The Danish Pesticide Leaching Assessment Program

1
(No Transcript)
2

• 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
3

• The Danish Pesticide Leaching Assessment Program
• a field based, early warning system.

PLAP
4
Institutions involved
5
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 gt 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

6
The bottom lineis it point or difffuse sources
that cause problems to our groundwater?
7
PLAP

• ..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

• .. shall funtion as an early warning system

8
PLAP sites - precipitation
Average precipitation 1961-90 Source DMI 1997
9
PLAP sites - soils
10
PLAP - sites

• 2 sandy soils
• 4 loamy soils
• 1-3 ha
• 26 pesticides

May 1999
11
Leaching of pesticides from PLAP-fields
12
Fine sandy soil
Tylstrup
13
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
14
Monitoring design -crossection
15
Agricultural management
16
Agricultural management
Metribuzin - Desamino-metribuzin -
Diketo-metribuzin - Desamino-diketo-metribuzin
17
Bromide concentration - unsaturated zone
18
Bromide concentration - unsaturated zone
19
Bromide concentration - saturated zone
20
Pesticide concentration - suction cup S1
21
Pesticide concentration - suction cup S1
22
Pesticide concentration - suction cup S1
23
Pesticide concentration - suction cup S1
24
Average concentration - 1 m depth
25
Average concentration - 1 m depth
26
Pesticide concentration in groundwater -
Tylstrup -
27
Pesticide concentration in groundwater -
Tylstrup -
Concentrations are due to applications at least
4-6 years ago
28
Pesticide concentration in groundwater
Diketo-metribuzin (µg/l)
29
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
30
Pesticide concentration in groundwater
Desamino-diketo-metribuzin (µg/l)
31
Previous use of metribuzine at Tylstrup
32
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.

33
Leaching of pesticides in PLAP
34
Leaching of pesticides in PLAP
Unacceptable leaching
35
Leaching of glyphosate - Estrup
Precip. ,mm/d
Drainage flow, mm/d
Drainage flow, mm/d
36
Leaching of glyphosate - Estrup
Precip. ,mm/d
Drainage flow, mm/d
Glyphosate, µg/l
Drainage flow, mm/d
Pesticide, µg/l
37
Leaching of glyphosate - Estrup
Precip. ,mm/d
Drainage flow, mm/d
Glyphosate, µg/l
AMPA, µg/l
Drainage flow, mm/d
Drainage flow, mm/d
Pesticide, µg/l
38
Leaching of pesticides in PLAP
Unacceptable leaching
Leaching
No leaching
39
Leaching of pesticides in PLAP
Unacceptable leaching
Leaching
No leaching
40
Leaching of pesticides in PLAP
Unacceptable leaching
Leaching
No leaching
41
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

42
Conclusion
The PLAP monitoring programme gives an important
contribution towards an improved risk assessment
of pesticides leaching

• 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

43

• Further information is available on
• www.pesticidvarsling.dk

44
(No Transcript)
45
Estrup- loamy soil
46
Sampling of drainage water
Campbell logger
ISCO samplers

Outlet
30o V notch
Inlet
Presure transducer
47
Geological profile -Tylstrup
48
Precipication

• 1047 mm
• 35 more than the yearly normal

49
(No Transcript)
50
(No Transcript)
51
Leaching of glyphosate - Silstrup
52
Leaching of glyphosate - Silstrup
53
Leaching of glyphosate - Silstrup
54
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