Brominated flame retardants and polychlorinated biphenyls in human breast milk from several locations in India: potential contaminant sources in a municipal dumping site

This study investigated the status of contamination of organohalogen compounds (OCs) such as polychlorinated biphenyls (PCBs) and brominated flame retardant (BFRs), including polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in human milk samples from several locations in India. The levels of OCs were significantly higher in the milk of mothers living in and near municipal dumping site than other locations indicating that the open dumping sites for municipal wastes act as potential sources of these contaminants in India. The PCB concentrations observed in this study tended to decrease compared to those in the matched locations reported previously, probably due to the restriction of technical PCB usage in India. PBDE levels in human milk were two to three folds lower than those of PCBs in all the sampling locations investigated. Congener profiles of PCBs and PBDEs were different between samples from the dumping site mothers and general populations in other areas suggesting the presence of region-specific sources and pathways. HBCDs were detected in human milk from only two sites, with much lower concentrations and detection frequencies compared to PCBs and PBDEs. When hazard quotients (HQs) of PCBs and PBDEs were estimated for infant health risk, the HQs in some milk samples from the dumping site exceeded the threshold value (HQ > 1) of PCBs, indicating the potential risk for infants in the specific site.     

Temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in mothers' milk from Sweden, 1972–2011

Temporal trends of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in mothers' milk are still quite rare. Data are particularly scarce when it comes to concentrations from the last decade, 2000 and onwards. The aims of the present study were to assess temporal trends of PCDD, PCDF and DL-PCB in mothers' milk from Stockholm, 1972–2011 and to compare the results with previous analysis of some of the older samples.The samples were analyzed by high resolution GC/MS and results were statistically evaluated for the periods, 1972–2011 and 2002–2011. The rate of which ∑PCDDs, ∑DL-PCBs and the ∑TEQ are decreasing (on pg/g fat WHO-TEQ2005) is higher in the last decade compared to the 40 year period, 1972–2011. A similar trend is indicated, but not confirmed, for ∑TEQ of PCDFs, probably due to too many PCDF congeners below LOQ in the period 2002–2011. Concentrations of ∑PCDDs, ∑PCDFs, ∑DLPCBs and ∑TEQ, all expressed as pg/g fat on TEQ-WHO2005-basis, show a statistically significant decline over time, 5.8–6.8% per year, 1972–2011. The last ten years the annual declines for ∑PCDDs, ∑DL-PCBs and ∑TEQ are 9.2–11% and for ∑PCDF, 5.4%. Congener specific trend analysis, 2002–2001, of PCDDs and DL-PCBs showed the same pattern, while the PCDF congeners showed no such general trend. The results from the re-analysis showed good agreement with slightly lower ∑TEQ1998 pg/g fat concentrations in six out of seven samples and mean difference of 13% in ∑TEQ1998. The study shows that time series can be elongated from previous studies, as long as the sample population remains the same.     

Concentrations of PCDD/PCDFs and PCBs in fish and seafood from the Catalan (Spain) market: estimated human intake

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) in samples from 14 fish and seafood species widely consumed by the population of Catalonia, Spain, were measured. These samples were randomly purchased independently of their geographical origin. The intake of PCDD/Fs and PCBs through consumption of these species was also estimated for various age and sex groups of this population. The highest and lowest levels of PCDD/Fs and dioxin-like PCBs (DL-PCBs) were found in red mullet and shrimp, respectively. For a standard adult man (70 kg body weight), the intake of PCDD/Fs plus DL-PCBs through consumption of fish and other seafood was estimated to be 38.0 pg WHO-TEQ/day. Tuna, hake, and sardine were the species with the highest contribution to this intake. The results of this study indicate that, in general terms, the dietary habits of the population of Catalonia (Spain) regarding fish and seafood consumption do not contribute remarkably to increase PCDD/F and DL-PCB intake.     

Concentrations of PCDD/PCDFs and PCBs in retail foods and an assessment of dietary intake for local population of Shenzhen in China

OBJECTIVES: Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 18 polychlorinated biphenyls (PCBs) were measured in 11 varieties of food groups collected from retail market of Shenzhen, Guangdong province, China from 2004 to 2006. PCDD/Fs and PCBs dietary intake from varies food for the local population was estimated in the study. METHODS: Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (PCBs) as well as 6 marker PCBs were measured in 11 varieties of food groups in total 110 food samples by isotope dilution HRGC/HRMS. PCDD/Fs and PCBs dietary intake for local population was estimated using total WHO-TEQ concentration and different food consumption amount of the local population. RESULTS: The median WHO-TEQ concentrations of sum of PCDD/Fs and DL-PCBs varied from 0.0093 pg/g (parts per trillion) in vegetable to 9.89 pg/g in fish. Fish was followed by egg 2.46, chicken 1.73, beef 0.94, mutton 0.82, duck 0.39, pork 0.37, milk powder 0.25, vegetable oil 0.076, cereals 0.022 pg/g and vegetable. The monthly intake of PCDD/Fs and PCBs were 40.9 pg WHO-TEQ/kg b.w. for local population. Sum of fish, livestock, and poultry contributed 77% to the Estimated Monthly Intake (EMI) in local population. CONCLUSION: Estimated dietary intake of PCDD/Fs and DL-PCBs for local population was below the provisional tolerable monthly intake(PTMI) set by Joint FAO/WHO Expert Committee on Food Additives (JECFA).     

High levels of dioxin-like PCBs found in organic-farmed eggs caused by coating materials of asbestos-cement fiber plates: A case study

During a regional monitoring project of organic-farmed, free-range and cage-free eggs, high levels of dioxin-like compounds were detected in organic-farmed eggs, using the dioxin responsive chemical-activated luciferase gene expression (DR-CALUX®) bioassay. Further evaluations performed with GC–HRMS (gas chromatography in combination with high resolution mass spectrometry) revealed elevated amounts of non-dioxin-like (non-dl) polychlorinated biphenyls (PCBs) dominated by most lipophilic congeners like PCB 138, 153 and 180 and of dioxin-like (dl) PCBs, with a congener pattern in the descending order of PCB 118, 156, 167, 105, 189, 157, 105, 126 and PCB 77. Contaminations with polychlorinated dibenzo-p-dioxins (PCDDs) appeared of minor priority, with only hepta- and octa-substituted dioxins above their limits of quantification (LOQs). The pattern of polychlorinated dibenzofurans (PCDFs) was dominated by low amounts of tetra- and penta-chlorinated congeners. To identify the source of contamination, several samples of organic-farmed eggs, soil, laying hens, feedstuff, corrugated asbestos-cement cover plates (ACPs), stable dust and debris collected in the gutter of the stable, were analyzed. Comparing PCB congener-pattern of individual samples, the source was traced back to the coating of ACPs, which covered roof and sidewalls of the stable. Because coating materials probably have been used for roofing and cladding in many countries worldwide, there is a high probability that the presented case report is not a local incident but rather describes a new source of PCB contamination, yet widely unknown or underestimated.     

Unexpected high PCB and total DDT levels in the breeding population of red kite (Milvus milvus) from Doñana National Park, south-western Spain

This study provides information on the current status of contamination by organochlorines (DDTs, PCBs, PCDDs and PCDFs) in the declining red kite (Milvus milvus L.) population breeding in the Do?ana National Park (DNP), south-western Spain. Analyses were performed in addled eggs collected between 1999 and 2001. DDE concentrations ranged from 0.1 to 33.5 microg/g ww, representing more than 86% of the total DDTs. Of the samples studied, 50% showed DDE levels above those associated with reproductive impairment in other raptor species. Concentrations of ortho PCBs (average 36.8 microg/g ww+/-37.7) in 50% of the eggs were much higher than levels reported to cause reduced hatching success, embryo mortality, and deformities in birds (>20 microg/g ww). It is remarkable that average ortho PCB and DDE concentrations showed an increase of one order of magnitude compared to previous data for the species during the 80s. Total PCDD/Fs showed levels in the low pg/g range (7.2-42 pg/g ww), having PCDDs and PCDFs similar contributions in most samples. Total mean TEQs were 238 pg/g (ww), being the range 7.02-667 pg/g (ww). Spatial variation within DNP was observed for PCBs, DDTs, as well as for TEQs. Since some eggs exceeded the NOEL (67%) and LOEL (33%) reported for other raptor species, we would expect the red kite to experience detrimental effects to dioxin-like toxicity. Our results suggest that organochlorine contaminants should be regarded as an element of concern in the population under study, in addition to other conservation problems already reported. Further investigations should be undertaken to identify potential sources of these chemicals in DNP, and to find out if organochlorine contamination is present in other predator species in the area, as well as their potential health effects on individuals and/or populations.     

Blood levels of dioxins,furans, dioxin-like PCBs,and TEQs in general populations: A review, 1989–2010

A comprehensive worldwide literature review of blood levels of dioxins and dioxin-like compounds in non-exposed adult general populations was performed. The studies published in 1989–2010 reporting information on polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-PCBs (nPCBs), mono-ortho-PCBs (mPCBs) levels and Toxic Equivalencies (TEQs, a summary weighted measure of their combined toxicity) were reviewed. TEQs were calculated using as standard the most recent WHO 2005 reevaluation of Toxic Equivalency Factors (TEFs). Weighted multiple regression analyses adjusted for year, subject's age, type of sample analyzed, method used for values below detection limit, and central tendency measure used were performed for each congener and standardized TEQs (log-transformed). We identified 187 studies regarding 29,687 subjects of 26 countries. Year of blood collection ranged from 1985 to 2008. The studies reporting congener levels 161. In adjusted analyses, European countries showed higher levels of most dioxin-like congeners and TEQs. A strong positive association of subjects' age with most congeners and with TEQ values was found, confirming previous findings. Significant decreases over time (1985–2008) were documented for PCCDs, PCDFs, and TEQs including their contributions. No significant decrease was found for non-ortho-PCBs, notably PCB 126. Only some mono-ortho-PCBs showed clear significant declines. Accordingly, TEQs including only PCB contribution did not decrease over time. In interpreting these findings, it should be considered that for dioxin-like PCBs the analysis period was shorter (17 years), since these compounds were first measured in 1992.     

Maternal exposure to high levels of dioxins in relation to birth weight in women affected by Yusho disease

Background

Studies on the association of maternal exposure to polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) with decreased birth weight in humans have produced conflicting results. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease.

Objective

The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on birth weight.

Methods

Blood samples, obtained from 101 Yusho women (190 births) who gave birth after exposure, were analyzed for congeners of seven PCDDs, ten PCDFs, and four non-ortho PCBs.

Results

Total PCDD TEQ (adjusted beta = − 161.9 g; 95% CI, −265.3 to − 58.6), total PCDF TEQ (adjusted beta = − 105.9 g; 95% CI, −179.5 to − 32.2), and total non-ortho PCBs (adjusted beta = − 178.4 g; 95% CI, −318.3 to − 38.5) levels were inversely associated with birth weight. Significant inverse associations with birth weight were also found for total PCDD TEQ, total PCDF TEQ, and total non-ortho PCB TEQ levels among male, but not female, infants. Significant inverse associations with birth weight were also found for nine congeners among all infants; the adjusted beta coefficients were largest for 1,2,3,6,7,8-HxCDD and smallest for 2,3,4,7,8-PeCDF.

Conclusion

In the setting of exposure to high levels of dioxins, maternal blood levels of PCDDs, PCDFs and PCBs are associated with lower birth weight in Yusho patients. The association exhibited gender-specific differences, as male infants are more susceptible than females to growth restriction induced by in utero dioxin exposures.     

Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China

PCB levels in fish (collected from local rivers), atmosphere and human milk samples have been studied to determine the exposure levels of PCBs for local residents and e-waste workers in Guiyu, a major electronic waste scrapping center in China. The source appointment and correlation analyses showed that homologue composition of PCBs in 7 species of fish were consistent and similar to commercial PCBs Aroclor 1248. PCB levels in air surrounding the open burning site were significantly higher than those in residential area. Inhalation exposure contributed 27% and 93% to the total body loadings (the sum of dietary and inhalation exposure) of the local residents, and e-waste workers engaged in open burning respectively. Total PCB concentrations in human milk ranged from N.D. to 57.6 ng/g lipid, with an average of 9.50 ng/g lipid. The present results indicated that commercial PCBs derived from e-waste recycling are major sources of PCBs accumulating in different environmental media, leading to the accumulation of high chlorinated biphenyls in human beings.     

Annual variation in the levels of metals and PCDD/PCDFs in soil and herbage samples collected near a cement plant

In May 2000, the levels of a number of metals (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Sn, Tl, V and Zn) and polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in soil and herbage samples collected near a cement plant from Sta. Margarida i els Monjos (Catalonia, Spain). To determine the temporal variation in the concentrations of metals and PCDD/PCDFs, in May 2001 soil and herbage samples were again collected at the same sampling points and analyzed for the levels of metals and PCDD/PCDFs. In general terms, metal concentrations in soils did not change between May 2000 and May 2001, while significant decreases in the levels of Cr, Ni and V were found in herbage. On the other hand, no significant differences in the mean I-TEQ values of PCDD/PCDFs were found in soil and herbage samples. The results of this survey show that according to the annual variation in the levels of metals and PCDD/PCDFs the environmental impact of the cement plant on the area under its direct influence is not relevant.     

Yusho and its latest findings—A review in studies conducted by the Yusho Group

The Yusho incident is an unprecedented mass food poisoning that occurred in Japan in 1968. It was caused by the ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds, such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). The victims of Yusho have suffered from characteristic skin manifestations associated with systemic, ophthalmological, and mucosal symptoms for a long period of time. The Study Group of Yusho (the Yusho Group) has been conducting annual medical check-ups on Yusho victims for more than 45 years. Since 2002, when concentrations of dioxins in the blood of Yusho patients started to be measured, the pharmacokinetics of dioxins, relationship between blood levels of dioxins and symptoms/signs in patients directly exposed to dioxins, and the adverse effects on the next generation have become dramatically clear. Herein we review recent findings of studies conducted by the Yusho Group to evaluate chronic dioxin-induced toxicity to the next generation as well as Yusho patients in comparison with a similar food mass poisoning, the Yucheng incident. Additionally, we summarized basic studies carried out by the Yusho Group to re-evaluate the mechanisms of dioxin toxicities in experimental models and various functions of the aryl hydrocarbon receptor (AhR), known as the dioxin receptor, pathway.     

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in Finnish semi-domesticated reindeer (Rangifer tarandus tarandus L.)

To explore the concentrations and dynamics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Finnish semi-domesticated reindeer (Rangifer tarandus tarandus L.) the reindeer milk and tissue samples were collected from the sub-arctic northern Finland. Reindeer milk's PCB sum (1.20 ng g(-1) wet weight) and PCDD/F sum (0.70 pg g(-1) ww) in autumn were higher than in summer (PCBs 0.50 ng g(-1) ww and PCDD/Fs 0.20 pg g(-1) ww). The mean fat content in autumn milk (26%) was significantly higher than in summer (10%). Concentrations in reindeer milk were generally far below 50% of that in adult reindeer body burden. However, the bioaccumulation factors were multiple in milk/reindeer calf ratio and that aroused the question of other important exposure routes than lactation. The muscle and liver of reindeer calves had higher PCDD/F and PCB concentrations than adult animals that possibly indicate the significance of transfer of these compounds from dam to calf through lactation and placenta. However, PBDE concentrations were higher in adult reindeer, especially in liver. In addition, reindeer liver seems to have a special feature to collect highly toxic PCDD/Fs, although the PCB sum concentrations (range from 0.33 to 1.69 ng g(-1) wet weight) were clearly higher than the sums of PCDD/Fs (range from 3.78 to 39.2 pg g(-1) ww). Stillborn reindeer calves represented individuals who had got their PCDD/F, PCB and PBDE load only via the placenta. Concentrations in muscle and brown adipose tissue samples did not indicate dependency on fat content. Obviously effective placental transfer of PCBs and PBDEs from reindeer dam to foetus was seen in this study.     

Analysis of human milk to assess exposure to PAHs,PCBs and organochlorine pesticides in the vicinity Mediterranean city Mersin,Turkey

Assessment of human exposure to environmental persistent organic pollutants such as organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polycyclic aromatic hydrocarbons (PAHs) based on the levels in human breast milk provides a reasonable tool not only to assess the contaminant burden in mothers but also to assess potential exposure of breast-fed neonates. There are limited data on levels of PCBs and OCPs in humans but no previous reports from Turkey on chemically determined levels PAHs in human milk. The aim of this study was to report the levels and accumulation profiles of OCPs, PCBs and PAHs in 47 breast milk samples obtained from a Mediterranean city, Mersin. High resolution analyses were performed by a gas chromatography coupled with mass spectrometer (GC–MS). Dichlorodiphenyldichloroethane (4.4′-DDE) was the dominant pollutant. Beta-hexachlorocyclohexane (ß-HCH), dichlorodiphenyltrichloroethane (4.4′-DDT), dieldrin, hexachlorobenzene, oxy-chlordane, cis-heptachlorepoxide were the other main OCPs detected. Mean levels of ΣPCB congeners and WHO_PCB-TEQ were 9.94 and 0.001 ng/g lipid, respectively. PCB 153 showed the highest concentration (3.37 ng/g lipid), followed by PCB 138 and 180. For the dioxin-like PCBs, PCB 118 was the dominant (0.97 ng/g lipid). Naphthalene, phenanthrene, pyrene and fluoranthene were the major PAHs among the 16 PAHs detected. The estimated daily intakes of DDTs, PCBs, HCHs and HCB were not exceeded the tolerable daily intake (TDI) proposed by the Health Canada Guideline. These results indicate that the neonates of Mersin city are exposed to persistent organic pollutants analyzed in this study. However, neonates born in Mersin province are less exposed than the ones born in other regions, considering OCP and PCB levels in breast milk.     

Dioxins and PCBs in game animals: Interspecies comparison and related consumer exposure

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCB) and non-dioxin-like polychlorinated biphenyls (NDL-PCB) are ubiquitous, persistent toxic compounds that are highly bioaccumulative in nature. Wild-living animals are vulnerable to the negative impacts of human activity. Dioxins and PCBs enter the animal organisms through foraging. Due to the toxicological threat, much attention is paid to these compounds worldwide. The aim of this study was to determine the dioxin contamination status of three game animal species (red deer, roe deer, and wild boar) and compare the PCDD/F and PCB congener bioaccumulation in the muscles, abdominal fat and liver. The chemical analysis was performed by the isotope dilution technique (IDMS) with high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC/HRMS). Dioxins and PCBs were found in specimens collected from all studied species, suggesting the presence of the test compounds in the environment of the animals. The highest concentrations were found in the livers of all animals. The toxic equivalent (TEQ) levels in the muscles, adipose tissue and liver were in the order red deer > roe deer > wild boar. PCDD/Fs were the dominant congeners in TEQ value. For all tested species, the dominant contributors to the total WHO-TEQ were PCB-126, 2,3,4,7,8-PeCDF and 1,2,3,7,8-PeCDD. Among the PCDD/F congeners in the deer tissues, OCDD, OCDF and 2,3,4,7,8-PeCDF were dominant, while in wild boar, OCDD, 1,2,3,4,6,7,8-HpCDD and 1,2,3,4,6,7,8-HpCF occurred in the highest amounts. Among PCBs, PCB-105, 118, 156, 138, 153 and 180 were dominant in all species, but with different levels. The regular consumption of muscle meat from game animals should not cause unacceptable dioxin intake above the Tolerable Weekly Intake (TWI) value for children and adults. However, liver consumption should be avoided, especially by children and pregnant or lactating women. High consumption of contaminated liver may cause dioxin intake at levels up to 300% of TWI for adults and up to 700% TWI for children.     

Polychlorinated diphenyl ethers (PCDEs): environmental levels, toxicity and human exposure: a review of the published literature

This paper reviews the state of the science regarding polychlorinated diphenyl ethers (PCDEs), a group of halogenated aromatic compounds, which are structurally related to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs). Special attention is paid to the environmental levels, toxicity, and human exposure. PCDEs have been detected in a number of environmental samples, and their widespread occurrence in the environment is mainly the result of their presence as impurities in chlorophenol preparations. In humans, PCDE congeners have been detected in adipose tissue. As for other persistent organic pollutants (POPs), dietary intake is very probably the main route of exposure to PCDEs for the general population. However, data concerning PCDE levels in foodstuffs are very limited. It is concluded that investigations on experimental toxicity, dietary intake, and potential human health effects of PCDEs are clearly necessary.     

Contrasting retinoid and thyroid hormone status in differentially-contaminated northern fulmar colonies from the Canadian Arctic,Svalbard and the Faroe Islands

The northern fulmar (Fulmarus glacialis) has previously been shown to accumulate a wide range, and occasionally high concentrations of organochlorines (OCs) (e.g., PCBs, chlorobenzenes, DDT- and chlordane-related compounds, dioxins and furans). The present study aimed to investigate, using a meta-analysis approach, the variations in cytochrome P450 (CYP) 1A-like enzyme induction based on ethoxyresorufin O-deethylase activity (EROD) and selected physiological variables (retinoids and thyroid hormones) in northern fulmar breeding in three differentially OC-exposed populations: Nunavut (Canadian Arctic), Svalbard (Norwegian Arctic) and the Faroe Islands. Substantially higher (roughly two-fold) OC levels were uncovered in the liver of this long-lived fulmarine petrel breeding in the Faroe Islands relative to Svalbard and Nunavut. Liver levels of PCDDs, PCDFs and non-ortho PCBs in Faroe Islands fulmars were amongst the highest reported thus far in any seabirds from the northern regions. Positive correlations were depicted in combined fulmars (all three populations) between hepatic EROD activity and concentrations of OCs, in which strongest associations were found for dioxin-like compound (PCDFs and PCDDs) and TEQ concentrations. Moreover, moderate to strong positive correlations were found between liver OC concentrations and plasma total thyroxin (TT₄) levels and TT₄/total triiodothyronine (TT₃) level ratios, as well as strong negative correlations between the same suite of OCs and plasma TT₃ levels. Hepatic OC concentrations (PCBs, PCDDs, PCDFs, HCB, p,p'-DDE and oxychlordane) also were positively correlated with hepatic retinyl palmitate levels which, in turn, were associated with a significant decrease in plasma retinol levels and somewhat unchanged liver retinol levels. The present meta-analysis investigation on northern fulmar breeding in three geographically-distant sites illustrated that OC exposure (mainly PCBs and dioxins/furans) may be associated with modulation of the thyroid and retinoid homeostasis. However, the impact of confounding environmental factors (e.g., temperature and nutritional status) on current physiological variable variations could not be ruled out, and thus any cause-effect linkages between thyroid and retinoid system perturbation and OC exposure cannot be ascertained.     

Development and validation of prediction models for blood concentrations of dioxins and PCBs using dietary intakes

BackgroundDioxins and PCBs accumulate in the food chain and might exert toxic effects in animals and humans. In large epidemiologic studies, exposure estimates of these compounds based on analyses of biological material might not be available or affordable.ObjectivesTo develop and then validate models for predicting concentrations of dioxins and PCBs in blood using a comprehensive food frequency questionnaire and blood concentrations.MethodsPrediction models were built on data from one study (n = 195), and validated in an independent study group (n = 66). We used linear regression to develop predictive models for dioxins and PCBs, both sums of congeners and 33 single congeners (7 and 10 polychlorinated dibenzo-p-dioxins and furans (PCDDs/PCDFs), 12 dioxin-like polychlorinated biphenyls (PCBs: 4 non-ortho and 8 mono-ortho), sum of all the 29 dioxin-like compounds (total TEQ) and sum of 4 non dioxin-like PCBs (∑ CB-101, 138, 153, 183 = PCB₄). We used the blood concentration and dietary intake of each of the above as dependent and independent variables, while sex, parity, age, place of living, smoking status, energy intake and education were covariates. We validated the models in a new study population comparing the predicted blood concentrations with the measured blood concentrations using correlation coefficients and Weighted Kappa (К_W) as measures of agreement, considering К_W > 0.40 as successful prediction.ResultsThe models explained 78% (sum dioxin-like compounds), 76% (PCDDs), 76% (PCDFs), 74% (no-PCBs), 69% (mo-PCBs), 68% (PCB₄) and 63% (CB-153) of the variance. In addition to dietary intake, age and sex were the most important covariates.The predicted blood concentrations were highly correlated with the measured values, with r = 0.75 for dl-compounds 0.70 for PCB₄, (p < 0.001) and 0.66 (p < 0.001) for CB-153. К_W was 0.68 for sum dl-compounds 0.65 for both PCB₄ and CB-153. Out of 33 congeners 16 (13 dl-compounds and 3 ndl PCBs) had К_W > 0.40.ConclusionsThe models developed had high power to predict blood levels of dioxins and PCBs and to correctly rank subjects according to high or low exposure based on dietary intake and demographic information. These models underline the value of dietary intake data for use in investigations of associations between dioxin and PCB exposure and health outcomes in large epidemiological studies with limited biomaterial for chemical analysis.     

Waste wood recycling as animal bedding and development of bio-monitoring tool using the CALUX assay

Animal bedding made of waste wood samples from seven different plants in Japan were chemically analyzed in terms of persistent organic pollutants (POPs) including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs), coplanar polychlorinated biphenyls (Co-PCBs), drin compounds, chlordane compounds and various inorganic toxic compounds (Cr, Cu, As, B, Cd and Pb) to investigate the chemical characteristics and levels of contamination. Further investigation was conducted to determine the success of applying the Chemically Activated Luciferase Expression (CALUX) bioassay to the waste wood samples in combination with a cleanup procedure for the detection of dioxin-like compounds in order to develop the CALUX bioassay as a rapid and cost-effective screening/monitoring method and a contributive tool to risk management in the waste wood recycling process. For the cleanup procedure, crude extracts from wood samples were prepared by dimethylsulfoxide (DMSO)/n-hexane extraction, and then the extracts were processed by silica gel-44% sulfuric acid reflux treatment at 70 degrees C for 60 min to yield the bioassay fractions. The presence of POPs and inorganic toxic compounds were confirmed in most of the litter samples. In particular, Co-PCBs in one sample (litter dust) showed a high concentration level (1200000 pg/g, 240 pg TEQ/g), suggesting the potential for contamination from demolition waste. The CALUX assay-determined TEQs (CALUX-TEQs) were significantly high in the sample after DMSO/n-hexane extraction, probably due to labile aryl hydrocarbon receptor (AhR) ligands such as PAHs; however, they were remarkably reduced through a single silica gel-44% sulfuric acid reflux treatment. The ratio between CALUX-TEQ values and WHO toxicity equivalent values (WHO-TEQ) obtained by congener-specific chemical analysis ranged from 0.058 to 22 and show comparatively good agreement. Underestimation in some samples, however, was observed where WHO-TEQ values of Co-PCBs contributed greatly to total WHO-TEQ values. Reasons for this gap could be lower CALUX assay-determined relative potencies (REPs) than the WHO-TEFs for these congeners or AhR-antagonistic effects of non dioxin-like PCBs which coexist at higher concentration than Co-PCBs. The CALUX assay is proposed as a promising application in the recycling process of wooden materials.     

Different profiles of anthropogenic and naturally produced organohalogen compounds in serum from residents living near a coastal area and e-waste recycling workers in India

We determined the contamination status and accumulation profiles of polychlorinated biphenyls (PCBs), hydroxylated PCB congeners (OH-PCBs), polybrominated diphenyl ethers (PBDEs), hydroxylated PBDEs (OH-PBDEs), methoxylated PBDEs (MeO-PBDEs), and bromophenols (BPhs) in serum from e-waste recycling workers and residents near a coastal area in India. Residue levels of penta- to octa-chlorinated PCBs, penta- to octa-chlorinated OH-PCBs, 6MeO-BDE47, 6OH-BDE47, and 2,4,6-tri-BPh in serum from residents living near the coastal area were significantly higher than those in serum from e-waste recycling workers. Residue levels of tri- to tetra-chlorinated PCBs, tri- to tetra-chlorinated OH-PCBs, PBDEs, octa-brominated OH-PBDEs, and tetra-BPhs in serum from e-waste recycling workers were higher than those in serum from residents living near the coastal area. Principal component analysis revealed that residents living near the coastal area and e-waste recycling workers had different serum profiles of chlorinated and brominated compounds.     

Brominated dioxin-like compounds: in vitro assessment in comparison to classical dioxin-like compounds and other polyaromatic compounds

Recently, several countries agreed to adopt the Stockholm convention on persistent organic pollutants (POPs). One future obligation will be to add other POPs as new evidence becomes available. In vitro cell-based bioassays offer a rapid, sensitive, and relatively inexpensive solution to screen possible POP candidates. In the present study, we investigated the aryl hydrocarbon (Ah)-receptor activity of several dioxin-like POPs by using the Micro-EROD (Ethoxy-Resorufin-O-Deethylase) and DR-CALUX (Dioxin-Responsive-Chemical Activated Luciferase gene eXpression) bioassays, which are two state-of-the-art methods. The Micro-EROD system used in our study utilizes a wild-type rat liver cell line (rat liver H4IIEC3/T cells), while the DR-CALUX bioassay consists of a genetically modified rat hepatoma H4IIE cell line that incorporates the firefly luciferase gene coupled to dioxin-responsive elements (DREs) as a reporter gene. In the case of the DR-CALUX bioassay, we used an exposure time of 24 h, whereas we used a 72-h exposure time in the Micro-EROD bioassay. The aim of this study was to compare conventional dioxin-like POPs (such as polychlorinated dibenzodioxins and -furans, PCDD/Fs and coplanar polychlorinated biphenyls, PCBs) with several other classes of possible candidates to be added to the current toxicity equivalent factor (TEF) model in the future. Therefore, this study compares in vitro CYP1A1 (Micro-EROD bioassay) and firefly luciferase induction (DR-CALUX bioassay) in several mixed polyhalogenated dibenzodioxins and -furans (PXDD/Fs; X=Br, Cl, or F), alkyl-substituted polyhalogenated dibenzodioxins and -furans (PMCDD/Fs; M=methyl), polyhalogenated biphenyls (PXBs, X=Br, Cl ), polybrominated diphenyl ethers (PBDEs), pentabromophenols (PBPs), and tetrabromobisphenol-A (TBBP-A). We also evaluate congener-specific relative potencies (REPs) and efficacies (% of TCDD(max)) and discuss the dose-response curves of these compounds, as well as the dioxin-like potency of several other Ah-receptor agonists, such as those of the polyaromatic hydrocarbons (PAHs) and polychlorinated naphthalenes (PCNs). The highest REP values were found for several PXDD/F congeners, followed by some coplanar PXBs, trichlorinated PCDD/Fs, PAHs, PBDE-126, 1-6-HxCN, and some brominated flame retardants (TBBP-A). These in vitro investigations indicate that further research is necessary to evaluate more Ah-receptor agonists for dioxin-like potency.