from the whaddya know files:

http://www.news.com.au/common/story...55E3462,00.html


Warning call of the wild
By SIMON BEVILACQUA
September 26, 2004

PLATYPUSES are the coalmine canaries for our environment.

That is why the discovery of surprisingly high levels of PCBs in platypuses, as revealed in the Sunday Tasmanian last week, concerns scientists.
PCBs are highly toxic man-made chemicals, contained in paints, oils and industrial waste.

The chemicals contaminate creatures low on the food chain.

The toxins, stored in fat, concentrate in the higher animals.

So, when a platypus eats contaminated freshwater crayfish, PCBs accumulate in the monotreme's fat.

Tasmanian researcher Niall Stewart has checked the tail fat of local platypuses and discovered organochlorines, including PCBs, DDT and Lindane.

The study by Dr Stewart, Swedish PCB researcher Anders Sodergren and the late Barry Munday, was published in 2001.

"These results indicate the platypus, which feeds on invertebrates, acts as an excellent bioindicator for environmental pollution," their study said.

The researchers said the study suggested there was widespread distribution of pollutants in Tasmanian aquatic ecosystems.

"Since the concentration of these compounds generally increases along the food chain, studies are urgently required to determine PCB concentrations in trout and other food fish for evaluation of potential risks for human consumption," the study said.

Organochlorines have been found in the fat of humans, whales, bears and dolphins.

Their accumulation in the breastmilk of mothers raises concerns about impacts on childhood development.

Virtually everyone has PCBs in their body. A study of country Victorian mothers found 25 per cent of samples of human milk in which PCB was detected were higher than the US Acceptable Daily Intake concentration.

The International Agency for Research on Cancer ranks PCBs as probable human carcinogens, and a major concern is the effect organochlorines have on sexual development.

These chemicals are shown to impact on the sex ratios of bird populations and cause abnormal development of sex organs.

The World Health Organisation warned the long-term effects of gender bending chemicals on health and fertility could be a nightmare waiting to unfold.

Fish, seals, panthers, crocodiles and polar bears are among animals born with female and male genitals or sexual abnormalities, and some scientists point the finger at post war chemical pollution.

Tasmanian authorities have taken blubber samples from dolphins, whales and seals. Organochlorines were detected but some research suggested levels had decreased since similar tests in the 1970s.

Australian fur seals from Bass Strait tested positive to PCBs.

Antarctic Wildlife Research Unit director Mark Hindell said samples were taken from stranded whales.

"They had levels of PCBs. Although they were lower than in the northern hemisphere, they were still quite high," Dr Hindell said.

"The problem is we don't know what is too high, we don't know what levels are dangerous."

Veterinary pathologist David Obendorf said organochlorines in Tasmanian platypuses should spark a major monitoring program.

"The platypus, higher up the food chain, is the canary in the coalmine," Dr Obendorf said.

The Sunday Tasmanian


This report appears on NEWS.com.au.

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