Joint 52nd Northeastern Annual Section / 51st North-Central Annual Section Meeting - 2017

Paper No. 38-41
Presentation Time: 8:00 AM-12:00 PM


WATERS, Linda1, OETTGEN, Hannah L.2, BRABANDER, Daniel J.3, ALLEN, Douglas E.1 and HANSON, Lindley S.4, (1)Geological Sciences, Salem State University, 352 Lafayette Street, Salem, MA 01970, (2)Geosciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, (3)Department of Geosciences, Wellesley College, 106 Central Street, Wellesley, MA 02481, (4)Geological Sciences, Salem State University, Salem, MA 01970,

The great conflagration of 1914 in Salem Massachusetts resulted in a legacy of toxic chemicals and heavy metals within the 250 acre fire zone and the landfills that contain the debris. Palmer Cove Park landfill remained an active fill until capped in 1970, and currently hosts a baseball field, and community garden. This study addresses safety concerns of using the landfill site for urban gardening.

An exploratory excavation was used to evaluate the thickness and composition of the landfill cap. To assess the potential for post-depositional mobility of metals, soils from various depths in the excavation site were sampled, along with surface soils near the community garden. Samples were dried, homogenized and analyzed using pED-XRF to measure bulk concentrations of arsenic, cadmium, lead, chromium, copper, nickel and zinc. XRF results of soil near the community garden were compared to safety standards maintained by Massachusetts Department of Environmental Affairs MCP S-1 (Massachusetts Contingency Plan) for soil contamination in areas of human activity such as residential, parks, playgrounds and schoolyards. The excavation revealed the landfill cap as approximately 76 cm in depth and composed of soil with pebble sized rocks to densely packed diamicton containing rocks sized up to 20cm. There is no evidence of bio remediating or impermeable layering. At 76 cm, notably dark soil was exposed with various items of debris, confirming the presence of the landfill material. Weathered and oxidized rock and soil suggests evidence of mobilization of metals in the subsurface. Within the excavation, the concentration of lead was 94 ppm at the surface and 4,940 ppm at the boundary with the top of the landfill, while chromium concentrations were 99 ppm at the surface and 144 ppm at 76 cm. Of the ten samples taken near the community garden, two were direct surface samples with chromium concentrations reaching or potentially exceeding MCP S-1 limits.