PESTAN is a one-dimensional analytical model for predicting the transport and degradation of dissolved pesticides through the unsaturated zone. PESTAN is commonly used for initial screening assessments to evaluate the potential for groundwater contamination by pesticides used in agriculture.

Model Details

• One layer profile
• Homogeneous soil properties
• Multiple initial pesticide applications
• Constant recharge rate
• Includes a limited database of soil and chemical properties

Simulated Processes

• Steady-state flow and transport of pesticides through the unsaturated zone
• Leaching of pesticides to infiltrating groundwater, sorption of dissolved pesticides on soil, and first-order decay of pesticides

Simulation Results

• Graphical and tabular reports of soil concentration vs. time for selected profile depths
• Graphical and tabular reports of groundwater concentration vs. time for selected profile depths
• Graphical and tabular reports of vapor phase concentration vs. time for selected profile depths
• Profile mass balances for soil, groundwater and vapor phase