From :  Thompson, Dean <dthompso@NRCan.gc.ca>
Sent :  January 18, 2005 2:05:55 PM
To :  "'theriaultjoel@hotmail.com'" <theriaultjoel@hotmail.com>
Subject :  Herbcide information for Canadian forestry
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Attachment :   ThompsonandPitt2003-AnnalsofForestScience.pdf (0.49 MB), PesticidesinForestryII.doc (0.24 MB)
Joel:

It was interesting talking with you last evening.  As promised please find
below references to a couple of websites that will provide a substantial
amount of information pertaining generally to your questions.  Both sites
are free access!  

http://www.glfc.cfs.nrcan.gc.ca/cfpm/
http://extoxnet.orst.edu/

The first is our own Canadian Forest Management Database website which
provides abstracts (1 page) of scientific information on literally thousands
of scientific journal articles pertaining to Canadian forest management with
a wealth on pesticide fate and effects in forestry.  The database is quite
user-friendly and completely searchable.  See instructions on how to conduct
searches on the first page of the website if you are not familiar with doing
this.  For your current issue, you may want to do a general search for any
article containing the keyword "glyphosate"  or the tradename for this
herbicide "Vision".  You can do a similar search for articles on "2,4-D".
You can narrow the search right down, for example to "glyphosate and bears"
but I doubt you would find anything there for the reasons we discussed.

The second is the EXTOXNET website which is maintained by Oregon State
University, this site provides detailed scientific summaries of
toxicological and environmental fate data for a great many pesticides
including 2,4-D and glyphosate.  On this sites main page, you will want to
click the link on Pesticide Information Profiles (PIPs) in order to go
directly to information summaries on these two compounds.
As I mentioned last evening, based on my knowledge there is an exceedingly
low probability that there would be any toxicologically significant residues
of either 2,4-D or glyphosate herbicides in bear meat.  Unlike DDT and some
other very old pesticides, neither of these herbicides have the appropriate
physical-chemical characteristics to be highly persistent in either the food
that bears eat nor to be bioconcentrated through the food chain and retained
in animal tissues.  Both are readily biodegradable in the environment and
both are easily metabolized (degraded) and excreted in the urine and feces
of  mammals.  To my knowledge there has never been any evidence of
accumulation of either compound in any test animals.  As an example, the
absorption of 2,4-D is almost complete in mammals after ingestion and nearly
all of the dose is excreted in the urine. In humans the majority (about 82%
of the dose) is excreted as unchanged 2,4-D in the urine  The half-life (the
time for 50% of the compound to dissipate from a given compartment in this
case the whole body) is between 10 and 20 hours in living organisms. There
is no evidence that 2,4-D accumulates to significant level in mammals or in
other organisms [20].  Very similar statements pertain to glyphosate and
both are discussed in the EXTOXNET database.
Another reference that deals with your issue directly is the United States
Department of Agriculture - Forest Service Publication entitled Pesticide
Background Statements.  In that huge reference book, there are calculated
estimates of dose levels and toxicological risk levels for common wildlife
species based on their foraging rates etc.  You could get your hands on it
through a local library if you are really interested in that aspect.  In a
nutshell, that data indicates that most animals cannot consume sufficient
amounts of contaminated food to generate a toxicologically significant dose
in their bodies, this is particularly true for large animals.
Finally, I am attaching herewith a review article and a book chapter that I
have written to give some background on herbicides and other pesticides used
in forestry, as some general background information.

 <<Thompson and Pitt 2003 - Annals of Forest Science.pdf>>  <<Pesticides in
Forestry II.doc>> 

I hope this addresses most of your concerns.    

Sincerely, 
Dean G. Thompson (Ph.D.) 

Canadian Forest Service - Natural Resources Canada.  
1219 Queen St. East
 Sault Ste. Marie Ontario.  P6A 2E5.
Tel:  705-541-5646
Fax: 705-541-5700
Email: dthompso@NRCan.gc.ca

Service canadien des forêts -  Ressources naturelles Canada
1219 rue Queen est
Sault Ste-Marie (Ontario) P6A 2E5
Bureau: (705) 541-5646
Télécopieur: (705) 541-5700
Courrier électronique: dthompso@nrcan.gc.ca