Applying one-dimensional deterministic chemical fate models on a regional scale

A deterministic one-dimensional chemical transport model was applied to soil and weather data from the northeastern United States. The model used a mobile-immobile capacity flow model. Simulations using 20 years of historical rainfall data from each of 13 weather stations applied to a single soil showed that predictions of leaching varied considerably from year to year. The model was then applied to 2270 soil-weather combinations to develop indices for atrazine-leaching potential. Issues relating to quality of soil data and temporal variability of rainfall are discussed. Simulated atrazine leaching was related to the amount and distribution of rainfall, modified by soil organic matter levels.