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Using Super Plants to Clean the Environment. Radin, J.W. June
2000. Agricultural Research. 48(6):2. (Journal article)
Certain plants can detoxify the soil. Plants described in this
article are virtual vacuums for cleaning up chemicals and harmful nutrients that
pose health threats to humans and the environment. The act of using nature to
detoxify, called phytoremediation, can be an effective way for the system to be
rehabilitated. For the backyard gardener, a number of plants have been suggested
to purify your soil. Alpine pennycress (Thlaspi caerulescens) has been reported
to accumulate excesses of zinc and cadmium — as much as 10 times more than
normal, and plants in the Brassica family, like mustard and canola, thrive on
selenium and boron-laden soils. The finish to the short article is a disclaimer
that research in phytoremediation is slow and complicated. Eight years later,
the research provides much more and we invite you to visit the Missouri
Botanical Garden website (www.mobot.org/jwcross/phytoremediation/)
for more current information on ferns accumulating arsenic and cottonwoods
accumulating mercury and more. You can also access complete articles at this
website.
Microbial Immobilization of Cadmium Released From CdO in the
Soil. Kurek, E. and J. Bollag. 2004. Biogeochemistry. 69(2):227-239.
(Journal article)
Cadmium is a heavy metal known to have harmful effects on soil
microorganisms. The writers provide us with the basics on cadmium and its
presence in the soil, and explain that synthetic fertilizers are the primary
source to spreading this toxin in the environment. Traditional solutions to
resolving most forms of soil poisoning include costly soil replacements or
chemical treatments, but detoxifying the soil is possible, only recently, as
this article suggests, with various specialized microbes. We caution that this
is a technical article but mention it because the toxicity and the understanding
of the fate of cadmium metal (or any other metal for that matter) in the soil
are important. The first step for us, as homeowners, is to know what chemicals
reside in our soils. This may involve reflective thinking about our properties
as historic urban places that most likely included multiple owners and chemical
usage at a time when application was more acceptable than it is today.
Evaluation of Extraction Procedures for Removing Lead from
Contaminated Soil. Tawinteung, N., P. Parkpian, R. Delaune, and A. Jugsujinda.
2005. Journal of Environmental Science and Health. 40(2):385-407.
(Journal article)
Lead is another metal known to be harmful to humans. The
researchers of this article chose to clean lead-contaminated soils that were
collected from sites located near an abandoned battery factory and a secondary
lead-smelting factory. Complicating their clean up is the fact that lead is very
difficult to remove once it is present in the soil. Identification, sampling,
transport, and extraction methods, including soil washing and flushing are all
documented as well as a good discussion of how lead interacts with the soil, and
where it might be found in our yards.
Graphs and tables show the soil washing process, distributions
of lead in the soil at the study area, and soil flushing. The tables show
certain soil types and physical characteristics of contaminated soil samples.
What are their conclusions? Soil farther from a lead source is less
contaminated, and soil flushing and washing are both effective in removal of
lead from the soil.
Improvement of Degraded Physical Properties of a Saline-Sodic
Soil by Reclamation with Kallar Grass. Akhter, J., R.Murray, K.Mahmood, and K.A.
Malik. 2004. Plant and Soil. 258(1):207-216. (Journal article)
While soil with salt build up may not be a problem in the
Portland area, salt-tolerant plants can improve the physical characteristics of
saline soil around your home. Just what saline soil is and why it is a growing
concern, is addressed in this Journal article. Akhter et al. recommend kallar
grass for better water-retention capabilities in your soil. Where to plant the
grass, how much to plant, and in what soil types, are covered in this issue of
Plant and Soil. The conclusion is that, over time, with age and maturity, kallar
grass improved soil’s ability to retain water along with soil porosity, which
allows salts to leach from the topsoil.
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