Shanghai authorities say water quality in the main part of a river where thousands of dead pigs have been found since last week has been restored to a level meeting mainland standards and that no diseased pork has been detected in markets.
In a statement released on the municipal government's website yesterday, the authorities said the retrieval of dead pigs from a section of the Huangpu River flowing through the southwestern Songjiang district was "basically" complete. Clean water supplies had been restored in the town of Maogang, where the carcasses were first discovered.
The water quality of the river in Songjiang met standards, according to hourly tests by the district's water affairs bureau.
Meanwhile, food safety regulators across the city had ramped up inspections of pork supplies and had found no sign that diseased pork had entered the city's markets, the statement said.
Songjiang's district government said it had adopted a series of measures to tackle the crisis, which had seen more than 5,900 dead pigs pulled out of the Huangpu River by yesterday afternoon, including workers adding no less than 20 parts per million of activated carbon into the affected water, and adding extra chlorine. Workers from the local tap water plant had been testing water within a kilometre upstream and downstream of the water intake point.
Local officials said tap water was safe mainly because there was a lot of water in the affected section of the river, the water intake point was far from where most of the dead pigs were found and a high percentage of the carcasses were intact.
However, some locals said they were still worried. Dora Wang, a marketing manager who lives in Jiuting town in the district, said she was concerned about the quality of her tap water.
"The government's statement has been some consolation, but I am still concerned," she said, adding that the dead pigs had reminded her of another water crisis in the district two months ago, when a factory had dumped chemical waste in a river. Many residents had to be evacuated then and tap water supplies were halted temporarily.
"I am thinking about whether I and my family should only drink bottled water and should I install water-purifying equipment [in my house]."
Yang Jing, a member of the medical staff at a hospital in Songjiang, said she was "numb" towards the authorities' efforts to ensure water and food safety.
"I don't think officials regard these problems seriously [...] nothing safe here," she said.
The propaganda chief of the neighbouring city of Jiaxing, in Zhejiang , denied claims by Shanghai that it was the source of most of the dead pigs.
"[The origin of the carcasses] is not 100 per cent sure and investigations are ongoing," Wang Dengfeng told a press conference, xinmin.cn  reported.
Shanghai's animal disease control department has found porcine circovirus, a common pig disease that is not known to be infectious to humans, in a sample taken from the carcasses.
Professor Zhu Guoqiang , a veterinarian at Yangzhou University in Jiangsu , suspected an epidemic. He said there was almost no possibility that the pigs had been killed by cold weather, as claimed by Zhejiang's agriculture department.