Sewage allegedly discharged by local plants have killed huge amounts of aquatic life -- an estimated 60,000 kilograms of fish -- in the Wenjiang section of the Tuojiang River in Zizhong County in Southwest China's Sichuan Province, local environmental officials said.

According to the Zizhong Environmental Protection Bureau, the sewage discharge occurred on Saturday night, leading to heavy losses of fish and contaminated water. Starting Sunday morning, the river turned black and fish began to die, local media quoted fisherman Li Bingyuan as saying.

Local fishery authorities have organized fishing operators to retreat from the polluted areas and asked them not to sell and eat the dead fish.

Within hours, however, the situation became better as the water dissipated, and local people were told they need not worry about their drinking water, officials said.

An investigative team, composed of provincial and county environmental protection authorities, is looking into the accident.

A serious pollution incident in February and March at the Tuojiang River, which feeds into China's main shipping artery, the Yangtze River, caused nationwide attention.

More than 1 million people then were left without potable water for nearly a month after a combination of synthetic ammonia and nitrogen from the No 2 Chemical Fertilizer Plant with the Sichuan General Chemical Group leaked into the river.

The density of ammonia and nitrogen in the affected section of the river was 152 times higher than the national standard when the serious leakage was reported in late March.

The State-owned plant was shut down on March 2. On the same day, local authorities shut down local water supplies.

(China Daily May 5, 2004)