Pigments as biomarkers of exposure to the vineyard herbicide flazasulfuron in freshwater algae.
Weed control in Champagne vineyards has long relied on the use of diuron and substituted triazines; these compounds are now being replaced by flazasulfuron, a sulfonylurea that is used at a much lower dosage. The vineyards of Champagne are planted on steep slopes and runoff is important, and even though low doses of these herbicides are used, they may present some potential risk for freshwater ecosystems. Therefore, the effects of the sulfonylurea herbicide, flazasulfuron (formulated as Katana) was investigated on the unicellular green alga Scenedesmus obliquus. The pigment content of the algal suspensions was followed as a biomarker of exposure to the herbicide. The results demonstrate that flazasulfuron induced a reduction in chlorophyll content at concentrations of 10 microg/L, while the increase of pigment content in the culture was reduced with the lowest concentration tested (0.1 microg/L). Among the three pigments tested, chlorophyll a appeared to be the most sensitive biomarker. In the algal medium, flazasulfuron was slowly degraded (DT(50) approximately 8 days) in a compound that was tentatively identified. The toxicity of this herbicide for the algae was comparable to that of older herbicides which are used at a much higher rate. Therefore, we may speculate that even if flazasulfuron comes into contact with freshwater ecosystems, its effects on algae will be less deleterious than that of traditional herbicides.
Couderchet
Michel
M
Laboratoire d'Eco-Toxicologie, Unité de Recherches Vigne et Vin de Champagne, UPRES EA 2069, Université de Reims Champagne-Ardenne, BP 1039, F-51687 Reims Cedex 02, France. michel.couderchet@univ-reims.fr
Vernet
Guy
G
D000383:Agriculture; D015415:Biomarkers / Q000032:analysis*; D002734:Chlorophyll / Q000032:analysis*; D000077194:Chlorophyll A; D000460:Chlorophyta / Q000737:chemistry* / Q000502:physiology*; D004781:Environmental Exposure; D006540:Herbicides / Q000009:adverse effects*; D010571:Pest Control; D018570:Risk Assessment; D013453:Sulfonylurea Compounds / Q000009:adverse effects*
D015415:Biomarkers; D006540:Herbicides; D013453:Sulfonylurea Compounds; D002734:Chlorophyll; C477139:flazasulfuron; D000077194:Chlorophyll A