Spatial Distribution of Lead in Urban Soils

Jeff Clark, Lawrence University

Summary

Students gather soil samples and collect information on property attributes (size, exterior type, condition, etc.) in order to analyze the spatial distribution of lead in soils in the neighborhood around Lawrence University in Appleton, WI. Once the trends are identified students develop hypotheses for the cause of the trends (for example they might notice that older buildings tend to have higher concentrations of lead in the soil). They then prepare a report of their findings, including a recommendation to the landowners. The recommendation requires that they do some background reading/research on the health effects of lead, pathways of lead exposure, and mitigation strategies.

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Learning Goals

The main goal is to analyze and explain spatial patterns of urban lead contamination.
Students are required to analyze data for spatial trends and then develop and test hypotheses explaining those trends. They will ultimately synthesize their observations into a written report which is integrated with the maps. Students are require to read papers based on similar work performed in larger cities like Chicago and Boston and to place their work into the context these previous studies. A conceptual model of lead exposure pathways is also prepared by the students.
Students will learn how to collect and prepare soil samples for XRF analysis. They will prepare a formal scientific report with associated figures. Students need to use ArcGIS to query the plat map data bases and to create maps showing property age and value. Though the data collection and sample preparation is done in groups, students are required to write individual lab reports.
Mobile technologies allows students to map sample locations and directly enter property characteristics. This ensures that the field data are found in one common location, and that the students analyze the correct property. The latter is particularly important because permission of homeowners is required.

Context for Use

Integrates mobile technologies into an introductory level course: Introduction to Environmental Science
Exercise is used as part of a sequence of exercises.

Skills that students should have mastered before beginning this activity:

Students need some knowledge of ArcGIS 9.3 including the Spatial Analyst extension and how to interface with a GPS receiver. They should also know how to collect and classify point data and how to contour data. Some knowledge of Excel™ is also beneficial.

Description and Teaching Materials

Lead in urban soils (Microsoft Word 64kB Aug5 10)

Assessment

The final report is read and graded by the instructor. A laboratory report rubric is listed under supporting references.

References and Resources

Supporting data

Underlying aerial photographs and plat maps were gleaned from the City of Appleton. All other data were created specifically for this activity.

References

Mielke, H. W., Gonzales, C., Powel, E., Cody, S., Shah, A., 2003, Anthropogenic Distribution of Lead, Oxford Univeristy Press, pp 119-124.

Clark, Heather F., Brabander, Daniel J., and Erdil, Rachel M, 2006, Sources, Sinks, and Exposure Pathways of Lead in Urban Garden Soil, J. Environ. Qual. 35:2066–2074.