Heidi,
       The confusion results from the method that contaminants reach
breastmilk. Breastmilk is one of the very few avenues for the body to remove
contaminants from a woman's fat stores.  So it is not the contamination that
she is presently ingesting that is the concern.  It is her life's
accumulation of contamination!  It is of greatest concern if the woman were
to drop a lot of weight suddenly, dumping a large amount of the chemicals
into her blood stream. The body does metabolize the contaminants just not at
a very fast rate.  It is my understanding that it is also of greater concern
for a first infant.
        The majority of the research is theoretical based on the analysis of
the body fat of cadavers, then extrapolating what the level would be in
breastmilk.  Obviously some situations such as the Michigan problem were
directly due to current contamination of the food and water supply.
        Personally I strongly support the LLLI recommendations of moderate
weight loss, and as close as possible to a 'clean' diet. They have an
excellent press release on the issue.
        In my experience, environmentalists use the possible contamination
of breastmilk as an emotional 'hook'.  They are not concerned about the
impact on breastfeeding rates, or the risks of formula.  They just want a
lovely issue that will catch the public's attention. The line that 'Even
Mother's milk is contaminated' is a great publicity getter.
        There has been considerable information/concern in Canada over this
issue, especially concentrating on the Great Lakes area and the far north.
Unfortunately over the years there has been some spectacularily
irresponsible news releases from some very prominant environmental lobby
groups.  It is a major source of frustration on my part that these groups do
not realize the damage they do, or recognize the value of breastfeeding.  In
some contacts I have had, the lobbyists have been extremely adament that
they will NOT breastfeed as it is so dangerous  -- and in one case, as a
feminist (and a scientist) she wouldn't participate in the barefoot and
breastfeeding at home tyrany. (No I did not scream).

        Rhoda