Environmental protection authorities have denied claims that a chemical agent in salt used for de-icing roads contaminated drinking water supplies in northern Guangdong province, the People's Daily reported yesterday.

About 10,000 residents in the province's Shaoguan area were facing a drinking water shortage because of the agent, local media had reported.

Scientific research has found that ingestion of 0.3 to 0.5 g of nitrite, a type of industrial salt, can be fatal.

The salt had allegedly been used on the Ruyuan-Lechang section of the Beijing-Zhuhai Expressway to thaw heavy snow and ice before the peak Chinese New Year travel period, when most of the country's southern regions were hit by the heaviest snows for decades.

Residents along the route reportedly suffered headaches, fever and vomiting after drinking contaminated water supplies.

The People's Daily, however, said the State Environmental Protection Administration and the Shaoguan municipal bureau of environmental protection had inspected local water quality.

The departments said they had found that common salt had been used to de-ice the roads and there was no danger to health.

Inspections on several water resources carried out on Sunday by the Shaoguan municipal environmental monitoring center (SMEMC) also found no link between the de-icing agent and water quality.

"We actually used 600 tons of edible salt on a 30 km-plus section, and it fused into surfaced water with melted snow because of the warm weather recently", a worker at Shaoguan's Salt Industry Corporation said.

The chloride content in drinking water sources in the villages of Gengxia and Keshuxia were 122 and 26.9 mg per liter, respectively. They were both within the national safety level of 250 mg, the SMEMC found.

The center also inspected the water quality along the Ruyuan section of Bejing-Zhuhai Expressway and found nothing amiss.