[Community_garden] Zinc and Cadmium and Heavy Metals

[Vicki Garrett]

Hi Karen,

All the biosolids arguments are in the archives. Are you volunteering to
compile them ;-) ?

Vicki


-----Original Message-----
From: community_garden-bounces at list.communitygarden.org
[mailto:community_garden-bounces at list.communitygarden.org]On Behalf Of Karen
Jones
Sent: Saturday, March 22, 2008 10:02 AM
To: community_garden at list.communitygarden.org
Subject: [Community_garden] Zinc and Cadmium and Heavy Metals

Hi All,  I could see this coming from the bio-solids conversations, which I
really enjoyed. (Too bad someone did not have the time to compile those
informative convos). I'm not a toxicologist but we tested our garden for
Nickle, Manganese and Lead and did a bit of research on heavy metals and
here is what I found out.  No levels of heavy metals are safe. Heavy metals
are not biologically active and they tend to accumulate in tissues until you
have physiological stress and wow, you are wandering around wondering where
you live, seeing double etc. Even sub-clinical levels of heavy metals can
contribute to things that look like Attention Deficit Disorder etc. But, The
organs of the plant that sequester the heavy metals are leaves and roots. If
you know your plant parts you can eat fairly safely. Potatoes are modified
stems, safe to eat, if washed well, rhurbarb is the petiole not the leaf,
safe to eat, all fruits (beans, corn, squashes, tomatoes, peas etc. are
safe,they are fruits)  and other things you think of as real fruits
(strawberries, apples, plums etc).  Any leafs (spinach,lettuce, cabbage) are
dodgy.  However, most heavy metals are breathed in as dust, so always wear
gloves and always wash anything that you eat from the garden. Also, bad news
if you live in a house that is older than 40 years, you have a heavy metal
halo around your house. Heavy metals are persistant. Children under 2 should
not be allowed in a garden because of the high incidence of pica (soil
eating). Last year 59 community gardens were shut down in Montreal, toxic
with heavy metals. This just happened to coincide with needing room to build
houses and it just became expedient to shut them down then. There are lots
of toxic gardens in Winnipeg. They just don't need the land for houses yet.
When gardening you have to know what you are doing and be careful. Land can
be rehabilitated through growing things like sunflowers and canola. But then
when these crops are taken off the soil they have to be treated as toxins. I
totally agree with Mike no heavy metals are safe. They bioaccumulate, they
are not biologically active and  every little bit accumulates.  Keep those
tires out of your garden.  Heavy metals and gardens do not mix. Garden
safely!  Karen

_______________________________________________
The American Community Gardening Association listserve is only one of ACGA's
services to community gardeners. To learn more about the ACGA and to find
out how to join, please go to http://www.communitygarden.org

To post an e-mail to the list:  community_garden at list.communitygarden.org

To subscribe, unsubscribe or change your subscription:
http://list.communitygarden.org/mailman/listinfo/community_garden_list.commu
nitygarden.org