Dioxin concentrations in the blood of workers at municipal waste incinerators.

OBJECTIVES--Increased concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo-furans (PCDFs) in pooled blood samples from workers at municipal waste incinerators have been reported. This study was undertaken to confirm these results in individual blood samples from potentially exposed and unexposed workers at municipal waste incinerators compared with matched unexposed controls and compared with concentrations in the slag and fly ash from the municipal waste incinerators. METHODS--Concentrations of PCDDs and PCDFs were determined in the blood of 10 workers from an old municipal waste incinerator without adequate pollution controls, 11 workers from a newer incinerator with modern pollution controls, and 25 controls from the general population group matched for age (+/- 10 years), sex, and race, and in the slag and fly ash from the older incinerator. RESULTS--Significant increases of certain PCDDs and PCDFs were found in the blood of the workers from the older incinerator compared with the controls as follows: octaCDD (1051 (438) v 637 (344), P < 0.001), hexaCDF (52.3 (28.7) v 30.2 (18.2), P < 0.01), heptaCDF (43.9 (30.4) v 22.7 (12.4), P < 0.001), total PCDDs (1262 (484) v 825 (454), P < 0.001), total PCDFs (133.0 (68.1) v 93.7 (36.7), P < 0.05), and total PCDD/Fs (1395 (537) v 918 (437), P < 0.001). The workers from the older incinerator with the greatest exposure were found to have the most significant increases of the blood PCDDs and PCDFs, and the pattern of increased PCDD and PCDF congeners in the blood corresponded to the pattern in the incinerator slag and ash. No significant differences were found between the blood concentrations of the workers at the newer incinerator and the controls. CONCLUSION--Occupational exposure to slag and fly ash from municipal waste incinerators may increase the blood concentrations of PCDDs and PCDFs. Modern pollution control technology in new incinerators may be able to minimise potential exposure to slag and fly ash and thus the absorption of PCDDs and PCDFs from this source.     

Harbor seals (Phoca vitulina) in British Columbia, Canada, and Washington State, USA, reveal a combination of local and global polychlorinated biphenyl, dioxin, and furan signals

The harbor seal (Phoca vitulina) can serve as a useful indicator of food web contamination by persistent organic pollutants (POPs) because of its high trophic level, wide distribution in temperate coastal waters of the Northern Hemisphere, and relative ease of capture. In 1996 through 1997, we live-captured 60 harbor seal pups from three regions, spanning remote (Queen Charlotte Strait, BC, Canada), moderately industrialized (Strait of Georgia, BC, Canada), and heavily industrialized (Puget Sound, WA, USA) marine basins straddling the Canada-United States border. Biopsy samples of blubber were taken and analyzed for congener-specific polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) by using high-resolution gas chromatography-high-resolution mass spectrometry. Harbor seals in Puget Sound were heavily contaminated with PCBs, whereas seals from the Strait of Georgia had relatively high concentrations of PCDDs and PCDFs. Pattern evaluation and principal components analysis suggested that proximity to sources influenced the mixture to which seals were exposed, with those inhabiting more remote areas being exposed to lighter PCB congeners (those with lower Henry's law constant and K(ow)) that disperse more readily through atmospheric and other processes. Total toxic equivalents to 2,3,7,8-tetrachlorodibenzo-p-dioxin for the PCBs, PCDDs, and PCDFs suggest that Puget Sound seals are at greatest risk for adverse health effects, and that PCBs represent the class of dioxinlike contaminants of greatest concern at all sites.     

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans from chemical manufacturers and waste disposal facilities

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were measured in various source and environmental samples obtained from eight chemical manufacturers producing agricultural chemicals, synthetic dye, or resin and eight chemical waste disposal facilities. The concentrations of PCDDs and PCDFs ranged from 3.0 to 3504 ng/g for PCDDs and from 1.2 to 1668 ng/g for PCDFs in fly ash. Their concentrations in emission were in the ranges of 21.8 to 3205 ng/m3 for PCDDs and not detected to 4344 ng/m3 for PCDFs. PCDD and PCDF concentrations were higher in fly and bottom ashes and in emissions from two manufacturers that incinerate waste plastics than in those from other manufacturers. For emission and liquid samples from the manufacturers. For emission and liquid samples from the manufacturers of agricultural chemicals, significantly high concentrations of tetra-CDDs were detected. Furthermore, the high concentrations of PCDFs, especially hepta- and octa-CDF congeners, existed in emissions from waste incinerators that manufacture rubber. Among manufacturers and disposal facilities, the total emission equivalent (2.94 ng/m3) of PCDDs and PCDFs was highest for a certain manufacturer of agricultural chemicals, showing that more 2,3,7,8-chlorine-substituted PCDDs and PCDFs were present in their emissions.     

Formation of Polychlorinated Naphthalenes,Dibenzo-<Emphasis Type="Italic">p</Emphasis>-Dioxins,Dibenzofurans, Biphenyls,and Organochlorine Pesticides in Thermal Processes and Their Occurrence in Ambient Air

Mono- through octachlorinated naphthalenes (PCNs) were measured in start-up, steady operation, and shutdown of machinery operation flue gas and fly ash generated during different stages of MSWI and other incineration thermal processes. Besides, electroprecipitator fly ash (EP-ash) was dechlorinated using the Hagenmeier process and analyzed for congener profiles. In addition to PCNs, polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), and major organochlorine pesticides were determined in ambient air samples from three different sites of western Japan in the summer and winter of 1992. The PCNs from flue gas contained 15,000, 4300, and 13,000 ng/m³ during start-up, steady operation, and shutdown conditions, respectively. Whereas fly ash contained 470, 370, and 1400 ng/g PCNs under start-up, steady operation, and shutdown condition, respectively. The dechlorination process reduced PCN concentrations considerably. Concentrations of PCNs and PCDD/PCDFs in air samples collected in winter were slightly higher than in summer. PCBs, organochlorine pesticides such as chlordanes, DDTs, and HCHs were higher in summer air samples. WHO toxic equivalency (WHO-TEQ) concentrations in air samples were 0.3–0.9 pg/m³ for PCDD/DFs and 0.029–0.31 pg/m³ for dioxin-like PCBs.     

Levels and Profiles of Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans, and Polychlorinated Biphenyls in Feedstuffs and Milk From Farms in the Vicinity of Incineration Plants in Tuscany, Italy

Levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorobiphenyls (PCBs) were determined in samples of bovine and ovine milk collected in farms located in the province of Grosseto, Tuscany, in the vicinity of two incineration plants as well as in farms located in areas with presumable background levels of contamination. Samples of feedstuffs of local origin used in the investigated farms were also collected and analysed. The cumulative levels of PCDDs, PCDFs, and dioxin-like PCBs (DL-PCBs) in feedstuffs ranged from 0.25 to 0.61 pg WHO-TE/g fresh weight (fw) in the farms under impact from incinerator emissions and from 0.21 to 0.34 pg WHO-TE/g fw in the control area farms. The sums of the six non–dioxin-like indicator PCB (NDL-PCB) congeners were 0.13 to 9.3 ng/g fw and 1.2 to 1.9 ng/g fw, respectively. In milk samples, the levels detected were 0.71 to 2.9 pg WHO-TE/g fat and 0.52 to 0.59 pg WHO-TE/g fat in farms under impact from the incinerators and in the control area farms, respectively. The corresponding sums of the six indicator PCB congeners were 1.4 to 8.2 ng/g fat and 0.90 to 1.6 ng/g fat. In all samples, contamination levels were below the limits set by the European Community (EC; Commission Directive 2006/13/EC and Commission Regulation 1881/2006/EC.) No relevant differences were found between samples collected in potentially exposed areas and control areas for total toxic equivalents and cumulative analytic levels of PCDDs, PCDFs, DL-PCBs, and NDL-PCBs (p > 0.05, Mann-Whitney U test). Observed levels were in agreement with those found in other countries in areas with background levels of exposure. Congener levels and profiles of PCDDs, PCDFs, and PCBs in feedstuffs and milk samples that were compared describe congener-specific transfer behavior.     

Polychlorinated naphthalenes, biphenyls, dibenzo-p-dioxins, and dibenzofurans as well as polycyclic aromatic hydrocarbons and alkylphenols in sediment from the Detroit and Rouge Rivers, Michigan, USA

Sediment from the upper Detroit and lower Rouge Rivers in southeastern Michigan, USA, were analyzed to examine the distribution of polychlorinated naphthalenes (PCNs), biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) as well as polycyclic aromatic hydrocarbons (PAHs) and alkylphenolic compounds such as butylphenol, octylphenol, and nonylphenol (NP). Sediments from a non-point source location in Lake Michigan were also analyzed for target compounds. Concentrations of target compounds in the upper Detroit and lower Rouge Rivers varied considerably among locations, and notable spatial variation existed. Concentrations of PCNs and PCDDs/PCDFs in sediments from the upper Detroit and lower Rouge Rivers ranged from 0.08 to 187 ng/g and 69 to 1420 pg/g dry weight, respectively. Total PCBs, PAHs, and NP concentrations ranged from 8 to 25,000, 17 to 44,000, and < 10 to 60,000 ng/g dry weight, respectively. Concentrations of all target compounds except PCNs were significantly correlated with total organic carbon content of sediments. Similarly, concentrations of PCBs, PCDDs, and PCDFs were significantly correlated with each other. The distribution of organic contaminants in the upper reaches of the Detroit River and lower Rouge River suggested the presence of localized, but multiple, sources of contamination for each compound class. Conners Creek combined sewer overflow has been identified as one of the potential sources for the upper Detroit River, where the highest concentrations PCBs and PCDDs/PCDFs were found. Polycyclic aromatic hydrocarbon and NP concentrations were consistently high in sediment from the lower Rouge River. Analysis of data from selected locations suggested that PCNs contributed a greater proportion of the dioxin-like activity than PCBs and PCDDs/PCDFs contributed.     

Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans, and Coplanar Polychlorinated Biphenyls in Human Milk in Osaka City, Japan

Forty-eight human milk samples were collected from primiparous mothers in Osaka City from June 1999 to January 2000 and analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like coplanar polychlorinated biphenyls (CoPCBs). Mean toxic equivalents (TEQs) in the milk were 13.86 pg I-TEQ/g fat or 16.50 pg World Health Organization (WHO)-TEQ/g fat for PCDDs and PCDFs; 9.87 pg WHO-TEQ/g fat for CoPCBs; and 23.74 pg TEQ/g fat using I-TEQ values of PCDDs and PCDFs or 26.36 pg TEQ/g fat using WHO-TEQ values of PCDDs and PCDFs for total PCDDs, PCDFs, and CoPCBs. The TEQ levels of these chemicals in human milk in Osaka City were in the range of levels in human milk surveyed in Japan, but the TEQ levels of PCDDs and PCDFs and total PCDDs, PCDFs, and CoPCBs from our study were slightly higher than average TEQ levels in human milk in Japan. When comparing our data with the latest data from the United States and some European countries, the TEQ levels of PCDDs and PCDFs in human milk from Osaka City were relatively high, whereas those of CoPCBs were ranked as being of intermediate level. Only TEQ values of CoPCBs in human milk were found to correlate with the increasing age of mothers and their estimated intake of seafood during the year before pregnancy. Concentrations of PCBs 105 and 118 contributed to TEQ values of CoPCBs associated with seafood intake, whereas those of PCBs 156, 157, 114, 189, 167, and 169 contributed to TEQ values of CoPCBs associated with increasing maternal age.     

PCDDs, PCDFs, and PCBs in human blood in relation to consumption of crabs from a contaminated Fjord area in Norway.

Consumption of fish and shellfish from contaminated areas may be an important source of human exposure to persistent organohalogen compounds such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). We determined concentrations of 2,3,7,8-substituted PCDDs and PCDFs and 19 PCB congeners in whole blood samples from three groups of men, 40-54 years of age, with different consumption levels of crabs from a fjord area in southern Norway polluted with organochlorine compounds from a magnesium production plant. A significant increase of many PCDD/PCDF congeners was found in the blood when comparing the referents, moderate-, and high-intake groups. The greatest difference was observed for several of the PCDFs that are characteristic for the contamination of the marine biota of the fjord. PCBs, in general, play a minor role in the contamination of the fjord by the magnesium production process, except for the highly chlorinated congeners such as PCB-209. Nevertheless, almost all PCBs increased from the referents to the high-intake group. However, the relative concentrations of several highly chlorinated PCBs (particularly PCB-209) in blood are unexpectedly low compared to their abundance in crabs, indicating low uptake of these congeners. The exposure to PCDDs/PCDFs from crab consumption calculated from individual body burdens of these compounds were in good agreement with the intake estimated from previously measured concentrations in crabs, reported fishing sites, and consumption. Almost all subjects in the high-intake group exceeded the tolerable weekly intake of 35 pg TEQ/kg body weight/week proposed by a Nordic Expert Group.     

Dioxin-Like Toxicity in the Saginaw River Watershed: Polychlorinated Dibenzo-<Emphasis Type="Italic">p</Emphasis>-Dioxins,Dibenzofurans, and Biphenyls in Sediments and Floodplain Soils from the Saginaw and Shiawassee Rivers and Saginaw Bay,Michigan, USA

Sediment and floodplain soils in the Saginaw River Watershed, Michigan, USA, have been demonstrated to be contaminated with a variety of organic compounds, including polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Existing data indicate that, at some locations, the contamination exceeds human health risk-based regulatory levels and ecological risk-based screening levels. In this study, concentrations of PCBs including non-ortho coplanar congeners, PCDDs, and PCDFs were measured in more than 120 sediment and floodplain soil samples collected from the Shiawassee River (a tributary of the Saginaw River), the Saginaw River, and Saginaw Bay, to determine the sources and magnitude of contamination, and to elucidate the contributions from individual contaminant groups to the overall 2,3,7,8-tetrachlorodibezo-p-dioxin equivalents (TEQs). Sediment and soil extracts were also analyzed for total dioxin-like activity by means of the H4IIE-luc cell bioassay. Elevated concentrations of PCBs (>1000 ng/g, dry weight) were found in surface sediment and floodplain soil samples collected from the Shiawassee River near Chase Lake, from Middleground Island in the Saginaw River, and from subsurface sediments in Saginaw Bay. Concentrations of PCDDs and PCDFs in sediment and floodplain soils from the Saginaw River and Saginaw Bay were 2 to 3 orders of magnitude higher than concentrations in the samples from the Shiawassee River. The highest PCDD/F concentration (55,200 pg/g, dry weight in a subsurface layer) was found in sediment collected at the mouth of the Saginaw River. Concentrations of PCDFs were greater than the concentrations of PCDDs in sediment from the Saginaw River. 2,3,7,8-TCDF, 1,2,3,7,8-PeCDF, and 2,3,4,7,8-PeCDF were the major PCDF congeners found in sediments from the Saginaw River. The elevated concentrations of PCDFs, and the predominance of the less highly chlorinated PCDF congeners, in sediments from the Saginaw River were similar to previously determined characteristics of the PCDF contamination of the Tittabawassee River, another tributary of the Saginaw River. These results suggest the existence of a major source of PCDFs within the watershed. A few localized areas of high PCDD/F and PCB concentrations, with unique congener compositions, in the Saginaw River indicated the presence of other minor sources, such as wastewater treatment plants. PCDFs were the major contributors to TEQs in sediment and soils from the Saginaw River and Saginaw Bay. Approximately 30% of the samples analyzed in this study had values exceeding the screening level of 50 pg TEQ/g, dry wt, suggested for soils by the Agency for Toxic Substances and Disease Registry.     

Lipid peroxidation and oxidative status compared in workers at a bottom ash recovery plant and fly ash treatment plants

Fly ash and ambient emissions of municipal solid waste incinerators contain polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), other organic compounds, metals, and gases. Hazardous substances such as PCDD/Fs, mercury vapors and other silicates, and the components of bottom ash and fly ash elevate the oxidative damage. We compared oxidative damage in workers exposed to hazardous substances at a bottom ash recovery plant and 3 fly ash treatment plants in Taiwan by measuring their levels of plasma malondialdehyde (MDA) and urine 8-hydroxydeoxyguanosine (8-OH-dG). Significantly higher MDA levels were found in fly ash treatment plant workers (3.20 microM) than in bottom ash plant workers (0.58 microM). There was a significant association between MDA levels in workers and their working environment, especially in the fly ash treatment plants. Levels of 8-OH-dG varied more widely in bottom ash workers than in fly ash workers. The association between occupational exposure and 8-OH-dG levels may be affected by the life style of the workers. Because more dioxins and metals may leach from fly ash than from bottom ash, fly ash treatment plant workers should, as much as possible, avoid exposing themselves to fly ash.     

Dioxin-Like TEQ of women from the Seveso, Italy area by ID-HRGC/HRMS and CALUX

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are widespread environmental contaminants that exist as complex mixtures and are frequently detected at part-per-trillion (ppt) levels in humans. Using isotope dilution high-resolution gas chromatography/ high-resolution mass spectrometry (HRGC/HRMS), we measure the PCDDs, PCDFs, and PCBs in serum of a population of 78 women residing in an area near Seveso, Italy where a TCDD explosion occurred in 1976 and where furniture is manufactured. The average total dioxin-like toxic equivalents (TEQ) of these women was 25.3 ppt, lipid-adjusted, comparable to other parts of Europe. TCDD levels, however, were higher among the few women who resided in the exposed area in 1976. We examined the possibility of using the CALUX (chemical-activated luciferase gene expression) bioassay to estimate total TEQ in a small volume of plasma from this population. A total of 32 archived plasma specimens were selected for CALUX bioassay, based on the distribution of Total TEQ by HRGC/HRMS. The CALUX bioassay was performed blind to HRGC/HRMS results with 2 ml plasma per replicate analysis. Of 32 samples, 10 were below detection limits in the CALUX bioassay. For the 32 samples, the CALUX-TEQ averaged 25.4 ppt, lipid-adjusted (range: 0-127.6) and was not significantly different from the HRGC/HRMS Total TEQ average of 31.2 ppt, lipid-adjusted (range: 12.7-88.3) (t = 0.88, P = 0.38), however, the two measures were not significantly correlated (R(s) = 0.04, P=0.82). More validation of the CALUX bioassay with larger sample volume is needed before application as an exposure measure in large-scale epidemiologic studies of health effects of dioxin-like compounds.     

Enzyme induction and acute endocrine effects in prepubertal female rats receiving environmental PCB/PCDF/PCDD mixtures.

Air, subsurface soil, and superficial dust from a National Priorities List landfill located in southern Illinois were sampled to determine their potential toxicities. The major components of these landfill extracts were polychlorinated biphenyls (PCBs), with significant amounts of polychlorinated dibenzofurans (PCDFs) and small amounts of polychlorinated dibenzodioxins (PCDDs). The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency factor approach has been proposed to estimate the toxic potency of complex mixtures of chlorinated aromatics for environmental risk assessment. However, most components of environmental residues are nonplanar and do not act as aryl hydrocarbon (Ah) receptor agonists, so there is a great risk of not identifying adverse responses that are not dioxinlike. We used a 2-day prepubertal female rat bioassay to examine multiple biological responses, including both dioxinlike and nondioxinlike effects from these landfill extracts. As expected, both types of effects were detected. The soil and dust extracts produced similar dose-response relationships for 7-ethoxyresorufin O-deethylase, 7-pentoxyresorufin O-depentylase, 7-benzyloxyresorufin O-debenzylase, and 4-nitrophenol UDP-glucuronyltransferase induction; the dose response for the air extract deviated from the other two extracts. Soil, dust, and air extracts effectively reduced serum total thyroxine (T4) with similar dose-response relationships, despite the significantly different TCDD toxic equivalent (TEQ) values of these three extracts. Both soil (346 mg PCB/kg) and air (175 mg PCB/kg) extracts caused a greater than 30% increase in uterine wet weight. This study suggests that a more comprehensive approach is required to improve current risk assessment of environmental mixtures. TCDD TEQs reflect only a portion of effects and may especially underpredict effects on T4.     

A Survey of Dietary Intake of Polychlorinated Dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins,Polychlorinated Dibenzofurans,and Dioxin-like Coplanar Polychlorinated Biphenyls from Food During 2000–2002 in Osaka City,Japan

Studies of the dietary intake of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like coplanar polychlorinated biphenyls (dioxin-like PCBs), collectively referred as dioxins, were conducted using the total diet study (TDS) method with food purchased in Osaka City, Japan during 2000–2002. The daily intake of dioxin-TEQ (toxic equivalent) from food per adult person was estimated respectively as 104.24 pg TEQ/person/day in 2000, 72.73 pg TEQ/person/day in 2001, and 87.28 pg TEQ/person/day in 2002, corresponding to 2.08, 1.45, and 1.74 pg TEQ/kg body weight (bw)/day for an adult weighing 50 kg. The highest contribution ratio to the total intake of dioxin-TEQ was from fish and shellfish (group 10) in each year, accounting for 77–92%. The next highest contributor was meat and eggs (groups 11-A and 11-B). An annual decrease of the intake of dioxin-TEQ was not observed clearly. Otherwise, the dietary intake of non-2,3,7,8-substituted PCDDs/PCDFs were estimated together. The intake of 1,3,6,8-TeCDD came mostly from intake of fish and shellfish (group 10), green vegetable (group 7), and the other vegetables, including mushrooms and seaweed (group 8). In addition, the intake of 1,3,6,8-TeCDF, which reportedly antagonizes 2,3,7,8-TeCDD-mediated aryl hydrocarbon hydroxylase (AHH) and ethoxyresorufin O-deethylase (EROD) induction activities, was an insufficient amount to suppress 2,3,7,8-TeCDD-mediated activities. Furthermore, we discussed different TEQ compositions of PCDDs/PCDFs to dioxin-like PCBs from food intake and in human samples and inferred that the difference was caused by low bioaccumulation properties of 3,3′,4,4′,5-PeCB (PCB 126).     

Analysis of trace organic contaminants in sediment,pore water,and water samples from Onsan Bay,Korea: instrumental analysis and in vitro gene expression assay

Persistent organic pollutants and alkylphenols (APs) were determined in sediment and water samples from Onsan Bay, Korea, by using instrumental analysis and in vitro gene expression cell bioassay. Polycyclic aromatic hydrocabons (PAHs) were the predominant compounds in sediments with concentrations as great as 573 ng/g dry weight. The PAH concentrations were elevated in sediment from inland rivers that flow through Onsan City (mean: 116 ng/g dry wt) and discharge into Onsan Bay. Concentrations of polychlorinated biphenyls (PCBs) in sediments ranged from <1.00 to 56.2 ng/g dry weight. Among different organochlorine (OC) pesticides analyzed (hexachlorobenzene, hexachlorocyclohexanes, chlordanes, and DDTs), DDT concentrations were the greatest, ranging from <0.01 to 7.58 ng/g dry weight. The spatial gradient of contaminant concentrations suggested that streams and rivers are the major sources of PCBs, PAHs, and APs to the bay. Maximum concentrations of nonylphenol, octylphenol, and bisphenol A in sediments were 860, 11, and 204 ng/g dry weight, respectively. Screening of Onsan Bay sediment samples for dioxinlike activity with the H4IIE-luc in vitro cell bioassay revealed that 17 of 22 samples contained significant dioxinlike activity. Further fractionation of sediment extracts indicated that mid-polar and more polar fractions were responsible for the significant dioxinlike activity. Based on a mass balance analysis, PAHs apparently accounted for only a small portion of dioxinlike responses elicited by sediment extracts. Only one raw extract of sediment elicited a significant estrogenic response by MVLN cells. The combination of instrumental analysis and in vitro bioassay was useful to assess sediment quality and characterize the causative agents or potential toxic compounds present.     

Polychlorinated Dibenzo-p-dioxins, Dibenzofurans and Dioxinlike Biphenyls in Sediments from the Suzhou Creek, China

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were detected in sediments from Suzhou Creek with mean concentrations of 478.1, 245.1, and 4727.6 pg/g dw, respectively. WHO–TEQ concentrations of PCDD/Fs in sediments ranged from 2.90 to 13.96 pg/g dw, while TEQ concentrations of PCBs varied from 0.27 to 1.41 pg/g dw. OCDD or HpCDD were the dominant congeners but PeCDF or HpCDD was the major contributor to PCDD/Fs-TEQ in all the sites. For dioxinlike biphenyls, PCB 118 was the major congener while PCB-TEQ was attributable to PCB 126 in all the samples.     

Associations of environmental exposure to dioxins with prevalent diabetes among general inhabitants in Japan

The aim of this study was to evaluate the associations of environmental exposure to dioxins with diabetes among general inhabitants in Japan. A cross-sectional study was performed on 1374 participants, who were not occupationally exposed to dioxins, aged 15-73 years, living widely in 75 different residential areas of 25 prefectures in Japan through 2002-2006. Seven polychlorinated dibenzo-p-dioxins (PCDDs), 10 polychlorinated dibenzofurans (PCDFs), 12 dioxin-like polychlorinated biphenyls (PCBs), which are assigned a toxic equivalency factor, and biochemical factors were determined in fasting blood. A questionnaire survey on life-style including past history of diseases and treatments was also performed. We examined the associations of the accumulated toxic equivalents (TEQs) of PCDDs+PCDFs, dioxin-like PCBs and total dioxins with prevalent diabetes. Simple and partial correlation analyses revealed that HbA1c correlated with the accumulated TEQs of PCDDs+PCDFs, dioxin-like PCBs and total dioxins. In logistic regression analyses, the third and the highest quartiles of dioxin-like PCBs had adjusted odds ratios (ORs) of 3.07 (95% CI 1.16-8.81) and 6.82 (95% CI 2.59-20.1) compared to the reference (first plus second quartiles). On the other hand, the highest but not the third quartiles of PCDDs+PCDFs and total dioxins had significantly higher adjusted ORs compared to the respective references. These associations persisted when the subjects with poor liver or poor renal function were removed from the analysis. This recent representative data from general inhabitants in Japan showed associations of environmental exposure to dioxins, especially dioxin-like PCBs, with diabetes.     

Human health risks of dioxins for populations living near modern municipal solid waste incinerators

Although incineration is an effective way of treating municipal solid waste (MSW), in many countries the potential health risks associated with stack emissions, particularly those of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), have become a cause of great controversy and concern. Given the interest and importance of this controversy, in the present paper a series of experimental data corresponding to a number of surveys made in the vicinity of three MSW incinerators (MSWIs) of Catalonia (Spain) are reviewed. In recent months, an adaptation to the EU legislation on pollutant emissions from the stack was carried out in these facilities. We assessed whether the pronounced reductions in the atmospheric PCDD/PCDFs emissions parallel the concurrent decreases in environmental matrices collected in the vicinity of the MSWIs. In comparison with other PCDD/PCDFs emission sources in the areas under direct influence of the MSWIs, the health risks from current emissions of PCDD/PCDFs by these incinerators would be of low significance for populations living in the neighborhood. For such populations, the daily intake of PCDD/PCDFs from direct and indirect (diet) exposure are currently within the rank recommended by the WHO as the maximum daily exposure to PCDD/PCDFs for non-carcinogenic adverse effects.     

Predictors of serum dioxin levels among adolescent boys in Chapaevsk, Russia: a cross-sectional pilot study

Background  

Toxicological studies and limited human studies have demonstrated associations between exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) and adverse developmental and reproductive health effects. Given that children may be particularly susceptible to reproductive and developmental effects of organochlorines, and the paucity of information available regarding childhood exposures to dioxins in particular, we undertook a pilot study to describe the distribution of, and identify potential predictors of exposure to, dioxin-like compounds and dioxins among adolescent boys in Chapaevsk, Russia. The pilot study was also designed to guide the development of a large prospective cohort study on the relationship of exposure to PCDDs, PCDFs, and PCBs with growth and pubertal development in peri-pubertal Chapaevsk boys.     

Investigation of a wood treatment facility: Impact on an aquatic ecosystem in the San Joaquin River, Stockton, California

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and metals were monitored in the river sediments near the McCormick and Baxter (MCB) wood treatment facility, Stockton, CA. Transplanted clams and resident fish species were used to assess bioavailability. The highest PCDD and PCDF contamination in sediments were confined to an area next to the facility and an area in the nearby Stockton harbor (DK location). Pentachlorophenol (PCP) wood treatment at MCB was the most probable source of the contamination. PCBs contaminated a wider area of the Stockton Ship Channel and harbor. Metal concentrations were uniformly low except for the metalloid arsenic in the Old Mormon Slough and lead and zinc near boat docks in the Stockton harbor. Despite high mortality rates, clams (Corbicula fluminea) bioaccumulated PCBs, PCDDs, and PCDFs. In clams, PCBs and 2,3,7,8 TCDD were much closer to equilibrium with the sediments than were higher chlorinated PCDDs and PCDFs. All fish were at background levels for 2,3,7,8 TCDD. All fish had lower lipid adjusted PCDD/F and PCB concentrations in the skinned muscle than in the whole fish. PCBs in fish were above background levels for United States river systems. Although high contamination exists in the river near this superfund site, adverse effects on the aquatic community could not be demonstrated.     

Toxic equivalency factors (TEFs) for PCBs, PCDDs, PCDFs for humans and wildlife.

An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, octachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in vivo evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049-1067 (1994)]. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize TEFs across different taxa to the extent possible. However, total synchronization of TEFs was not feasible, as there were orders of a magnitude difference in TEFs between taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammals and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment of halogenated aromatic hydrocarbons with dioxinlike properties.