Science is not just for the elite. Anyone can wield its power, including when it comes to planting. Phytoremediation is when plants are used to make contaminants in soil, air and water less harmful. The method makes it easy to get your guerilla gardening on.
Specific plant species have the ability to remediate certain contaminants like heavy metals, petroleum-based chemicals and Polychlorinated Biphenyls, commonly known as PCBs. The conventional way to handle on-site pollution is to excavate soil and replace it with clean soil from somewhere else. This is expensive.
The Environmental Protection Agency holds landowners responsible for cleaning up any contamination on their property, even if it happened before they bought the property. This makes former industrial sites less appealing to buy.
Instead of waiting around for a developer to clean up vacant lots, citizens can do it themselves. The ground has thawed; it’s time to get seeds started.
Chromium is taken up by sunflowers and stored in the stems and leaves. Paul’s Scarlet Climber Rose releases chemicals that support bacteria that degrade PCBs into a nontoxic form. Mercury can be taken in by a plant and then released into the air, but that is still being researched.
Scientists made these connections seemingly by accident. On highly polluted sites where it appeared no life should exist, these plants got along fine. Slowly, the cases were studied until phytoremediation became a viable technique for cleaning up contaminants. This isn’t something you could sit down and do calculations to figure it out. You had to be there in Tyvek suits taking samples.
You Are the City published ‘Brownfields to Greenfields: A Field Guide to Phytoremediation.’ This is a booklet of instructions for soil testing and planting plans to encourage citizens to use phytoremediation in their neighborhoods. The plants listed in the guide are available and inexpensive. A field lab at la Finca del Sur in the South Bronx is demonstrating the techniques discussed in the field guide.
Though this project is directed at New York City residents, it is relevant for the city of Syracuse. More than 10 percent of Syracuse is vacant lots, some of which people are hesitant to buy or use because of potential contamination. I know an urban ecology class here tests for lead in the soil of student rentals in the university neighborhood, and the results are not comforting.
Phytoremediation can be highly effective under the right conditions and frequent retesting of soil is imperative to determine its success. Thoroughly consider the site’s history to determine if this is a project that requires an expert. Is the pollution very deep in the soil or is it just on the surface? Do you need to consider how the groundwater is affected?
The field guide gives guidelines about appropriate levels of different toxic materials depending on the site’s use. Proceed with extra caution if you intend on growing food or if young children will be playing there.
Let the plants take care of all the biochemistry. All you have to do is take a few soil samples and make a couple of strategic planting decisions.
Science is for everyone. And so are flowers.
Leanna Mulvihill is a senior forest engineering major and environmental writing and rhetoric minor. Her column appears every Tuesday. She can be reached at lpmulvih@syr.edu or followed on Twitter at @LeannaMulvihill.