The Pesticide Root Zone Model Groundwater (PRZM-GW) was developed as a regulatory model to estimate pesticide concentrations in vulnerable groundwater sources as part of a North American Free Trade Agreement (NAFTA) to develop a harmonized groundwater modeling protocol. The Office of Pesticide Programs implemented the use of PRZM-GW as an exposure model in 2012.
Following a one-year evaluation period, the EFED PRZM-GW Team has concluded that the Pesticide Root Zone Model for Ground Water (PRZM-GW) is an effective and versatile exposure model that can be used as a Tier 1 and Tier 2 risk assessment tool for estimating pesticide concentrations in groundwater.
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Standard Operating Procedure for Using PRZM-GW to Estimate Pesticide Concentrations in Groundwater for Drinking Water Exposure Assessments (PDF)(16 pp, 832 K,
September 8, 2015)
This document provides guidance on how to prepare Tier 1 and Tier 2 groundwater assessments using PRZM-GW. Guidance is also provided on how to characterize the resulting exposure estimates.