Sat, Nov 13, 2004 - Page 2 News List

Scientists: contamination leading to abnormalities


There are recent signs that chemicals in Taiwan's increasingly polluted environment may disrupt endocrine systems in human and wildlife populations, researchers said yesterday.

At an international conference on environmental hormones and what's known as "persistent organic pollutants," Lee Ching-chang (李俊璋), director of the Research Center for Environmental Trace Toxic Substances at National Cheng Kung University, reported his investigation on the levels and spatial distribution of toxic chemicals in 21 main rivers, four international harbors and 17 fishing ports in the country.

"We found that levels of total mercury in the sediment and fish samples of two rivers were higher than the rest. The sources [of the mercury] have yet to be identified," Lee said.

Around the world, scientific evidence is mounting that suggests that exposure to certain toxic chemicals in industrial waste has caused abnormal growth in shellfish and slowed the breeding rate of aquatic creatures.

Lee measured the levels of mercury, polychlorinated biphenyls (PCBs), organochlorine pesticides, phthalates and others in his report.

He said that the sediments and fish samples in 17 harbors collected from 2001 to 2003 contained higher levels of tributyltin (TBT) than previous samples collected in 1990 and in 1997. TBT is a chemical compound used in paint to keep ships' hulls clear of marine life.

"The result suggests that the coastal areas of Taiwan have been seriously polluted by TBT," Lee said.

Meanwhile, researchers in Taiwan also found the high levels of TBT are associated with a phenomenon whereby female oysters develop male sexual characteristics. Western scientists have also confirmed that TBT boosts the production of testosterone in female mollusks, causing them to change from female to male.

Officials of the Environmental Protection Administration (EPA) told the Taipei Times yesterday that the use of TBT for boats less than 24m long has been prohibited since last year.

"Although we have not regulated the use of TBT for large international merchant ships, we at least limit the spread of TBT by regulating local small boats," Yuan Shaw-ying (袁紹英), the deputy director-general of the Bureau of Environmental Sanitation and Toxic Chemical Control, said.

Yuan said the poisonous, hormone-disrupting compounds have been used in ships' paint for decades, leaving a toxic legacy around the world. But the EPA will tighten its regulations if other countries decide to ban the use of TBT.

In addition to coastal pollution, researchers said that freshwater pollution has also caused abnormalities in other creatures such as the South American apple snail (福壽螺), introduced into Taiwan in late 1970s. Now, the spread of the apple snail seriously jeopardizes many crops, such as lotus, rice and water chestnut. The apple snail has been listed as a hazardous introduced species by the Council of Agriculture.

Liu Li-lien (劉莉蓮), a marine biologist from National Sun Yat-sen University, also observed the sex change phenomenon in apple snails in a study she finished last year.

"We found that the change from female to male in apple snails could be linked to the overuse of pesticides containing triphenyltin, which is considered to be an endocrine disruptor," Liu said.

At yesterday's conference, Louis Guillette, a zoologist from the University of Florida, presented a report discussing how aquatic ecosystems are increasingly at risk because of chemical contamination.

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