BSLA
/ TOOLBOX
POLLUTANT
PURGING PLANTS
Us in g Phy t ot e c h n olog i e s To
Cl e a n Up C ont ami n at e d S o i l s
A n d G ro u n dwat e r
KATE KENNON, ASLA
S
o you’ve had the soil tested and it’s not good news. Can
plants help remediate your site’s contaminants? Costeffective phytotechnology (phytoremediation) plantings
can be effective in mitigating on-site pollutants, but these
interactions are complicated, sometimes taking decades
for remediation, and many times plant-based remediation
strategies are not a good fit for environmental cleanup. When
do they work and when don’t they? There is a lot of confusion
around what phytotechnology can and cannot accomplish.
However, with careful research and planning, integrating this
relatively new technology into design work can result in huge
financial and environmental benefits.
Definition
Phytotechnology is the use of vegetation and their associated
microbes to remediate, contain or prevent contaminants in
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Potential contaminants can be anticipated by site
program and landscape systems can be designed to
intercept contamination events before they occur.
soils, sediments and groundwater. The
term phytoremediation, where plants are
used to remediate sites that are already
polluted, is often used interchangeably
with phytotechnology, but is only one
subset of the field. Phytotechnology
is a much broader term that includes
techniques such as pre-emptive
installation of vegetation to mitigate
ecological problems before they actually
occur, as well as stabilization of pollutants
on site, beyond just contaminant removal.
Green roofs, constructed wetlands,
bioswales, bioenergy crop cultivation
and phytoremediation plantings are all
forms of phytotechnology, a term which
encompasses all uses of plants to meet
environmental and technological goals.
History of the Field
The field of phytotechnology in the US
was named and formally established in
the 1980s. In the 1990’s a large number
of phytotechnology greenhouse and lab
experiments were published, showing
a potential for plant-based clean-up
approaches to a broad range of pollutants
in groundwater and soils across many
site contexts. Quite a few plants found to
hyperaccumulate metals were discovered
during the same time period, and