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Constant elimination half-life is usually used in first-order one-compartment pharmacokinetic models to assess human exposure to dioxin-like polychlorinated biphenyls (PCBs). However, hepatic clearance rates are usually lower for elders than for young people. In this study, levels of 12 dioxin-like PCBs were determined in blood samples collected in 2012 from 305 individuals from the general population. We estimated the historical daily intake of dioxin-like PCBs for individuals with a validated annual exponential decay function. Based on the blood levels and historical daily intake levels, and using the maximum likelihood estimation by running the first-order one-compartment pharmacokinetic model, elimination rates were optimized as exponential functions of age for PCB118, PCB157, PCB189 and PCB126; linear functions of age for PCB114, PCB123, PCB167 and PCB169; and constant functions of age for PCB105 and PCB156. With the exception of PCB105 and PCB156, half-lives generally increased with age for individuals from 24 to 50 years old: from 0.805 to 1.95 years for PCB189, 2.08-4.54 years for PCB157, 3.32-5.58 years for PCB126, 3.52-6.81 years for PCB123, 5.24-12.29 years for PCB169, 6.60-14.40 years for PCB114, 7.50-14.01 years for PCB118, and 9.97-21.97 years for PCB167. The half-lives of PCB105 (5.79 years) and PCB156 (15.1 years) were independent of age. Our research for the first time clarified the effects of age on the elimination rate of dioxin-like PCBs in individuals from the general population, thus reducing uncertainty in future health risk assessments., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In South Africa, 26-50% of households use solid fuel for cooking food and heating houses. When used as fuel, wood and chlorinated waste are known sources of polychlorinated dibenzo-para-dioxins, polychlorinated dibenzofurans (PCDD/Fs), and polychlorinated biphenyls (PCBs). Here, we compare PCDD/F, dioxin-like PCB (DL-PCB), and non-DL-PCB (NDL-PCB) levels in serum of 693 Tswana individuals in the North West province, who either burn solid biofuels or have access to electricity, gas, and paraffin. This is the first South African study on dioxin levels in humans with more than 100 participants. Serum was pooled according to fuel use, as well as to confounding factors such as gender and age. Solid-phase extraction was used to remove the target analytes from serum, after which the extracts were further refined automatically using a combination of multilayer sorbents. Compound concentrations were determined by high-resolution mass spectrometry after high-resolution gas chromatography. Mean serum lipid content was determined enzymatically to be 5.91 ± 0.42 g/L. The PCDD/F and DL-PCB levels were similar to global concentrations reported for non-exposed adults. The mean of the total Toxic Equivalencies (ΣTEQ) was 6.9 ± 3.3 pg/g lipid and the mean NDL-PCB was 70.1 ± 42.8 ng/g lipid. The mean concentrations of the PCDDs, PCDFs and the corresponding World Health Organization-TEQ (WHO-TEQ) of the population using electricity, gas, and paraffin were greater than of those reliant on solid biomass (p = 0), whereas the DL-PCBs, their corresponding WHO-TEQ, and NDL-PCBs were greater for the population who use biofuels but not significantly so. The females had higher serum levels of the PCDDs (p = 0) and PCDFs (not significant) whereas the PCBs were higher for the males (p = 0). Breastfeeding women presented lower levels of all compound classes than their non-breastfeeding counterparts (p=0) and older subjects manifested greater pollutant loads than the younger generation (p = 0). For our study population, being regularly exposed to the combustion of solid biofuels caused higher serum levels of DL-PCBs and NDL-PCBs but not of PCDDs and PCDFs., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: to conduct a survey on blood levels of metals and organochlorine compounds (dioxins and PCBs) among workers of livestock farms, and to identify the factors able to explain the magnitude and variability of the measured concentrations., Design: exploratory human biomonitoring study., Setting and Participants: a sample of 45 workers from farms (masserie) located in the Province of Taranto was included in the study. The farms, located between 6 and 43 km from the industrial area, are family owned and animals (mainly sheep and goats) are locally reared outdoors. The study subjects have similar eating habits, including food consumption resulting from their production., Results: manganese concentrations and, to a lesser extent, arsenic, cadmium and lead are in the medium-high range of levels observed in the Italian general population. This study does not identify factors able to explain the variability in the blood levels of metals. The amount of dioxins and PCBs, on the other hand, is strongly associated both with subjects age and the distance of farm from the industrial site., Conclusion: the results of this survey are suggestive of research hypotheses that need to be confirmed by biomonitoring studies of adequate design and size, in particular the hypothesis that the blood level of dioxins and PCBs decreases with increasing distance from the industrial site. We recommend ad hoc studies to better characterize the exposure of farmers (also associated with agricultural activities), and of the inhabitants of Taranto, to environmental persistent pollutants, also in terms of food matrices locally produced and consumed.

Dioxins and dioxin-like (DL) compounds are some of the most toxic chemicals being highly persistent in the environment. The toxicological effects of dioxins are mediated via the aryl hydrocarbon receptor (AhR). Compounds of diverse structure and lipophility can bind and activate AhR. The AhR transactivation bioassay is utilized in an array of projects to study the AhR-mediated activities of individual chemicals and mixtures and for epidemiological purposes. This review summarizes a series of studies regarding the DL-activity of single compounds and complex compound mixtures in the environment and humans. We found that some pesticides, plasticizers and phytoestrogens can activate the AhR, and the combined effect of compounds with no or weak AhR potency cannot be ignored. The significant DL-activity in the wastewater effluent indicates the treatment is not sufficient to prevent contamination of surface waters with dioxins. Our results from human studies suggest that the serum DL-activity reflect the complex mixture of persistent organic pollutants (POPs). Greenlandic Inuit had lower serum DL-activity level compared to Europeans, probably due to long distance from the dioxin sources and UV degradation of the high potent dioxin and/or the inhibitory effect of the high level of non-DL POPs. Selective bioaccumulation of PCBs in the food chain may contribute to the negative correlation between serum POPs and DL-activity observed in Greenlandic Inuit. Hence the AhR transactivation bioassay provides a cost-effective and integrated screening tool for measurement of the DL-activity in human, environmental and commercial samples., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objective: to evaluate the degree of exposure to PCB in a population resident in the lower Susa Valley and its effects on general and endocrine homeostasis. DESIGN, SETTING, PARTICIPANTS AND MAIN OUTCOME MEASURES: in the lower Susa Valley (Piedmont, Italy), there is a steel secondary casting plant (i.e. by fusion of scrap iron), active since the '50s. The emissions of PCB and dioxin coming from the furnace were found in samples of herb, pulse and ground in a preliminary environmental characterisation study. During 2005-2006 we run an epidemiologic study of biomonitoring (measuring as outcome common haematochemical parameters, hormonal parameters, haematic PCB) on a sample of subjects resident in the municipalities with higher levels of PCB and dioxin contamination (exposed subjects), that was compared with another sample (unexposed) of subjects residing in other areas of the Susa Valley., Results: the final sample consisted of 244 subjects (119 unexposed and 125 exposed), balanced by gender, age, education and representative of the Susa Valley population. The greater part of hormonal and toxic parameters showed worse values among exposed than among unexposed, including PCB median value (2.30 μg/l among exposed vs. 1.90 μg/l among unexposed). The difference however was not statistically significant and the values were lower than the population reference values (7.2 μg/l). Haematic PCB values were significantly and positively correlated with age and alcohol consumption and not significantly with male gender. The distribution of the principal haematochemical parameters (hemochrome, total, LDL and HDL cholesterol, triglycerides, glucose, creatinine, bilirubin, transaminases, gamma-glutamiltranspeptidase, proteine electrophoresis) showed also, on the whole, worse values among exposed compared to unexposed, even if the difference was not statistically significant for single values., Conclusions: the exposed population showed higher values of PCB haematic values and alterations of the hormonal and common heamatochemical parameters compared to unexposed population, even if within reference limits.

Background: A total of 265000 m(3) of dioxin contaminated soil and sediments from past industrial activity was treated on site in an urban setting in Sydney, Australia. To respond to local community concerns about potential dioxin exposure from fugitive emissions a human biomonitoring study was undertaken., Objective: To determine whether local residents were exposed to significant amounts of dioxin from the remediation process., Methods: Blood samples were collected from local residents around the site and a representative metropolitan control group. They were pooled within age and sex strata and the change in dioxin concentrations over the remediation period and a summary of the mid point and post remediation dioxin concentrations were compared between groups. Information on dietary intake was collected to look for possible confounding., Results: The mean dioxin Toxic Equivalent concentrations (TeQ) decreased among both the local resident and control groups over the remediation period by 1.9 and 2.1 pg gm(-1) lipid respectively. Modelled blood concentrations adjusting for age and sex did not detect a significant difference between groups for changes in either TeQ or 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8 TCDD). The summary measure approach did however demonstrate that the 2,3,7,8 TCDD concentrations among the local resident group was approximately 0.7 pg g(-1) lipid higher compared to the control group post remediation. There were no significant changes in dietary intake sources of dioxin., Conclusion: Biomonitoring demonstrated that local residents were not exposed to significant quantities of dioxin. Large scale remediation of dioxin contaminated land can be safely undertaken in an urban setting., (Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.)

Dioxins are a family of chemical compounds that has received considerable attention, both historically and currently. This article reviews scientific field studies that examine the relationship between living on soil contaminated with dioxins and the level of dioxins in people's serum, with an emphasis on the University of Michigan Dioxin Exposure Study (UMDES), the largest and most comprehensive study of its kind. These studies conclude that the levels of dioxins in serum are most strongly correlated with age, gender, body mass index, weight loss, breast feeding, and smoking. Levels of dioxins in soil are not significant predictors for dioxin concentrations in serum. The increase in serum dioxin levels that is seen with age results from historic exposure and does not represent ongoing exposure. Based on the scientific field studies conducted to date, it appears that, in the absence of the consumption of contaminated animal products, there is little evidence of ongoing exposure from contaminated soil.

This manuscript presents highlights of recent studies and perspectives from the French human biomonitoring (HBM) programme. Until recently, HBM studies focused on specific populations or pollutants to gain a better understanding of exposure to environmental chemicals, to help regulators reduce environmental exposure and to monitor existing policies on specific concerns. Highlights of recent multicentre biomonitoring studies with specific population or pollutant focus are given. These French HBM studies have been implemented to know: (1) the influence of living near an incinerator on serum dioxin and polychlorinated biphenyl (PCB) levels, (2) the influence of consuming river fish contaminated by PCBs on serum PCBs of fishermen, and (3) the evolution of blood lead levels in children from 1 to 6 years old since 1995. Special emphasis is placed on the use of an integrated (HBM coupled with nutrition and health studies), multipollutant approach. This approach has been initiated in France with a recent national population-based biomonitoring survey, the Etude Nationale Nutrition Santé (ENNS; French Nutrition and Health Survey). This survey will provide the first reference distribution for 42 biomarkers in the French population. The current national HBM strategy will build upon the ENNS and include a national survey of people aged between 6 and 74 years complemented for the neonatal period and childhood by the Etude Longitudinale Française depuis l'Enfance (ELFE; French longitudinal study of children). France also contributes to the harmonization of HBM activities in Europe through participation in European HBM projects., (Copyright © 2011 Elsevier GmbH. All rights reserved.)

The purpose of this study was to establish an economic and efficient method to screen total PCBs and total dioxins (PCDDs+PCDFs+Co-PCBs) in the highly exposed people in Japan. In this paper, we suggest use of total PCBs in human blood to represent other persistent organic pollutants, especially dioxins. Twenty blood samples were collected from Japanese volunteers. Total PCBs and total dioxins (PCDDs+PCDFs+Co-PCBs) were detected from all twenty blood samples. We carried out detailed analysis of correlation between concentration of total PCBs and each dioxin congener with both measured value and TEQ calculated value. The mean concentration of total PCBs was 250 ng g-fat(-1), and the mean concentration of total dioxins was 37 ng g-fat(-1) or 40 pg TEQ g-fat(-1). Correlations between the total PCBs (ng g-fat(-1)) and the total measured dioxins (ng g-fat(-1)), and between the total PCBs (ng g-fat(-1)) and the total dioxin TEQ calculated value (pg-TEQ g-fat(-1)) were 0.95 and 0.90, respectively. It became clear that the concentrations of total PCBs in human blood is a good indicator of the concentrations of total dioxins in Japan. If a mass screening is conducted on women of reproductive age in order to detect highly exposed women, it is possible that women with the highest contamination may be treated in order to decrease the levels of these chemicals before pregnancy. In conclusion, measurement of total PCBs concentration is useful for exposure assessment of dioxins in human blood.

Organochlorines (polychlorinated biphenyls and dioxin-like compounds) are suspected to play a role in the etiopathogenesis of endometriosis. This hypothesis, based on experimental data, has been circulating for years in the scientific community and several epidemiologic surveys have attempted to obtain confirmatory human data. The purpose of this mini-review is to provide an overview of the twelve epidemiological studies that have assessed the relationship between endometriosis and organochlorine exposure. Several studies did not observe a significant association between peritoneal endometriosis and organochlorines. The deep nodular form of endometriosis appears associated with a higher serum level of both dioxin-like compounds and polychlorobiphenyls. The type of control women, the nature of the chemicals measured, and the definition of the disease could modulate the ability to detect the possible relationship between endometriosis and organochlorine exposure.

In the Federal State of Baden-Wuerttemberg, Germany, an environmental health surveillance system has been established focusing on children aged 10 years. Four study regions (two larger cities, one small city, and one rural area) were designated in order to get information about the body burden of persistent chemicals (toxic metals and chlorinated compounds) in children and about lung function, frequency of respiratory diseases, and allergies. From 1992/1993 to 2002/2003, seven cross-sectional investigations were carried out, and more than 10,000 children took part in the study. DDE, HCB, PCB-138, PCB-153 and PCB-180 were measured in individual blood samples of about 400 children per year, whereas PCDD/PCDF and coplanar PCBs were determined in pooled blood samples. From 1993 to 2003, blood concentrations of these compounds decreased 2 to 4-fold. Concerning regional differences, slightly lower concentrations of DDE, PCBs and PCDD/PCDF could be seen in children from the municipal population of Mannheim compared to other regions. Breast feeding was associated with considerably higher concentrations of PCBs and most other chlorinated compounds. Static and dynamic lung function parameters showed no differences between the investigated areas. For prevalences of respiratory diseases and allergies, no time trend was observed except for pertussis, which showed a decrease in 2002/2003 probably due to an increase of vaccination rates. In addition, the prevalence of atopic sensitization against aero allergenes remained unchanged at about 35% during the observation period. In conclusion, this environmental health survey delivers objective data about spatial and temporal trends and provides information about possible sources of children's exposure to toxic compounds in the environment. Adaptations of the survey to new problems are discussed.

In 2005 the World Health Organization (WHO) re-evaluated toxicity equivalency factors (TEFs) for dioxins and dioxin-like compounds. WHO 2005 toxicity equivalent (TEq) levels were calculated based on our data on German background levels of polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) in human blood and milk of the Duisburg birth cohort study. Levels of WHO 2005 TEq (PCDD/F+PCB) were in the range of 3.77-63.6 pg/g(lipid base) (n=226, median: 19.38, arithmetic mean: 20.86) for blood, or 2.62-59.2 pg/g(lipid base) (n=176, median: 19.78, arithmetic mean: 20.57) for milk, respectively. Compared to WHO 1998 TEq values WHO 2005 TEq levels were about 25% lower in both matrices. The shares of PCB (31% blood, 43% milk), especially of mono-ortho-substituted PCB (4% blood and milk), on total WHO 2005 TEq has become lower. If similar congener patterns can be assumed for certain matrices, appropriate multiplication factors can be used to convert TEq values of other TEF models sufficiently to WHO 2005 TEq values.

Polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran and dioxin-like polychlorinated biphenyl concentrations in human blood, lung, liver, bile, pancreas, spleen, kidney and mesentery fat were determined to assess the concentrations and distribution of these chemicals in human tissues from 20 donors. The mean TEQ concentrations in blood, lung, liver, bile, spleen, pancreas, kidney and mesentery fat were 119, 178, 228, 50, 113, 163, 138 and 139 pg TEQ/g lipid, respectively. Parallel levels were seen in the blood, spleen, kidney and mesentery fat; in the lungs and pancreas, the levels were somewhat higher. Among the organ tissues samples, the highest concentration was observed in the liver and the lowest in the bile. Mean total-TEQ concentration of the liver was about 4.5 times higher than that of bile. Positive correlations were observed among the concentrations of dioxins in various tissues. However, the concentrations in bile were not correlated with any tissues. It is suggested that the distribution behavior of dioxin-like congeners in human tissues varies among tissues and the kinds of congeners ingested. To evaluate the relationship between the accumulation levels of dioxins and their pathophysiological significance or risk, data must be accumulated from a more extensive group of human samples.

Objective: The objective of this study was to find sites in Vietnam where there was human exposure from Agent Orange herbicide sprayed between 1962 and 1971, as determined by congener-specific measurement of dioxins, including 2,3,7,8-tetrachlorodibenzodioxin (TCDD), the dioxin that contaminated Agent Orange, in blood., Methods: Blood was collected from residents of eight heavily sprayed regions in the south of Vietnam and analyzed for TCDD and in some cases the dioxin-like dibenzofurans and dioxin-like PCBs., Results: Six of the eight newly studied sites did not show substantial or any elevated TCDD in blood. Marked elevation of TCDD in Vietnamese blood was found in one new location with a suggestion of slightly elevated TCDD in a second location., Conclusions: In newly studied locations in Vietnam, we found some persons with elevation of TCDD consistent with exposure to dioxin from Agent Orange. In our previous studies, we found PCBs, PCDDs, and PCDFs as well as pesticides in human milk, blood, or in food. Health effects from Agent Orange need to be differentiated from effects caused by chemicals other than TCDD from Agent Orange.

Many studies have been conducted that monitor and trace the sources of polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs) by comparing congener patterns of environmental samples with those of possible sources. In this study, we measured PCDD/F concentrations and compared congener patterns of samples of various media found in and around an industrial waste incinerator in Korea, including stack gas, fly ash, bottom ash, ambient air, soil, pine needle, and human blood. We obtained reliable data on the relationship between the PCDD/F distributions in these sources and the environment, and thus found indicators with which to assess the impact of such sources on the surrounding environment. In addition, the difference between the levels of PCDD/Fs in the blood of short-term workers and long-term workers demonstrates that these workers are exposed to the compounds produced by the indicator.

Dioxins, including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs) and coplanar polychlorinated biphenyls (Co-PCBs), such as mono-ortho-PCBs and non-ortho-PCBs, are environmental pollutants that have deleterious effects on human health. Although screening of blood samples for dioxins is necessary, the current methods are time-, reagent- and labor-intensive. To optimize the extraction and cleanup of dioxins, we have designed a column chromatography method, coupled with a water washing step. We used a tandem simplified multilayer silica gel-activated carbon dispersed silica gel column (TS-ML-AC) rather than the conventional two columns. We compared three liquid-liquid extraction (LLE) methods and two pressurized liquid extraction (PLE) methods, when used with this column. For each of these extraction methods, we compared the quantity of lipid obtained when the water washing step was omitted and when it was performed by shaking 30 times by hand or 30 min by a machine. We found that TS-ML-AC was superior to the conventional pair of columns in that only about one third of the solvent and only one quarter of the time was necessary. Of the five extraction methods, the acetone/hexane PLE (AcP) method was superior, since it reduced the amount of organic solvent to half or less of the amount required for the LLE methods. The cleanup step using water was best accomplished by the hand-shaking method. Our results indicate that, for the analysis of dioxin in whole blood samples, the use of AcP together with TS-ML-AC and water washing by hand shaking should be used.

The aim of this study was to evaluate the serum polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) concentration distribution in residents living in the vicinity of an incinerator and its association with annual ambient dioxin exposure predicted by an atmospheric dispersion model. A municipal waste incinerator in Northern Taiwan was chosen for this study. This incinerator had been in operation for 6 years at the time of this study. Using the incinerator site as the center, based on the simulated ambient annual average PCDD/F concentrations. Ninety-five volunteers, all live within a radius of 5 km from the incinerator for at least 5 years, who had no occupational exposure potential, were selected based on the population distribution in each district. The average serum PCDD/F concentration for these subjects living within four zones was about 14 pg I-TEQ/g lipid. The serum distribution levels of people of the four study zones, however, were not consistent with the predicted ambient levels. Results also suggest that ambient exposure might not be the most important contributor to serum concentrations when compared to other exposure sources, such as dietary intake.

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and organochlorine pesticides were measured in the serum of a sample of the New Zealand population aged 15 years and older. This was the first study to obtain representative measures of PCDDs, PCDFs and PCBs in the adult population of an entire country. Serum samples were obtained in 1996-1997. Potentially occupationally exposed individuals were excluded. Serum samples were pooled according to stratification criteria for area of residence, ethnicity, age, and sex. Of the 80 possible strata, sufficient serum for chemical analysis was available for 60, to which 1,834 individual samples contributed. For the PCDDs and PCDFs, most 2,3,7,8-chlorinated congeners were measured in all strata, with a mean toxic equivalents concentration across all strata of 12.8 ng TEQ kg(-1) lipid. Seven PCB congeners were frequently measured, including the coplanar congeners #126 and #169, quantified in all strata. Of the pesticides and their metabolites, only beta-HCH, dieldrin and pp'-DDE were consistently detected across strata. There was a general trend of increasing concentration with age. There were no consistent differences between the sexes, or between people of Maori (the indigenous people of New Zealand) and non-Maori ethnicity. Concentrations of PCDDs and PCDFs tended to increase in a North-South direction, possibly reflecting greater levels of industrialization and population concentration, and concentrations of the pesticide products were highest in the South, possibly reflecting historical use patterns. Results were consistent with a recent study of concentrations of these compounds in the milk of first-time mothers.

To perform high quality and high throughput measurements, complicated purification procedure by two rounds of open column chromatography was simplified by appraising the components and adding a sufficient amount of adsorbents to the column. The procedure consists of two open column techniques using a multi-layer silica gel column and an active carbon dispersed silica gel column. This purification procedure is used in "Standard manual for dioxin analysis in human blood" published in 2000 (Ministry of Health and Welfare, Japan, 2000). Consequently, a purification procedure using only 1 g of 10% AgNO(3)/silica gel can remove the matrix of blood serum as effectively as a multi-layer silica gel column. In addition, 0.1 g of carbon silica gel, equivalent to 1/10 the weight used currently in analyses, separates and recovers the dioxins in purified extract of blood serum. Furthermore, changes in the background level in the general population were clarified by monitoring the dioxin concentrations in human blood. The dioxin concentrations and ratios in blood in the general population remained at a tolerable level for three months. Therefore, the blood serum was available for the detection of a remarkable elevation in dioxins level considered to be indicative of contamination due to high-density exposure.

Biomonitoring is the assessment of human exposure to environmental chemicals by measuring the chemicals or their metabolites in human specimens such as blood, urine, saliva, or tissue. It has become a powerful public health tool. This article discusses the practical application of biomonitoring to address a public health problem in a state, to explain how biomonitoring differs from predicting exposure through environmental monitoring, to describe the influence biomonitoring has had on promulgating regulations aimed at protecting public health, and to discuss the position biomonitoring holds in the legal landscape as well as its promise in forging laws that will regulate toxic chemicals more effectively.

Measurement of blood dioxin levels to monitor human exposure is tedious and expensive work, although high-resolution mass spectrometers equipped with high-resolution gas chromatography are becoming relatively common in Japan. The Ministry of Health and Welfare and the Environmental Agency require measurement of 17 dioxins, seven PCDDs and 10 PCDFs, according to a statement in "Dioxin Measurement Guidelines" published in 1997. Additionally, three coplanar polychlorinated biphenyls, for which TEFs were determined, have been included for measurement ad libitum. Recently, we have examined 316 blood samples from four groups of subjects, living in areas 5 km away from any incinerator (A), within 2 km from incinerators that emitted slightly higher levels of dioxins than the allowed level (higher than 80 ng/Nm3) (B), within 2 km of an incinerator which emitted a high level of dioxin (C), and workers at this incinerator (D), for dioxin levels by measuring 20 congeners, including three coplanar PCBs. The average pg TEQ/g lipid values were 23.8 +/- 12.3, 25.6 +/- 11.6, 39.1 +/- 18.8 and 100.7 +/- 127.4 for A, B, C and D, respectively. It was found that more than 90% of the total TEQs of the subjects in all groups were accounted for by eight congeners, 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxCDD, 2,3,4,7,8-PeCDF, 3,3',4,4',5-PeCB, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF and 2,3,4,6,7,8-HxCDF. This is also the case for a further 30 blood samples that had no connection with incinerators. Further, regression analysis of the 346 samples leads to an equation of y = 1.109x - 1.077, with a correlation coefficient, r = 0.9996. Here, y = total pg TEQ of 20 congeners/g lipid of blood, and x = total pg TEQs of eight congeners/g lipid. Accordingly, we propose that measurement of eight instead of 20 congeners is appropriate to obtain dioxin TEQ values of blood, at low cost, with high accuracy and with high efficiency, in a short time.

The authors conducted a biomonitoring study in the town of Mataró, Spain, of 104 subjects who lived near (i.e., within 0.5-1.5 km) an incinerator, 97 subjects who lived far (i.e., within 3.5 km-4.0 km) from an incinerator, and 17 workers at a new municipal solid-waste incinerator. The study commenced before the incinerator started functioning in 1995, and 2 y later (1977) the authors undertook the final part of the study. Dioxins, furans, and polychlorinated biphenyls were studied in pooled blood samples (n = 22), and individual blood and urine samples were analyzed for the detection of lead, chromium, cadmium, and mercury. In 1995, dioxin blood levels were low-both among those living close to the incinerator (mean = 13.5 ng international-dioxin toxic equivalents/kg fat) and among those living far away (mean = 13.4 ng international-dioxin toxic equivalents/kg fat). In 1997, dioxin and polychlorinated biphenyl levels had increased in both groups of residents by approximately 25% and 12%, respectively. (The increase in dioxin levels was about 10% when the authors took into account the mean of two repeated quality-control analyses.) Blood lead levels decreased, but no difference was observed for chromium, cadmium, and mercury. Minimal changes were seen among workers. Given the low dioxin stack emissions from this plant (mean = 2.5-0.98 ng international-dioxin toxic equivalents/m3) and that the blood dioxin levels did not depend on distance of residence from the incinerator, it would appear unlikely that the small increase in dioxin blood levels resulted from the incinerator's emissions.

Using the 95% prediction limits of an age-related multiplicative regression model describing the datasets of blood examinations carried out on subjects suspected of having been exposed to lead and to polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F), it was shown that the relevant curves can be used as an alternative to reference ranges describing the actual background exposure to these pollutants. The upper limit of the actual German background exposure can be estimated by the following equations: PCDD/F as International Toxicity Equivalents in the age range of 10-70 years [pg/g lipid basis] = 1.64.age0.871 and lead in the age range of 15-80 years [microgram/l] = 18.15.age0.3638.

Osprey (Pandion haliaetus) eggs were collected from 1991 to 1997 at nests (n = 121) upstream and downstream of bleached kraft pulp mills and at reference sites in the Fraser and Columbia River drainage systems of British Columbia, Washington, and Oregon. Blood samples were collected from nestling ospreys during the 1992 breeding season on the Thompson River. Samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and -dibenzofurans (PCDFs). Mean concentrations of 2,3,7,8-TCDD were significantly higher in eggs collected in 1991 at downstream compared to upstream nests near pulp mills at Kamloops and Castlegar, British Columbia. There were no significant temporal trends in 2,3,7,8-TCDD, -TCDF or other measured compounds at a sample of nests monitored between 1991 and 1994 downstream of the Castlegar pulp mill, despite changes in bleaching technology (CIO2 substitution). However, by 1997 concentrations of 2, 3,7,8-TCDD and -TCDF were significantly lower than previous years in nests sampled downstream at both Castlegar and Kamloops. An unusual pattern of higher chlorinated PCDDs and PCDFs was found in many of the osprey eggs collected in this study, and considerable individual variation in the pattern existed among eggs from the same site. For example, eggs from four different nests at one study area (Quesnel) on the Fraser River had concentrations of 1,2,3,4,6,7,8-HpCDD ranging from <1 to 1,100 ng/kg and OCDD from <1 to 7,000 ng/kg wet weight. Higher mean concentrations of HpCDD and OCDD were found in eggs from the Thompson River, a tributary of the Fraser, compared to the Columbia River, and concentrations were generally higher at nests upstream of pulp mills. In plasma samples, 1,2,3,4,6,7,8-HpCDD and OCDD were the main compounds detected, with no significant differences measured between samples upstream versus downstream or earlier versus later in the breeding season. Use of chlorophenolic wood preservatives by lumber processors was considered the main source of higher chlorinated PCDD/Fs throughout the systems, based on patterns of trace PCDFs in eggs and significant correlations between egg concentrations of pentachlorophenol and both HpCDD (r = 0.891, p < 0.01) and OCDD (r = 0.870, p < 0.01).

This paper focuses on one aspect of occupational dioxin exposure that is novel and unexpected. Exposures in excess of the German threshold limit value of 50 pg international toxicity equivalent (I-TEQ)/m3 are very frequent, unpredictable, and sometimes very high--up to 6612 pg I-TEQ/m3--during thermal oxygen cutting at scrap metal and demolition sites. The same procedure involving virgin steel in steel trade and mass production of steel objects gave no such evidence, even though no final conclusions can be drawn because of the low number of samples analyzed. Low dioxin exposures during inert gas electric arc welding confirm previous literature findings, whereas soldering and thermal oxygen cutting in the presence of polyvinyl chloride give rise to concern. The consequences of occupational dioxin exposure were studied by analysis of the dioxin-blood concentration, the body burden, of men performing thermal oxygen cutting at scrap metal reclamation and demolition sites, in steel trade and producing plants as well as for industrial welders and white-collar workers. The results concerning body burdens are in excellent agreement with the dioxin exposure as characterized by dioxin air concentration in the workplace. The significant positive correlation between duration and frequency of performing thermal oxygen cutting at metal reclamation and demolition sites expressed in job-years and dioxin body burden speaks for the occupational origin of the observed overload after long times. The results reported here lead to consequences for occupational health, which are discussed and require immediate attention.