Jon:
>If lead (or heavy metals or whatever) are NOT relatively stable when
>buried by silts/clays/organic materials (relative to Exposed toxins) then
>we are all in jeopardy every time we get splashed with water waiting for
>a Ferry in Elliott Bay or Commencement Bay.... The fishes should be
>turning belly-up and the birds kicking their little feets into the air...

This actually reminds me of a real-life mystery. The eagles on the
lower Columbia still lay eggs which have very fragile, thin shells.
This despite the fact that in other places eagles lay eggs which,
while thinner to some degree than those in museum collections,
are strong enough to resist crushing during brooding - "good enough
for now".

The sediments on the river floor at the mouth are known to be
laden with PCBs and other long-lived contaminants.

The problem is that, as of a few years go, no one could come
up with a mechanism which explained how the contaminants were
gettingn from the sediment into the eagles. A lot of testing
of fish, other birds, etc was going on and indeed it's still
an area of research there (currently, I understand that they're
testing heron eggs to see they can correlate the PCB load of
them with that of eagle eggs - important because the test
destroys the egg and we got a lot more herons than eagles).

Don't know if they've figured out the chain of events, though
obviously if they're looking at herons they must believe the
chain of events leads to contamination of fish.

But this should serve as an example that demonstrates that
"locking up" of contaminants in stable sentiment is not
necessarily an unusual occurance.

Oh, the "eagles" in question are, of course, baldies - didn't
say that explicitly.

- Don Baccus, Portland OR <donb at rational.com>