LHASA, June 6 (Xinhua) -- Chinese environmental scientists said they had found no evidence of damage to the environment along the world's highest Qinghai-Tibet Railway a year after it went into operation, but intensive studies were needed on the long-term impact of the railway on the environment and wildlife in the area.

    The landscape, lakes and the frozen earth are well preserved and wildlife migration patterns have not changed, according to a panel of officials and experts from the State Environmental Protection Administration (SEPA) and the Ministry of Railways, as well as Tibet and Qinghai Province.

    The panel has completed a three-day on-the-spot inspection from May 30 to June 1 for an environmental impact assessment of the Golmud-Lhasa section, which runs through the frozen earth zone and some wildlife migration routes.

    The latest assessment report gave the thumbs-up to the ecological protection and pollution control measures implemented.

    Chinese media have carried spectacular photos of antelopes crossing under the Qinghai-Tibet railway via some of the 33 special passageways built to enable animals to follow their normal routes without being hampered.

    But the existence of the passageways has not been wholly successful: some bears and wild yaks have been hit by trains.

    "Some passageways have had to be closed. We need to study the impact of these closures on wildlife migration," said Zhu Xingxiang from the SEPA.

    "We have set up a long-term system to monitor water, air, noise and ecology at all times," said Zhang Tianhua, vice head of the environmental protection bureau in southwest China's Tibet Autonomous Region on Tuesday.

    "Every train running on the Qinghai-Tibet Railway has special tanks for storing garbage and waste water. Waste is collected from the trains and treated in designated stations," said Zhang.

    A total of 60,000 tons of waste collected from the Qinghai-Tibet Railway stations has been treated so far and no pollution incidents have been reported, he added.

    The assessment claimed that 96.9 percent of the residents along the Qinghai-Tibet railway are satisfied with the environmental protection measures adopted by constructors.

    Cering, a villager from the Tibetan ethnic group in Qinghai Province, said the constructors did a good job protecting the environment and the project had not had an adverse impact on their pasture.

    "It's excellent that they established special passageways for Tibetan antelopes and other animals to move freely," Cering told Xinhua.

    The 1,956-kilometer-long Qinghai-Tibet railway is not only the world's highest and longest plateau railroad. It is also the first railway connecting Tibet with other parts of China, and has triggered a tourism boom in the autonomous region.

    Last year Tibet received 2.5 million tourists, an increase of 39.5 percent over the previous year. Local tourism officials said the number of tourists to Tibet would likely rise to 3 million this year.

    But the environment does not appear to have suffered. A regional environmental report published Tuesday says Tibet remains "one of the regions in the world with the best quality in terms of the environment."

    Construction of the Golmud-Lhasa section of the Qinghai-Tibet railway cost more than 33 billion yuan (about 4 billion U.S. dollars). Of the total 1.5 billion yuan, or 4.6 percent, was used for environmental protection, a record high in China's history of railroad construction.