This document presents the harmonized guidance for the conduct of terrestrial field studies of conventional pesticide dissipation to satisfy the Pest Management Regulatory Agency's environmental chemistry and fate date requirements. This harmonized guidance was developed jointly with the United States Environmental Protection Agency under the North American Free Trade Agreement (NAFTA) Technical Working Group on Pesticides. It builds upon the guidance published in Trade Memorandum T-1-255, Environmental Chemistry and Fate Guidelines for Registration of Pesticides in Canada. The guidance document, entitled NAFTA Guidance Document for Conducting Terrestrial Field Dissipation Studies, represents the field dissipation studies which are conducted to demonstrate the transformation, transport and fate of pesticides under representative actual use conditions. The objective of this document is to help ensure that TFD studies are conducted in a manner that will provide risk assessors and risk managers with more confidence in the data generated and with a better understanding of the assumptions and limitations of the data and estimated half-lives of the chemical.

This document provides guidance on how to conduct terrestrial field dissipation studies to demonstrate the transformation, transport and fate of pesticides under representative actual use conditions when a pesticide product is used according to the label.

Terrestrial Field Dissipation Studies: Purpose, Design, and Interpretation discusses the design, conduct, and interpretation of terrestrial field dissipation studies. Field studies provide information on the effects of agricultural chemicals in the environment. Field studies differ from laboratory studies because they study the effects of active ingredients in soil and/or water under actual field conditions as opposed to a controlled environment in the laboratory. Terrestrial Field Dissipation Studies: Purpose, Design, and Interpretation includes analytical method requirements, examples of modeling pesticide dissipation, and summaries of regulatory guidelines, such as the EPA/PMRA proposed guidance in 1998.

This document provides additional detailed guidance on rotational crop residue studies conducted according to OECD TG 504: Residues in Rotational Crops with expanded flexibility in crop commodities to be tested, and approaches to mitigate additional testing.