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The elimination of Beta-hexachlorocyclohexane (Beta-HCH) in humans was investigated in a group of 40 former workers of a lindane-producing plant by analyzing at least 2 blood specimens (3 specimens in 3 workers) from different time points. Assuming a first-order kinetic model for excretion, the median half-life of Beta-HCH is 7.2 yr calculated by concentrations in whole blood and 7.6 yr calculated by concentrations in extractable lipids. In univariate analyses an influence of age, percent body fat, and liver disease (additionally in whole blood an influence of contents of extractable lipids) on clearance was observed. All factors show a positive correlation with half-life. According to a multiple regression model, influence of percent body fat calculated according to Deurenberg et al. (1991) is an important covariate in the description of the variations of the clearance rate (calculated on the basis of extractable lipids) of Beta-HCH. The data supportthe assumption of first-order kinetics. [ABSTRACT FROM AUTHOR]

Investigates the effect of heavy indoor air polychlorinated biphenyl PCB), polychlorinated dibenzodioxins and dibenzofuranes (PCDD) on teachers working in a PCB-contaminated school. Source of PCB emissions in indoor air in buildings; Cause of the health effects of PCB in the body; Effect of the PCB contaminated air on the concentration of PCB in the blood levels of teachers.

Examines the presence of dioxins, dibenzofurans and polychlorinated biphenyl (PCB) in the breast milk of women in the industrialized cities of Angarsk and Usolye-Sibirskoye in Siberia, Russia. Comparison of the levels of dibenzofurans in the breast milk of the women between the two cities; Possible sources of PCB; Discussion on the dioxin levels in the breast milk in several countries.

Investigates the dioxin exposure of firefighters, residents and chemical workers in Irkutsk Region in Siberia, Russia. Information on the measured levels of dioxin, dibenzofurans and polychlorinated biphenyls levels in all the groups; Details on the dioxin toxic equivalents of the groups; Discussion on the group found to have the highest level of dioxin exposure.

The concentrations of stable organic chlorine pollutants (SOCP) in the breast milk of women living in Irkutsk, Baikalsk, and the settlement of Kachug are lower than those in the increased SOCP-burdened areas of the Irkutsk Region (the town of Usolye-Sibirskoye, settlements on the shore of the Baikal Lake) and comparable with those in Russia and industrially developed countries of the world. The content of SOPC is much lower than those in the developing countries where this pesticide continues to be applied. The breast milk levels of OCP, TEQ (polychlorinated dibento-para-dioxines and polychlorinated dibenzofurans) in all towns and individual indicator polychlorinated biphenyls (PCB) in Irkutsk significantly decreased as compared with those in the 1980s. However, in Kachug and Baikalsk, the concentrations of PCB practically unchanged and the level of some congeners increased. The absence of changes in the content of PCB in Kachug and Baikalsk may be associated with no decrease in environmental pollution in the Irkutsk Region. Altered breast concentrations of SOCPs caused a reduction in their intake in babies.

For analysis of organochlorine contaminants in human tissue, the "gold standard" for preservation, storage, and shipping is usually freezing. However, this method can be difficult, if samples are taken in remote areas, and costly, when the samples must be shipped on dry ice. Therefore, a more simple and cost effective method of preservation is essential for remote field work. Potassium dichromate (K(2)Cr(2)O(7)) has been successfully employed in the preservation of human and cows' milk as well as chicken eggs. Our previous studies described the use of potassium dichromate for preservation of whole blood for analysis of dioxins, dibenzofurans, and PCBs. Potassium dichromate was found to successfully preserve blood at room temperature for 34 d with no significant differences in the measured concentrations of chemical contaminants or blood lipid level when compared to frozen samples. However, in a follow-up study, 3 months and 6 months of potassium dichromate preservation proved inadequate to preserve the samples for organic pollutant analysis. We noted that the lipid portion of the blood in the chemically preserved samples was declining in level or degrading, while the persistent organic pollutants remained intact at the same levels on a whole weight basis. To narrow down the window of efficacy for the use of potassium dichromate to preserve blood samples for analysis, the present study compared chemical preservation to freezing for an intermediate time period, 2 months. Similar to our previous findings at 3 and 6 months, at 2 months significant lipid degradation was observed in the chemically preserved samples. Chemically preserved samples had significantly higher levels of organochlorine contaminants (dioxins, dibenzofurans, and PCBs) when measured on a blood lipid basis but not on a wet weight basis compared to frozen samples. While 2 months of potassium dichromate preservation was not useful for obtaining accurate measure of dioxins, furans, and PCBs on a lipid basis, previous studies found this method of preservation to be useful for at least one month (Schecter, A., Pavuk, M., Päpke, O., Malisch, R., 2004. The use of potassium dichromate and ethyl alcohol as blood preservatives for analysis of organochlorine contaminants. Chemosphere 57, 1-7). However blood stored at -70 degrees C and at 22 degrees C with potassium dichromate gave similar results when expressed on a wet weight basis.

Recent investigations have demonstrated the presence of an unidentified source of polychlorinated dibenzo-p-dioxins (PCDDs) in the coastal zone of Queensland (Australia). The present study provides new information on the possible PCDD sources and their temporal input to this environment. Two estuarine sediment cores were collected in northern Queensland for which radiochemical chronologies were established. Core sections from different depositional ages, up to three centuries, have been analyzed for 2,3,7,8-substituted PCDDs and polychlorinated dibenzofurans (PCDFs). Variations of PCDD concentrations in the sediment cores over several centuries of depositional history were relatively small, and elevated PCDD levels were still present in sediment slices from the early 17th century. PCDD/F isomer patterns and congener profiles in sediments deposited during the last 350 years were almost identical and correlated well to the characteristic profiles observed in surface sediments and soils from the entire Queensland coastline. Profiles were dominated by higher chlorinated PCDDs, in particular octachlorodibenzodioxin (OCDD), whereas PCDF concentrations were below or near the limit of detection. These results indicate the presence of a PCDD source prior to industrialization and production of commercial organochlorine products. Further, the present study demonstrates that PCDD input patterns have been similar along an extensive but localized area over at least several centuries, contributing relatively high concentrations of PCDDs to the coastal system of Queensland.

Animal models suggest that dioxins have a negative effect on the level of expression of the epidermal growth factor receptor in cells. In vivo the level of expression in tissue of the epidermal growth factor receptor can be monitored by assaying for the extracellular domain in blood using an enzyme linked immunosorbent assay. We have determined the levels of the extracellular domain of the epidermal growth factor receptor in the plasma of 30 individuals: 10 with high blood dioxin levels (TEQ range = 318-673 ppt), 10 with medium blood dioxin levels (TEQ range = 16-60 ppt), and 10 with low background blood dioxin levels (TEQ range = 3-10 ppt). The levels of the epidermal growth factor receptor extracellular domain were lower in the high blood dioxin group (mean +/- SD = 45 +/- 26 fmol/ml) and the medium blood dioxin group (mean +/- SD = 41 +/- 23 fmol/ml) compared with the low blood dioxin group (mean +/- SD = 73 +/- 43 fmol/ml). These results suggest that the extracellular domain of the epidermal growth factor receptor may be a marker of the biological effect of dioxin exposure.

The city of Ufa, in the Bashkortostan Republic of Russia, is believed to have dioxin contamination of its water supply from 30 years of gas ejections, sewage and buried sludge from the Chimprom industrial factory, and possibly other sources. A project was developed to provide technology at relatively low cost for treating dioxin contaminated water in routine and also in emergency situations. This paper describes the results of the 15-year research project to remove dioxins from drinking water. Three different methods were experimentally tested for efficiency at removing dioxins from tap water. The methods used were: (1) ozonization plus filtration through powder sorbents, (2) filtration through sand, and (3) filtration through granulated sorbents. It was found that the method of filtration through granulated sorbents was most effective at removing dioxins from water: 90-95% of all PCDD and PCDF isomers were removed from water samples. This research also shows that the most toxic congener, 2,3,7,8-TCDD, can be removed effectively and efficiently. In addition, there are no significant differences between the extractability of PCDDs and PCDFs. Reductions in exposure to humans from contaminated drinking water can be accomplished via sorptive water treatments for relatively reasonable cost, making this a practical approach. This method of decreasing toxic chemicals is being implemented in Ufa, Russia.

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.

We report the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) found in human placentas and fetal tissue from the U.S. and in placentas from Yu-Cheng mothers. In placental material from sources in the U.S. we found concentrations, expressed as dioxin toxic equivalence (TEQ) values and on a lipid basis, between 8.4 and 17.6 ng/kg. In a pooled sample of fetal tissue (8-14 week) the concentration, 5.3 ng/kg, was somewhat smaller. In placental material from Taiwanese Yu-Cheng subjects much higher concentrations were found, in the range 610 to 9010 TEQ ng/kg, again on a lipid basis.

This study addresses the issue of breast-feeding and its reduction of maternal dioxin body burden. Nursing is also a source of infant dioxin exposure. This study extends our previous efforts to investigate a nursing mother's milk and blood dioxin levels. We report polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) dioxin toxic equivalents (TEQs) in milk (M) and blood (B) both before and also after two years of nursing twins to be 16.9 ppt (M), 14.9 ppt (B), and 3.1 ppt (M) and 4.9 ppt (B), respectively. The ratios of measured congeners comparing milk to whole blood from a nursing mother taken initially and after two years of nursing vary from 0.36 to 8.40 in 1992 and 0.17 to 1.0 in 1994. The mother's body burden was initially calculated to be 329 ng TEQ from milk levels and 291 ng TEQ from blood levels using samples taken in February 1992 and decreased to 60.1 ng TEQ from milk and 96 ng TEQ from measured blood using samples collected in December 1994. We calculate that the excretion of dioxin TEQ by the mother through breast-feeding is 269 ng TEQ, which is similar to the 303 ng TEQ estimated total dioxin intake by the twins over two years. The average daily dioxin intake from nursing is 66 pg TEQ/kg-BW/day for each twin over the two years.

Blood-fat concentrations of polychlorinated biphenyls (PCB) congeners: no. 105, 118, 156 (mono-ortho-substituted) and no. 77, 126, 169 (non-ortho-substituted) and PCB congeners no. 28, 52, 101, 138, 153 and 180 were measured. The investigations were carried out in pooled samples from children and in individual samples from adults. Additionally polychloro-p-dibenzodioxins and -furans (PCDD/PCDF) were investigated.