Higher concentrations of heavy water kills fish, amphibians and insects.
Experiments conducted on rodents
showed that a high level of deuterium of as much as 25% in the body water causes sterility, because neither the gametes nor the zygotes can develop.
Small mammals such as rodents die after approximately a week of consuming heavy water. The cause of death is similar to that of cytotoxic poisoning (the case of chemotherapy) or acute radiation syndrome.