However, "most treatment plants would not be designed to accommodate that level of shock loading. It's such an unusual event," he added.

Fyfe spoke in general terms about water quality issues, as he is not involved with Shanghai's water treatment.

"If they are chlorinating heavily, which a lot of places may do, especially if they've got a very polluted water body to start with, then the effects could potentially be small," Fyfe said.

Pig corpses that have been in the water for days would leak blood, intestinal fluids and other pollutants, which could alter the taste and color of tap water.

Many residents have begun drinking bottled water due to fears of contamination, according to the Global Times, a Chinese newspaper.

Ripe for satire

The agricultural commission in China said it had tested organ samples from the pigs and the results suggested the animals had contracted a porcine circovirus.

On Tuesday, national officials acknowledged the pig incident in a press conference Tuesday.

"According to monitoring statistics, there's no evidence to show that there's an outbreak of any major animal epidemics," said Chen Xiaohua, the national vice minister of agriculture. "But in the meantime, the incident shows how we need to improve our work in the future."

The situation appeared ripe for satire.

A movie poster for "Life of Pi" was doctored and replaced with "Life of Pigs," with the main character's boat filled with dead pigs, and the water dotted with the bruised corpses.

One weibo user, @Fujiadiandianxiaoya, joked: "I finally figured out why drinking boiled water makes me gain weight -- because it is in fact pork soup!"

Local authorities say they're looking into how the pigs ended up in the river.