POLLUTANTS BLAMED FOR DUAL-SEX POLAR BEARS
Times of London (TL) - Monday, June 1, 1998
By: Nick Nuttall, Environment Correspondent, in Tromso
Section: Home news
Word Count: 534
SCIENTISTS have discovered polar bear cubs with both male and female sex organs. The deformities are thought to be linked to the increasing pollution in polar regions.
The four hermaphroditic bears were found in the Norwegian Arctic territory of Svalbard, where pollution levels are known to be high. Government officials and the researchers who found the newborn cubs on the islands of Edgeoya and Hopen suspect that the deformities are caused by polychlorinated biphenol chemicals (PCBs).
The chemicals, which accumulate in fat reserves, are used in everything from electrical transformer fluids to degreasing agents in nuclear submarines, and are building up in the seals on which the polar bears feed. PCBs are among the thousands of man-made substances that scientists believe mimic animal and human sex hormones. Sex changes in fish have been monitored in Britain and in alligators in America, but the polar bears are believed to be the first mammal to show such acute damage. Dagfinn Stenseth, the Norwegian Governments special adviser on polar affairs, said yesterday that the findings had implications for wildlife and human beings. "The polar bear, like us, is at the top of the food chain. We are very concerned," he said.
PCBs are banned in many countries, although Russia is believed still to use them. They are persistent pollutants that remain in the environment for many years.
The polar bear research adds to worldwide attempts to identify possible links between man-made chemicals and sexual deformities and diseases in human beings, as well as animals. Over the past 50 years, sperm counts have fallen in men living in industrialised countries. Some of the chemicals appear to mimic the female hormone oestrogen, while others appear to block or copy the male androgen hormones.
A spokeswoman for the Norwegian Polar Institute, said researchers had studied 90 polar bears this season out of the territorys population of some 2,000.
Andrew Derocher, the research scientist who made the findings, said yesterday that the bears were seen in April and May. The researchers had been discovering polar bears with both female and male characteristics for three years, he said, but this years tally was the highest so far. It means that bears with both sex organs may make up nearly 4 per cent of the population, which is far higher than chance, and indicates that up to 80 polar bears in Svalbard may now be affected. "What we dont know is if this phenomenon is circum-polar or just confined to polar bears in the Barents, which is more polluted," he said. Details of the findings have been published during the 22nd Antarctic Treaty Consultative Meeting, taking place in Tromso, Norway. Delegates from 43 nations that have signed the treaty, including Britain, are discussing how best to deal with a string of threats to the continent in the wake of the ratification of the Protocol on Environmental Protection earlier this year. The Norwegian findings relating to the Arctic, which is better studied, have strengthened moves to increase monitoring of wildlife and the environment in the Antarctic. Over the weekend, delegates agreed that a comprehensive report on the Antarctic environment, drawing on studies from countries such as Britain, was a priority.