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Environ Sci Technol 2003 Feb 1;37(3):468-74

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentration profiles
in sediments and flood-plain soils of the Tittabawassee River, Michigan.

Hilscherova K, Kannan K, Nakata H, Hanari N, Yamashita N, Bradley PW,
McCabe JM, Taylor AB, Giesy JP.
National Food Safety and Toxicology Center, Department of Zoology,
Institute for Environmental Toxicology, Michigan State University, East
Lansing, Michigan 48824, USA.

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and
dibenzofurans (PCDFs) in sediments and flood-plain soils collected along
the Tittabawassee River in Michigan ranged from 102 to 53,600 pg/g, dry
wt. Mean PCDD/PCDF concentrations in downstream sediment and soil were
from 10- to 20-fold greater than those found at locations upstream of
Midland, Michigan. Concentrations of PCDD/PCDF in sediments and
flood-plain soils from the Tittabawassee watershed were comparable to
those found in industrialized areas such as the Housatonic and lower
Passaic Rivers in the U.S. Concentrations of PCDDs/PCDFs in soil and
sediment were not correlated with total organic carbon (TOC) in
sediments or soils. OCDD and 2,3,7,8-TeCDF were the predominant
congeners in sediment/soil collected from locations downstream of
Midland, Michigan. Principal component analysis of the PCDD/PCDF
congener profile suggested the presence of sources originating from a
mixture of chlorophenol and other chlorinated compound production. Mass
balance analysis of TCDD equivalents (TCDD-EQs) derived from H4IIE-luc
bioassay of sediment extracts and 2,3,7,8-tetrachlorodibenzo-p-dioxin
equivalents (TEQs) estimated from instrumental analysis suggested that
PCDDs/PCDFs were the major dioxin-like compounds present in sediments. A
significant correlation existed between bioassay-derived TCDD-EQs and
instrumentally measured TEQs (r2 = 0.94).