Urban Soils in a Historically Industrial City:

Concentration and Biogeochemical Speciation of Trace Metals in Pittsburgh, Pennsylvania

This thesis focuses on mapping the distribution of urban relevant trace metals: lead (Pb), zinc (Zn), copper (Cu) and cadmium (Cd), within the City of Pittsburgh. There are only a few cities with mapped patterns of trace metal distributions. These studies largely focus on Pb contamination near roads and residences. As a result, we do not know the “background” concentration of trace metals in urban environments. To understand the distribution of background metal soil concentrations in the City of Pittsburgh a gridded set of 56 soil samples were collected and metal concentrations measured in these samples. In addition, sequential extraction was used to determine the metal distribution among exchangeable, reducible and oxidizable biogeochemical phases. These analyses revealed distinct spatial patterns: Pb, Cd, and Zn concentrations are elevated in the eastern portion of the study area along the paleochannel. The metal enrichment of the soil in this low-lying area is a result of dominant wind patterns and temperature inversions depositing these trace metals.