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phytoremediation - how to use plants to heal the soil

i was recently reading in the local newspaper about the discovery of heavy metals in the soil of our community gardens. well, i'm sure that this is no new reality - yes, this city has relied heavily on industry and yes, there are still quite a few nasty factory plants around. however, i know that this is by no means a unique situation. i have dabbled in reading about bioremediation and phytoremediation, but am not very science-minded. yes, the chemistry, etc makes enough sense to me, but i want to learn more about people's experience of using plants to rehabilitate soil.

i've heard about a lot of phytoremediation projects over the past couple of years. i'm aware that there has been a lot of research done on the subject, particularly in relation to genetically modified plants - i know, we all hate monsanto but some good things do come out of pandora's box on the occasion. however, i also remember hearing something about phytoremediation projects to rehabilitate the soil in new orleans after katrina hit.

DOES ANYBODY OUT THERE KNOW ANYTHING MORE ON THE TOPIC??? OR DO YOU KNOW OF WHERE TO SEEK OUT OTHER INFORMATION??

the presence of heavy metals, etc isn't a common topic for discussion but as people connecting to the land, trying to make the earth a better place, we need to be thinking about this and talking about it. of course, i'm approaching it from a purely selfish point of view because i want to help rehab the soils in the community gardens in my area... but still, folks, let's start talking about what we can't see - just because heavy metals are out of sight does not mean that it should be out of mind!

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Permalink Reply by Cornelia on April 5, 2010 at 1:56pm

Some information that came across a listserv over the weekend

Here is a neat article from Purdue on recent phytoremediation research:

http://www.agriculture.purdue.edu/agricultures/past/fall2003/featur...

Phytoremediation can be quite effective. I have worked in Superfund cleanup at really badly contaminated Dept of Energy sites (i.e., including nuclear waste!), and we've used it successfully for mercury. I believe the pioneering work was in the EU and Britain, at mine waste sites. But it depends on the metal, and the local soil as well. Different plants must be used for each metal, and not all may take it up in enough to actually reduce the levels. Sunflowers and other flowers, and mustard and other greens have been tried (leafy greens are the biggest bioaccumulators of soil metals; root vegies the next highest in uptake, and "closed" fruits like corn, peas, and tomatoes the least likely to take up the contaminants).

Here's an experiment The Food Project in Boston did with promising, but not sure-fire results:
http://thefoodproject.org/soil-testing-and-remediation

Ok. Now I'm involved. Here's my del.icio.us links for info available online. (There is of course much more in the scholarly literature, but only via libraries or similar subscriptions.)

US-EPA Soil Screening Guidance:
http://www.epa.gov/superfund/health/conmedia/soil/index.htm
Soil Contamination and Urban Agriculture - A Practical Guide:
http://www.ruaf.org/node/1003
(A grad student team project now online at RUAF, this isn't a detailed research review but gives a good overview of the remediation approaches available. Also available at http://mse-research.mcgill.ca/envr401_2002/brownfields/index.html).
Urban Soils Potential Contaminants and Remediation Techniques:
http://www.cityfarmer.org/urbansoils.html
A good short overview by an environmental scientist, who reports good results with spinach - but it's not clear what soil that was in, so "YMMV" (your mileage may vary!)
Lead info from U-Minnesota Extension:
http://www.extension.umn.edu/distribution/horticulture/DG2543.html
Lead in Soil: CA Dept of Education:
http://www.cde.ca.gov/ls/fa/hs/leadsoil.asp
Lead info in detail from Gray Environmental, a private professional consultant:
http://www.grayenvironmental.com/lead.htm
Abstracts of articles about urban soils and Pb:
http://asap.sustainability.uiuc.edu/groups/Urbansoil/usqipublicdocs...
What the White House Garden did to lower lead availability in its soil:
http://www.nytimes.com/2009/08/13/garden/13lead.html
New York's situation, as reported by NYT:
http://www.nytimes.com/2009/05/14/garden/14lead.html?_r=1&hpw=&...
Boston article, a nicely done thorough examination:
http://www.boston.com/news/science/articles/2008/08/11/lead_may_lur...
Problems in industrializing countries as well, like India:
http://www.new-ag.info/03-5/focuson/focuson4.html
(Interesting, though undocumented note: "Although contamination by lead can be reduced by 50% with two separate washings in clean water, further washing has no effect, and washing does not reduce the level of zinc and cadmium.")
Typical soil testing types and procedures, Univ Delaware Extension:
http://ag.udel.edu/other_websites/DSTP/general_information.htm

As you can see, I'm collecting links on Urban Gardening & Lead! Any additional links would be appreciated.

Claudia
Soil Stewards campus organic farm
Moscow, Idaho