Herbicide and estrogen leaching potential assessment by Pesticide Root Zone Modeling (PRZM)

Baljeet Singh, Annemieke Farenhorst and Ross McQueen

Department of Soil Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2 Corresponding author: umsingh4@cc.umanitoba.ca

The Pesticide Root Zone Model (PRZM version 3.12.2) is a one dimensional pesticide fate model being used by the United States Environmental Protection Agency, Agricultural and Agri-Food Canada and Health Canada to assess pesticide fate processes in agricultural soils and the broader environment. Recent laboratory studies suggest that pesticide fate models can be used to predict of estrogen leaching in soils. Like most pesticides, estrogens are organic molecules, and hence their chemical sorption coefficients are among the most sensitive input parameters in pesticide fate models. In fact, studies of pesticide fate modeling at the large-scale have indicated that site-specific data on chemical sorption parameters are more important than the choice of the pesticide fate model itself. In this study, a total of 609 soil samples were collected from 140 soil profiles across each of 7 landform elements delineated in two agricultural fields in western Canada by using a landform segmentation technique (with the DEM being 5x5m²). Soil properties and chemical sorption parameters of these soil samples were measured, and various PRZM scenarios (including various climatic scenarios) were simulated to determine the impacts of the field sampling density and location used on stochastic PRZM predictions of chemical leaching to depth. The poster summarized the findings of these hundreds of PRZM simulations.

Key words: Pesticide Root Zone Model, 17β-estradiol, 2,4-D, atrazine, glyphosate, leaching.