A man and his girlfriend were charged yesterday over the death of a South Carolina toddler whose remains were found buried in 180kg of concrete in a rubbish bin.

The child's body was found two days after police said the couple concocted a story about the boy falling into a harbour near a popular tourist destination.

Roger Williams, 29, and Grace Nichole Trotman, 24, were charged with homicide by child abuse.

An autopsy revealed the concrete held the body of a young boy who matched the description the couple had given Charleston police for Williams' missing son, Rodricus Williams, said Berkeley County Sheriff Wayne DeWitt.