Soil Amendments to Decrease Lead and Arsenic Bioaccessibility in Delray, Detroit, MI

Abstract

The Delray neighborhood of Southwest Detroit has a long history of environmental pollution. A section of the neighborhood, located adjacent to a brownfield site, was previously identified for elevated concentrations of soil lead (Pb) and arsenic (As) by researchers at the University of Michigan-Dearborn (Peterman, 2013). In this study, soil samples were collected from three decision units using the Incremental Sampling Methodology (ISM). Samples were treated at 5 and 10% by weight with three different amendments: triple superphosphate (TSP), phosphate rock (PR), and zeolite (ZE). After an incubation period of 48 days, the samples were then processed, underwent bioaccessibility (BA) digestion, and analyzed by ICP-MS for Pb and As. Statistical analysis using a paired t-test showed a very significant decrease in soil Pb BA for both addition rates of PR, and a significant decrease with TSP and ZE. The impact of the amendments on soil As BA was inconclusive. Based on this study, PR shows potential as an efficient and affordable means to remediate the soil Pb contamination in Delray. This finding may also be applicable for other postindustrial cities with similar soil type and contamination profiles.