Patricia,

You wrote:
>I fail to understand how something that is airborne will get into
>breastmilk and not into cows milk.... don;t they breath the same air we do?
>and if this toxin  binds won't we eat it?

I grew up in an area that suffered dioxin contamination--along the James
River in Virginia, below Hopewell, where a chemical plant (or was it a paper
plant?) discharged dioxin into the water.  My understanding is that the
dioxin travels up through the food chain.  The dioxin settles to the bottom
of the river, and along the banks, and is consumed by the fish, clams, etc.
living the river.  These are in turn consumed by the mammals and birds
living along the river, and are absorbed by grasses and plants along the
river (this is a tidal area, so there are marshes involved).  Eventually,
the dioxin is passed into human food sources (game, farm animals, vegetables
and grains), and to humans.

Scientists at the College of William and Mary in Williamsburg were doing an
ongoing study to monitor dioxin levels along the river, and in the organisms
that lived there, to track its movement through the food chain.  As I recall
(and this is based on memory, so don't trust it completely), 10 years after
the contamination was discovered and halted, they were still seeing dioxin
levels *rising* in animals living along the river.

You can see that there is effectively no way to clean up an estuary such as
the James River, and that the contamination in this case affects the
communities downstream (Newport News, Portsmouth, Hampton) and then the
mouth of the Chesapeake Bay and it's egress into the Atlantic Ocean.
Because all this is a tidal area, there is potential for the dioxin to
travel downstream to the bay, and then back into the bay on the rising tide,
and into other rivers such as the York River (the next river north of the
James).

This contamination must have been discovered in the late '60s or early '70s,
because I last lived there in 1975.  Obviously, those people who relied on
fish, shellfish, and game from along the river for food were exposed
earliest and have the highest potential for problems from dioxin.
Shellfishing in the river was banned for some time, but the ban was
subsequently removed (can't remember when).  Presumeably, the removal was
based on reduction of dioxin levels, but it could have been influenced by
pressure from the fishermen and crabbers, whose livelihood had been destroyed.

Margaret K.K. Radcliffe ([log in to unmask])
Mining & Minerals Engr, Virginia Tech, Blacksburg, VA