China has suspended approval of, or rejected, proposed industrial plants worth billions of dollars because they could threaten the environment, an environmental chief said Wednesday.

Pan Yue, deputy director of the State Environmental Protection Administration (SEPA), said his bureau suspended approval for 44 proposed industrial plants and rejected plans for another 16 in the first quarter.

The plants would have been worth a total of 189.5 billion yuan (23.6 billion dollars) in investment, said the bureau's website.

The location of scores of chemical, petrochemical and power plants along major rivers means they still pose a major risk to the environment, according to the bureau's interim results from a major assessment.

Many industrial areas are close to the upper reaches of rivers or are too near residential areas and many have not carried out environmental risk assessments, thw website quoted Pan as saying.

"This is to say, when the chemical and petrochemical industries planned their location, there was much consideration on the economic development and few on environmental protection," Pan said.

The risk assessment, launched two months ago, was carried out on 127 chemical and petrochemical plants, with some 450 billion yuan (55.7 billion dollars) in investment. They were considered key plants.

SEPA, once seen as a powerless agency, has been given a new lease of life since the government of President Hu Jintao and Prime Minister Wen Jiabao came to power in 2003.

The assessment was carried out after a toxic spill in the northeast in November shut down water supplies from the Songhua river to four million residents in the city of Harbin, while threatening Russian water supplies down river.

"There have been 76 incidents related to water pollution since the Songhua incident, more than the total in 2005," Pan said.

A combination of rapid economic development and continued population growth means China is putting unsustainable pressure on its water resources.

Previous government reports have said that more than 70 percent of China's rivers and lakes are polluted, while underground water in 90 percent of Chinese cities is polluted.