T238 Geochemistry of Urban Environments (Posters)

Wednesday, 7 November 2012
9:00 AM - 6:00 PM
Hall B

CITY SOILS INITIATIVE: A PRELIMINARY STUDY OF LEAD AND OTHER HEAVY METALS IN PHILADELPHIA URBAN SOILS

Paper number: T238-10
Program: Technical Sessions
Time: 9:00 AM – 6:00 PM

Authors

Abstract

Urban renewal in Philadelphia, Pennsylvania, in recent years has led to many changes in the urban landscape. Urban gardens, both private and community, have been a part of this emerging philosophy of revitalization and sustainability. While these “greener” activities have positive effects on the surrounding communities by promoting urban renewal of previously unused or under-used spaces, and acting in a more environmentally responsible way, the history of land use in the Philadelphia is extremely diverse, including transportation, industrial, commercial, and residential. This urban tapestry of historical land use creates the potential for human exposure to heavy-metals in contaminated dust or bio-concentrated in food crops. In order to evaluate this potential public health hazard, we have begun to analyze urban gardens and other open spaces in Philadelphia in order to define protocols and best practices for current and future sustainable garden sites.

We have obtained soil samples from selected areas of the city and analyzed them with a Thermo Niton X-Ray Fluorescence XL3t Analyzer, focusing on Lead, Arsenic, and Sulfur. Most areas selected for this preliminary study are from largely undisturbed forested land in Philadelphia’s Fairmount Park (the largest inner-city park in the U.S.) and urban recreation centers. At each location, three samples (one bulk and two 1”core samples) were taken at various geomorphic positions or, if little to no topographic change is present at a specific site, then samples have been taken systematically at specific intervals from structures.

In initial results, Pb and As concentrations in largely undisturbed park land soils range from 17 to 1550 ppm and <10 to 60 ppm, respectively. However, in soils from a former orchard, Pb and As concentrations are as high as 1.8% and 500 ppm, respectively, and are positively correlated. Median measured values in largely undisturbed soils are ca. 230 and 22 ppm, respectively. Concentrations are approximately log-normally distributed. Pb concentrations the largely undisturbed soils are generally less than those found in the previous Soil Kitchen study in Northeast Philadelphia. These data should allow better land use decisions by informed Philadelphia citizens.