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Polybrominated dibenzo-p-dioxins (PBDDs) and mixed bromo/chloro dibenzo-p-dioxins (PXDDs) are persistent organic pollutants that can possess the same toxicity as their fully chlorinated analogs (PCDDs) and have been identified in the same matrices. Herein a general synthetic methodology is described to produce multiple congeners of PBDDs and PXDDs with varying degrees of halogenation and substitution patterns for use as analytical and/or internal standards, and for absorption, disposition, metabolism, and excretion (ADME) studies. The syntheses of PBDDs and PXDDs were accomplished by condensing a common precursor, 4,5-dibromo catechol, with variable precursors, i.e., polychlorinated 1-chloro-2-nitrobenzenes or polybrominated 1-fluoro-2-nitrobenzenes, to introduce a desired number of halogens and specific substitution patterns. Initial attempts to synthesize PBDDs and PXDDs were performed in potassium carbonate with DMSO at 145-150 °C. PXDDs syntheses resulted in formation of the desired products at >90% purity but attempts at higher brominated PBDDs syntheses resulted in dehalogenated by-products. To preclude by-product formation, additional syntheses for some PBDDs were conducted by refluxing the precursors in acetonitrile, which resulted in pure products at higher yield. Six PXDDs ranging from four to six halogens were synthesized (20-84% yield), of which three contained the halogen substitution pattern of 2,3,7,8. Five PBDDs ranging from four to six bromines were produced in 23-83% yield, three of which were toxic. Using the initial DMSO method, [ 14 C]-1,3,7,8-tetrabromodibenzo-p-dioxin (0.26 μCi/μmol; 11% overall yield) was synthesized from commercially available [ 14 C]-phenol to allow an ADME study to be conducted., (Published by Elsevier Ltd.)

Male common carp (Cyprinus carpio) from eastern Lake Erie, which is greatly effected by urbanization, agriculture, and industry, were analyzed for PCB and PBDE concentrations in plasma, muscle, and liver to evaluate exposure to these chemicals through habitat interactions. Additional male carp from two nearby relatively clean lakes (Bear Lake and Hemlock Lake, NY) were also sampled as controls. While PCBs were detected in muscle, liver, and plasma of Lake Erie carp, the largest concentrations were found in muscle, which also had the most number of congeners. The dominant congeners were PCB 138 and PCB 153. Concentrations of PCB 153 in the muscle were correlated with fish length, total weight, and age. Therefore, larger (and generally older) carp had the highest concentrations of PCB 153. In contrast, PBDEs were found only in muscle with the predominant congener being PBDE 47. The total PCB concentrations in muscle of male carp from eastern Lake Erie (ranging from nd to 15,000 ng g(-1) lipid) were 100-fold higher than the total PBDE observed (1.5-100 ng g(-1) lipid), indicating a higher level of contamination of PCBs in Lake Erie. The high PCB levels in carp points to PCB resistance to metabolic degradation., (Copyright © 2010 Elsevier Ltd. All rights reserved.)