Posts Tagged ‘heavy metal’

“Superworms” Eat Heavy Metals

Wednesday, October 8th, 2008

Researchers in England have found “superworms” that feast on heavy metals like lead, zinc, arsenic, and copper. The worms digest the metals and then secrete a form of the metal that is easier for plants to absorb. Then the plants can be harvested leaving behind cleaner, more usable soil.

“These worms seem to be able to tolerate incredibly high concentrations of heavy metals, and the metals seem to be driving their evolution,” said lead researcher Mark Hodson of the University of Reading in England.

“If you took an earthworm from the back of your garden and put it in these soils, it would die,” Hodson said.

DNA analysis of lead-tolerant worms living at Cwmystwyth, Wales, show they belong to a newly evolved species that has yet to be named, he said.

Two other superworms, including an arsenic-munching population from southwest England, are also likely new to science, Hodson said.

“It’s a good bet they are also different species, but we haven’t categorically proved that,” he said.

The toxicity of the metal particles once they have passed through the worms isn’t yet known, since the protective protein wrappings will degrade over time, the study authors noted.

But experiments suggest the superworms make the metals easier for plants to extract from the soil, Hodson said.

“The earthworms don’t necessarily render the metals less toxic, but they do seem to make them available for plant uptake,” he said. This raises this possibility of using the earthworms as part of efforts to clean up land contaminated by mining and heavy industry.

via nationalgeographic