Can you answer a question or two?

[Stuart Blood]

A friend referred me to this address for a question I have about
plant chemistry.  Can you help me, or tell me who can?

There's a group in my town that's working on building a small 
garden plot at the elementary school.  The idea is that it will be a great
educational tool, and it will involve the community.  We're
planning on building a raised bed in front of the school, not far 
from the main driveway.  One of the people involved in the planning
raised the concern about exhaust from buses, which will be idling
next to the garden.  The question is, is there a problem with 
toxins from the exhaust being taken up by plants, either through 
the leaves or the roots?

This first question reminds me of another that I'm not able to
answer.  Some friends who recently moved to the suburbs outside of
Boston were concerned about lead in the soil near there new home
(I don't know if the supposed source is lead paint chips, discarded
building materials, or what.)  They have a small child.  The 
question they had was, are there plants that can absorb heavy 
metals through their roots and concentrate them in the leaves or 
fruit.

Thanks in advance for any information you can offer.
_________________________________________________________________
Stuart Blood
RR1 Box 29 
Thetford Center, VT 05075
(802) 785-4950
stuart.blood at valley.net