The number of villagers affected by arsenic-contaminated water in Hechi city, the Guangxi Zhuang autonomous region, has increased to 200, according to statistics released by the local government on Wednesday afternoon.
Nineteen victims, including children and an elderly man, were in hospital under observation.
"All of the 19 severely poisoned are in a stable condition, while all the affected are in good health so far," Huang Jiale, director of Guangxi regional occupational disease prevention and control institute, said.
Huang was among the 20 medical experts sent by the provincial government from the local poison and disease and prevention center and Guangxi regional occupational disease prevention and control institute.
Residents of two villages in Hechi began to suffer symptoms, such as facial swelling, vomiting and blurred vision, on Friday.
"Only a small number of the villagers affected show excessive amounts of arsenic in their urine samples, which usually can be cleansed in nine to 15 days in general," Huang said.
The local government carried out urine tests on all 640 residents, but results are yet to be published, the Xinhua News Agency reported yesterday.
Environmental monitoring measures indicated the villages' water source was polluted by industrial waste from a nearby metallurgy enterprise, which has since been closed.
Authorities said torrential rain during Typhoon Hagupit on Sept 25 caused an overflow of wastewater that polluted nearby ponds and wells.
They have been sealed off indefinitely. The local fire brigade has sent safe water to the affected villages at noon and 5 pm every day since Oct 3.
According to industry sources, Hechi stopped operation of all smelting plants on Wednesday for the next two months for inspection.
Hechi is one of Guangxi's most important mineral producers with an annual smelting capacity of 700,000 tons of nonferrous metal.