Chlorinated Dibenzo-p-dioxins Research Articles

Concentrations of chlorinated dibenzo-p-dioxins (CDD) and dibenzofurans (CDF) in soil from the vicinity of a large refuse incinerator in Hamilton Ontario

Soil in the vicinity of a large municipal refuse incinerator was analyzed for CDDs/CDFs. Fourteen locations which included three control sites were examined. The results showed that CDDs/CDFs emitted from the incinerator since 1973 have not accumulated in surface soil in the vicinity of the plant.

Determination of dioxins and furans in precipitation collected in urban and rural Ontario locations

The results of a monitoring program carried out by the Ontario Ministry of Environment during 1987–1988 for the presence of chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) in atmospheric precipitation are presented. Varying levels of octa-CDD were detected throughout the sampling period, mainly at the rural location. None of the lower chlorinated CDDs/CDFs were observed with the exception of a single HxCDF isomer detected in Sept/Oct 1987 in an XAD cartridge sample at the rural site.

Determination of chlorinated dibenzo-p-dioxins (CDD) and dibenzofurans (CDF) in environmental samples by tandem mass spectrometry

A round-robin study is reported which compares the technique of quadrupole MS/MS to that of HRMS and LRMS for the detection of CDD and CDF in typical environmental samples. Three different commercially available MS/MS instruments were included in the study. The data indicate that chromatographic pre-treatment of sample extracts can be reduced due to the additional selectivity of MS/MS. However, validation by comparative analysis is recommended.

Novel extraction device for the determination of chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs) in matrices containing water

The efficient extraction of CDDs/CDFs from particulate matrices containing measurable amounts of water is complicated by the need to remove the water from the particles before beginning the extraction process. Traditionally, this has been done by pre-extracting the sample with a water miscible solvent such as isopropanol or by air drying for an extended period of time over various desiccants such as sulfuric acid or phosphorus pentoxide. These techniques can suffer from three possible problems: potential loss of analytes, accidental sample contamination, or an unacceptably long sample drying time. In response to these drawbacks, we have developed an extraction device that combines the simultaneous removal and measurement of water from a particulate sample with an exhaustive Soxhlet extraction of the dried particulates.

Concentrations of chlorinated dibenzo-p-dioxins and dibenzofurans in effluents and centrifuged particulates from Ontario pulp and paper mills

Chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs) were determined in effluents and centrifuged particulates from nine pulp and paper mills situated in Ontario, Canada. The centrifuged particulates from all mills contained some CDD/CDF congeners, although they were not always detected in the corresponding effluents. The greatest concentrations of CDDs/CDFs were found in the effluents and particulates from the bleached kraft mills, where the tetrachlorinated CDDs/CDFs were the predominant congeners.

Analysis of large volume water samples near chemical dump sites using the aqueous phase liquid extractor (APLE)

A large volume water extraction device was used to determine concentrations of chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) in surface water sampled near known chemical dump sites. Results using the APLE extraction device were similar to those obtained by conventional liquid/liquid extraction. Total CDD and CDF levels in the water were in the low parts-per-billion (ppb) range, while levels in the suspended particulates centrifuged from the water were 10 times greater.

Monitoring dioxins and furans in precipitation samples

Low levels of the higher chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) have been found in samples taken from remote areas. This study investigates the long range transport of CDDs and CDFs and their subsequent deposition via precipitation.

Gas chromatographic/mass spectrometric determination of chlorinated dibenzo-p-dioxins and dibenzofurans in incinerator stack emissions and fly-ash: A 13-test study

A 13-test study was performed to determine whether the overfire air and nominal steam load of a waste-to-energy municipal incinerator could be adjusted to minimize formation of the chlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs). Stack emissions and precipitator fly-ash were analyzed for chlorobenzenes, chlorophenols, and polychlorinated biphenyls in addition to the CDDs/CDFs. The results showed that efficient collection of stack-emitted CDDs/CDFs was obtained, and that a single overnight soxhlet extraction with toluene was sufficient for complete recovery of all extractable CDDs/CDFs in fly-ash. No strong correlations were observed between the incinerator variables studied and the CDD/CDF emissions. Likewise, no strong correlations between the concentrations of CDDs/CDFs in stack emissions and concentrations of precursors were obtained, although some trends were observed. Results suggest that the CDD:CDF ratio and relative CDD/CDF congener distributions may be affected by incinerator conditions. Although a specific set of incinerator conditions to minimize CDD/CDF emissions were not developed, it was found that with efficient incinerator operation these emissions can be held below the Ontario provisional guideline.

Determination of picogram per cubic meter concentrations of tetra- and pentachlorinated dibenzofurans and dibenzo-p-dioxins in indoor air by high-resolution gas chromatography/high-resolution mass spectrometry

An analytical method is presented for the collection and quantification of tetra- and pentachlorinated dibenzofurans (CDFs) and chlorinated dibenzo-p-dioxins (CDDs) in ambient air. This method is the first to deal with gaseous CDFs and CDDs as well as particulate-bound compounds and the first to validate and report the quantification of these compounds at 1 pg/m/sup 3/. Samples were collected with a glass fiber filter followed by silica gel contained in a removable extraction thimble in a housing made of Teflon. The samples were Soxhlet extracted with benzene, cleaned up with alumina and carbon adsorption liquid chromatography, and quantified with SP2330 capillary GC/mass profile high-resolution mass spectrometry. A complex isomer pattern of tetra- and penta-CDFs and tetra-CDDs including the 2,3,7,8-substituted tetras was found in air samples taken from a contaminated office building. Concentrations ranged from 0.23 pg/m/sup 3/ 2,3,7,8-tetra-CDD to 185 pg/m/sup 3/ for total tetra-CDFs. Chlorinated biphenylenes were also found.

Reporting chlorinated dibenzo-p-dioxin and dibenzofuran data in scientific publications

A literature review of recent work involving the determination of chlorinated dibenzo-p-dioxins (CDD) and dibenzofurans (CDF) in fish and incinerator samples has shown many irregularities and omissions in the reported data. Although some of these result from non-standardized nomenclature and reporting practices and do not affect the overall conclusions reached, in some cases omissions in reporting experimental procedures raise important concerns regarding the validity of data and make comparison of data from different investigations difficult. It is not always necessary or even desirable to report every experimental detail of work performed, however, the ultra-trace determination of CDDs and CDFs in complex environmental samples is still at a stage where omission of key experimental details can affect the interpretation of results.

Comparative toxicity of PCBs and related compounds in various species of animals.

There are several basic principles that apply to the clinicopathologic syndrome produced by polychlorinated biphenyls (PCBs). They are as follows: The degree of halogenation and position of the halogen atoms determine the potency of PCB, PBB, CDD, CDF and CN; in a given species of animals, the clinicopathologic syndrome induced by PCB is comparable to that induced by polybrominated biphenyls (PBB), chlorinated dibenzo-p-dioxins (CDD), chlorinated dibenzofurans (CDF), and chlorinated naphthalenes (CN) when an equitoxic dose is achieved; The clinicopathologic syndrome is different in each species of animals; Different species of animals vary in their susceptibility to intoxication; intoxication is more readily effected in young animals that in adults; at lethal doses the time between exposure and death is prolonged (greater than 2 weeks).

Comparative Toxicity of PCBs and Related Compounds in Various Species of Animals

There are several basic principles that apply to the clinicopathologic syndrome produced by polychlorinated biphenyls (PCBs). They are as follows: The degree of halogenation and position of the halogen atoms determine the potency of PCB, PBB, CDD, CDF and CN; in a given species of animals, the clinicopathologic syndrome induced by PCB is comparable to that induced by polybrominated biphenyls (PBB), chlorinated dibenzo-p-dioxins (CDD), chlorinated dibenzofurans (CDF), and chlorinated naphthalenes (CN) when an equitoxic dose is achieved; The clinicopathologic syndrome is different in each species of animals; Different species of animals vary in their susceptibility to intoxication; intoxication is more readily effected in young animals that in adults; at lethal doses the time between exposure and death is prolonged (greater than 2 weeks).

Characteristics of an extraction and purification procedure for chlorinated dibenzo- p-dioxins and dibenzofurans in soil and liver

Liver is extracted with chlorofor—methanol to give essentially quantitative transfer of endogenous chlorinated dibenzo- p-dioxins (CDDs) and dibenzofurans (CDFs) into the organic phase. A new procedure involving LH-20 Sephadex is used to remove most of the lipids from the extract. Soil es extracted by a simple, rapid and economical procedure giving very high recoveries of CDDs and CDFs from sandy soil, various types of clay, and humus-rich loam. Subsequent cleanup on basic and acidic alumina complete the preparation for gas chromatography-mass spectrometric analysis. The use of propylene glycol as a “keeper” and of 2,3,7-trichlorodibenzo- p-dioxin as a carrier minimizes losses during evaporation of solvents and on glass surfaces. Interactions of 2,3,7,8-CDD with organic material in loam slightly reduce recovery but thre is no indication of high affinity binding sites, the losses being apparently associated with simple distribution coefficients. Special precautins needed to avoid losses of CDFs on alumina chromatography are described, and the effect of “aging” spiked soil is discussed.

Metabolism of Dibenzo- p -Dioxin and Chlorinated Dibenzo- p - Dioxins by a Beijerinckia Species

Whole cells of the parent strain of Beijerinckia, grown with succinate and biphenyl, oxidized dibenzo-p-dioxin and several chlorinated dioxins. The rate of oxidation of the chlorinated dibenzo-p-dioxins decreased with an increasing degree of chlorine substitution. A mutant strain (B8/36) of Beijerinckia oxidized dibenzo-p-dioxin to cis-1,2-dihydroxy-1,2-dihydrodibenzo-p-dioxin. The mutant organism also oxidized two monochlorinated dibenzo-p-dioxins to cis-dihydrodiols. No metabolites were detected from two dichlorinated dibenzo-p-dioxins. Growth of the parent strain of Beijerinckia on succinate was inhibited after 4 h when 0.05% dibenzo-p-dioxin was present in the culture medium. Resting cell suspensions of the parent organism, previously grown with succinate and biphenyl, oxidized dibenzo-p-dioxin to a compound identified as 1,2-dihydroxydibenzo-p-dioxin. Further degradation of this metabolite was not detected, as the compound was found to be a potent mixed-type inhibitor of two ring-fission oxygenases present in this organism.

ChemInform Abstract: PHOTOLYSIS OF HIGHLY CHLORINATED DIBENZO‐P‐DIOXINS BY SUNLIGHT

CHLORINATED dibenzo-p-dioxins (CDDs) are now widely recognised as contaminants of commercial chlorinated phenols and related products. These compounds possess a remarkable range of toxicity; the LD50 for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in female rats is 45 µg per kg, that of the octachloro compound (OCDD) is > l g per kg (ref. 1). Although the degree of toxicity is related to the extent of chlorination, positional isomerisation also Plays a critical and perhaps dominant part; 1,2,3,4-TCDD is at least 800 times less toxic than 2,3,7,8-TCDD (ref. 2). The extreme toxicity of some of these compounds, coupled with the large variations with extent of chlorination and positional isomerisation, make accurate identification of CDDs essential in any assessment of environmental or safety implications. The study reported here is concerned with the photolysis of octa-, hepta (Hp)- and some hexa (Hx)-chlorodibenzo-p-dioxins and shows that the structural isomers which are expected to be the most toxic are most rapidly photodecomposed. We also report that despite photo-lytic reductive dechlorination which gives rise to less highly chlorinated dioxins, the reaction mechanism favours the formation of the less toxic isomers.

Photolysis of highly chlorinated dibenzo-p-dioxins by sunlight

CHLORINATED dibenzo-p-dioxins (CDDs) are now widely recognised as contaminants of commercial chlorinated phenols and related products. These compounds possess a remarkable range of toxicity; the LD50 for 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) in female rats is 45 µg per kg, that of the octachloro compound (OCDD) is > l g per kg (ref. 1). Although the degree of toxicity is related to the extent of chlorination, positional isomerisation also Plays a critical and perhaps dominant part; 1,2,3,4-TCDD is at least 800 times less toxic than 2,3,7,8-TCDD (ref. 2). The extreme toxicity of some of these compounds, coupled with the large variations with extent of chlorination and positional isomerisation, make accurate identification of CDDs essential in any assessment of environmental or safety implications. The study reported here is concerned with the photolysis of octa-, hepta (Hp)- and some hexa (Hx)-chlorodibenzo-p-dioxins and shows that the structural isomers which are expected to be the most toxic are most rapidly photodecomposed. We also report that despite photo-lytic reductive dechlorination which gives rise to less highly chlorinated dioxins, the reaction mechanism favours the formation of the less toxic isomers.

The comparative toxicity of chlorinated dibenzo- p-dioxins in mice and guinea pigs

Mice and guinea pigs were given a single oral dose of various chlorinated dibenzo- p-dioxins (CDD) to establish and compare the LD50 and clinical and pathologic manifestations of toxicity. It was apparent that the 2,3,7, and 8 positions must be chlorinated to achieve the greatest degree of toxicity. Additional chlorine atoms at an ortho position reduced toxicity but not nearly to the degree caused by deletion of a chlorine atom at one of the lateral positions. A decrease in body weight gain was the most sensitive clinical parameter and animals severely intoxicated showed a marked weight loss, especially guinea pigs. The median time to death at a LD50 was 17 to 20 days in guinea pigs and 22 to 25 days in mice. Doses 10 times greater did not markedly shorten this period. At the toxic dose the spectrum and severity of lesions and organ weight effects were similar for all homologs and isomers within the same animal species; however, there were interspecies differences. The thymus was greatly reduced in size in both animal species due to a reduction in the number of cortical lymphocytes. Significant macroscopic and histopathologic hepatic effects including porphyria were observed only in the mouse and were found at does levels well below the LD50. Hyperplasia of the transitional epithelium in the urinary tract was found in guinea pigs. There was a reduction of total serum protein in the mouse due to lower levels of α-globulin. Other lesions were generally interpreted to be a secondary response to debilitation.

Riboflavin photosensitized oxidation of 2,4-dichlorophenol: assessment of possible chlorinated dioxin formation.

Dimeric products are formed by riboflavin-sensitized photooxidation of 2,4-dichlorophenol. The products of this reaction were examined to determine whether chlorinated dibenzo-p-dioxins could be formed from chlorophenols in water by the action of light of wavelengths greater than 280 nanometers. Dimers are formed by union of phenoxy radicals through carbon-carbon or carbon-oxygen bonds. 4,6-Dichloro-2-(2,4-dichlorophenoxy) phenol was obtained in greater quantity than other dimers. Products were characterized by combined gas chromatography and mass spectrometry. Chlorinated dibenzo-p-dioxins which could result from ring closure of a 2-phenoxyphenol derivative were not detected in the products of photolysis. The failure to detect chlorinated dibenzo-p-dioxins may result from the rapid photolytic breakdown of the lower chlorinated dibenzop-dioxins. Under environmental conditions, dioxins are unlikely products of the lower chlorinated phenols or phenoxyalkanoic acids.