ICE-BREAKERS are polluting Antarctica鈥檚 supposedly pristine seas with toxic chemicals. Samples collected from the ocean floor at McMurdo Sound have been found to contain high levels of tributyltin (TBT), a key component of antifouling paints used to coat the ships鈥� hulls. The site is close to a turning circle used by ice-breakers cutting paths for tourists and scientists visiting US and New Zealand bases.
鈥淭he levels are close the maximum you鈥檒l find anywhere, apart from ship grounding sites,鈥� says Andrew Negri of the Australian Institute of Marine Science in Townsville, Queensland, who led the study, which will be published in Marine Pollution Bulletin.
Antifouling paints kill algae, barnacles and other marine life that sticks to ships鈥� hulls. They also harm non-target organisms 鈥� notoriously, causing female dog whelks to grow rudimentary penises that prevent them from reproducing 鈥� and this has led to an International Maritime Organization proposal to ban TBT-based paints by 2008. But the replacements, which contain copper and herbicides, will also kill non-target organisms, critics say.
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Martin Riddle of the Australian Antarctic Division in Hobart, Tasmania, says there is no need to use antifouling paints on ice-breakers as the passage of the boats through the ice itself dislodges most organisms from the hull.