By: Leanna Ehrlich, Office of Sustainability Initiatives
Q: What are the origins of the soil remediation project?
ES: My lab is working on greenhouse gas emissions, and we’re interested in how different agricultural techniques for growing corn affect greenhouse gas and ammonia emissions. We realized there was a lot of urban gardening going on in Atlanta, but no regulation for heavy metal testing before you grew food. We found the addresses of where the city was planning to lease land for the AgLanta Grows-A-Lot program and decided to test the soil before people started practicing agriculture on the land. One of the sites had higher than 400 parts per million (ppm) of lead—the threshold decided by the EPA to determine unsafe levels of lead in soil. Then we thought, if that’s the case, maybe other parts of Atlanta, especially West Atlanta, might also have high lead levels. We started testing the soil, and unfortunately found a lot of contamination. That led to a current EPA investigation.
Q: How was the soil contamination issue addressed through the results of your research and the work that you’ve done?
ES: We partnered with an organization called Historic West Side Gardens ATL, Inc (HWG). We tested the soil of the community garden that’s owned by HWG, and then also the backyards and house gardens of the HWG members. After we tested those initial gardens, we brought the test results to people called the “Garden Angels” —the leaders of HWG. We shared the results that we found, especially noting the several sites that had lead levels much higher than 400 ppm. Two sites were actually backyards belonging to two of the Garden Angels that were there at the meeting.
We discussed the issues and what they could do. One of the Garden Angels brought in a sample of slag—a waste material that comes from smelting [metal]—to the tomato festival that we organized together. She thought the slag might explain high contamination levels around her backyard. An EPA colleague and I tested the slag at the site, which showed very high levels of lead. This finding led to the EPA investigation. The EPA tested more soils from the neighborhood, and since the beginning of January, have started to excavate the contaminated soils. They cut the trees, dig up to two feet of soil found to have more than 400 ppm of lead, and then put in new clean soil. But the soil had to meet the 400 ppm threshold— if it was even a few ppm below that, they would not excavate.
In my lab, we tested if plant-based soil remediation could work instead to remove heavy metals from the soil. Two of my masters students did this experiment for their thesis. One student, Xinyi Yao, worked with four different plants in a greenhouse. She got soil from a contaminated site and then grew the plants in the soil in a greenhouse. Another student, Alicia Wun, worked with one of the Garden Angels, Rosario Hernandez, to plant sunflowers in Rosario’s backyard for remediation. Cowpeas, also, turned out to be pretty effective for soil remediation. Cowpeas are also edible, but we found out that it is actually dangerous to be eating these fruits after being used for soil remediation, especially for children. For this reason, we did not recommend planting cowpeas as a soil remediation measure. We will now test further to see if phytoremediation could be used for places where the lead contamination is below 400 ppm, but above 75 ppm, the level deemed by the University of Georgia to be safe for agriculture.
Q; How has the COVID-19 pandemic affected the remediation strategy?
ES: There are so many different layers to this project. The EPA decided to investigate based on the contaminated slag sample. They went into the neighborhood to first investigate 60 sites, and they found so much contamination that they increased it to 368 lots. Then after that, they increased to about 1100 lots. With the first group of 368 lots, the EPA found that they were only able to get about 30% of the lots to be tested, because many residents weren’t agreeing to have the soil tested. This stemmed from a lot of distrust, so my lab at Emory, together with HWG partners, were knocking on doors, explaining the reasons for the soil testing. Luckily, more residents agreed to have their soil tested. Now, because of COVID-19, we had to stop this community outreach. That has been really hard for us. The EPA is still excavating the soil, though less frequently, even with the shelter in place order for Atlanta.
There is also another problem entirely, which is the link between nutrition and lead exposure. Residents would want to be taking certain vitamins, calcium, and zinc to counteract lead toxicity. Poor nutrition can worsen the effects of lead exposure, and this is especially true for children. That’s not something that people are thinking about too much right now, but because of the rising unemployment rate and everything else going on, people might have worse nutrition than usual. That can intensify the impact from lead exposure. We’re very concerned about this.
Q: Is there anything that Emory community residents can do to support the work?
ES: We’ve been thinking about creating a virtual community where people can learn about our project and about how to raise awareness. It would be really great to find people who, for example, could make videos about soil safety and gardening, since so many people are now interested in having urban gardens because of COVID-19. We want to make sure people know there’s potential heavy metal contamination and how they should address this before planting. I think that’s going to be very important. We’re open to good ideas from anyone about how to get people involved in an online community. They can also donate here to Emory’s Office of Sustainability Initiatives and earmark the donation for funding Dr. Saikawa’s research.
To learn more, visit atlsoilsafety.com, and to get involved, contact Dr. Eri Saikawa at eri.saikawa@emory.edu