Heavy metals in plants

MEK104 at psuvm.psu.edu MEK104 at psuvm.psu.edu
Fri Dec 11 09:03:23 EST 1992


I'm out of my field here, but I'm somewhat involved in a study here at Penn
State which might at least be interesting, if not relevant to this budding
'heavy metal' discussion.  About 100 years ago in the Eastern US, the
"cahrcoal-iron" industry was pretty big business.  Travelers through
Pennsylvania can still see the huge, stone iron furnaces in state parks and
the like.  The iron workers would fire the furnaces with charcoal which they
produced themselves from the surrounding forests.  One can walk through the
woods almost anywhere in PA and encounter numerous "charcoal hearths" -
elliptical or circular flat areas about 10 to 12 meters across with very
little or no woody vegetation.  The study was designed to try and pin down
why woody vegetation is virtually excluded from these hearths even after 100
years.  I might add that the surrounding woods were heavily logged during
this period, clearcut on 40 year rotations was common.  Needless to say the
woods are growing quite vigerously, but not the hearths.  Tissue-water
relations of test plants (my field) suggest some form of drought stress.
The soil on these hearths is up to 70% organic matter due to charcoal dust
and fragments.  Can there be some heavy metal residue that may have been
concentrated by stacking 10 cords at a time on these hearths and coaling
them?  Some hearths were used very many times over.

Mark Kubiske                < MEK104 at PSUVM.PSU.EDU >
School of Forest Resources
Penn State University



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