There has been a fair bit of work on this issue in the past. For example, you may be aware of the book edited by D.A. Kurtz entitled Long Range Transport of Pesticides, published by Lewis Publishers, Chelsea Michigan, 1990. If you haven't seen this book, this would be a good place to start.
Another useful document -- that you can download from the web -- is the recently released Technical Summary of Progress Under IADN 1990-1996 (January 1998), a summary of the Integrated Atmospheric Deposition Network. If you are not already familiar with this, IADN is a joint project of the U.S. and Canada which measures pollutants in the atmosphere in the Great Lakes region. You can download this document from: http://www.epa.gov/glnpo/monitoring/air/iadn/iadn.html
There have been a number of articles in the scientific literature, particularly in the journal Environmental Science and Technology, but also in many other journals as well.
Modeling the long-range transport of pesticides is somewhat complicated as: (a) emissions inventories are quite difficult to estimate; (b) information about the atmospheric phenomena affecting fate is very limited for most (if not all) compounds of interest; and (c) there are very few (or no) ambient monitoring data to evaluate modeling results.
I am aware of several ongoing project being conducted at NOAA and/or the U.S. EPA regarding the regional and long-range transport of atrazine.
Recently, I completed a study modeling the regional and long-range transport of atrazine in the U.S. and Canada. I am conducting a followup analysis here at NOAA, and comparing this with an analysis for atrazine recently done for the EPA by SAI, a consulting firm. I am using the HYSPLIT model; SAI used a model called REMSAD. I hope to be able to publish this work in the coming year.
The U.S. EPA is conducting a modeling study of long range transport of atrazine in conjunction with the Lake Michigan Mass Balance Study. This modeling is being conducted using the Models-3 framework being developed by the EPA. Dr. Ellen Cooter, a NOAA employee on assignment to the EPA in Research Triangle Park, is a lead investigator in this research. I believe that she will be publishing some of her results in the near future. However the overall project may take some time (~ years) before full results are available. The Lake Michigan Mass Balance Study has a great deal of material on the web at: http://www.epa.gov/glnpo/lmmb/
Last year, I submitted a five volume study to the International Joint Commission regarding the regional and long range atmospheric transport of toxic compounds to the Great Lakes. I am not sure of the policy of releasing documents at the IJC, but if you want, you could contact John McDonald, the secretary of the International Air Quality Advisory Board, and ask to get at least the summary volume of this work (volume 5). John can be reached at: mcdonaldj@ijc.wincom.net. He is located at the IJC offices in Windsor, Ontario.
Finally, the Commission for Environmental Cooperation (organized by the NAFTA agreement), located in Montreal, recently prepared a report entitled Continental Pollutant Pathways. There is a summary report and a lengthy volume of Case Studies. I know that the summary report is available, but, I am not sure if the Case Study volume is available. The CEC web page is at http://www.cec.org
Dr. Mark Cohen