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(77-17) Pesticide exposure in spraying-free zones and water-streams using plant biomarkers and Gammarus pulex. Ravn, H.*,1, Løkke, H.1, Petersen, D.1, Lauridsen, I.1, Battrup-Pedersen, A.2, Friberg, N.2, Husted, S.2, Nielsen, J.2, Vejrup, K.3, 1 National Environmental Research Institute, Silkeborg, Denmark2 National Environmental Research Institute, Silkeborg, Denmark3 National Environmental Research Institute, Roskilde, Denmark ABSTRACT- Effects of exposure to pesticides from conventional agriculture on biological communities in small Danish stream ecosystems were investigated in the present study. Terrestrial plant communities in buffer zones (2-12 m wide) extending from the field to the stream were characterised. Natural growing species Urtica dioica L. and Anagallis arvensis L. transplanted from a greenhouse culture were screened for biomarkers. The screening included several samples taken in three zones from 0 to 18 m from water-stream to the field. The plants were harvested 7, 14 and 21 days after supposed exposure to pesticides from the field. Effects of exposure on in-stream macroinvertebrate communities were evaluated using community composition and mortality of Gammurus pulex as measures. Macro invertebrate samples were taken randomly in the impacted stream reaches and in six control reaches unexposed to pesticides. Similarly mortality of G. pulex in caves placed on the stream bottom was followed weekly for five weeks after exposure and in the control reaches. Water samples were taken and analysed for pesticides. Data are correlated to pesticide load, wind direction, distance from water-stream, distribution of plant species and mortality of Gammurus pulex. A plant biomarker pattern was found in plants affected by the pesticides. In contrast the effects of conventional use of pesticides on the in-stream macroinvertebrate communities were only minor as differences in community. Key words: water-streams, biomarkers, herbicide, screening |
