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Chronological Thread  
  • From: "David Tannen" <david AT centerville.net>
  • To: "Market Farming" <market-farming AT lists.ibiblio.org>
  • Subject: Re: [Market-farming] Cadmium in auto exhaust
  • Date: Sat, 11 Sep 2004 07:26:18 -0500

Dainty plant can power-clean cadmium-contaminated soils
September 10, 2004
ARS News Service
Agricultural Research Service, USDA
Delicate, white flowers belie the ability of the small plant called alpine
pennycress to lift huge amounts of cadmium from contaminated soil.
Agricultural Research Service agronomist Rufus Chaney, of the Animal Manure
and By-Products Laboratory in Beltsville, Md., and a group of international
scientists have found the plant can concentrate about 8,000 parts per
million of cadmium in its leaves.
Cadmium is a naturally occurring element that is widely distributed in the
Earth's crust, but zinc mining and smelting wastes can cause high cadmium
contamination.
In 1992, the team of scientists from ARS, the University of Maryland, the
University of Melbourne-Australia and Massey University-New Zealand began
working with alpine pennycress (Thlaspi caerulescens), a plant capable of
accumulating vast amounts of cadmium and zinc in aboveground leaves and
stems.
Using this plant, each year farmers could move soil metals into the
harvestable plant shoots, making it possible to gradually reduce the soil
concentration of cadmium to safe levels.
The cost of this remediation method, called phytoextraction, is about $250
to $1,000 per acre per year, according to Chaney. The alternative cleanup
method--removal of contaminated soil and replacement with clean soil--costs
about $1 million per acre. Most highly contaminated soils can be deemed safe
after 10 years of phytoextraction, thus producing an effective cleanup at a
far lower cost.
In 2000, a patent was filed by the University of Maryland on the use of
alpine pennycress to remove cadmium from soil. No other similar technologies
currently exist for remediation of cadmium-contaminated soils using plants.
Cadmium phytoextraction using alpine pennycress has since been licensed to
Phytoextraction Associates, LLC, of Baltimore, Md., which will soon conduct
a commercial demonstration of the process.
Research is under way to develop a "super" phytoextraction plant.
Chaney's research is described in the September issue of Agricultural
Research
magazine, available online at:
http://www.ars.usda.gov/is/AR/archive/sep04/plant0904.htm
ARS is the chief scientific research agency of the U.S. Department of
Agriculture.

----- Original Message -----
From: <miranda AT tagoresmith.com>
To: <market-farming AT lists.ibiblio.org>
Sent: Friday, September 10, 2004 5:15 PM
Subject: [Market-farming] Cadmium in auto exhaust


> Cadmium and other heavy metals are just as injurious as lead is. The
> plants that absorb the greatest amounts of these pollutants are leafy
> greens, then root crops, flowers, and fruits, in that order. As a
> general rule of thumb, community gardeners in urban areas are advised
> not to feed anything but fruits--tomatoes, cucumbers, and so on--that
> have been grown in their gardens to children under six.
>
> One of the best indicator crops is green chard. If the leaves are
> particularly curled, you can bet that the cause is air pollution.
>
> Soil testing labs can test for heavy metal contamination at a low enough
> cost to completely justify it.
>
> Miranda Smith
>
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