North American Fruit Explorers mailing list at ibiblio

[Rick Valley <bamboogrove@cmug.com>]

> From: list@ginda.us

> 2)  Lead from gasoline fumes is more prevalent than I would have
> guessed.  I nearly bought one house that bordered a semi-major road.
> (Not a highway, but a town road with traffic most of the day.)  There
> was a striking gradient across the yard.  The gradient isn't nearly as
> steep as with paint - obviously, fumes travel farther than chips.
> Right by the road the levels were about 500 ppm which is high enough
> that I'd prefer not to grow edible leaves, and maybe not edible roots.
> Edible fruits would probably be okay, though.  100 feet from the road
> the levels were down to perhaps 100-200 ppm (I don't remember exactly,)

This is interesting because it contradicts findings cited in Lead in Seattle
Community Gardens, a paper from Center for Urban Hort. in Seattle from
around '86. They said that levels correlated with intensity and length of
human (read "civilized" human) occupation of a site, not distance from a
road. Probably sampling differences, also the gardens are all tilled.
 
> 4)  Covering the soil with mulch works pretty well to keep the lead out
> of reach.  

it also impedes dust and splash contamination
> 

> One hypothesis:  Lead in plants seems to show up in the same places as
> calcium.  So "green leafy vegetables" are the most dangerous, and
> fruits the least dangerous.  I don't know this for sure, but if I was
> growing veggies in modestly contaminated soil, I would avoid the ones
> that are supposed to be good calcium sources.

and lead hits children harder because they are adding more calcium to their
bodies.

A health officer told me the #1 best thing to do was to take your shoes off
before entering the house, Japanese style.

I have, more than once, scalped an entire yard, and re-contured to eliminate
lead. I think its a very quick way to procede, if you're re-doing a
landscape, because lead doesn't leach down, but stays in the surface zone.
I've never had a yard that couldn't spare some dirt, and it makes fine
landfill cap.

-Rick