Sociology, Department of


Document Type


Date of this Version



Published in Environmental Science and Technology 42(15)[August 1, 2008]: 5441-5448. Copyright 2008 American Chemical Society.
The American Chemical Society’s policy on archiving permits the posting of only the author names, title, abstract, tables, and figures of articles published and/or copyright by the ACS. In respect of this policy, other portions of this article have been suppressed. The complete article may be found on the publisher’s website (requires subscription) at: [PDF file] or [html text]


The University of Michigan dioxin exposure study was undertaken to address concerns that the industrial discharge of dioxin-like compounds in the Midland, MI area had resulted in contamination of soils in the Tittabawassee River floodplain and downwind of the incinerator. The study was designed in a rigorously statistical manner comprising soil measurements of 29 polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) from 766 residential properties, selected probabilistically, in the Midland area and in Jackson and Calhoun Counties (Michigan) as a background comparison. A statistical comparison determined that the geometric mean toxic equivalent (TEQ) levels in samples from the target populations were statistically significantly above background. In addition, the probabilities of being above the 75th and 95th percentiles of background were also greater. Congener contributions to the TEQ were dominated by 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF in the floodplain and by 2,3,7,8-TCDD in the incinerator plume. However, PCB 126 was the top congener contributing to the background TEQ. On the basis of statistical inference to the total population, it was estimated that about 36% of the properties in the floodplain and incinerator plume have at least one soil sample over the MichiganDepartmentof Environmental Quality’s soil direct contact criterion of 90 pg/g TEQ.

Included in

Sociology Commons