Despite pledges on water safety by Shanghai authorities, public concerns remain after reports that another 300 dead pigs were found floating in the upper Songjiang section of the Huangpu River.

Xu Rong, head of Songjiang district's environment department, told online portal xinmin.cn that on Sunday morning 300 pig carcasses were retrieved by local authorities.

Twelve boats are working to retrieve the carcasses, which will be treated for potential biohazards, Xu said.