Tracing source of P in contaminated plume in the Cape Cod Aquifer
This page is under construction.
Groundwater is the major source of freshwater in Cape Cod. A historical wastewater treatment plant built in the 1920s had led to a contaminant plume along the direction of groundwater flow (Fig. 1). This contaminant plume remains active, with high concentrations of C. N, and P, even after 30 years since the wastewater discharge was stopped in 1990s. To investigate the sources of P, We took samples from six locations along the direction of groundwater flow (Fig. 1), characterized the geochemistry and measured phosphate oxygen isotopes of the sediments and groundwater. (Click here to learn more about phosphate oxygen isotopes).
The contaminated plume had resulted in persistent anoxia in the groundwater (Fig. 2), with high concentrations of PO4 in the areas of anoxia (Fig. 3).
Phosphate in the contaminated plume may came from two possible source, reductive dissolution of iron oxide bound P, as indicative by the high concentration of dissolved Fe in close proximity to the PO4 plume (Fig. 4), and remineralization of organic matter (Fig. 5).
