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Phytoremediation, Park Intern Hannah Schanzer’s Summer Project

Hannah Schanzer is a Park Intern at Solar One this summer, working in Stuyvesant Cove Park. She is a rising junior at Washington University in St. Louis, studying Environmental Policy and Urban Studies. She has come to the Park this summer to learn more about urban park stewardship and urban ecology.

For my summer research project, I really wanted to focus on studying how the urban setting impacts the biodiversity of the park. Stuyvesant Cove Park is situated between a gas station, a power plant, and the highway. Additionally, it is located on the former site of a cement mixing factory.

Preliminary testing revealed that the soil in some beds of the park have slightly elevated levels of lead, although not enough to cause concern with park operations (highest lead concentration in a bed was 80 ppm (parts per million), anything less than 100 ppm is considered safe for children to play in). I was curious to find out whether there was a way to “clean” the soil with the highest lead concentration without treating it with chemicals or replacing it with imported soil.

Some light internet browsing led me to the process of phytoremediation. Phytoremediation is the direct use of living green plants for the  removal, degradation, or containment of contaminants in soils, sludges, sediments, surface water and groundwater. Basically it is a solar powered, natural clean up process. Sunflowers (Helianthus annuus) are famous phytoremediators. Sunflowers are not only able to absorb lead, but other dangerous heavy metals such as arsenic, zinc, chromium, copper, and manganese. Additionally, sunflowers are basically native to New York. There are records of the species in the state dating back 5,000 years.

I decided to test if sunflowers would improve the quality of the soil here at Stuyvesant Cove Park. I have cleared out two 3 meter by 8 meter plots in Beds 12 and 14, the beds with the highest levels of lead. In the coming weeks, I am going to plant a quarter pound of sunflower seeds in trays, then transplant them to the empty plots. In the autumn, when the growing season of the sunflowers is over, the staff of Solar 1 will pull out all of the sunflowers and dispose of them in a landfill so the contaminants the sunflowers have extracted aren’t returned to the soil. Then, the staff will do follow up soil tests in the two plots to see if the lead levels are greater than or less than prior to the sunflowers being planted.

Though this project is small in scale, the potential impacts are wide reaching. If the sunflowers are successful at phytoremediation the soil at Stuyvesant Cove Park, this method could be used at future brownfield sites around the city to make them viable urban parks. – Hannah Schanzer

PS If you have visited the Park lately, you may have noticed some common sunflowers blooming in one of our beds (although the current drought has wilted them some). Those are not Hannah’s sunflowers; those are rogues. We have a few every year!