Pesticides in European Groundwaters: detailed study of

14,0

MB

representative Aquifers and Simulation of possible Evolution

359

stron

scenarios - PEGASE

4206

ID

BRGM - Centre scientifique et technique

2004

rok

Table of contents

Introduction . 37

Chapter 1 - Monitoring of pesticide fate in the soil-unsaturated zonesaturated zone continuum. 39

1. Brévilles [BRGM] 44

1.1. Material and methods . 44

1.1.1. Catchment characterization 44

1.1.2. Fate of acetochlor and its main metabolites . 45

1.1.3. Water quality monitoring. 45

1.2. Results 46

1.2.1. Hydrogeologic basin. 46

1.2.2. Fate of acetochlor and its main metabolites . 49

1.2.3. Water quality 50

1.3. Discussion 52

1.3.1. Functioning of the catchment . 52

1.3.2. Fate of pesticides . 52

1.4. Summary. 53

2. Les Trois Fontaines [BRGM] 53

2.1. Material and methods . 54

2.1.1. Flow at the spring . 54

2.1.2. Piezometric map. 54

2.1.3. Pesticide concentrations 54

2.2. Results 55

2.2.1. Hydrogeologic basin. 55

2.2.2. Pesticide concentrations 57

2.3. Discussion 57

2.3.1. Functioning of the catchment . 57

2.3.2. Pesticide fate 58

2.4. Summary 59

3. Zwischenscholle [FZJ] . 59

3.1. Material and methods . 60

3.2. Results 61

3.3. Discussion 67

3.4. Summary 68

4. Roswinkel [Alterra] . 68

4.1. Experimental field . 68

4.2. Application of bromide and test compounds. 70

4.3. Irrigation procedures. 71

4.4. Monitoring of groundwater level and soil temperature 72

4.5. Sampling of soil profiles 72

4.6. Treatment of soil samples in the laboratory 73

4.7. Crop sampling 74

4.8. Bromide analysis 75

4.9. Carbofuran analysis 76

4.10. Degradation experiments 77

4.11. Sorption experiments 78

4.12. Desorption of aged residues. 79

5. Martigny [EPFL] . 79

5.1. Material and methods . 80

5.1.1. Local scale experiments. 81

5.1.2. Regional observations 81

5.2. Results 82

5.2.1. Local flow experiments. 82

5.2.2. Regional observations 86

5.3. Discussion / conclusions 89

5.4. Summary 90

6. Havdrup [E&R DTU]. 90

7. Laboratory sorption and degradation of selected pesticides [E&R DTU] . 90

7.1. Materials and methods . 91

7.1.1. Sediment and water characterisation . 91

7.1.2. Compounds 92

7.1.3. Adsorption studies 92

7.1.4. Degradation studies . 93

7.1.5. Data analysis 94

7.2. Results 95

7.2.1. Characterisation of the aquifer sediment and water . 95

7.2.2. Linear distribution coefficients (Kd values) . 97

7.2.3. Degradation bioassays. 99

7.3. Summary 107

8. Discussion of data monitoring activities . 108

Chapter 2 - Development and refinement of modelling tools 111

1. Adaptation and improvement of root zone models. 113

1.1. Macro [SLU] 113

1.1.1. Context . 113

1.1.2. Methods 114

1.1.3. Summary 117

1.2. ANSWERS [LTHE] . 118

1.2.1. Model description . 118

1.2.2. Model refinement 119

1.2.3. Summary 121

2. Combination of models 121

2.1. Combination of TRACE and 3DLEWASTE [FZJ] . 121

2.1.1. Modelling approaches 121

2.1.2. Model evaluation 123

2.1.3. Discussion / implications 126

2.1.4. Summary 126

2.2. Combination of MACRO and FRAC3DVS [SLU, E&R DTU] 126

2.2.1. Modelling 127

2.2.2. Summary 128

2.3. Combination of MACRO and MODFLOWT [SAPROV] 129

2.3.1. Material and methods. 129

2.3.2. Results and discussion. 131

2.3.3. Summary 132

2.4. Combination of ANSWERS and MODFLOWT [LTHE] . 133

2.4.1. Adaptation of ANSWERS to allow an automatic coupling with MODFLOW. 133

2.4.2. Interconnection between models 135

2.4.3. Summary 136

3. Refinements of integrated models . 136

3.1. MARTHE [BRGM]. 136

3.1.1. Addition of subroutines for pesticide sorption in MARTHE. 137

3.1.2. Addition of subroutines for pesticide degradation in MARTHE. 138

3.1.3. Addition of subroutines for cropping in MARTHE. 141

3.1.4. Summary 147

3.2. TRACE [FZJ] 147

3.2.1. Modelling approach 148

3.2.2. Modelling results 153

3.2.3. Summary 155

3.3. POWER [LTHE] 155

3.3.1. Spatial discretisation strategy. 155

3.3.2. Time resolution and flow processes . 160

3.3.3. Data provision 162

3.3.4. Conclusions 165

3.3.5. Summary 165

3.4. PESTGW [WRc] . 166

3.4.1. PESTGW methodology 166

3.4.2. Summary 169

4. Discussion of model development and model refinement activities. 169

Chapter 3 - Application of modelling tools 171

1. Model verification using numerical tests, litterature datasets and hypothetical scenarios . 173

1.1. Verification of new vegetation subroutines implemented in MARTHE [BRGM]. 173

1.1.1. Description of the evaluation dataset . 173

1.1.2. Modelling with MARTHE. 174

1.1.3. Modelling results 175

1.1.4. Discussion 175

1.1.5. Summary 178

1.2. Verification of new sorption subroutines implemented in MARTHE [BRGM]. 178

1.2.1. Evaluation through simulations in 1D . 178

1.2.2 Evaluation through unsaturated flow modelling 182

1.2.3. Evaluation through simulations in 2D . 183

1.2.4. Summary 184

1.3. Verification of new degradation subroutines implemented in MARTHE [BRGM]. 184

1.3.1. Evaluation through simulations in 1D . 185

1.3.2. Evaluation through simulations in 2D . 186

1.3.3. Evaluation of the subroutines for the influence on degradation of temperature and humidity.

187

1.3.4. Summary 188

1.4. Verification of new subroutines implemented in MACRO [SLU] . 189

1.4.1. Modelling 189

1.4.2. Modelling results 192

1.4.3. Discussion and conclusions . 198

1.4.4. Summary 198

2. Application of modelling tools at the Brévilles site . 199

2.1. MARTHE modelling in 1 dimension [BRGM] 199

2.1.1. Conceptual model and MARTHE parameterisation 200

2.1.2. Modelling results 201

2.1.3. Sensitivity analysis based on simulated bromide concentrations. 204

2.1.4. Acetochlor simulations . 205