Residents warned off polluted river’s fish

Residents have been warned not to eat fish from the Beiyun River as the water is polluted.

According to the Sina microblog of Beijing Water Authority (BWA), after a dredging project started in the Tongzhou district section of the river on March 13, many local residents went to the river to catch fish which had become stranded in the mud.

"These fish are not suitable to eat," BWA posted.

Beiyun River is the largest and one of the most polluted water systems in Beijing.

Water in China is rated on a scale of one to nine, with water from levels five to nine rated as dangerous to human health and unusable even for industry.

According to the latest statistics available on BWA's website from December, 2012, of the Beiyun's 48 tributaries, 34 are rated worse than grade five.

Kang Tianfang, a professor in environmental science with the Beijing University of Technology, said that if it is rated worse than grade five, the river is seriously polluted.

"Fish living in this kind of water may have toxins in their bodies and are not fit for consumption," said Kang.

Much of the city's sewage flows into the Beiyun River, the Beijing Evening News reported in January.

Zhu Yi, a professor in food security at China Agricultural University, said that toilet sewage contains antibiotics and hormones, which collects in fish in polluted water.

"Eating these fish may not kill you, but will certainly bring negative effects. Some may think keeping the fish in fresh water for some days will help clean up the toxins but it won't. These fish should not be anywhere near the table," Zhu said.