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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Implementation of the Pesticide Root Zone Model Groundwater (PRZM-GW) for Use in EPA’s Pesticide Exposure Assessments (PDF)(49 pp, 6 MB,
September 8, 2015)
Data collected from 43 drinking water assessments and one registration review problem formulation were evaluated to determine: effectiveness of PRZM-GW as Tier 1 screen; impacts of standard refinements; comparison of PRZM-GW estimated drinking water concentrations with the SCI-GROW model estimated values; risk assessment and risk management outcomes. Results demonstrate PRZM-GW can be used as a Tier 1 and Tier 2 risk assessment tool for estimating pesticide concentrations in groundwater.