- Toxic chips of paint flaking away from the hulls of ships
may affect the sex life of Antarctic marine animals, say Australian and
New Zealand researchers.
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- The paint contains the chemical tributyltin (TBT), which
the researchers say has been flaking away from icebreakers as they plough
through thick ice fields.
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- The researchers are concerned as this is the first time
that TBT, a known disrupter of marine life, has been found in
Antarctica.
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- Researchers led by toxicologist Dr Andrew Negri from
the Australian Institute of Marine Science (AIMS) in Townsville published
details of the contamination online ahead of print publication in the
Marine
Pollution Bulletin.
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- Negri and team found TBT in sediments from the Ross Sea,
off the east coast of Antarctica.
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- TBT is a made almost exclusively as an ingredient for
marine antifouling paints to prevent the growth of organisms such as
barnacles
and algae on ships' hulls.
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- As well as icebreakers, Negri said that tourist ships,
supply ships and fishing vessels could be responsible for the
contamination.
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- "People in Antarctica have told us they see paint
on the ice where it's scraped off from the ships," he said.
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- "We have spoken to paint companies who supply
antifouling
paint and they confirmed that TBT was being used on ships regularly going
to Antarctica."
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- In some areas the researchers found concentrations of
1000 micrograms of TBT per kilogram of sediments.
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- This is the same as the concentration found in Queensland
in November 2000 when a ship collided with Sudbury Reef east of Cairns,
scraping antifouling paints onto rocks and sediments of the coral
reef.
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- The Great Barrier Reef Marine Park Authority said this
cost A$2 million (about US$1.4 million) to clean up and monitor.
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- And the researchers said the TBT caused marine snails
there to have an unwanted sex-change.
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- Marine snails change sex depending if that improves their
chance of reproducing.
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- AIMS microbiologist Dr Nicole Webster said the effect
on the snails in Antarctica could be drastic as snails reproduced very
slowly in cold temperatures.
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- The TBT could also affect the ability of sponge and coral
buds or larvae to settle on the sea floor, said Webster, and could have
a longer-term affect on animals higher up the food chain, such as marine
mammals.
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- The team found TBT in marine sediments near the research
station Scott Base, operated by New Zealand, and the U.S. McMurdo Station,
which are serviced by large icebreakers. They also found TBT at two
pristine
sites further from the bases.
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- TBT is banned on ships smaller than 25 metres and is
being phased out on larger ships. But its replacement, a copper-based
paint,
is also acutely toxic to marine invertebrates, Webster said.
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- "In tropical waters where there is a lot of algal
growth they really need to use antifouling paints," she said. "In
Antarctic water maybe these heavy duty antifouling paints aren't
necessary."
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- She said this was because algae and barnacles grow more
slowly in colder waters and don't significantly foul the hulls of ships
travelling there.
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- ©2004 ABC
- http://www.abc.net.au/science/news/stories/s1114758.htm
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