Document Type

Article

Publication Date

12-2019

Abstract

High levels of lead contamination have detrimental health implications for communities, with the most profound impacts of lead poisoning affecting young children. The City of Lewiston, Maine, is home to a disproportionate amount of reported lead poisoning cases as compared to the rest of the state. Within Lewiston, the downtown “Tree Street” neighborhood contains 72% of all reported lead-poisoning cases in the city, signifying a need to identify the source(s) of lead exposure and minimize the impact of lead contamination on Tree Street residents. In collaboration with Healthy Neighborhoods, we identified 19 vacant lots in the Tree Street neighborhood to test for soil lead contamination. With the aim of quantifying and contextualizing the distribution of lead across the vacant lots, we took 9 composite samples from each lot and tested them for lead using an X-Ray Fluorescence (XRF) gun. The XRF gun provided an elemental analysis of each sample in parts per million (ppm). Using this data, we created maps showing the geographic distribution of lead across the neighborhood and each site. We also created graphs showing the concentration distribution across and within sites. The most concerning site (site 17) had an average lead concentration of 634 ppm and a maximum value of 2370 ppm, which surpasses the Environmental Protection Agency (EPA) safety threshold of 400ppm for bare soil in play areas. Along with identifying the extent and distribution of lead contamination in the vacant lots, we considered which types of lead remediation are best suitable for minimizing exposure to lead contamination in the Tree Street neighborhood. In this report, we examine the remediation strategies of phytoremediation, soil caps and raised beds, and soil amendments. After a comprehensive discussion of these three strategies in relation to the criteria of cost, feasibility, and effectiveness, we determine which strategies are most suitable for use in the lead-contaminated Tree Street neighborhood vacant lots. We recommend the use of sunflower phytoremediation as our primary remediation technique. We also recommend the use of certain soil amendments as a secondary remediation technique; the use of this strategy, however, is contingent on whether Healthy Neighborhoods and the City of Lewiston have access to the appropriate equipment necessary for the processing of these amendments. Finally, we end our report with recommendations for next steps for Healthy Neighborhoods and the City of Lewiston in continuing the project of creating a lead-free community.

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