[permaculture] Study about lead in gardens

Lawrence F. London, Jr. lfl at intrex.net
Fri Dec 12 03:11:19 EST 2003


Marimike6 at cs.com wrote:

> In a message dated 12/11/2003 8:58:12 AM Eastern Standard Time, 
> dtv at mwt.net writes:
> 
>>
>>   The good news, engineers at Northwestern University now report, is
>> that even in heavily lead-tainted dirt, most of the metal usually
>> becomes trapped in the parts of plants that few people eat, such as
>> roots and stems. Indeed, the new data indicate that intentionally using
>> inedible plants to sop up lead could prove a low-cost strategy for
>> detoxifying backyards and school grounds, making them safer for
>> children.
> 
> 
> 
> Lawrence--  Help us out here. What are the names of some grasses that 
> are good for sequestering heavy metals?

Here's something:

Something you should research is the pH ofyour soil.  I understand that
lead will only become available to plants when the soil in more acidic.  I
am not sure whether this applies to leafy vegetables.  As far as removeing
the lead from the soil, a big problem.  You might be better off building
beds with a soil compost mixture.  Getting back to the availability of lead
to plants, a soil fertility text book would present the effect of pH on
lead availabilty.  Contact me if you are not able to locate it.
-- 
               Thomas Hansmeyer
               USDA-ARS
               St. Paul MN
               hansm001 at maroon.tc.umn.edu

 From dgilrein at cce.cornell.eduTue Sep  5 23:12:14 1995
Date: Tue, 5 Sep 1995 17:42:01 -0400 (EDT)
From: Daniel Gilrein <dgilrein at cce.cornell.edu>
To: sanet-mg at amani.ces.ncsu.edu
Cc: Andrew Senesac <asenesac at cce.cornell.edu>
Subject: Plant for reclaiming lead-contaminated land

     A co-worker is interested in any information related to
growth/production of Paspalum conjugatum, or sour paspalum, a grass he
claims is an accumulator of lead.  His thinking is that it may have value
in reclaiming lead-contaminated soils.  Any references or sources of
information on its growth, management, production or use for this purpose
would be of interest - please pass along to me.  Thanks.

Date: Sun, 23 May 1999 22:26:21 -0400
From: Kevin Topek <ktopek at bellsouth.net>
Reply-To: permaculture <permaculture at franklin.oit.unc.edu>
To: permaculture <permaculture at franklin.oit.unc.edu>
Subject: Re: Soil toxin bioremediation

Regarding lead remediation in soil:
     At the Eco Fair in Austin, Texas four years ago there was a symposium on hemp. The
issue of lead contaminated soil in Hungary was addressed and hemp was being used as the
remedial crop. The hemp seed was then pressed for oil and the high concentration of
lead in the hemp oil made it very suitable for stable paint base.  This application was
for non food consumption. I do not remember the refering source, try Hemptech.
     Hempstead, Texas was founded by Sherwin Williams to grow hemp seed for oil based
paints.

<><>
I know of a fern for arsenic update & eventual disposal/recycling. I'd really have to do
some searching to find specific plants for lead. Search words would include bioremediation,
remediation, hyperaccumulation, heavy metals uptake in plants, etc.
Lead, arsenic and mercury are particularly nasty stuff.
I'll try to followup on this and come up with something. A sure bet would be
John Todd's Ocean Ark International website. They deal with issues such as this
all the time. Maybe they would share information with us. Here's URL:
http://www.oceanarks.org/
I have a somewhat old collection of possibly useful material in the following URLs:
http://www.ibiblio.org/ecolandtech/orgfarm/hyperaccumulation/
there's definitely stuff on lead in this one (there are 10 references (documents) here:
http://www.ibiblio.org/ecolandtech/orgfarm/bioremediation/
and possibly in:
http://www.ibiblio.org/ecolandtech/orgfarm/composting
> One fallow season growing these grasses and removing them, rather than 
> turning them under, should clean up an urban garden and make it ready 
> for veggies. The problem is what to do with the chaff. Take it to the 
> landfill, if they will accept it, I suppose.
Absolutely your local hazmat people, county waste management, building inspections
will know exactly what to do. There will be industrial services specializing in removal and tereatment/disposal/recycling of toxic 
materials. Also real estate companies and appraisers will know because when someone sells a house lead pollution in the form of lead paint
anywhere or around the structure(s) will have to be reposted and documented and put on the new deed. You can count on that.

Here's more:

On 29 May 2001 11:02:36 -0600, in sci.environment.waste Tom Hennessy
<watchman at nucleus.com> wrote:

Subject: RE: soil remediation

I have been studying the use of chelators in the removal of metals
from the body.

This seems at the moment to have become very important due to the
lowering of the 'acceptable' levels of lead in the environment.
The soil in the housing project has now become .. unacceptable.. and
the parents and home owners have become very concerned.
The following snip is from the Argonne site and since
their work will probably take years to determine the efficacy of
this remediation I am hoping someone may be able to theorize as to
the effects of simply spraying a solution of phytic acid.. and water
on the affected soil and planting the proper metal accumulating
plants.
The phytic acid .. in theory .. would bind up the metals and therefore
would extend the safety window thus allowing the residents to
continue to live in the area with.. peace of mind.
The phytic acid would render the lead insoluble? and thus allow the
plants to remove the lead over a few growing seasons?
Thanx.
Tom

Subject: RE: soil remediation

Capturing Heavy Metals

Argonne chemists have begun laboratory testing of a new technology to
limit the movement of hazardous radionuclides through the environment.
The
technology is designed to capture heavy metals, such as uranium and
plutonium,
and reduce their solubility, thus keeping them from being transported
in
groundwater. It uses phytic acid, a natural chelating agent
which captures the heavy metal ion through a process called a
cation exchange. In this process, one atom or group of atoms in the
agent
swaps places with the heavy metal atoms in the contaminated material.
Phytic
acid has the added advantage of spontaneously decomposing over time,
releasing
phosphate - which joins with the heavy metal ions to form an insoluble
mineral
- and harmless sugars.

If successful, the technology would be used to treat contaminated soil
at U.S. Department of Energy production facilities. The research is
funded
by the Efficient Separations and Processes Program at DOE.

Funding for the research is provided by the U.S. Department of
Energy's
Office of Basic Energy Sciences, Division of Chemical Sciences.

--
Who loves ya.
Tom
Jesus was a Vegetarian! http://www.nucleus.com/watchman
Moses was a Mystic! http://www.nucleus.com/watchman/light.html
<><>

LL
-- 
L.F.London
lfl at intrex.net
http://market-farming.com
http://www.ibiblio.org/ecolandtech




More information about the permaculture mailing list