Dry deposition and spray drift of pesticides to nearby water bodies

Dry deposition and spray drift of pesticides to nearby water bodies

1 Introduction

This report treats the following subjects:

Theory and development of a model for deposition of pesticides to water bodies (rivers, lakes and seas) as a function of the distance to a nearby field onto which pesticides are applied.
Evaluation of spray drift experiments and selection of information that can be used to estimate the spray drift as a function of the distance to a nearby field onto which pesticides are applied.
Theory on spray drift.
Discussion and conclusions where the (potential) contribution from dry deposition and spray drift to various water bodies are compared.

It should be noted that it was not planned to develop a model for spray drift within the framework of this (sub)project; only the basic processes are described that are needed to model spray drift. This project does not cover the contribution of pesticides to water bodies by wind erosion or the contribution from more distant sources.

A special version of the model for deposition to water bodies was made, so that it could be incorporated in the integrated decision tool that includes the contribution from all pathways to water bodies. The number of parameters that can be chosen by the user of this version of the model is restricted. A documentation of this model version and an overview of the parameter values chosen in this version are reported in Appendix G.