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At least 19 recordsLinked to original sources
PubMed1998

Blood levels of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in the general population of a Spanish Mediterranean city.

Polychlorinated dibenzodioxins (PCDDs), Polychlorinated dibenzofurans (PCDFs) and Polychlorinated biphenyls (PCBs) are among the most toxic environmental pollutants. We determined blood levels of these compounds in a population sample of the city of Mataró, Spain. Blood samples were drawn from a randomly selected sample of 198 subjects, of both genders, aged 18 to 69 years. These samples were pooled into 10 groups for laboratory analysis. For males, total level of PCDDs was 505.7 ppt, of PCDFs was 26.7 ppt, and the international toxic equivalent (I-TEQ) was 12.5. For females the levels were 739 ppt, 28.8 ppt and 14.71-TEQ, respectively. The most important contributors to the total I-TEQ were HexaCDD, PentaCDD and PentaCDF. The blood concentration of total PCBs was 2.02 mg/l in males, and 1.58 mg/l in females. Levels of PCDDs, PCDFs and PCBs increased by age in both sexes. The levels of PCDDs and PCDFs in residents of this Mediterranean city are among the lowest observed in industrialized countries.

Adolescent↗
PubMed1999

Polychlorinated dibenzodioxins and polychlorinated dibenzofurans.

Polychlorinated dibenzodioxins and polychlorinated dibenzofurans (dioxins) are contaminants with long biological half-lives. The most toxic dioxin, 2,3,7,8-tetrachlorodibenzodioxin (TCDD), has a half-life in humans of 9 years. A tolerable daily intake (TDI) of 10 pg/kg body wt/day has been recommended, which was derived from steady-state concentrations of TCDD at the no-observed-adverse-effect level in animal studies. Intakes of dioxins by breast-fed babies can exceed the TDI by almost 20-fold. However, assuming a half-life of 9 years for all dioxins, it can be shown that the steady-state body burden is not increased by the short period of high intake during breast feeding, compared to that resulting from ingestion of the TDI daily from birth. Therefore, the TDI appears to accommodate the high intakes of dioxins by breast-fed babies. For dioxins with a significantly shorter half-life than TCDD, it can be shown that breast feeding will lead to higher body burdens in early life than would have been reached by ingestion of the TDI daily from birth. However, these peak body burdens will still be below the steady-state body burden achieved by ingestion of 10 pg TCDD/kg body wt/day from birth.

Animals↗
PubMed1996

Exposure of laboratory animals to polychlorinated dibenzodioxins and polychlorinated dibenzofurans from commerical rodent chow.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) are ubiquitous low level environmental contaminants. Present finding of PCDDs and PCDFs in the human food supply suggested that laboratory animals maintained under controlled conditions may also receive unwanted exposure to these compounds from food. In this study, a commercial rodent chow, Prolab-RMH 1000, was analyzed for the toxicologically active 2,3,7,8-substituted PCDDs and PCDFs. The results show that the feed had a total PCDD/F dioxin toxic equivalence (I-TEq) of 0.13 pg/kg (ppt) wet weight. OCDD was the most abundant congener present, followed by 1,2,3,4,6,7,8-HpCDD, with these congeners representing the 5th and 6th greatest contributors to the calculated TEq. Daily ingestion of I-TEqs for the rats is calculated to be 3.9-6.5 pg/kg/day, and 13.0-32.5 pg/kg/day for mice. It is therefore important to consider the potential for background exposure to PCDDs and PCDFs from the diet when conducting studies with laboratory animals. This is particularly important when sensitive responses, such as enzyme induction, immunotoxicity, and developmental/reproductive toxicity are being investigated at very low exposures to this class of compounds.

Animal Feed↗
PubMed1980

Long-term hazards of polychlorinated dibenzodioxins and polychlorinated dibenzofurans.

During January 10-11, 1978 in Lyon, France, a joint National Institute of Environmental Health Sciences/International Agency for Research on Cancer ad hoc Working Group considered and discussed the feasibility of coordinating epidemiological studies on the long-term hazards associated with the chlorinated dibenzo-p-dioxins and chlorinated dibenzofurans (PCDDs and and PCDFs). Nineteen invited scientists from eight countries presented introductory working papers summarizing the most up-to-date and relevant information available from their individual programs. This report represents the collective views and scientific opinions of the Working Group. The greater part of this document comprises epidemiological studies related to episodes of human exposures. The review begins with a brief section concerning possible routes of human exposure, an overview of the pertinent chemical characteristics, and the salient toxicological properties of the structurally similar PCDDs/PCDFs. The Working Group report ends with recommendations for future activities.

Abnormalities, Drug-Induced↗
PubMed2005

Emissions of polychlorinated dibenzodioxins and dibenzofurans and polychlorinated biphenyls from uncontrolled burning of garden and domestic waste (backyard burning).

To assess emissions of dioxins (chlorinated dibenzodioxins and dibenzofurans) and PCB from uncontrolled domestic combustion of waste ("backyard burning"), test combustions in barrels and open fires were monitored. The waste fuels used were garden waste, paper, paper and plastic packaging, refuse-derived fuel (RDF), PVC, and electronic scrap. Combustions including PVC and electronic scrap emitted several orders of magnitude more dioxins than the other waste fuels. Emissions from the other fuels had considerable variations, but the levels were difficult to relate to waste composition. Emission factors of PCDD/F and PCB from the backyard burning ranged from 2.2 to 13 000 ng (WHO-TEQ)/kg. The levels found in ash usually were less than 5% of the total. For assessment of total emissions of dioxins and PCB from backyard burning of low and moderately contaminated wastes, an emission factor range of 4-72 ng (WHO-TEQ)/kg is suggested. These figures implythat combusting waste in the backyard could contribute substantially to total emissions, even if the amounts of fuel involved are equivalent to just a few tenths of a percent of the amounts combusted in municipal waste incinerators.

Air Pollutants↗
PubMed1989

[Analytical methods for the determination of polychlorinated dibenzodioxins and dibenzofurans in human milk].

A method is described for the determination of polychlorinated dibenzodioxins and dibenzofurans in breast milk. After addition of potassium oxalate, the compounds are extracted, along with fat and other lipophilic compounds, using ethanol, ethyl ether and pentane. An aliquot of the fat is fortified with seven 13C-labelled dioxins and furans. Gel permeation chromatography on Bio-Beads S-X3 is used for removal of fat followed by column chromatography on florisil, charcoal and acid alumina. Except for 2,3,7,8-tetrachlorodibenzodioxin (2,3,7,8-TCDD), all other congeners are determined by combined capillary gas chromatography/mass spectrometry by use of negative chemical ionization employing methane as reagent gas. MS analysis is performed in the SIM mode (selected ion monitoring). For each isomer group two ions are monitored. Octachloronaphthalene is used as a syringe spike for the quantification based on a calibration run of standards. The calibration mixture, which contains the spike as well as all 2,3,7,8-chlorine substituted dioxins and furans and the 13C-labelled surrogates at a concentration level of 3-5 pg/microliters, is injected twice every day. For the determination of 2,3,7,8-TCDD a mass selective detector is used operating in electron impact mode. The MS analysis is also performed in SIM mode monitoring two ions for TCDDs and one ion for 13C-2,3,7,8-TCDD. Dependent on the level of each congener in breast milk, the coefficient of variation of the method varies between 3% for 2,3,4,7,8-pentachlorodibenzofuran and 40.9% for octachlorodibenzofuran. More than 200 human milk samples, mostly from nursing mothers living in North Rhine-Westphalia, have been analysed for residues of polychlorinated dibenzodioxins and polychlorodibenzofurans.(ABSTRACT TRUNCATED AT 250 WORDS)

Benzofurans↗
PubMed1985

Sources and fate of polychlorinated dibenzodioxins, dibenzofurans and related compounds in human environments.

Several of the major incidents resulting in potential human exposures to polychlorinated dibenzodioxins (PCDDs) and/or polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and related compounds which have occurred in the U.S. in recent periods have resulted from improper disposal of hazardous chemical wastes. Prominent examples of such environmental contamination episodes are the Love Canal, into which ton quantities of chlorinated organic compounds containing substantial concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were deposited; numerous sites in the State of Missouri which were contaminated by the dumping of chlorinated organic wastes containing various PCDDs and possibly PCDFs, and PCBs; and the environs of a 2,4-D/2,4,5-T manufacturing plant site in Arkansas, which were contaminated with PCDDs. Environmental assessments of such sites have revealed extensive contamination of soils, waterways, fish and other biological species with these toxic compounds, which in turn could lead to human exposures. Other recently identified sources of PCDDs, PCDFs and related compounds in human environments include stack effluents from municipal refuse incineration, and fires and explosions involving electrical devices containing PCBs and polychlorinated benzenes. Data obtained in assessments of such incidents are presented, and the implications of these findings with respect to the distribution and persistence of PCDDs, PCDFs and related chemicals in the environment and possible effects on humans are discussed.

Accidents↗
PubMed1989

Residues of polychlorinated-dibenzodioxins, -dibenzofurans and -biphenyls in human milk samples collected in a continental town in Croatia, Yugoslavia.

The levels of several polychlorinated-dibenzodioxins (PCDDs), polychlorinated-dibenzofurans (PCDFs) and total polychlorinated-biphenyls (PCBs) were determined in pooled human milk samples. The samples were collected in a continental town of Croatia, Yugoslavia, during the years 1981/82 and 1985. The concentrations of seven PCDDs and nine PCDFs were within the range less than 0.2-116 ng/kg milk fat; the total PCBs were 0.47 and 0.32 mg/kg milk fat. The levels determined were about the same as those reported for the general population in other countries.

Benzofurans↗
PubMed1986

Health risk analysis of human exposures to soil amended with sewage sludge contaminated with polychlorinated dibenzodioxins and dibenzofurans.

The risk of cancer to humans exposed to soil treated with wastewater/sewage treatment plant sludge, known to be contaminated with small amounts of polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs), was evaluated. The particulate-bound PCDDs and PCDFs are found in trace amounts in the effluent from ground water pumping (dewatering) at an abandoned wood preservation facility. The water, which was sent to a water recovery plant, underwent primary and secondary treatment prior to discharge. The residual sludge was added to agricultural soil as a conditioner. The present analysis treats the extreme case of sludge applied near the home of a target individual, a lifetime resident, who is also a farm worker in the area of the application. The successive stages of infancy, childhood and adulthood are treated separately to assess the contributions of typical age-specific indoor and outdoor activities on exposure rates. Five toxicity rating schemes using so-called TCDD equivalents, and two unit risk slopes are applied to the chemical profile in sludge to determine the cancer potency of the soil contaminants. These risk estimates range from 1 X 10-8 to 3 X 10-7.

Adult↗
PubMed2002

Human biomonitoring of polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofuranes in teachers working in a PCB-contaminated school.

Eighteen teachers from a highly contaminated school and 11 teachers from a control school participated in this study. Total polychlorinated biphenyl (PCB) indoor air concentration (six indicator congeners x 5) was beyond 12000 ng/m3 in some rooms of the contaminated school. PCB 28 and PCB 52 were the prevailing congeners. Whole blood was taken from each participant by the local health authority, pooled in two groups and analysed for the six PCB indicator congeners, non-ortho PCBs and polychlorinated dibenzodioxins (PCDD)/polychlorinated dibenzofurans (PCDF). Blood analysis showed elevated mean PCB 28 and PCB 52 levels for the exposed group, however the two groups were almost identical with regard to PCB 101, 138, 153 and 180. Moreover no difference can be observed for the concentration of non-ortho PCBs and PCDD/PCDF. The data support the finding, that heavy indoor air contamination with low chlorinated PCBs causes an increase of PCB 28 and PCB 52 blood levels. However, this increment was small compared to their total PCB load.

Adult↗
PubMed2006

Elimination half-lives of selected polychlorinated dibenzodioxins and dibenzofurans in breast-fed human infants.

Elimination half-life estimates for several polychlorinated dibenzodioxins/furans (PCDD/F) were calculated by modeling the blood and breast milk concentrations in two breast-fed human infants as reported by Abraham et al. (1996, 1998). Our analysis differs from that of other investigators in that we analyzed individual dioxin and furan congeners while the other studies considered TCDD only and we determined the half-lives in infants, rather than simply predicting body burdens in infants and older children. The average half-life values for each consistently measurable congener were determined to be less than about 6 mo and did not vary substantially between the two infants studied. The average elimination half-life values for 2,3,7,8-tetraCDD, 1,2,3,7,8-pentaCDD, 1,2,3,6,7,8-hexaCDD, 1,2,3,4,6,7,8-heptaCDD, and octaCDD were 0.40, 0.32, 0.39, 0.32, and 0.46 yr, respectively, and 0.27 yr for 2,3,4,7,8-pentaCDF. These values are in stark contrast with the 7 to 15+ yr values reported for these congeners in human adults (Michalek et al., 1996). These much shorter half-life values, likely attributable to rapid growth of the adipose tissue volume and enhanced fecal excretion of dioxins for breast-fed infants, explain why the much higher daily dioxin intake during breastfeeding does not translate to proportionately higher tissue concentrations. Thus, the shorter half-life of dioxins during breastfeeding needs to be considered when evaluating the dioxin hazard to children.

Adult↗
PubMed2002

Combining NMR spectral and structural data to form models of polychlorinated dibenzodioxins, dibenzofurans, and biphenyls binding to the AhR.

A three-dimensional quantitative spectrometric data-activity relationship (3D-QSDAR) modeling technique which uses NMR spectral and structural information that is combined in a 3D-connectivity matrix has been developed. A 3D-connectivity matrix was built by displaying all possible assigned carbon NMR chemical shifts, carbon-to-carbon connections, and distances between the carbons. Two-dimensional 13C-13C COSY and 2D slices from the distance dimension of the 3D-connectivity matrix were used to produce a relationship among the 2D spectral patterns for polychlorinated dibenzofurans, dibenzodioxins, and biphenyls (PCDFs, PCDDs, and PCBs respectively) binding to the aryl hydrocarbon receptor (AhR). We refer to this technique as comparative structural connectivity spectral analysis (CoSCoSA) modeling. All CoSCoSA models were developed using forward multiple linear regression analysis of the predicted 13C NMR structure-connectivity spectral bins. A CoSCoSA model for 26 PCDFs had an explained variance (r2) of 0.93 and an average leave-four-out cross-validated variance (q(2)4) of 0.89. A CoSCoSA model for 14 PCDDs produced an r2 of 0.90 and an average leave-two-out cross-validated variance (q(2)2) of 0.79. One CoSCoSA model for 12 PCBs gave an r2 of 0.91 and an average q(2)2 of 0.80. Another CoSCoSA model for all 52 compounds had an r2 of 0.85 and an average q(2)2 of 0.52. Major benefits of CoSCoSA modeling include ease of development since the technique does not use molecular docking routines.

Algorithms↗
PubMedDate not supplied

Models of polychlorinated dibenzodioxins, dibenzofurans, and biphenyls binding affinity to the aryl hydrocarbon receptor developed using (13)c NMR data.

Quantitative spectroscopic data-activity relationship (QSDAR) models for polychlorinated dibenzofurans (PCDFs), dibenzodioxins (PCDDs), and biphenyls (PCBs) binding to the aryl hydrocarbon receptor (AhR) have been developed based on simulated (13)C nuclear magnetic resonance (NMR) data. All the models were based on multiple linear regression of comparative spectral analysis (CoSA) between compounds. A 1.0 ppm resolution CoSA model for 26 PCDF compounds based on chemical shifts in five bins had an explained variance (r(2)) of 0.93 and a leave-one-out (LOO) cross-validated variance (q(2)) of 0.90. A 2.0 ppm resolution CoSA model for 14 PCDD compounds based on chemical shifts in five bins had an r(2) of 0.91 and a q(2) of 0.81. The 1.0 ppm resolution CoSA model for 12 PCB compounds based on chemical shifts in five bins had an r(2) of 0.87 and a q(2) of 0.45. The models with more compounds had a better q(2) because there are more multiple chemical shift populated bins available on which to base the linear regression. A 1.0 ppm resolution CoSA model for all 52 compounds that was based on chemical shifts in 12 bins had an r(2) of 0.85 and q(2) of 0.71. A canonical variance analysis of the 1.0 ppm CoSA model for all 52 compounds when they were separated into 27 strong binding and 25 weak binding compounds was 98% correct. Conventional quantitative structure-activity relationship (QSAR) modeling suffer from errors introduced by the assumptions and approximations involved in calculated electrostatic potentials and the molecular alignment process. QSDAR modeling is not limited by such errors since electrostatic potential calculations and molecular alignment are not done. The QSDAR models provide a rapid, simple and valid way to model the PCDF, PCDD, and PCB binding activity in relation to the aryl hydrocarbon receptor (AhR).

Benzofurans↗
PubMed2001

Polychlorinated dibenzodioxins and dibenzofurans in butter from different states in Australia.

Nine samples of butter from producers in various states of Australia were analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Detectable concentrations of 2,3,7,8-chlorine substituted PCDD/Fs were found in all samples. The mean PCDD/F concentration expressed as 2,3,7,8-TCDD equivalents (TEQs) was 0.19 pg TEQ g-1 fat. The highest concentration (0.46 pg TEQ g-1 fat) was observable in a sample from Victoria which is the most densely populated state. Overall the results indicate that PCDD/F concentrations in dairy products from Australia are low in comparison to the levels in dairy products of industrialized countries on the Northern Hemisphere. As expected, this study provides evidence that the environmental and consequently the human body burden of PCDD/Fs to be relatively low in Australia.

Air Pollutants↗