Water quality in the coastal Zhejiang Province was returning to normal, Chinese officials said Tuesday, more than two days after a collision of two heavy trucks spilled 20 tons of carbolic acid into a river that supplies drinking water for hundreds of thousands of people, including one major city, Hangzhou. A Hangzhou environmental official, Lao Xinxiang, told news agencies on Monday that the spill had fouled drinking water for at least 552,200 people in that city and surrounding communities. Hourly measurements posed on the city’s environmental Web site showed that acid concentrations at one test site had dropped below the safe level of 0.005 milligrams per liter of water, while levels at a second test site remained well above acceptable limits.
Carbolic acid, also called phenol, is a sweet-smelling industrial chemical used to make plastics and a variety of other products. It can cause burns, convulsions and other reactions when swallowed. Authorities said that the spill occurred about 11 p.m. Saturday when a truck carrying 31 tons of the chemical from Shanghai to a factory in western Zhejiang Province broke down on a road just under a mile from the Xin’an River. As workers tried to fix the tanker, it was struck by another large truck, killing one repairman. The collision ruptured the tanker, and heavy rains washed the acid downhill into the river.
Officials fought the spill by increasing the flow from an upstream dam more than fourfold, trying to dilute the acid and wash it downstream. Word of the spill set off panic buying of bottled water in the region, and officials advised residents to refrain from using tap water until an all-clear was declared. By Tuesday, authorities said that water supplies in some cities were safe, but that river water would remain off limits until the bulk of the spill was washed out to sea, according to Tuesday’s English-language edition of Global Times, a Communist Party newspaper.