New 'super worms' may clean up heavy metals

A metal-eating earthworm that can survive the toxic environment of heavily contaminated soils is being recruited in the fight to clean up the polluted land of former industrial sites.

Scientists believe earthworms have undergone rapid evolutionary changes at abandoned mines in Britain, which have enabled them to survive and even thrive in an environment rich in toxic heavy metals. The researchers hope it may be possible to breed the worms and distribute them around contaminated sites in the hope they can help rid the soil of heavy metals.

"A combination of laboratory, field and synchrotron X-ray experiments have led to the finding that metal-tolerant populations of super earthworms are evolving," said Mark Hodson of the University of Reading.

Earthworms can consume 30 times their own body weight each day and the super worms ingest large quantities of potentially toxic metals such as arsenic, lead, zinc and caesium, Dr Hodson told the science festival.