Emory University’s HERCULES Exposome Research Center funded a community-engaged pilot project investigating urban soil contamination in Atlanta. The study has led to an EPA site investigation and is an example of how partnering with communities strengthens science and expands its impact.
The original goals of the study were to: 1) quantify levels of heavy metal and metalloid (HMM) soil contamination and bioavailability in urban gardens; and 2) determine the potential of commonly used plants and practices to reduce the HMM concentration and bioavailability. In total, 355 soil samples from 19 neighborhood home gardens and yards were analyzed for lead, arsenic, chromium, cadmium, and 20+ other HMM.
The study was co-designed with a local community-based organization and HERCULES partner, Historic Westside Gardens (HWG). HWG installs home gardens in residents’ homes and provides training, mentorship, and a food market collective. Their home gardeners wanted more information about HMM soil contamination in their gardens and helped identify community researchers to collect soil samples from their home gardens and yards.
All samples were analyzed via X-ray fluorescence (XRF), a handheld instrument that can test for over 25 HMM in 90 seconds. For lead, most samples were above the University of Georgia’s Low Risk Levels for agriculture of 75 ppm and a few were also above the Environmental Protection Agency’s (EPA) residential regional screening level (RSL) of 400 ppm. The samples above the RSL were generally near older housing and not used for growing food. Samples from garden beds and active growing sites were lower than those without beds or anything growing. One community partner lowered the concentration of lead in one bed from above the EPA RSL to below 75 ppm by adding in new soil and plants. By sharing data, partners were able to make relatively simple behavior changes to lower exposure risks.
A subset of samples was also analyzed through the HERCULES Targeted Analysis Core to test the validity of XRF readings and the bioavailability of HMM in simulated stomach and intestine environments. Lead concentrations analyzed in the lab correlated well with XRF results, but other HMM did not. Additionally, the bioavailability of lead was significantly correlated with the soil concentrations, illustrating the importance of further research.
During a soil shop event hosted by HWG, community partners asked about an unknown rock-like material seen in their yards. The team consulted with a geologist who identified it as industrial slag. Analysis showed that the slag and the soil beneath it had lead and arsenic concentrations well above EPA RSLs. The academic and community partners met with the EPA and Georgia Department of Public Health to discuss strategies. The EPA initiated a Removal Site Evaluation and is assessing the scope of the investigation – slag has now been identified at multiple sites in the neighborhood. It was only through partnership with the community that this potentially harmful exposure source was identified, leading to immediate action by regulatory agencies.
The HERCULES scientists and Community Engagement Core continue to collaborate with the affected community and involve community residents in the ongoing investigation and dissemination of results. Most recently, the team co-hosted an event through the Atlanta Science Festival showcasing study results, offering free soil testing, and promoting best practices to lower exposure. A new HERCULES pilot grant has been awarded to continue the project through Spring 2020. The next phase will focus on greenhouse and field phytoremediation projects, as well as biomarker analysis of children to assess health impacts of the elevated soil concentrations found in the initial pilot.
Learn more about the project here: https://atlsoilsafety.com/