ABSTRACT

Ecotox Assessment ..................................................................................... 185 12.6.1 Risk Assessments Where Spray Drift Dominates ....................... 185 12.6.2 Risk Assessments Where Runoff or Drain Flow Dominate ....... 186 12.6.3 Other Experiences ....................................................................... 187

12.6.3.1 “Pulsed” Exposure ..................................................... 187 12.6.3.2 FOCUS Steps 1 and 2 and Metabolites ..................... 187 12.6.3.3 Sediment PEC Values ................................................ 187 12.6.3.4 Potential for “Overinterpretation” of FOCUS

Step 3 Exposure Proles ............................................ 187 12.7 Regulatory Context, Reality Check, and Condence Overview ................ 188

12.7.1 Regulatory Context ...................................................................... 188 12.7.2 Reality Check .............................................................................. 189

12.7.3 Model Performance: Drainage .................................................... 191 12.7.4 Model Performance: Runoff ........................................................ 192

12.8 Frequently Asked Questions ...................................................................... 193 12.8.1 Validation Is Important to Ensure Regulatory Condence in

Risk Assessment Tools; How Would You Characterize the Validation Status of the FOCUS SW Framework? ..................... 193

12.8.2 What Are the Strengths and Weaknesses of the FOCUS SW Modeling Framework?................................................................. 194

12.8.3 Can a Relatively Simple Explanation Be Provided of How Drainage, Runoff, and Drift Are Simulated by the FOCUS SW Framework? .......................................................................... 195

12.8.4 Can a Relatively Simple Explanation Be Provided of How TOXSWA Simulates Chemical Behavior? .................................. 197

12.8.5 How and When Should Mitigation Be Represented in the FOCUS SW Framework? ............................................................200