New Apparatus Should Help Farmers Detect
By Tara Weaver
November 17, 1998
A new device called a biosensor will help farmers and regulators detect
herbicides and pesticides in soil and water. The biosensor relies on living
organisms or their by-products to identify traces of chemical residues in only
Molecular biologist Autar K. Mattoo at the
Agricultural Research Service
co-developed the biosensor with scientists from the Czech Republic and Italy
through a grant supported by the North American Treaty Organization. In
Beltsville, Md., Mattoo leads the
Vegetable Laboratory of
the ARS, the chief research agency of the U. S.
Department of Agriculture.
Heavy applications of herbicides and pesticides can leave environmentally
unsafe residues in soil and water.
The biosensor detects these residues by using a chlorophyll-protein complex
that measures oxygen levels. To use the biosensor, the farmer or regulator
passes a soil or water sample through the device. If the sample contains an
herbicide, the chemical will react with the biosensor's proteins and inhibit
oxygen production. This information is relayed to a computer that displays the
data in graph form.
The biosensor can only measure herbicides that inhibit
photosynthesis--diuron, atrazine, simazine, ioxynil, bromoxynil and dinoseb.
But this group constitutes about 50 percent of all herbicides used in
The test is ultra-sensitive. Its detection limits are similar to or slightly
better than the more complex, highly sensitive ELISA test, which is
antibody-based. The biosensor works well at room or warmer temperatures. Its
membrane is stable for up to about 40 hours and can be re-used within that
period for any number of measurements.
Once commercialized, it should be economical and easy to use--distinct
advantages over currently available herbicide detectors.
A story about the biosensor appears in the November issue of ARS Agricultural Research magazine.
The story is also on the World Wide Web at:
Scientific contact: Autar K. Mattoo, ARS Vegetable Laboratory,
Beltsville, Md., phone (301) 504-7380, fax (301) 504-5555,