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The Danish Pesticide Leaching Assessment Program – a field based, early warning system. Preben Olsen - Danish Institute of Agricultural Sciences Jeanne Kjær & Marlene Ullum - Geological Survey of Denmark and Greenland Ruth Grant - The National Environmental Research Institute.
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The Danish Pesticide Leaching Assessment Program – a field based, early warning system. Preben Olsen - Danish Institute of Agricultural Sciences Jeanne Kjær & Marlene Ullum - Geological Survey of Denmark and Greenland Ruth Grant - The National Environmental Research Institute
The Danish Pesticide Leaching Assessment Program – a field based, early warning system. PLAP
GEUS - Geological Survey of Denmark and Greenland DIAS - Danish Institute of Agricultural Sciences NERI - The National Environmental Research Institute EPA EPA - Environmental Protection Agency Institutions involved
Is the existing approval procedure for pesticides sufficient? Improving the current risk assessment of pesticide leaching Background of the project Increasing concern about pesticide contamination of the Danish groundwater: • 98% of drinking water supplies in DK derives from ground water • Pesticides and their degradation products have been detected in about 30% of all screens monitored and 10% are > 0.1 µg/l Limitations comprises: • Scale problems • Spatial variability of the soil parameters • Hydraulic boundary condition (e.g. tile drains) Include field studies in the actual risk assessment
The bottom line…is it point or difffuse sources that cause problems to our groundwater?
PLAP • .. shall funtion as an early warning system ..is a monitoring programme for the evaluation of pesticide leaching risk under field conditions .. has the objective to analyse, whether approved pesticides – when applied in accordance with current regulations – leach to the groundwater in unacceptable concentrations
PLAP sites - precipitation Average precipitation 1961-90 Source: DMI 1997
Tylstrup Silstrup Estrup Slæggerup Fårdrup Jyndevad PLAP sites - soils
Apr 2000 Apr 2000 Apr 2000 Sep 1999 Sep 1999 PLAP - sites 2 sandy soils 4 loamy soils 1-3 ha 26 pesticides May 1999
Fine sandy soil Tylstrup
P6 P4 P3 P7 M2 M1 M3 M4 Moniteringwells Piezometer M5 S2 P5 Suction cups, TDR og Pt-100 S1 P8 Rain Gauge M6 M7 Tylstrup N • 70 x 166 m • 1,1 ha • Loamy sand • 6 % clay • 2% TOC • 666 mm/y • Groundwater: 3-4 m.b.g.s. 0 50 m
Active ingedients Date Product Dosage Potatoes planted 4. May Var. Dianella 2200 kg/ha Herbicide application 25. May Sencor WG Metribuzin 0,2 kg/ha 25. May Afalon Linuron 1 l/ha 7. Jun Sencor WG Metribuzin 0,15 kg/ha Tracer application 27. May Potasium bromide 30 kg/ha Fungicide application 22. Jun - 14 Sep Dithane DG Mancozeb (ETU) 10*2,0 kg/ha Irrigation 33 mm 12. Sep Harvest 28. Oct Agricultural management
Active ingedients Date Product Dosage Potatoes planted 4. May Var. Dianella 2200 kg/ha Herbicide application 25. May Sencor WG Metribuzin 0,2 kg/ha 25. May Afalon Linuron 1 l/ha 7. Jun Sencor WG Metribuzin 0,15 kg/ha Tracer application 27. May Potasium bromide 30 kg/ha Fungicide application 22. Jun - 14 Sep Dithane DG Mancozeb (ETU) 10*2,0 kg/ha Irrigation 33 mm 12. Sep Harvest 28. Oct Agricultural management Metribuzin - Desamino-metribuzin - Diketo-metribuzin - Desamino-diketo-metribuzin
Pesticide concentration in groundwater - Tylstrup - Concentrations are due to applications at least 4-6 years ago
Pesticide concentration in groundwater Diketo-metribuzin (µg/l)
Pesticide concentration in groundwater Diketo-metribuzin (µg/l) The maximum allowed concentration of 0.1 µg/l was exeeded in 36% of the samples analysed
Pesticide concentration in groundwater Desamino-diketo-metribuzin (µg/l)
Conclusion - Tylstrup • ETU (degradation product of mancozeb) linuron or metribuzin did not leach from the root zone • Diketo-metribuzin, desamino-diketo-metribuzin (degradation products of metribuzin) leached from the root zone in concentrations exceeding 0.1 µg/l. • Previous application of metribuzin has caused a marked groundwater contamination with 2 degradation products • The degradation products of metribuzin are quite stable.
Leaching of pesticides in PLAP Unacceptable leaching
Leaching of glyphosate - Estrup Precip. ,mm/d Drainage flow, mm/d Drainage flow, mm/d
Leaching of glyphosate - Estrup Precip. ,mm/d Drainage flow, mm/d Glyphosate, µg/l Pesticide, µg/l Drainage flow, mm/d
0,54 µg/l 0,17 µg/l Leaching of glyphosate - Estrup Precip. ,mm/d Drainage flow, mm/d Glyphosate, µg/l AMPA, µg/l Drainage flow, mm/d Pesticide, µg/l Drainage flow, mm/d
Leaching of pesticides in PLAP Unacceptable leaching Leaching No leaching
Leaching of pesticides in PLAP Unacceptable leaching Leaching No leaching
Leaching of pesticides in PLAP 2 13 11 Unacceptable leaching Leaching No leaching
Status after 3 years of monitoring • Leaching from fields can significantly pollute groundwater with pesticides • Some approved pesticides can cause significant groundwater pollution • When the damage is done, pesticides can be around for several years within the groundwater
Conclusion • It provides a realistic description of the leaching behaviour of pesticides under field conditions • It provides essential data for the calibration/validation of the models used in the current risk assessment of pesticides leaching The PLAP monitoring programme gives an important contribution towards an improved risk assessment of pesticides leaching:
Further information is available on www.pesticidvarsling.dk
Sampling of drainage water Campbell logger ISCO samplers Outlet 30o V notch Presure transducer Inlet
(1960-1991) Precipication 1047 mm 35% more than the yearly normal