coral bleaching.
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“Pesticides still pouring into reef waters”
The herbicides atrazine and diuron were present at river mouths, inshore reefs and intertidal seagrass monitoring locations, the Great Barrier Reef Marine Park Authority report said.
Monitoring over the past 12 months confirmed pesticides were “an ubiquitous contaminant” in the inshore areas of the reef, the Annual Marine Monitoring Report 2006 said.
The report was released on Friday after the Herald reported concerns in environmental circles that it had been withheld for several months.
Environmental groups say that despite knowing about the problem for decades, the Queensland and federal governments have not done enough to protect the reef from pastoral and sugar cane plantation activities that are pouring mud and chemicals into rivers.
“I don’t think Australians would accept that level of toxicity in the Great Barrier Reef,” said a reef expert at WWF-Australia, Nick Heath. “These pesticides are used on the ground to kill weeds and will have the same effect in the ocean.”
The high level of pollution could not come at a worse time because of the reef’s vulnerability to rising ocean temperatures caused by climate change.
By 2030, coral bleaching – the death of coral caused by the warming of the oceans – could result in a dramatic fall in the number of visitors to the reef.
A recent travel and tourism conference in Sydney grappled with the threat to the reef and other natural tourism attractions such as rainforests from greenhouse gas pollution emitted by, among other things, air travel.
The Reef Water Quality Protection Plan released by the Australian and Queensland governments in October 2003 aimed to halt and reverse the decline in the quality of water entering the reef within 10 years.
The 2006 report, the second annual report so far, indicated that that may be a bigger challenge than originally thought, noting that the use of pesticides in the reef’s catchments had increased in recent years, particularly in agricultural and urban areas.
It singled out diuron and atrazine as the main problems. Diuron is used to control weeds by inhibiting photosynthesis, which means plants cannot convert sunlight into energy to grow. Atrazine, most widely used by the sugar cane industry, is used to control annual grasses and broadleaf weeds by inhibiting photosynthesis.
Mr Heath said that three years ago, in a draft report, the Australian Pesticides and Veterinary Medicines Authority said it believed sugar cane farmers were over-applying pesticides by 75 per cent.
“The next key step would be for the agency to finalise its report with recommendations and I think they should ban atrazine and diuron tomorrow,” he said.
The monitoring also detected banned organochlorine pesticides in mud crabs collected along the reef coast from seven of the 11 rivers sampled. Pollutants detected included PCBs, dieldrin and the breakdown products of DDT. However, the report noted the level of pollutants found in the mud crabs was well below food safety standards and said the tissue sampled was not usually eaten.
“The ecological consequences of chronic low-level exposure to these types of pollutants are yet to be fully understood, although laboratory experiments have demonstrated their acute toxicity to seagrass and corals,” the report said.
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