Photo: hb.xinhuanet.com

Yangtze River protection authorities have reassured the public that the 33.9 billion tons of industrial waste poured annually into the Yangtze River would not degrade the quality of drinking water.

Zang Xiaoping, the deputy director of Yangtze Valley Water Resources Protection Bureau, said Saturday that the water quality of the Yangtze River was generally better than other rivers in China, and 86 percent of the Yangtze River region met standards set for drinking water, the Wuhan Evening News reported Sunday.

According to Zang, compared to the 1 trillion tons of water the Yangtze River pours into the sea annually, about 30 billion tons of wastewater was only a small portion and would not heavily affect water quality.

Ma Jun, director of the Institute of Public and Environmental Affairs, told the Global Times Sunday that pollution in the Yangtze River still poses a threat to human health despite the relatively small portion of wastewater.

"The main stream of the Yangtze River has a higher quality than that of other rivers in China due to its massive flow," Ma said, "but the water quality of branches of and lakes connected to the Yangtze River might easily be polluted."

"The self-purification capacity of branches and lakes is weaker than that of the main stream," Ma said, "the water flow of branches is smaller, and lake water is almost still. If we ignore the protection of the branches and lakes of the Yangtze River, drinking water from them will also threaten our health."

According to Zang, the monitoring of wastewater poured into the Yangtze River is tightening, especially since 2007.

"2007 was the turning point for the prevention of water pollution of the Yangtze River," said Zang, "Between 2005 and 2007, the wastewater poured into the Yangtze River increased by 4 percent annually, but since 2008, the rate of increase yearly is down to 2 percent."

According to Zang, the situation in major cities along the Yangtze River is under control at present, but small industrial cities with outdated pollution control technology have been the main cause of Yangtze River pollution.

On November 10, 51 illegal concentration plants which discharged wastewater into the Yangtze River without appropriate treatment were shut down by the government in Ezhou, Hubei Province, a city located along the River, according to the People's Daily website.

Ma told the Global Times that apart from small factories with substandard pollution control technology, some construction should also be considered as a factor which aggravates the problem.

"The construction of reservoirs, known as the South-North Water Diversion Project, in the upriver section of the Yangtze River might reduce the water flow of the river, which will diminish its self-purification capacity," said Ma.