Order No: FOS 71
Version: 1.02 (April 1994)
Price: Contact for more info

PRZM2 links two subordinate models in order to predict pesticide fate and transport through the crop root zone, and the unsaturated zone: PRZM and VADOFT. PRZM is a one-dimensional finite-difference model which accounts for pesticide fate and transport in the crop root zone. This release of PRZM incorporates several features in addition to those simulated in the original PRZM code: specifically, soil temperature simulation, volatilization and vapor phase transport in soils, irrigation simulation, microbial transformation, and a method of characteristics (MOC) algorithm to eliminate numerical dispersion. PRZM is now capable of simulating fate and transport of the parent compound and up to two daughter species. VADOFT is a one-dimensional finite-element code which solves the Richard's equation for flow in the unsaturated zone. The user may make use of the constitutive relationships between pressure, water content, and hydraulic conductivity to solve the flow equations. VADOFT may also simulate the fate and transport of two parent and two daughter products. The codes are linked together with the aid of a flexible execution supervisor which allows the user to build models which are tailored to site-specific situations. In order to perform exposure assessments, the code is equipped with a Monte Carlo per- and post-processor.

Program data input is interactive and the program produces tabular output to files. PRZM2 is distributed on DOS-formatted diskettes containing compressed files with the source code and executable image. The documentation consists of installation instructions and user's manual by EPA.


Author: J.A. Mullins, et al. (EPA Center for Exposure Assessment Modeling)