Hierarchical cluster analysis of polychlorinated dioxins and furans in Michigan, USA, soils: evaluation of industrial and background congener profiles.
As part of the University of Michigan Dioxin Exposure Study, soil samples were collected from 766 residential properties near the Tittabawassee River between Midland and Saginaw; near the Dow Chemical Facility in Midland; and, for comparison, in the other areas of Midland and Saginaw Counties and in Jackson and Calhoun Counties, all located in the state of Michigan, USA. A total of 2,081 soil samples were analyzed for 17 polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). In order to better understand the distribution and sources of the PCDD/F congeners in the study area, hierarchical cluster analysis (HCA) was used to statistically group samples with similar congener patterns. The analysis yielded a total of 13 clusters, including: 3 clusters among the soils impacted by contamination present in the Tittabawassee River sediments, a cluster comprised mainly of samples collected within the depositional area of the Dow incinerator complex, a small cluster of samples with elevated 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TCDD), and several clusters exhibiting background patterns. The clusters related to the Tittabawassee River floodplain contamination all contained elevated PCDF levels and were differentiated from one another primarily by their relative concentrations of higher-chlorinated PCDDs, a difference likely related to both extent and timing of impacts from Tittabawassee sediments. The background clusters appear to be related to combustion processes and are differentiated, in part, by their relative fractions of TCDD. Thus, HCA was useful for identifying congener profile characteristics in both contaminated and background soil samples.
Towey
Timothy P
TP
Department of Civil and Environmental Engineering, University of Michigan College of Engineering, Ann Arbor, Michigan 48109, USA. ttowey@limno.com
Chang
Shu-Chi
SC
Demond
Avery
A
Wright
Daniel
D
Barabás
Noémi
N
Franzblau
Alfred
A
Garabrant
David H
DH
Gillespie
Brenda W
BW
Lepkowski
James
J
Luksemburg
William
W
Adriaens
Peter
P
D001572:Benzofurans / Q000032:analysis*; D016000:Cluster Analysis; D000072338:Dibenzofurans, Polychlorinated; D019015:Geologic Sediments / Q000032:analysis; D015999:Multivariate Analysis; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis; D045483:Rivers / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis
D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical