File photo:Xinhua 

A garbage treatment plant is being held responsible for contaminating residents' tap water in Hangzhou, East China's Zhejiang Province, investigation showed on Friday. The person in charge of the company is currently under criminal detention.

The investigation comes after villagers in a district in Hangzhou expressed worry about long-term damage to their health after their local tap water pipelines were connected with pipelines leading to a garbage treatment site. 

The water quality has returned to normal in the affected Hubu village and water supply resumed on Tuesday after the water quality test was passed, an employee from Hangzhou Water told the Global Times on Friday, adding other areas in Hangzhou were not affected. However, some villagers still dare not use the tap water and demand more investigation. 

Some villagers from Hubu village in Xihu district, Hangzhou, complained to the local water supplier, Hangzhou Water Holding Group, about an odor that was permeating from their tap water on July 26. 

After a preliminary investigation was conducted, the water supplier found that a waste water pipeline from a perishable trash treatment site was connected to the village's water supply pipeline by the employees at the garbage treatment plant. 

The garbage treatment plant, operated by Xihu Environment Group, was put into trial use in 2019 and has been mainly dealing with kitchen waste. Its maximum daily disposal capacity is 10 tons on average. 

Local authorities collected water samples from the village after the report and arranged medical treatment for free to the residents affected by the incident, according to the local mayor hotline staffers. 

A villager, surnamed Feng, told the Global Times that all 1,600 villagers on July 26 noticed the odd smell in the tap water and the water appeared murky.

"It smelled like dead mice," Feng said.

Feng said the tap water was cut off from July 26 and resumed on 28 July after the examination was completed. During this period, the villagers were given bottled water to drink and had to use the mountain spring water to bathe.

"The local government has arranged free inspections to test our intestines, skin, and cause of fever; however we want a full physical examination and full investigation," Feng said.

Some villagers complained on Wednesday that their fellow villagers had symptoms such as allergies, diarrhea and dizziness after they drank the contaminated tap water. 

Several villagers shared photos of rashes on their bodies in their WeChat groups. Others claimed they suffered from diarrhea and itchy skin for unknown reasons. 

Another resident, surnamed Zheng, told the Global Times that some villagers have developed severe symptoms such as diarrhea.

"Me and my family still have diarrhea now," Zheng said.

The water supply company allocated water resources and sent water to villagers around the clock after the incident to ensure the quality of the local residents' water supply. But some villagers still not dare use the tap water and continue to use bottled water provided by the local government. 

"The smell has gone, but we don't dare drink the water as we're worried about residue in the pipe," Feng said.

According to the villagers, the smell started as early as the beginning of the year, and they are worried that they have been drinking the sewage water for months, and may have suffered long term damage to their health.

The villagers said the garbage plant stands on a hill around 300 meters away from their village. 

"We are very worried about it polluting the upstream water source and environment," Zheng said