Crew have pulled more than 7,500 carcasses from the Huangpu River in the past week, RIA Novosti reported Friday. The river provides water to 22 percent of the people in Shanghai, but city officials insist the water has not been polluted by the rotting animals.
Tests performed on the carcasses found at least some of them died of circovirus, which cannot be passed to humans. Ear tags on some of the pigs identified them as coming from farms in Jiaxing, a city northeast of Shanghai.
Farmers in Jiaxing admitted dumping the animals in the river, but said the pigs did not die of any disease communicable to humans.
Authorities in Jiaxing said poor farming practices and extreme weather have killed 70,000 of its 7 million pigs since January.
Chinese farmers are paid $13 for every pig sterilized and buried in accordance with the law. That compensation is considered too small and can take months to collect, media reports indicate.
The fine for dumping pigs is $320.