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Biomedical subjects

O Päpke

Publications and source records attributed to O Päpke.

At least 19 recordsLinked to original sources
PubMed2006

Placental transfer of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls in Taiwanese mothers in relation to menstrual cycle characteristics.

The aim was to determine the body burden of dioxins and polychlorinated biphenyls (PCBs) and whether they are associated with variables influencing reproduction. Our subjects were healthy women (mean age of 29 [SD=4.5]) from central Taiwan. The congeners of dioxins and dioxin-like PCBs in placentas (n=119) were identified using gas chromatography/high resolution mass spectrometry. The median levels of polychlorinated dibenzo-p-dioxins/dibenzofurans and PCBs were 10.2 (geometric mean [GM]: 9.8, 95% confidence interval [95% CI]: 8.8-10.9) and 2.7 (GM: 2.7, 95% CI: 2.3-3.1) pg WHO-TEQ/g lipid, respectively. Total TEQ level in placentas was significantly correlated with mothers' arm circumference (r=0.22, p=0.043). Increased body fat percentage was associated with higher total TEQ level in placentas. After adjustment for maternal age, pre-pregnant body mass index (BMI), and parity, placental dioxin-TEQ level higher in women (age 19 years) with irregular menstrual cycle than in those (age <18 years) with regular menstrual cycle (p=0.032) and placental PCB-TEQ level was higher in women with menstrual cycles longer than 33 days versus less than 33 days (p=0.006). Thus, environmental exposure to dioxins and PCBs may be related to changes in current menstrual cycle characteristics.

Adipose Tissue↗
PubMed2005

Contamination of the alluvial plain, feeding-stuffs and foodstuffs with polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs) and mercury from the River Elbe in the light of the flood event in August 2002.

Meadow soils, feeding-stuffs and foodstuffs from the alluvial plain of the river Elbe were analyzed in respect of PCDD/Fs, DL-PCBs and mercury with a view to assessing the consequences of the extreme flood of August 2002. The PCDD/F concentrations in the soils range from 3 to 2100 ng WHO-TEQ/kg dm, and for the DL-PCBs the range was 0.32 to 28 ng WHO-TEQ/kg dm. On the basis of established threshold values >40% of the areas are only fit for restricted usage. Mercury concentrations range from 0.11 to 17 mg/kg dm, whereby the action value of 2 mg/kg dm is exceeded in about 50% of the soil samples. A cumulative memory effect from past floods rather than a recent contamination from August 2002 is documented. Soils taken from behind broken dykes showed significantly lower concentrations. Grass, hay and grass silage originating from pasture land in Lower Saxony were taken before and immediately after the flooding. PCDD/Fs range from 0.29 to 16 ng WHO-TEQ/kg, the maximum permitted value of 0.75 ng WHO-TEQ/kg was exceeded in about 50% of the samples. Muscle-tissue from cattle, sheep, lamb and a roe deer as well as untreated milk from individual cows returned values ranging from 0.76 to 5.9 pg WHO-PCDD/F-TEQ/g fat, and 10% of the samples returned values higher than the permitted maximum of 3 pg WHO-PCDD/F-TEQ/g fat. The action value of 2 pg WHO-PCDD/F-TEQ/g fat was exceeded in 33% of the samples. No direct connection between these results and the effects of the flood could be established. A major input path for PCDD/Fs is the tributary Mulde, which discharges contaminated sediments from its catchment area into the Elbe.

Animal Feed↗
PubMed2005

Sorbent-assisted liquid-liquid extraction (Chem-Elut) of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in the lipid fraction of human blood plasma.

This work compares two lipid extraction methods for determining 24 polychlorinated biphenyls (PCBs), seven dibenzo-p-dioxins (PCDDs) and ten dibenzofurans (PCDFs) in human blood plasma. The first method was based on conventional liquid-liquid partitioning with chloroform-methanol and the other made use of a sorbent (Chem-Elut) to facilitate the partitioning of lipids into a mixture of hexane and 2-propanol. A multi-layer-silica column including acid- and base-impregnated silica gel was used to reduce the amounts of lipid present in the samples before a basic alumina clean-up step and activated carbon fractionation of planar analytes (PCDD/Fs and non-ortho-PCBs) and non-planar analytes (including ortho-chlorinated PCBs). Gas chromatography coupled to high resolution mass spectrometry was used to identify and quantify the analytes in the two fractions. The wet weight based concentrations obtained by the two methods were in agreement but both methods suffer from large organic solvent consumption. The toxic equivalencies derived for PCBs and PCDD/Fs using the two methods were also in agreement. However, the chloroform-methanol method gave slightly higher lipid recoveries, although with greater variation, than the sorbent-assisted method. Nevertheless, despite giving lower lipid recoveries, the sorbent-assisted method has advantages in ease of use and applicability to whole blood samples. The formation of emulsions was avoided with the Chem-Elut method, which probably explains the lower variability in the lipid determinations.

Adsorption↗
PubMed2005

[Human biomonitoring investigations of organochlorine compounds -- PCB, DDE, HCB, beta- and gamma-HCH, PCDD/PCDF, Dioxin-like PCB's and polybrominated biphenyl ethers].

Although PCB and PCB-containing materials are not processed for a long time, PCB is under discussion again and again caused by the pollution of indoor environments. To objectify the discussion, the dates of the PCB-biomonitoring, the organochlorine-compounds (DDE, HCB, beta-/gamma -HCH, PCDD/PCDF) and the polybrominated biphenyl ethers concerning the investigations within the project "Sentinel Health Departments" in Baden-Wurttemberg are represented. Additionally results from children from Kazakhstan (Aral-Sea area) and from teachers which are working in PCB polluted schools as well as from a long term investigated test person are reported. Blood concentrations of the following compounds decreased from 1996/97 to 2002/03: the sum of the concentration of PCB 138,153 and 180 decreased from 0.46 microg/L to 0.20 microg/L, DDE from 0.32 microg/L to 0.17 microg/, HCB from 0.20 microg/L to 0.08 microg/L, beta-HCH below the level of detection, I-TEQ NATO to 4.8 pg/g blood fat, TEQ WHO (without PCB) to 5.5 pg/g blood fat, PCB 126 to 18,8,pg/g blood fat and PCB 169 to 12.8 pg/g blood fat. The influence of breast feeding and the gender on the level of the pollution is conspicious. No local correlations were found in Baden-Wurttemberg, but they were found in comparison with the results of Kazakhstan (Aral-Sea area). The difficulty to produce time series while the analyzing pollutants are more and more decreasing, as well as the change of the calculation base of the summation of parameters like I-TEQ NATO to TEQ WHO are discussed.

Adult↗
PubMed2004

Level of polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls (PCDD/Fs, PCBs) in human milk and the input to infant body burden.

This study determined PCDD/F and PCB levels in human milk, examined factors associated with levels of contamination, and assessed the infant body burden from breast-feeding. The congeners of PCDD/Fs, dioxin-like PCBs, and indicator PCBs were analyzed by HRGC/HRMS for 36 human milk samples from healthy women, aged 20-35 years, from December 2000 to November 2001 in central Taiwan. Mean levels of WHO-TEQs in human milk were 10.5 (95% CI=8.8-12.2) and 14.5 (95% CI=12.5-16.5) pg-TEQ/g lipid for those <29 and > or =29 years old, respectively. PCB 138 concentration significantly predicted total WHO-TEQs with r2=0.84 (p <0.001). Milk level of dioxin-TEQ was 9.63 pg-TEQ/g lipid (95% CI=7.0-13.2) in those with a yearly income $29,000 compared to 6.3 pg-TEQ/g lipid (95% CI=5.2-7.6) for those whose yearly income was $18,000 per year. Women who reported being Buddhist (64.3 ng/glipid) had significantly higher indicator PCB concentrations than did those who reported being Taoist (35.3 ng/g lipid). The monthly dioxin intake of exclusively breastfed infants decreased with increasing duration of lactation. The cumulative dose of exclusively breastfed infants (76.5 ng TEQ, 95% CI=69.7-83.3) was significantly greater compared to that of formula-fed infants (CI=16.4-17.0) at one year and to that of infants at birth (3.90 ng TEQ, 95% CI=3.6-4.2). Our findings suggest that breast-feeding should be strongly encouraged for infants in Taiwan.

Adult↗
PubMed2004

The Elbe flood in August 2002--occurrence of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/F) and dioxin-like PCB in suspended particulate matter (SPM), sediment and fish.

As a result of extreme precipitation in August 2002 major flooding occurred in the catchment area of the rivers Elbe, Vltava (Moldau) and Mulde. Pollutants from industrial sites and from municipal sewage treatment works (STW) entered the Elbe and led to a serious pollution problem in the river. PCDD/F concentrations (in pg WHO-TEQ/g dw) in SPM ranged from 7-150, in sediments from 3-140; the "safe sediment value" of 20 was exceeded in 46% of the samples. 24 eels showed a wide concentration variation for these contaminants. The WHO-PCDD/F+PCB-TEQ values lay in the range from 11-56 pg/g ww, whereby the WHO-PCB-TEQ values were several times higher than the WHO-PCDD/F-TEQ values. The maximum permitted value of 4 pg WHO-PCDD/F/g ww (EU Directive No. 2375/2001) was reached or exceeded in 54% of the individuals. A statistical analysis using data from SPM and sediment samples showed that in the Czech river section the flooding activated a contamination source in the vicinity of the Spolana works. The influence of the tributary Mulde could be clearly demonstrated. Only a major clean-up of the contaminated sites in Bitterfeld can lead to a mid to long term improvement in respect of PCDD/F and dioxin-like PCB input into the Elbe.

Animals↗
PubMed2003

Concentrations of dioxins and other organochlorines (PCBs, DDTs, HCHs) in human milk from Seveso, Milan and a Lombardian rural area in Italy: a study performed 25 years after the heavy dioxin exposure in Seveso.

AIM: To investigate whether those who were exposed to high levels of the dioxin TCDD 25 years ago in Seveso, northern Italy still have higher than the expected levels of dioxins in their fat stores, and to investigate the concentrations of dioxins in the breast milk of mothers in Seveso and in two other regions in Italy. The load of vertically transmitted dioxins to the next generation, if being breastfed, was also investigated. METHODS: As there may be a synergistic effect of mixtures of organic chlorines, the concentrations of pesticides such as DDTs and PCBs have also been studied in the same human milk samples. Breast milk from 12 mothers from Seveso, Central Milan and a Lombardian village was collected for analysis during the first week and 1 and 3 mo after delivery. Individual samples were used for the analysis of pesticides and PCBs, whereas dioxins were analysed in pooled samples from all 12 mothers on each occasion. RESULTS: In human milk from Seveso, the TCDD concentration in fat calculated on a fresh weight basis was more than twice as high as the level in the other two regions, whereas the concentrations of investigated other toxins were lower in Seveso possible due to induction of the enzyme cytochrome P4501A, which means that the total level of dioxins was the same in all three locations. The congener profile, measured as mean toxic equivalency (TEQ) values, was the same in the Italian samples as previously reported from Stockholm. The calculations are based on the most recent WHO TCDD equivalency factors (TEF). The DDE concentration was higher in the samples from Milan than in the samples from the other two Italian regions, which may be due to the fact that, to a greater extent than in the other regions, Milanese food is imported from countries where DDT is still used as a pesticide. CONCLUSION: Twenty-five years after the dioxin catastrophe, human milk from mothers in Seveso has concentrations of the highly toxic dioxin congener TCDD that are more than twice as high as those in central Milan and a Lombardian village. This means that breastfed infants in Seveso still store an appreciable amount of TCDD in their body fat. The health consequences of this fact remain to be elucidated. The effect of the high load of DDTs in central Milan also has to be considered

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↗
PubMed2001

Intake of dioxins and related compounds from food in the U.S. population.

The first U.S. nationwide food sampling with measurement of dioxins, dibenzofurans, and coplanar, mono-ortho and di-ortho polychlorinated biphenyls (PCBs) is reported in this study. Twelve separate analyses were conducted on 110 food samples divided into pooled lots by category. The samples were purchased in 1995 in supermarkets in Atlanta, GA, Binghamton, NY, Chicago, IL, Louisville, KY, and San Diego, CA. Human milk also was collected to estimate nursing infants' consumption. The food category with highest World Health Organization (WHO) dioxin toxic equivalent (TEQ) concentration was farm-grown freshwater fish fillet with 1.7 pg/g, or parts per trillion (ppt), wet, or whole, weight. The category with the lowest TEQ level was a simulated vegandiet, with 0.09 ppt. TEQ concentrations in ocean fish, beef, chicken, pork, sandwich meat, eggs, cheese, and ice cream, as well as human milk, were in the range O.33 to 0.51 ppt, wet weight. In whole dairy milk TEQ was 0.16 ppt, and in butter 1.1 ppt. Mean daily intake of TEQ for U.S. breast-fed infants during the first year of life was estimated at 42 pg/kg body weight. For children aged 1-11 yr the estimated daily TEQ intake was 6.2 pg/kg body weight. For males and females aged 12-19 yr, the estimated TEQ intake was 3.5 and 2.7 pg/kg body weight, respectively. For adult men and women aged 20-79 yr, estimated mean daily TEQ intakes were 2.4 and 2.2 pg/kg body weight, respectively. Estimated mean daily intake of TEQ declined with age to a low of 1.9 pg/kg body weight at age 80 yr and older. For all ages except 80 yr and over, estimates were higher for males than females. For adults, dioxins, dibenzofurans, and PCBs contributed 42%, 30%, and 28% of dietary TEQ intake, respectively. DDE was also analyzed in the pooled food samples.

Adolescent↗
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↗
PubMed2001

Dioxin contamination in food. Bayreuth, Germany, from September 28 to October 1, 2000.

Dioxin and PCB monitoring programs for food and feeding stuff in most countries of the world, including many European Countries are currently inadequate. Better control of food production lines and food processing procedures is needed to minimize entry of dioxin to the food chain and will help to avoid dioxin contamination accidents. This would also improve the ability to trace back a possible contamination to its source. European guidelines for monitoring programs should be established to ensure comparable and meaningful results. These guidelines should define the minimum requirements for the design of monitoring programs, analytical methods, and quality assurance. Though data from Northern Europe shows that the general population exposure to dioxin and PCB has decreased during the last ten years these compounds continue to be a risk of accidental contamination of the food chain. The most prominent recent example is the Belgian dioxin contamination of feeding stuff in 1999. The Belgian dioxin contamination was not detected due to dioxin monitoring programs but by their direct biological effects seen in animals. Four other cases of dioxin contamination have been detected in Europe since 1997 due to local monitoring programs. One of them (citrus pulp pellets 1998) was in a much larger scale than the Belgian dioxin contamination. The general population's exposure to dioxins and PCBs is still in the same range (1-4 pg WHO-TEQ/kg body weight and day) as the recently revised WHO tolerable daily intake (TDI). There is concern that short-term high level exposure to dioxins, furans, and PCB may cause biological effects on the human fetal development and further research is required. Further actions to control sources building on considerable advances already made in many countries may need to be supplemented by measures to prevent direct contamination of feeding stuff or food to reduce general population exposure further.

Animal Feed↗
PubMed2001

Cutaneous elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

BACKGROUND: After exposure, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is excreted via the faeces, breast milk and epidermal lipids. OBJECTIVES: To determine to what extent TCDD is eliminated via the skin and to evaluate whethe cutaneous elimination can be accelerated by the application of petrolatum. METHODS: In two patients severely intoxicated with TCDD, material obtained from the skin surface and, in one patient, cerumen and the content of epithelial cysts, was analysed for TCDD. RESULTS: The TCDD concentration in the initial blood sample taken was 144 000 pg g(-1) blood fa in patient 1, and 26 000 pg g(-1) blood fat in patient 2. Six months later, when the skin tests were performed, the blood TCDD levels had decreased to 80 900 and 16 100 pg g(-1) blood fat, respectively. In the two samples of pooled cyst contents from patient 1, TCDD levels of 34 400 an 18 600 pg g(-1) fat were found. A cerumen sample contained TCDD at 20 500 pg g(-1) fat. In the material collected from the skin surface we observed a linear increase of the amount of TCD measured per test field with time, indicating a continuous elimination of TCDD via the skin. Th daily amount of TCDD eliminated via the skin was 1.51 pg cm(-2) in patient 1 and 0.57 pg cm(-2) in patient 2. Application of petrolatum led to a twofold increase in the amount of TCDD measured in patient 1, but had no significant effect in patient 2. CONCLUSIONS: In our patients, elimination of TCDD via the skin, most probably through desquamating scales, represented 1-2% of the overall daily TCDD elimination rate, with regard to the body surface and when calculated on the basis of the half-life of TCDD at the time of the skin test. If a more typical overall elimination half-life of 7 years is used as the basis for the calculatio the skin would account for 9% (patient 1) and 15% (patient 2) of the overall elimination. Although we observed an increase in TCDD in material derived from the skin surface of up to 100% after application of petrolatum in patient 1, such an approach appears not to be a feasible means to increase elimination. Owing to the small amount of TCDD measured in skin-surface material, as well as in the cyst contents and cerumen obtained from one patient, contamination of the environment and other persons appears highly unlikely.

Acne Vulgaris↗
PubMed2001

[Home transfer of 2,3,7,8-tetrachlorodibenzo-p-dioxin and beta-hexachlorocyclohexane?].

Persons living together with workers who have been exposed to dioxins, furans or hexachlorocyclohexane, accumulate increased concentrations of these molecules in the blood and in fatty tissue, in comparison with normal people. This result is based on an investigation of 14 workers and their female partners. The workers had been contaminated with high concentrations of 2,3,7,8-TCDD and moderate concentrations of beta-HCH, respectively, in contrast with their female partners who had never been exposed to these poisons. Nevertheless, the female partners accumulated a significant amount of these molecules, corresponding to 10% of the concentrations of their male partners. The origin of this correlation is still unknown. As a working hypothesis, we discuss the possibility of molecular transfer by clothing and underwear. The clinical consequences of these findings are still unclear. Further observations are needed.

Adult↗
PubMed2001

Recent dioxin contamination from Agent Orange in residents of a southern Vietnam city.

Marked elevation of dioxin associated with the herbicide Agent Orange was recently found in 19 of 20 blood samples from persons living in Bien Hoa, a large city in southern Vietnam. This city is located near an air base that was used for Agent Orange spray missions between 1962 and 1970. A spill of Agent Orange occurred at this air base more than 30 years before blood samples were collected in 1999. Samples were collected, frozen, and sent to a World Health Organization--certified dioxin laboratory for congener-specific analysis as part of a Vietnam Red Cross project. Previous analyses of more than 2200 pooled blood samples collected in the 1990s identified Bien Hoa as one of several southern Vietnam areas with persons having elevated blood dioxin levels from exposure to Agent Orange. In sharp contrast to this study, our previous research showed decreasing tissue dioxin levels over time since 1970. Only the dioxin that contaminated Agent Orange, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), was elevated in the blood of 19 of 20 persons sampled from Bien Hoa. A comparison, pooled sample from 100 residents of Hanoi, where Agent Orange was not used, measured blood TCDD levels of 2 parts per trillion (ppt). TCDD levels of up to 271 ppt, a 135-fold increase, were found in Bien Hoa residents. TCDD contamination was also found in some nearby soil and sediment samples. Persons new to this region and children born after Agent Orange spraying ended also had elevated TCDD levels. This TCDD uptake was recent and occurred decades after spraying ended. We hypothesize that a major route of current and past exposures is from the movement of dioxin from soil into river sediment, then into fish, and from fish consumption into people.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1999

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and coplanar polychlorinated biphenyls in breast milk from two cities in Ukraine.

Substantial environmental pollution has been alleged in Ukraine, but little information is available to allow an assessment of the possible impact on humans. To help remedy this lack of information, it was of interest to investigate whether certain polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), or coplanar polychlorinated biphenyls (PCBs) were elevated in people from Ukraine. Samples of breast milk were obtained from 200 women from the cities of Kyiv and Dniprodzerzhinsk; Kyiv is the capital and Dniprodzerzhinsk is a highly industrialized city. The samples were combined into four pools by city and age, and analyzed for 7 PCDDs, 10 PCDFs, and 2 coplanar PCBs (126 and 169). The total of the measured PCDDs, expressed as toxic equivalent, ranged from 5.1 to 7.6 pg/g lipid; for PCDFs from 3.6 to 5.2, and for PCBs from 11 to 18 pg/g lipid. Results from the two cities were similar; older women had slightly higher concentrations than did younger women. Levels of these compounds seen in Ukraine were similar to or lower than those seen in other recent studies from European and Asian countries.

Adult↗
PubMed1999

Olestra increases faecal excretion of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

Two patients with chloracne had concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) of 144,000 and 26,000 pg/g blood lipids. Olestra, a non-digestible, lipophilic dietary fat substitute accelerated the patients' intestinal excretion of TCDD by eight to ten fold. This is sufficient to reduce the normally observed elimination half life of TCDD from about 7 years to 1-2 years.

Acne Vulgaris↗
PubMed1999

Clearance of PCDD/Fs via the gastrointestinal tract in occupationally exposed persons.

A digestive tract mass balance was performed on six men with high body burdens of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Intake via food was measured by analyzing duplicate portions of the food consumed by the volunteers and excretion via feces was determined by quantitative collection and analysis of the feces. Blood samples were taken to determine the current body burden. The results showed that the quantity of non-metabolized chemical excreted in the feces clearly exceeded the uptake via food for all of the 2,3,7,8-substituted PCDDs and some of the PCDFs, indicating a significant clearance across the gastrointestinal tract. The concentrations of these PCDD/F congeners in blood and feces were highly correlated (r > 0.8), demonstrating that the fecal PCDD/F content was determined by the body burden. The half lives in the test persons due to fecal clearance of non-metabolized chemical were estimated from the excretion rate and the current body burden and ranged between 10 years (Cl8DD) and 33 years (2,3,4,7,8-Cl5DF). These were compared with the overall contaminant half-lives due to all clearance processes which were calculated from the body burden and the decrease in blood concentrations measured over several years. The fecal clearance of non-metabolized PCDD/F contributed on average between 37% (2,3,7,8-Cl4DD) and 90% (Cl8DD) to the total elimination. This indicates that the gastrointestinal pathway plays a decisive role in the clearance of most 2,3,7,8-subsituted PCDD/F congeners.

Adult↗