Experts from the Chinese Research Academy of Environmental Sciences, Chinese Academy of Sciences, Peking University and Tsinghua University have been discussing the bloom of blue-green algae afflicting Taihu Lake.

They have identified the algae as microcystis.

Professor Yu Shunzhang from Fudan University told China Daily that microcystis is the most poisonous of blue-green algae, giving out microcystin, a poisonous substance harmful to both plant and animal life.

The Chinese Academy of Sciences' ecology center tested water from the lake, from which the Gonghu Tap Water Firm sources its raw material.

They discovered that every liter of water contained 0.06 mg of microcystin. The national and World Trade Organization quality standard for surface water is 1 mg per liter.

"Since we have tested lake water, it is safe to assume that the tap water in Wuxi is very safe," Yu said. "And water from the lake goes through several processing procedures before it becomes tap water."

According to information from Wuxi's disease control center, there has been no change in the frequency of epidemic diseases related to drinking water this year.

Yu attributed the bloom to a high concentration of nutrients off which the blue-green algae feed. The condition is known as rich nutritional pollution.

Industrial pollution and human waste have introduced large amounts of phosphorus into the water, which nourishes the algae. However, rich nutritional pollution has become increasingly evident in the past few years. Experts warned that if pollution emissions cannot be controlled in the short term, blooms of blue-green algae will happen again.

A man surnamed Ding from Wuxi was arrested on June 6 for distributing mobile phone text messages that claimed Taihu Lake contained large amounts of cancer-causing chemicals, which was later proved to be untrue.

The text message quickly made its way around Wuxi over the course of several days, causing a general panic. Police traced the message back to Ding before making an arrest.

The message said Taihu water contained "200 times more harmful material than the national standard", but the Wuxi disease control center rejected these claims.

The temperature in Wuxi has risen past 31 C in the past few days. The heat wave could also lead to fresh blooms of blue-green algae, experts warned.

(China Daily 06/13/2007 page4)