Presentation on theme: "The Danish Pesticide Leaching Assessment Program – a field based, early warning system. Preben Olsen - Danish Institute of Agricultural Sciences Jeanne."— Presentation transcript:
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
Institutions involved DIAS - Danish Institute of Agricultural Sciences NERI - The National Environmental Research Institute EPA - Environmental Protection Agency EPA GEUS - Geological Survey of Denmark and Greenland
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 Increasing concern about pesticide contamination of the Danish groundwater: Is the existing approval procedure for pesticides sufficient? Limitations comprises: Scale problems Spatial variability of the soil parameters Hydraulic boundary condition (e.g. tile drains) Improving the current risk assessment of pesticide leaching Include field studies in the actual risk assessment Background of the project
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
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 No leaching Unacceptable leachingLeaching
Leaching of pesticides in PLAP Unacceptable leachingLeaching No leaching
Leaching of pesticides in PLAP Unacceptable leachingLeaching No leaching 11 13 2
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
Required by locations included in the PLAP (examples) Be fields in crop rotations with a size of 1-3 ha Past cultivation known for at least 10 years Undisturbed soil - no previous excavations Irrigation system (sandy soils) Room for a bufferzone Tracers could be applied (bromide) Inside an infiltration area -downward gradient A thin, unsaturated zone (shallow groundwater) A well defined groundwater table Old drainage system (loamy soils) Homogenius soil And several more……
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