ANTHROPOGENIC FOOTPRINT OF TRACE METAL CONTAMINATION IN PALMER COVE PARK, SALEM MASSACHUSETTS

Urban community gardens and parks are prone to the possibility of anthropogenic contamination. Many urban parks and gardens, especially along the rocky northeast coast, are constructed above past landfill sites. Along with road dust, leaded gasoline, and paint; superimposed landfills have potential to be an important source of contaminants. This study focuses on a community garden located at Palmer Cove Park in Salem, MA. The park was created in 1970 on top of a landfill site that was active for more than 50 years. Much of the landfill contains debris from the great conflagration of 1914, a massive fire that demolished many buildings of historic Salem. Previous studies at the park directly sampled the buried debris and results show that both Pb and Cr are above MDEP standards. The primary objective of this study is to evaluate the potential for metal mobility from the landfill to the garden soil. The garden is bordered on one side by a storm wall along a mesotidal cove. The possibilities of storm waves flooding the garden, tidal shifting of the water table, and road salting; all increase the chance of salinity fluctuation in the park enabling mobilization. To test this, samples of garden soil were collected and analyzed for trace metals, using a pED-XRF (Spectro-Analytical XEPOS). Soil samples were collected spatially around the garden at the surface, and depths up to 38cm.

Results show the Pb concentration in the garden soil ranged from 39-265 ppm and the Cr concentrations ranged from 63-111 ppm. The Pb concentrations within the landfill material are an order of magnitude greater than in the garden soil (4840 ppm) while the Cr concentrations are similar (144 ppm). The data also indicates a spatial relationship of Pb with depth. The soil on the southern side of the garden contains Pb concentrations that increase or stays the same with depth, while the northern side of the garden contains Pb concentrations that decrease with depth. Cr does not display the same spatial relationship as Pb where Cr concentrations remain consistent with depth throughout the entire garden area. These preliminary results suggest that the Pb and Cr within the garden soil are from seperate sources or that Pb and Cr are being mobilized differently from the landfill.