Scientists from Diamond Light Source, the Universities of Reading, Glasgow and the Natural History Museum in London have used the Diamond synchrotron to help determine whether worms can play a part in soil remediation. Their latest findings were published online in the journal Geochimica et Cosmochimica Acta.
"We're interested in how earthworms interact with metals at contaminated sites. In this study, we added lead to some of the soils the earthworms inhabited and then looked at the granules they excreted. Using the Microfocus spectroscopy beamline (I18) at Diamond, which can map the elements within a sample to the micron scale, we were able to confirm that the granules picked up a lot of lead. Unfortunately, the granules are so small that they pick up less than 1% of lead in the soil. So although the earthworms can survive in these toxic environments, their granules won't have a big impact on lead in contaminated soils. The next step is to look at different elements such as strontium and zinc within the granules which might be concentrated more heavily."
Professor Mark Hodson, University of Reading
Scope for new materials
“Synthesising an amorphous carbonate in the lab is not so easy,” says Professor Hodson. “It’s possible, but the substance is so unstable that it quickly converts to calcite or aragonite – more stable forms of calcium carbonate. The more we can find out about the composition of the earthworm granules and how it affects the mineralogy, the more we can learn about how to create a stable amorphous material.”
Answering Darwin’s questions
Incorporation of lead into calcium carbonate granules secreted by earthworms living in lead contaminated soils
A. Fraser, D.C. Lambkin, M.R. Lee, P.F. Schofield, J.F.W. Mosselmans and M.E. Hodson
Geochimica et Cosmochimica, 18 February 2011
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