TITLE:
Polychlorinated Dibenzofurans and Dibenzo-p-Dioxin in Tree Bark from an Industrialized Area: What the 2,3,7,8-Cl Substituted Congeners Tell Us, and What Is Missing
AUTHORS:
Mark H. Hermanson, Glenn W. Johnson
KEYWORDS:
Tree Bark, Polychlorinated Dibenzofurans, Polychlorinated Dibenzo-p-Dioxins, Principal Components Analysis
JOURNAL NAME:
Journal of Environmental Protection,
Vol.7 No.3,
February
26,
2016
ABSTRACT: We analyzed
polychlorinated dibenzofurans (PCDF) and dibenzo-p-dioxins (PCDD) in 27 tree
bark samples from the industrialized area near Sauget, Illinois, USA. The trees
were located within 4 km of the W. G. Krummrich (WGK) plant, the oldest and
largest chemical plant in Sauget, with 24 of 27 samples collected from
residential areas. The percent of total PCDF or PCDD profiles of ten 2,3,7,8-
Cl substituted PCDF and seven PCDD congeners is homogeneous: 90% of the
variance among the samples is explained by 3 eigenvalues in a principal
components analysis. The homogeneity of the data suggests that samples were
affected by similar types of sources which may have been influenced by electric
power generation, chemical waste incineration, and large-scale thermal production
of chlorinated chemicals. Quantitatively, the 2,3,7,8-Cl substituted congener
analysis does not account for 90% of the concentration of tetra- and penta-Cl
homologues and 80% of hexa-Cl and 50% of hepta-Cl homologues. The World Health
Organization stated during establishment of toxic equivalence factors (TEF,
2005 version) that calculation of toxic equivalents (TEQs) is not suitable for
abiotic matrices, such as tree bark, which are not involved in human exposures.
Our results show that the non-2,3,7,8-Cl substituted congeners have high
concentrations and should be included in analysis.