[GBlist] About fruit trees in contaminated soil.

[Bob Burns <bobburns61@yahoo.com>]

Try doing your searches and research using the word
"bioremediation".  Essentially, active microbial
activity will break down or bind up most chemical
contaminants.  Bringing in lots of organic matter and
encouraging a lot of very active composting on the
site, perhaps feeding most of the topsoil gradually
through some compost systems; ought to do the trick
after a few years.  Microbes of various kinds are now
being specifically bred and multiplied for release
onto particular types of spills. I suppose you could
spend a bunch of money and have residue testing done
periodically for several key
(i.e. resistant to breakdown compounds) chemicals till
these reach safe levels before planting edibles.
You could also try a canary in the mine approach by
establishing a pond ecosystem on the site and put soil
from the site into the pond and observe the effect on
the pond life.   A healthy aquatic ecosystem, able to
support and breed healthy fish, amphibians, aquatic
insects and plants is a pretty good indicator that
serious contaminants have been taken care of.
       The other option might be to altogether remove
a lot of the contaminated soil and replacing it with
other soil, though that sounds a little like passing
the buck.
               --Bob Burns
               Salamander Springs Permaculture

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