Modelling pesticide leaching at the regional scale in Austria with GeoPEARL

Transcription

1 Modelling pesticide leaching at the regional scale in Austria with GeoPEARL Michael Stemmer Department for Environmental Behaviour and Integrative Pest Management Institute for Plant Protection Products Austrian Agency for Health and Food Safety

2 Content Intention Model description Results - GeoPEARL-Austria vs. FOCUS scenarios - Actives and metabolites - GeoPEARL-Austria vs. groundwater monitoring data Summary Outlook 2

3 Intention for spatial modelling For risk managers/local governmental organisation Major: - Identification of critical actives and metabolites under Austrian conditions - Where do we have to expect them? - Identification of suitable risk mitigation measures Minor: - Representativeness of FOCUS scenarios - Option for higher tier assessment 3

4 GeoPEARL-Austria Model description Version GeoPEARL Raster model ( km 2, resolution 1 1 km) 2808 soil profiles - Agricultural sites only (no grassland) - 2 m soil depth - PTF for soil hydraulic properties 55 national climatic stations - Daily data from High resolution maps on long-term average precipitation, mean temperature and grass-evapotranspiration for regional scaling of daily input data Crop parameterisation based on FOCUS GW 2009 (Kremsmünster) Groundwater level set to -2 m Overall parameterisation close to FOCUS recommendations Preferential flow not accounted for 4

5 GeoPEARL-Austria Target depht Leachate at 1 m (FOCUS) Leachate close to groundwater (higher tier) - Assumption of uniform dilution (spatial and temporal) with leachate from nontreated areas Concentration in leachate at 1 m divided by the relative crop area for each raster cell - Yearly application necessary for calculation also in case of rotational crops 5

6 GeoPEARL-Austria Target depht Maize area No crop Cmp D in maize 50 th temporal percentile concentration Cmp D in maize 50 th temporal percentile concentration No calculation Crop area < 5 ha/km 2 No calculation Crop area < 5 ha/km 2 Leachate at 1 m Leachate close to groundwater 6

7 Compounds calculated Properties Approved in AT actives with ~700 metabolites (LoEP) - ~350 metabolites with potential to exceed 0.1 µg/l (LoEP) Several GeoPEARL runs with most critical compounds actives metabolites Representative worst case use in AT Agreed endpoints (LoEP) with some exceptions - Relationships between compound properties and soil properties 7

8 GeoPEARL-Austria GeoPEARL-Austria GeoPEARL-Austria GeoPEARL-Austria Results GeoPEARL-Austria vs. FOCUS scenarios 80 th /80 th percentile concentration (µg/l) Leachate at 1 m Leachate close to groundwater 100 1: :1 FOCUS Hamburg FOCUS 100 1:1 FOCUS 100 1:1 FOCUS Kremsmünster FOCUS FOCUS

9 Number Number Results Individual compounds (preliminary results) 50 th temp./90 th spat. percentile concentration (µg/l) in leachate close to groundwater Actives Metabolites Concentration (µg/l) Concentration (µg/l) 9

10 Results Individual compounds One active slightly above 0.1 µg/l - Ethofumesate (sugarbeet) Five metabolites predicted to exceed 3 µg/l: - Chloridazon-desphenyl (sugar beet) - Dimethachlor-oxalic acid (winter oil seed rape) - Dimethenamid-P-sulfonic acid (maize) - Metazachlor-sulfonic acid (winter oil seed rape) - S-Metolachlor-sulfonic acid (maize) 10

11 Results Spatial modelling vs. groundwater monitoring Governmental organizations and risk managers asked to verify spatial modelling results with groundwater monitoring data Extremely challenging task and prone to misinterpretation - Serious model limitations (simple, conservative, missing processes, etc.) - Representativeness of groundwater monitoring data (diffuse vs. point source contamination, etc.)? - Comparison defendable for broadly used actives only 11

12 Results Spatial modelling vs. groundwater monitoring Concentration of active always higher than metabolites or no metabolites at all indication for preferential flow, point source contamination, etc. 12

13 Results Spatial modelling vs. groundwater monitoring 13

14 Results Spatial modelling vs. groundwater monitoring Bentazon GeoPEARL-Austria (50 th temp. leaching conc.) Austria Groundwater monitoring (2010) Upper Austria Groundwater Monitoring (2011) < LOQ < LOQ >

15 Results Spatial modelling vs. groundwater monitoring Chloridazon-Desphenyl GeoPEARL-Austria (50 th temp. leaching conc.) Austria Groundwater monitoring (2010) Upper Austria Groundwater Monitoring (2011) < LOQ < LOQ >

16 Bromid (mg/l) Bromid (mg/l) Bromid (mg/l) Results Spatial modelling vs. groundwater monitoring Preferential flow Gemessen measured Berechnet calculated (adaptiert) (adopted) Berechnet calculated (Standard) (std.) Tracer-Applikation tracer application Gemessen measured Berechnet calculated Tracer-Applikation tracer application Soil structure (visual assessment) Not structured Structured, small-sized units Structured, medium-sized units Structured, large-sized units 0 Okt Mai Nov Jun Dez Jul Jan Okt Mai Nov Jun Dez Jul Jan Gemessen measured Berechnet calculated Tracer-Applikation tracer application Jun Dez Mai Nov Apr Sep Mrz

17 Summary GeoPEARL-Austria vs. FOCUS scenarios FOCUS scenarios do not cover entire crop area of Austria in respect to a target depth of 1 m - yearly precipitation to low (Hamburg) - organic matter to high (Kremsmünster) FOCUS scenarios sufficient conservative in respect to the target depth close to groundwater 17

18 Summary Spatial modelling vs. groundwater monitoring Metabolite pattern from individual monitoring wells indicate preferential flow or point source contamination GeoPEARL-Austria fails to predict leaching of observed actives - Lack of preferential flow, only matrix flow considered - Point source contamination, misuse - Only mean/median properties considered - Relationship between compound and soil properties not considered - Compound properties (LoEP) maybe not appropriate (e.g. Bentazon K om ) GeoPEARL-Austria overestimates leaching of metabolites - Extensive formation in uppermost soil horizons - Conservative compound properties 18

19 Outlook Implementation of preferential flow in GeoPEARL-Austria Extensive groundwater monitoring campaign in 2013 for several actives and metabolites (~ 2100 wells, 4 times in the year) maybe more in detail reality-check possible model refinements Implementation of spatial modelling into the national authorization process strongly depends on the acceptance of the results 19