Variability of pesticide exposure in a stream mesocosm system: macrophyte-dominated vs. non-vegetated sections.
For flowing water bodies no information is available about patterns of contaminant distribution in flowing water compared to macrophyte-dominated structures. The aim of the study was to examine temporal dynamic and spatial cross-channel variability of pulse exposure of the insecticide thiacloprid in outdoor stream mesocosms. Two distinct cross-channel sections have been considered: macrophyte-dominated littoral and non-vegetated midstream. Median disappearance time ranged from 17 to 43 h (water phase, midstream). We showed that during the exposure pulse (10h) thiacloprid concentrations in the macrophyte-dominated section were 20-60% lower than those in the non-vegetated section. This suggests that spatial variability in contaminant concentrations, particularly in streams containing macrophytes, should be taken into account to enable a more realistic assessment of (i) exposure and associated effects and (ii) mass transport of pesticides and other chemicals into river systems (e.g. losses with surface runoff).
UFZ-Helmholtz Centre for Environmental Research, Department of System Ecotoxicology, Permoserstrasse 15, D-04318 Leipzig, Germany. mikhail.beketov@ufz.de
Mikhail A
MA
Beketov
Matthias
M
Liess
D004463:Ecology / Q000379:methods*; D017753:Ecosystem; D004781:Environmental Exposure; D007306:Insecticides / Q000032:analysis*; D000073943:Neonicotinoids; D010944:Plants; D011725:Pyridines / Q000032:analysis*; D045483:Rivers; D013843:Thiazines / Q000032:analysis*; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*
D007306:Insecticides; D000073943:Neonicotinoids; D011725:Pyridines; D013843:Thiazines; D014874:Water Pollutants, Chemical; C417209:thiacloprid