The corpses were discovered near a bridge in Jining, a city in Shandong province on China's east coast, abandoned there by staff at a local hospital morgue, according to Chinese news reports that have stirred sharp public criticism.
Authorities have not said how the infants and fetuses died, but news reports said some of the fetuses had been aborted.
Police and medical investigators found that two morgue workers, Zhu Zhenyu and Wang Zhijun, had privately struck oral agreements with the families of the deceased babies to dispose of their remains and had taken payments from them, the state-run Xinhua news agency said. The two have been detained.
The parents, apparently unable or reluctant to pay for proper burial or cremation, entrusted their dead to the two. Cremation in China can cost thousands of yuan (hundreds of dollars), depending on how elaborate the service.
They took the corpses to near the Guangfu River and disposed off them. They failed to bury them properly, so that they were exposed to view and discovered, reported Xinhua.
For many ordinary Chinese, who often lament lax and increasingly expensive medical care, the dumping of the 21 dead fetuses and infants is indicative of deeper healthcare woes.
This is shocking. It makes me wonder whether this is a civilized society, said one commentator on a Chinese-language Internet website.
One of the corpses was found by a local resident on Sunday. Alarmed residents then discovered more of the dead, including seven in the river, which is used for drinking water, said local news reports.
Some of the corpses still had green tags attacked to their legs, giving their birth date, mother's name and hospital bed number, the Beijing News reported, citing witnesses. One of the dead was in a plastic bag marked medical refuse.
A deputy head of the Jining Medical University hospital, where the fetuses and infants died, was suspended, and two other hospital managers were sacked.