After more than three weeks of suffering due to a chemical slick, the levels of toxicity in the stretch of the Songhua River in Harbin, capital of Northeast China's Heilongjiang Province, have returned to normal.

Local officials have now pledged to focus on restoring day-to-day life, and examine the long-term impact of the accident.

"It is now time to switch our attention from emergency prevention to appraisal work of the impact of the slick on the ecology of the Songhua River, and also speed up our attempts to resume normal business and social order," said Zhang Zuoji, governor of Heilongjiang Province.

The toxic slick was caused by a chemical plant blast on November 13 in Jilin City, Jilin Province, which led to more than 100 tons of chemicals, mainly benzene and nitrobenzene, entering the adjacent Songhua River.

The toxic slick forced Harbin, with an urban population of 3.8 million and Dalianhe, where 26,000 out of the 36,000 residents rely on river water as their drinking water source, to cut their water supply for several days.

By 8 am yesterday, the concentration of benzene and nitrobenzene at all water checking stations within the precinct of Harbin remained under the national standard, which means the toxic slick has passed through, sources with the Heilongjiang Provincial Environment Protection Bureau said.

And yesterday, Dalianhe, which cut its water inlet from the river on November 30, resumed water supply both for industrial and civilian use, although the local government advised residents not to drink it before receiving the go-ahead from the local health bureau.

By noontime yesterday, the front of the contaminated water arrived at Suibin County, Jiamusi, the second major city in Heilongjiang to be affected.

Residents' life has not been affected as they mainly rely on underground water sources.

No poisonous pollutants were detected in the drinking water in Jiamusi, which has an overall population of more than two million, according to Jiamusi Environment Protection Bureau.

There are still some 200 kilometres before the slick reaches Tongjiang, where the Songhua River joins the Heilong River, the border river between China and Russia.

Source: China Daily