The number of dead pigs found in Chinese rivers has risen to 16,000 as of this week, and 1,000 ducks have now been found floating down the South River in Pengshan county.

The dead pigs were recovered within the last two weeks in rivers that supply water to Shanghai. The government said 10,570 carcasses had been pulled from Huangpu River and 5,528 were removed from upstream tributaries in Zhejiang province's Jiaxing area.

More from GlobalPost: 900 pigs found floating dead in Shanghai river

No official explanation has been given for the massive pig-carcass dumping, but authorities have assured the public that tests have shown Shanghai's water to be safe.

More than 1,000 dead ducks were also found floating Pengshan county's South River on Tuesday. A resident phoned the environmental protection office, saying the ducks were giving off a terrible smell, leading officials to rush to the scene.

The carcasses were found in varying degrees of decay, with some wrapped in white bags. They were thought to be piled up downstream a few days earlier — by whom, no one knows — and had gradually been washed along by the river.

No one knows why the ducks were disposed of on the riverbank, but hog farmers have said that pig carcasses were being dumped because the police cracked down on the illicit sale of pork products made from dead and diseased pigs.