A senior scientist warned Sunday that human carelessness is putting the delicate ecological balance of Mount Qomolangma in peril.

China Association for Scientific Expedition President Gao Dengyi revealed an alarming 615 tons of waste were dumped by visitors to the peak between 1921 and 1999.

Gao asked the central government to establish a national station to strengthen environmental monitoring and research on the world's highest peak.

"The effort will not only benefit China but the rest of the world," said Gao, adding that data collected on the mountain could shed more light on global environmental and climate change trends.

Gao, whose team at the Chinese Academy of Sciences has researched the mountain since the 1960s, said: "We need the government's backing to continue the effort."

Further activities are required to increase environmental awareness and cut pollution on the mountain.

The greater popularity of the mountain is taking its toll, with its snow becoming increasingly contaminated by DDT and lead.

"We have monitored more and more poisonous elements on the mountain," Gao said.

"The waste left behind has resulted in a worse environment there," warned Gao.

Gao, who has also been conducting environmental research on the Qinghai-Tibet Plateau since the 1960s, said that the hole in the ozone layer over the plateau has not expanded in recent years.

"Ozone depletion over the plateau was not caused by human activity, so it didn't change much during previous years," said Gao.

In fact, there is no "hole" over the region and the amount of ozone is just less than other parts of the world, excluding the Antarctic and Arctic, Gao said.

"So far, the ozone layer above the Qinghai-Tibet Plateau can ward off ultraviolet radiation," said Gao.

But the ozone holes above the North and South poles are extending, said Gao. Each spring, when the sun rises over Antarctica, chemical reactions involving chlorine and bromine from man-made CFCs (chlorofluorocarbons) and bromine-containing compounds occur in the stratosphere and destroy ozone, causing the ozone hole. This also happens over the Arctic.

"But the ozone depletion area over China's sky is caused by meteoric and geological factors."

The low ozone area over the plateau has been formed by atmospheric convergence and divergence near the plateau's surface and in the sky, scientific data has shown since 1987.

Despite that, China has been working with the international community to protect the world's ozone layer for many years.

With the help of funds donated by the international community and measures taken by the Chinese government, the country has achieved a great deal in stopping the production and consumption of ozone depleting substances.

For example, figures from the State Environmental Protection Administration show that the production of CFCs in China now stands at nearly 30,000 tons a year, down from 45,000 tons in 1999, when the country started to phase out CFC production. By 2010 -- as agreed by the Montreal Protocol -- China will have ended CFC production.

China has received US$450 million from the Multilateral Fund for the Implementation of the Montreal Protocol since 1992 and more than 200 projects have been started.

(China Daily August 9, 2004)