The National Environmental Research Institute (NERI) has developed a method to detect whether plants have been exposed to herbicides. The method is developed by Senior Scientist Helle Weber Ravn, and NERI has applied for an International patent for the method. At present, the prospect of method is to distinguish between plants that have been exposed to herbicides and plants cultivated without use of herbicides, e.g. products from organic farming.

What is a biomarker?

A biomarker is the change in an organism, which can be attributed to a specific impact factor. The biological response may be observed as changes in molecules, cells, or for the whole organism. In this case, the biomarkers for exposure or effects of herbicides are changes in the composition and content of natural compounds in the plants.

Screening of plants for biomarkers

The biomarker method measures phytochemicals as a "fingerprint" of exposure. It has been shown that the method can distinguish between the exposure from different herbicides. Other types of exposure, e.g. coldness or drought stress, do not affect the plants in the same way. The method has a high sensitivity and a characteristic pattern of biomarkers in plants exposed to 1% of maximum recommended field rate of glyphosate only 4 days after exposure. The plants did not show any morphological responses to the treatment. The biochemical reaction is very consistent. In annual plants investigated, the alterations remain for the whole growth season. The method is, therefore, very suitable for screening plants for herbicide exposure.

Possible applications of the method:

· Screening food and fodder plants for herbicide treatment

· A tool for farmers to evaluate herbicide effects on weeds at an early stage and hereby contribute towards a potential reduction in the use of herbicides

· A tool for biological effect studies (to be able to observe a herbicide effect at an early stage )

· Control of herbicide free buffer zones, set-asides, protected ground water areas, and other similar areas where use of herbicides are prohibited

· A tool to investigate whether plants are genetically modified or not and in the situation where plants are treated and changes in their natural composition and content are detected.