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Explore the impact of pesticides in Danish streams and lakes, analyzing concentrations, loss, and ecological effects on aquatic life. Understand the pathways, detection frequencies, and potential ecological consequences. Discover data on pesticide application rates, detection limits, and possible solutions to reduce the environmental impact.
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Pesticides in Danish streams and lakes: Concentrations, loss and ecological effects Brian Kronvang, NERI BKR@DMU.DK
Introduction • 2.841.000 kg active ingredients was applied in Danish agriculture during the year 2000 • Following spraying pesticides can reach surface water due to wind drift, leaching, runoff and bad handling • Our knowledge about the presence of pesticides in surface waters have been very limited
NOVA-2003 • Analysed for 68 pesticides i 5 larger streams and 48 pesticides i 25 small streams in agricultural catchments during 2000 og 2001 • In total measured 43 pesticides and metabolites above the detection limit • Detection limit normally 0.001 ug/l
Pesticide detection frequencies and maximum concentrations measured in streams in the Danish Aquatic Monitoring Programme 2000
Is there any ecological effects of pesticides in streams? Fyns amt (2002)
NOVA-2003 • Measured for 48 pesticides in 8 lakes in 2001 • In total measured 42 pesticides or metabolites • Maximum concentration was 0,22 µg/l (diuron) • Maximum median concentration was 0,03 µg/l
Concentrations of pesticides in 69 lakes and 47 ponds sampled in regional programs
Lillebæk (culverted sub-catchment) Water 104 Suspended sediment 8 Streambed sediment 6 Lillebæk (entire catchment) Water 96 Suspended sediment 8 Streambed sediment 6 Odderbæk Water 68 Suspended sediment 10 Streambed sediment 6 Number of samples taken in the two catchments during 1999-2001
Applied amount of pesticides in the 3 catchments and the detection frequency and concentration levels in streams
Pesticide application, loss and loss ratios18 different pesticides during 2000 ____________________________________________________ Applied Loss Loss ratio (kg a.i.) (gram) (%) ____________________________________________________ Odderbæk 634.32 9.75 0.00154 Lillebæk 119.45 12.51 0.0105 (culverted sub-catchment) Lillebæk 66.29 5.30 0.00800 (Open sub-catchment ____________________________________________________
Gammarus survival • Caves installed 10 m upstream, at the tile drain outlet and 10 m downstream • 6 caves each with 10 Gammarus • The experiment prevailed for 8 hours only • Mortality and inactivity
Conclusions • Under “normal” conditions the concentration of pesticides are generally low in Danish streams and lakes • During storm events short lived high and ecological critical concentrations can occur • The highest concentrations are detected in small streams and ponds • Effects have been documented on the macroinvertebrate Gammarus pulex during an experiment