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 ...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.展开更多
Pentachlorphenol (PCP) was widely used as a biocide and insecticide for wood preservation. Chlorinated dioxins and furans (2,3,7,8-substituted PCDD and PCDF congeners) were inadvertent byproducts of PCP production. As...Pentachlorphenol (PCP) was widely used as a biocide and insecticide for wood preservation. Chlorinated dioxins and furans (2,3,7,8-substituted PCDD and PCDF congeners) were inadvertent byproducts of PCP production. As such, it is an important source of PCDD/F contamination in treated wood and in soil/ sediment near sites that produced or used PCP. It has been noted in the literature, that PCP congener profiles are similar to some combustion profiles, as well as sewage sludge and particulate deposition. In a very broad sense, this is true. OCDD and 1,2,3,4,6,7,8-HpCDD are typically the dominant constituents in these source categories. There is however, a distinct, consistent and repeatable feature in the lower chlorinated tetra, penta and hexa PCDD/F range of PCP related samples: an order of magnitude increase in concentration as a function of degree of chlorination. Because lower chlorinated furans concentrations make up less than 1% of the total PCDD/F in PCP, it is difficult to differentiate PCP from other OCDD dominated source profiles on bargraphs that use a linear-scale y axis. Using a log-scale y axis, however, PCP impacted profiles are obvious, and are not easily confused with congener profiles from other sources.展开更多
文摘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.
文摘Pentachlorphenol (PCP) was widely used as a biocide and insecticide for wood preservation. Chlorinated dioxins and furans (2,3,7,8-substituted PCDD and PCDF congeners) were inadvertent byproducts of PCP production. As such, it is an important source of PCDD/F contamination in treated wood and in soil/ sediment near sites that produced or used PCP. It has been noted in the literature, that PCP congener profiles are similar to some combustion profiles, as well as sewage sludge and particulate deposition. In a very broad sense, this is true. OCDD and 1,2,3,4,6,7,8-HpCDD are typically the dominant constituents in these source categories. There is however, a distinct, consistent and repeatable feature in the lower chlorinated tetra, penta and hexa PCDD/F range of PCP related samples: an order of magnitude increase in concentration as a function of degree of chlorination. Because lower chlorinated furans concentrations make up less than 1% of the total PCDD/F in PCP, it is difficult to differentiate PCP from other OCDD dominated source profiles on bargraphs that use a linear-scale y axis. Using a log-scale y axis, however, PCP impacted profiles are obvious, and are not easily confused with congener profiles from other sources.
