Steven Connor

Polychlorinated biphenyl congeners (PCBs),p,p′-DDE and hexachlorobenzene in human milk in three areas of upstate New York

Forty human milk samples from women in an urban and a rural vicinity on Lake Ontario (Rochester and Oswego) and a mixed urban and rural location on the Hudson River (Albany), New York, were analyzed for 74 PCB congeners,p,p′-DDE, hexachlorobenzene, and mirex in order to determine the intake of breast-fed infants. All of the compounds were detected in the samples, but only eight PCB congeners andp,p′-DDE accounted for 88% of the chlorinated hydrocarbons detected.p,p′-DDE was the predominant pollutant (mean 78 ng/g wet weight), but the levels detected were low compared with the results from other parts of North America. Eight individual PCB congeners comprise 52% of the total PCB residue (mean 26.5 ng/g of whole milk); they ranged in mean concentration from 3.2 ng/g (2,4,5,2′,4′,5′-hexachlorobiphenyl) to 1 ng/g (2,3,4,3′,4′-pentachlorobiphenyl). Statistical correlation analysis among PCB congeners indicates a possible higher exposure to less chlorinated congeners at Oswego than at Albany.

Stimulation of 17β‐estradiol metabolism in MCF‐7 cells by bromochloro‐ and chloromethyl‐substituted dibenzo‐p‐dioxins and dibenzofurans: Correlations with antiestrogenic activity

Mixed halo- and haloalkyl-substituted dibenzo-p-dioxins (DD) and dibenzofurans (DF) are known environmental contaminants, although there is limited information on the toxic effects of these compounds in human cells. In this study antiestrogenicity, a property of 2,3,7,8-Cl4-DD, was investigated with a series of bromochloro- and chloromethyl-substituted DDs and DFs. The effects of these compounds on the metabolism of 17 beta-estradiol (E2) and on the estrogen-dependent formation of multicellular foci in cultures of MCF-7 human breast cells were examined. Pretreatment of MCF-7 cells with 2,3,7,8-Cl4-DD induced pathways of E2 metabolism involving cytochrome P-450-catalyzed hydroxylation, methylation of the catechol estrogens, and conjugation. Several Br-Cl3-DD and Br2-Cl2-DD congeners with halogen substitution at the 2, 3, 7, and 8 positions also stimulated E2 metabolism with similar potency to that of 2,3,7,8-Cl4-DD; however, compounds with substitution of a methyl group for a halogen at any of these positions did not stimulate the metabolism of E2. For the series of compounds tested in MCF-7 cultures, a close correlation was observed between the antiestrogenicity as measured by the inhibition of estrogen-dependent postconfluent growth that results in focus formation and the efficacy with which the compounds stimulated the metabolism of E2. 2,3,7,8-TetrahaloDDs with one or two bromine atoms at these positions were highly antiestrogenic as determined by their inhibition of estrogen-dependent focus formation, whereas the methyl-substituted polychlorinated DDs and DFs investigated did not inhibit focus formation. These results indicate that the 2,3,7,8-substituted mixed halo-substituted DDs and DFs are of importance when the biologic effects of halogenated DD and DF congeners are considered, and provide additional evidence for the role of increased metabolism of E2 in the antiestrogenic effects of halogenated DDs and DFs.

A survey of twenty community water systems in New York State for PCDDs and PCDFs

Abstract Two tetrachlorodibenzofurans (TCDFs) were found at concentrations of 1 part-per-quadrillion (ppq) in finished drinking water from one of 20 community water systems in New York State. A follow-up study also revealed that tetra- to octa-chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) were present at part-per-trillion (ppt) to part-per-billion (ppb) concentrations in sediments taken from the same community water system and at ppq in raw water entering the plant.

Mirex in human milk in upstate New York

Human milk and colostrum samples were collected from women living in the vicinity of Albany, Oswego, and Rochester, New York. Analysis by a highly sensitive method based on glass-capillary gas chromatography with electron-capture detection showed that mirex was present only at very low concentrations (generally less than 0.1 ng/g wet weight whole milk). Gas chromatographic/mass spectrometric analysis with both a quadrupole spectrometer and a double-focusing instrument confirmed the presence of mirex in three samples which had been shown by electron-capture analysis to contain more than 1 ng of mirex/g wet weight.

Application of multivariate statistical analysis to evaluate local sources of chlorobenzene congeners in soil samples

Abstract The distribution of tri- thru hexachlorobenzene congeners in the surface soil from five locations in the Niagara Falls/Erie County area of western New York State has been determined. The extract obtained by steam distillation was used directly with minimal additional clean-up steps for GC/MS analysis. Using GC/MS in the selected ion monitoring mode, a detection level of 100 pg/g (100 pptr) of the chlorobenzene congeners was achieved. Application of SIMCA pattern recognition and multiple discriminant analysis showed that the pattern of chlorobenzene congeners in soil samples collected near Love Canal is similar to the patterns found in other areas of Niagara Falls. The sources of these congeners may be nearby industrial plants and combustion sources. The soil samples from the town of Cheektowaga (comparison area) in nearby Erie County exhibit a different pattern of chlorobenzene congeners from the other soil samples.

Separation of extracts from biological tissues into polycyclic aromatic hydrocarbon, polychlorinated biphenyl and polychlorinated dibenzo-p-dioxin/polychlorinated dibenzofuran fractions prior to analysis.

A low-pressure liquid chromatography method is presented for separating polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDDs/PCDFs) from biological tissue extracts. After removing lipid from extracts, the PAHs are separated from PCBs and PCDDs/PCDFs on a deactivated 13-24 microns silica gel column. The PCBs are subsequently separated from PCDDs/PCDFs by collecting the first fraction from an automated three column cleanup procedure for PCDDs/PCDFs. The complete method has been used to obtain high recoveries of the three compound classes for analysis by GC-electron capture detection (PCBs) or GC-MS (PAHs and PCDDs/PCDFs).

Interlaboratory validation of PCDD and PCDF concentrations found in municipal incinerator emissions

Abstract Extracts from five stack-gas samples and a National Bureau of Standards dust sample were analyzed for PCDDs and PCDFs by three laboratories. The coefficients of variation were less than 50% for 84% of the results from the analysis of 2,3,7,8-tetra-CDD, 2,3,7,8-tetra-CDF and the tetra- to octa- congener groups.

Application of multivariate data analysis to evaluate total PCDDs and PCDFs in municipal incinerator emission

Abstract Total concentrations of PCDDs and PCDFs were predicted from the concentrations of specifically identified dioxin and furan isomers of each congener group by partial least-squares (PLS). The accuracy of this prediction can be used to evaluate results from different data sets or different sources which were calculated by an automatic identification and quantification program-TASQ R .

Interlaboratory comparison of PCDF and PCDD analysis in transformers and capacitors dioxin 88

Abstract The major object of the study was to evaluate and upgrade methods of analysis; analysis of field samples was an important secondary output. The study involving five participating laboratories, was conducted in two phases. Phase I was designed to locate glaring discrepancies in the techniques, and Phase II to statistically improve the accuracy of results from the different laboratories on a series of unknown samples. The impetus for the studies has been the wide range of toxicities (4–5 orders of magnitude) seen for the individual compounds in animal tests, and the difficulty of quantitatively analyzing for some of these chemically similar compounds of dissimilar toxicity, often in the presence of a great excess of PCBs. This study suggests that there is no strongly preferred analytical procedure among those using a combination of extraction/chemical cleanup, gas chromatography, and mass spectrometry for measuring compound-specific concentrations of PCDF and PCDD. In the field samples, the maximum concentration for 2, 3, 7, 8-Tetra-CDD was 32 ng/g and the maximum concentration of the combination of 2,3,7,8-tetra-CDF + 2,3,4,8-tetra-CDF was 459 ng/g. The highest concentration measured was for one sample of the much less environmentally significant octachlorinated dibenzofuran at 65,000 ng/g. These concentrations are reported with a statistical 95% confidence level.