An Alternative Method for Remediating Lead-Contaminated Soils in Residential Areas: A Decision Case Study

Abstract

Lead (Pb) is one of the most significant environmental contaminants worldwide and has significant human health effects. Historic use of Pb in paint and gasoline, in particular, have made this contaminant ubiquitous in our environment although widespread use of Pb has declined in the USA. Unfortunately, segments of the population are still receiving unacceptable doses of Pb. In the case reported here, citizens of Joplin, MO, will have input on a critical decision regarding the method by which the USEPA will remediate the Pb-contaminated soil in their community. Soil excavation is currently being used with the possibility of switching to phosphorus (P) amendment. Phosphorus added to the soil reacts with Pb to form an insoluble solid phase that is believed to be less harmful to humans compared with untreated soil. The use of P amendment offers advantages compared with soil excavation but has not been used before in residential areas. This case can be used to introduce students to the concepts of soil remediation, toxicology, and soil chemistry as well as social issues such as the use of tax dollars to support remediation. The learning objectives of this case are to understand the most common remediation strategy for Pb-contaminated soils and an alternative to that strategy, understand the concept of bioavailability and how it relates to the physiological effects of a soil contaminant on an organism, appreciate how soil amendments can change the bioavailability of a soil constituent, and to be able to identify the primary pathways of exposure for a soil contaminant and humans.