Just as authorities pulled the last of thousands of dead pigs from Shanghai’s main waterway, hundreds of duck carcasses were found in another Chinese river, state media reported Monday.

At least 1,000 dead ducks inside 50 woven bags were fished out of a section of Nanhe river in Pengshan country, Sichuan province, the official Xinhua News Agency said.

Officials were unable to determine the cause of death as some of the ducks were already decomposed, said Lian Weidong, a deputy director in Pengshan’s publicity department, BBC reports.

Local residents and livestock were not at risk as the river was not used for drinking water, officials added. The ducks had been disinfected and buried in plastic bags three meters underground, according to Xinhua.

The report came as the toll of dead pigs pulled from Huangpu river in Shanghai reached 16,000, prompting public criticism over China’s troubles with food safety and environmental issues.

“Dead pigs, dead ducks… this soup is getting thicker and thicker,” wrote one user on microblogging site Weibo, China’s version of Twitter.