This nasty mess is the result of sheep blowflies. Once they could be killed by organophosphate insecticide, but in the 60's they developed a resistance to it.

Scientists from Australia's science agency CSIRO were curious as to how it had happened. They discovered that an enzyme in the resistant flies was changing just one amino acid in the insecticide making it useless.

When the blow fly larvae was sprayed instead of keeling over and dying, they ate the insecticide and spat out non-toxic products. And we thought well if this enzyme can do such a good job inside the fly, why can't it do a good job outside of the fly.

Dr. Robyn Russell and her colleagues thought they'd see if this enzyme would do its trick in cleaning up insecticide contaminated soil. And along the way they discovered a bacteria that did an even better job.

Bacteria, when they're faced with, if they're sitting in the soil, in a cotton field for instance and they come in contact with a lot of insecticide, they'll use the insecticide as a food source. So rather than, like an insect does chew up a little bit that might kill them, these bacteria will eat it for breakfast.

After growing large amounts of the right enzymes, in collaboration with the company Orica, tests were conducted on run off water from cotton fields, where large amounts of insecticides are used.

In the first instance what we're going to be trying to do is to clean up residues in run off water. The irrigation has occurred after the pesticides have been applied so the water that then runs off is contaminated there with pesticides. And that's what we'll be trying to clean up in the first instance.

It's hoped that eventually the enzyme can be developed as a powder. Dr. Russell hopes it may even be possible to insert genes, which produce the enzyme, into trees and bushes. They could then clean up contaminated sites as they grow.

That's something I dream about. Why not?

Robyn Russell
CSIRO Entomology
GPO Box 1700
Canberra ACT 2601
Robyn.Russell@csiro.au