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Track: Environmental Management
Robert Werner
University of St. Thomas
2115 Summit Avenue
St. Paul, MN 55105-1096
Telephone: 612-962-5565
Fax: 612-962-6410
E-mail: RJWERNER@STTHOMAS.EDU
Toxic Releases and Demography in Minneapolis/St. Paul: A GIS Exploration
Defining Issue: Does environmental quality vary with race, age, or income? Are minorities, the poor, the young, or old exposed to more toxins than the general public? GIS Solution: After correcting the positional inaccuracies of toxic release data, various buffers were created and overlaid with demographic data. Methodology: This study compared race, age, and income in areas that were near or far from airborne toxic releases (using EPA Toxic Release Inventory data). Since toxins disperse variously according to what toxin is being released, how much of the toxin is released, and the atmospheric conditions present at the time of release, a variety of buffers were used to measure nearness. Buffers were either fixed distances or variable according to the amount of toxin released. A GIS overlay was performed that intersected demographic data with the buffers and aggregated those data inside and outside the buffers. Statistical tests were performed that calculated whether or not the numbers of toxic
releases were significantly different according to whether people lived inside or outside the buffers. Various maps were created to help communicate results and explain spatial relationships. Exploring the relationships between toxic releases and waterways, railroads, and highways helps explain why toxic releases occur where they do and suggests that a historical development of industrial patterns is necessary to explain spatial patterns between toxic releases and race, age, and income. Software: ArcInfo, ArcView, SPSS
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