Dioxins: WHO's tolerable daily intake (TDI) revisited

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in marine mussels from French coasts: levels, patterns and temporal trends from 1981 to 2005

The levels and temporal trends of toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were determined in archived marine mussels collected between 1981 and 2005 from selected sites along French coasts. The geographical distribution and levels of PCDD/Fs generally reflect regional inputs of these contaminants: the highest concentrations were determined in samples from the Seine river estuary (English Channel) and Toulon area (Mediterranean coast); the lowest levels were determined in Corsica (Mediterranean Sea). PCDD/F isomeric composition showed a fairly homogeneous distribution pattern throughout the various sampling sites. This pattern, dominated by 2,3,7,8-TCDF and OCDD, can be considered as typical for the study species. However, on a more local scale, some differences in isomeric composition in mussels were identified in relation to local source characteristics. The time trend study showed a pronounced decrease in PCDD/F concentrations over the 24-year period at most sites, except Toulon on the Mediterranean Sea, where the decrease was not significant. This overall decrease probably reflects the general drop in PCDD/F emissions in Europe since 1980. However, high concentrations were determined in mussels collected in recent years (1999, 2001 and 2005) from the mouth of the Seine river. These concentrations are related to particular hydrological conditions, and intensive sediment dredging due to a new port construction at the mouth of the estuary. The results presented in this paper provide reference data on the contamination of shellfish by persistent organic pollutants in the marine environment.

Dietary intake of PCDDs/PCDFs and coplanar PCBs among the Japanese population estimated by duplicate portion analysis: a low proportion of adults exceed the tolerable daily intake

Dietary intake of dioxins was estimated by duplicate portion analysis of consecutive 3-day food samples among 86 men and 288 women (aged 17-72 years), who were living in 75 different areas of 25 prefectures in Japan. The mean (median) intake of PCDDs+PCDFs, coplanar PCBs (co-PCBs), and total dioxins, expressed on the basis of toxicity equivalents (TEQ), was 0.46 (0.34), 0.59 (0.39), and 1.06 (0.79)pg/kg body weight/day, respectively. Dietary intake was highest in fishing areas, followed by farming and urban areas. In multiple regression analysis, TEQs of PCDDs+PCDFs, co-PCBs, and total dioxins were positively associated with age and intake amount of fish and shellfish, and milk and dairy products, and negatively associated with survey year. There were significant positive correlations between dietary intake and blood levels for TEQs of PCDDs+PCDFs, co-PCBs, and total dioxins (Pearson r=0.35-0.36). The proportion of those whose dietary intake exceeded the tolerable daily intake (TDI), set by the World Health Organization (4pg TEQ/kg/day) and European Union (2pg TEQ/kg/day), was estimated at 2.1% and 10.4%, respectively. However, these proportions were considered to be overestimated because of the effect of day-to-day within-person variation. Therefore, the ratio of within- and between-person variance was estimated by applying random effects one-way analysis of variance to repeated measurements for another group of 35 persons. When the effect of within-person variation of dietary intake was accounted for, the proportion of subjects whose long-term intake exceeded the TDI of WHO and EU decreased to 0.06% and 2.9%, respectively.

From dioxin to drug lead--the development of 2,3,7,8-tetrachlorophenothiazine

Polychlorinated dibenzo-p-dioxins are persistent environmental pollutants. The most potent congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), causes a wasting syndrome and is a potent carcinogen and immunosuppressant in the rat at high doses. However, low doses cause opposite effects to some of those observed at higher doses, resulting in chemoprevention, stimulation of the immune system, and longevity in experimental animals. The new TCDD analogue, 2,3,7,8-tetrachlorophenothiazine (TCPT), was developed to take advantage of the low-dose effects of dioxins that have potential application as therapeutics. Its development marked a deviation from the traditional scope of phenothiazine drug design by deriving biological effects from aryl substituents. TCPT was synthesized in three steps. The key ring-closing step was performed utilizing a Buchwald-Hartwig amination to provide TCPT in 37% yield. Its potency to induce CYP1A1 activity over 24 h was 370 times lower than that of TCDD in vitro. The elimination half-life of the parent compound in serum was 5.4 h in the rat and 2.7 h in the guinea pig, compared to 11 and 30 days, respectively, for TCDD. These initial findings clearly differentiate TCPT from TCDD and provide the basis for further studies of its potential as a drug lead.

Transfer and accumulation of persistent organochlorine compounds from bovine dams to newborn and suckling calves

The maternal-fetal and neonatal transfers of polychlorinated dibenzo- p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) were measured in the blood and milk of dams and in the blood of newborn and suckling calves. Calf blood toxic equivalent quantities (TEQs) were drastically increased by suckling. Blood concentrations of individual congeners were greater in suckling calves than in newborn calves, excluding octachlorodibenzo- p-dioxin (O 8CDD); O 8CDD did not readily transfer to milk but was readily absorbed by the gastrointestinal tract and remained in systemic circulation longer than other congeners. Congener concentrations in milk were correlated with maternal blood levels, and those in suckling calf blood were dependent on their concentrations in milk. These results suggest that neonatal calves absorb more lipophilic organochlorine compounds than prenatal fetuses, that those compounds that are transferred from dams to calves are associated not only with lipid transport but also with other carriers, and that the distribution of congeners is structure-dependent.

Effects on growth and biochemical responses in juvenile gilthead seabream 'Sparus aurata' after long-term dietary exposure to low levels of dioxins

The farmed fish gilthead seabream (Sparus aurata) were fed with a dry feed spiked with a low level (23 ng WHO-TEQ/kg of feed) polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) mixture in order to assess bioaccumulation of these contaminants in the muscle and liver tissues after long-term exposure (approximately 390 days). Furthermore, effects on fish growth, feeding and on the response of some biochemical markers (induction of the CYP1A dependent EROD activity, the conjugating enzyme GST, the antioxidant enzymes CAT, t-GPX and DTD, lipid peroxidation and the AhR gene expression) were also evaluated. After feeding with the spiked dry feed for 3 months the PCDD/F concentrations in the exposed fish were 5.50 pg WHO-TEQ/g fresh weight (f.w.) in flesh and 8.45 pg WHO-TEQ/g f.w in liver tissue, which are approximately 24-fold and 14-fold higher than background levels, respectively. However, a progressive increase in PCDD/F levels was not found during the rest of the exposure period. Differences in fish growth were not observed between dioxin-exposed and non-exposed animals and, in addition, no mortalities were recorded attributable to the dioxin intake. Significant increases in the EROD activity, as well as in AhR gene expression were observed in liver after approximately 300 days of exposure. However, no effect on the antioxidant enzymes CAT and t-GPX was found.

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).

Residues of dioxin in egg samples collected from west zone of India

The residues of the congeners of dioxin and furan have been identified in the egg samples collected from the western zone of the India. The samples were collected from the chicken grown in sites where Municipal Corporation incinerates the municipal and hazardous wastes. All the samples showed the presence of the residues of PCDDs/Fs. The mean TEQ of dioxin and furan were 7.10 pg/g and 0.39 pg/g respectively.

Assessment of dioxin and dioxin-like compounds in mainstream smoke from selected US cigarette brands and reference cigarettes

Mainstream cigarette smoke (MSS) from 12 US cigarette brands and two reference cigarettes was evaluated to determine concentrations of dioxins (i.e., polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs)). The study included three 'tar' ranges based on Federal Trade Commission (FTC) determination: Low Yield (LY) < or = 5.5, Medium Yield (MY) 9.6-12.2, and High Yield (HY)> or = 14.5 mg/cig. Of the brands studied, the HY cigarettes yielded the greatest mean concentrations of 2005 World Health Organization Toxic Equivalents (WHO-TEQs) on a per cigarette basis. WHO-TEQ levels in LY cigarettes were significantly lower than for HY cigarettes (p=0.039) on a yield per cigarette basis and WHO-TEQ concentrations correlated with 'tar' yield (r=0.73, p=0.007), as did concentration on a WHO-TEQ per body mass per day basis (r=0.73, p=0.007). However, a statistically significant relationship was not observed between 'tar' yield levels and WHO-TEQ concentrations on a per mg Total Particulate Matter (TPM) basis. Concentrations for all brands tested ranged from 0.44 to 3.88 fg WHO-TEQ/mg TPM. Maximum daily exposure estimates calculated from this range (0.004-0.074 pg WHO-TEQ/kg bw/day) are below the current WHO Tolerable Daily Intake range of 1-5 pg/kg bw/day.

Polychlorinated biphenyls (PCBs) and hydroxy-PCBs in adipose tissue of women in Southeast Spain

Polychlorinated biphenyls (PCBs) and hydroxylated PCBs (OH-PCBs) were investigated in human adipose tissue samples collected from 20 women undergoing surgery. Mean sum of PCB and sum of OH-PCB levels were 737ng/g of lipid and 8pg/g of lipid, respectively. Among PCBs, congeners 180, 153, 138 and 170 were the most frequent and abundant, and together constituted 72% of the total amount of PCBs in adipose tissue. The PCB congener pattern and the frequencies and concentrations of non-dioxin-like and non-hydroxylated congeners observed in adipose tissue were similar in distribution and order of magnitude to the profile previously published in Spain but lower than that found in other European countries. Among OH-PCB congeners studied, 4-OH-PCB 107/118 was found at the highest concentrations followed by 3'-OH-PCB 180 and 3-OH-PCB 138. To date, no information on levels of PCB metabolites in the Spanish population is available for comparison. These three predominant OH-PCBs contributed 97% of all OH-PCBs. Twelve dioxin-like PCBs contributed around 8% of the total PCB exposure, and all were present in all study subjects. Further research is required to determine trends in human exposure to PCBs and OH-PCBs and how existing banning measures affect exposure.

Is there a link between hypospadias and organochlorine exposure in East Greenland sledge dogs (Canis familiaris)?

In a clinical survey on East Greenland male sledge dogs (Canis familiaris), one dog exhibited malformation of the external genital organs. The clinically in situ examination of the sledge dog revealed a rare congenital malformation of the urethra and penis corresponding to severe perineal and penile hypospadias. The testes showed spermiogenesis and no sign of true hermaphroditism. We did not have the opportunity to examine the dam for endocrine organ pathology or tumours. But, based on organochlorine data in ringed seal (Phoca hispida) blubber and information from the owners, the potential in uteri OC exposure of the sledge dog was estimated to 320 microg/day which correspond to 128 pg TEQ/kg/day. This is 32-128-folds above WHO guidelines and threshold levels for teratogen and reproductive effects. We suggest that the congenital malformation was due to endocrine organ pathology/tumours of the dam, enzyme/receptor defects (mutation) in the pup or in uteri exposure to environmental xenoestrogens.

Dietary exposure to PCDD/PCDFs by individuals living near a hazardous waste incinerator in Catalonia, Spain: temporal trend

The levels of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) were measured in foodstuffs randomly acquired in July 2006 in various locations of Tarragona County (Catalonia, Spain), which are near a hazardous waste incinerator (HWI). A total of 35 composite samples, belonging to various food groups (vegetables, pulses, cereals, fruits, fish and seafood, meat and meat products, eggs, milk, dairy products, and oils and fats) were analyzed by HRGC/HRMS. The dietary intake of PCDD/PCDFs was subsequently determined and compared with a previous survey performed in 2002. For calculations, recent data on consumption of the selected food items were used. Total dietary intake of PCDD/PCDFs for the general population of Tarragona County was estimated to be 27.81 pg WHO-TEQ/day, value notably lower than that found in the 2002 study, 63.80 pg WHO-TEQ/day. Fish and seafood (28%), oils and fats (22%), eggs (17%), and dairy products (11%) were the most important contributors to this intake, while pulses (1%), milk (2%), vegetables (3%) and fruits (3%) showed the lowest contribution to total WHO-TEQ. The current PCDD/PCDF intake is also considerably lower than the intake estimated in 1998 for the population of the same geographical area, 210.1 pg I-TEQ/day, when a baseline study was carried out during the construction of the HWI. The present intake is also compared with the dietary intakes of PCDD/PCDFs recently (2006-2007) reported for a number of regions and countries.

Chlorella (Chlorella pyrenoidosa) supplementation decreases dioxin and increases immunoglobulin a concentrations in breast milk

In addition to meeting nutritional requirements, breast milk plays important roles in biodefense for nursing infants. Dioxins have been detected at high concentrations in breast milk, raising concerns about disorders in nursing infants caused by breast milk containing dioxins in Japan. We analyzed dioxin levels in breast milk and maternal blood samples from 35 pregnant women in Japan. We also measured immunoglobulin (Ig) A concentrations in breast milk and investigated correlations with dioxin concentrations. In addition, 18 of the 35 women took Chlorella pyrenoidosa (Chlorella) supplements during pregnancy, and the effects on dioxin and IgA concentrations in breast milk were investigated. Toxic equivalents were significantly lower in the breast milk of women taking Chlorella tablets than in the Control group (P = .003). These results suggest that Chlorella supplementation by the mother may reduce transfer of dioxins to the child through breast milk. No significant correlation was identified between dioxin and IgA concentrations in breast milk in the Control group. It is unlikely that normal levels of dioxin exposure via food have a remarkable influence on IgA in breast milk. IgA concentrations in breast milk in the Chlorella group were significantly higher than in the Control group (P = .03). Increasing IgA levels in breast milk is considered to be effective for reducing the risk of infection in nursing infants. The present results suggest that Chlorella supplementation not only reduces dioxin levels in breast milk, but may also have beneficial effects on nursing infants by increasing IgA levels in breast milk.

Risk and benefits from consuming salmon and trout: A Canadian perspective

Recent reports on the presence of persistent organic chemicals in wild and farmed salmon have left consumers and health professionals confused regarding the safety of regular fish consumption. The objectives of this study were (1) to compare concentrations of key contaminants and the essential nutrients omega-3 fatty acids between farmed and wild salmon and trout, and (2) to balance risks and benefits from regularly consuming these species. Concentrations of mercury, polychlorinated biphenyls, dioxins and furans as well as omega-3 fatty acids were determined in fillets from farmed salmon and trout bought in various markets located in Quebec, Canada, as well as in fillets from wild salmonids obtained from fishermen and various Canadian agencies. While differences were observed between market (farmed) and wild fish with regard to the concentrations of mercury and polychlorinated biphenyls, overall the concentrations of contaminants were low, such that the regular consumption of these fish would not cause tolerable daily intakes to be exceeded. Our results indicate that salmon and trout sold in Quebec markets, which as in markets located elsewhere in North America originate for the most part from Chilean farms, can be consumed regularly to achieve optimal nutritional benefits from omega-3 fatty acids, without incurring significant contaminant related health risks.

Health risk assessment of background PCDD/F exposure levels in Kocaeli, Turkey

An estimation and assessment of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) exposure levels for the people living in Kocaeli, the most industrialized area of Turkey, are presented. The information is based on the results of PCDD/F analyses in the samples collected from various environmental media and the multimedia exposure assessment methodology. Exposure scenarios were constructed on a site-specific basis by combining the exposure pathways appropriate to the area, and the activity patterns of the people living in Kocaeli. The model showed that the exposure levels of PCDD/Fs were in the range of 3.7-13.1 pg I-TEQ.kg-1 bw for adult receptors, which are higher than the recommended TDI value of 2 pg TEQ.kg-1 bw. The PCDD/F intakes for rural receptors were estimated to be three times higher than those for urban and semi-urban receptors due mainly to the consumption of locally grown foods. The assessment of the contributions of various exposure pathways to the total exposure and the sensitivity analysis performed based on a probabilistic approach indicated that PCDD/F intakes for adult receptors are directly proportional to the locally grown fraction of plant groups consumed.

PCB and dioxin-like PCB in indoor air of public buildings contaminated with different PCB sources--deriving toxicity equivalent concentrations from standard PCB congeners

Data on dioxin-like PCB in indoor air of buildings with PCB-containing materials and on possible correlation between toxicity equivalent concentrations (TEQ) and levels of non-dioxin-like standard PCB is sparse. As part of a larger survey on indoor-air contamination with PCB, the connection between the concentration of standard PCB congeners and the dioxin-like toxicity expressed as TEQ was investigated. Indoor air samples (n=8) were collected in four public buildings with known PCB sources and total PCB levels in the range from 715 to 2250 ng/m3 and analyzed for the six non-dioxin-like standard PCB (congeners 28, 52, 101, 138, 153, 180), the twelve dioxin-like PCB congeners according to WHO and the 17 2,3,7,8-substituted PCDD/PCDF congeners. In three buildings where PCB were used as flame retardant coatings of acoustic ceiling tiles, PCB 101 had the maximum level among the six standard PCB, while in the building with permanent elastic sealants as PCB source, congeners 28 and 52 dominated the pattern by far. In the case of permanent elastic sealants as PCB source (n=3) a total PCB concentration of 1000 ng/m3 corresponded to a total TEQ level of 0.3-0.6 pg/m3. In contrast, in rooms with acoustic ceiling tiles as PCB source, 1.8-4.7 pg TEQ/m3 per 1000 ng total PCB/m3 were found. Linear regression analysis between PCB and TEQ indicated that PCB 118 might be used to calculate the total TEQ of dioxin-like PCB and PCDD/PCDF. By means of such a correlation it is possible to estimate TEQ by extrapolation from the results of less sophisticated analytical methods. It is tentatively recommended to use PCB 118 for screening purposes or re-evaluation of standard PCB indoor-air measurements. If only the six non-dioxin-like PCB standard congeners are available, a regression algorithm using the sum of PCB 101, 138, 153 and 180 might be used instead.

Determinants of dioxins and furans in blood of non-occupationally exposed populations living near Portuguese solid waste incinerators

Biomonitoring of dioxin body burden, as evaluated by PCDD/F levels in blood, has been carried out in a total of 138 adults from general population living in the vicinity of solid waste incinerators in Portugal. Measurements were performed included in cross-sectional surveys within two Environmental Health Surveillance Programs launched in response to ecotoxicological concern in relation to solid waste incinerators near Lisbon and in Madeira Island. Overall conclusion from first published results is indicative that dioxin exposure of global populations cannot be related to the emissions of these facilities, meaning that dioxin sources control seems to be effective in relation to both incinerators. Main objective of present work was to investigate potential determinants of dioxin levels in the studied populations. Findings from this investigation also suggest that incineration does not impact on dioxin blood levels of nearby residents. Follow-up of a small group of individuals (22) from Lisbon gives preliminary indication on temporal control effectiveness of the Lisbon facility. Regarding comparison between PCDD/F levels from Lisbon and Madeira communities, individuals from Lisbon show higher median PCDD/F levels, likely to be better explained by more highly polluted areas in Lisbon than by eventual differences in dietary habits of the studied groups. In fact, analysis performed on the diet of both groups (not detailed in the present study) does not show a statistically significant difference in relation to any of the most relevant foodstuffs in the context of dioxin exposure. Comparison between Lisbon and Madeira in relation to pattern of the single congeners for PCDD/Fs shows a very similar profile. The highest contributions to the PCDD/Fs toxicity came from 12378-PCDD, 23478-PCDF, Hexa-CDD, 2378-TCDD and Hexa-CDF.

Persistent organic pollutants in human breast milk from Asian countries

In this paper, we concisely reviewed the contamination of persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), biphenyls (PCBs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) in human breast milk collected from Asian countries such as Japan, China, Philippines, Vietnam, Cambodia, India, Malaysia, and Indonesia during 1999-2003. Dioxins, PCBs, CHLs in Japanese, and DDTs in Vietnamese, Chinese, Cambodian, Malaysian, and HCHs in Chinese, Indian, and HCB in Chinese breast milk were predominant. In India, levels of dioxins and related compounds (DRCs) in the mothers living around the open dumping site were notably higher than those from the reference site and other Asian developing countries, indicating that significant pollution sources of DRCs are present in the dumping site of India and the residents there have been exposed to relatively higher levels of these contaminants possibly via bovine milk.

Dietary intake of polychlorinated dioxins, furans and dioxin-like polychlorinated biphenyls from foods of animal origin in China

Four food groups of animal origin from the Chinese Total Diet Study (TDS) in 2000 were analysed for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (PCBs). The samples were from four regions, covering 12 provinces of China. PCDD/Fs, expressed as WHO toxic equivalents (TEQ), ranged from 0.02 to 0.28 pg TEQ g-1 and dioxin-like PCBs ranged from 0.01 to 0.24 pg TEQ g-1 (wet weight, ND = LOD), in all samples. Using food consumption data from a 3-day household dietary survey, daily dietary intake of dioxin-like compounds from foods of animal origin in China was estimated. Daily intake among regions ranged 0.09-0.59 pg TEQ kg-1 body eight day-1.

A comparison of PCDD/PCDFs exposure in infants via formula milk or breast milk feeding

Food is the major source for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) accumulation in human body. In infant period, breast milk and formula milk are the major food sources. Congener-specific analyses of 17 PCDD/PCDFs were performed on 10 brands of formula milk samples which were milk-based and 37 breast milk samples collected from women living in southern Taiwan. The levels of 17 PCDD/PCDFs in 10 formula milk samples ranged from 0.468 to 0.962 pg WHO-TEQ/g lipid, with a mean value of 0.713+/-0.163 pg WHO-TEQ/g lipid. For the 37 breast milk samples, their PCDD/PCDF levels were 14.7+/-9.36 pg WHO-TEQ/g lipid, with a range between 4.21 and 52.8 pg WHO-TEQ/g lipid. At 12th month of age for infants, average daily intakes (ADI) of PCDD/PCDFs were 2.1 pg WHO-TEQ/kg/day for the formula-feeding infants, and 13 pg WHO-TEQ/kg/day for the breast-feeding infants. The present data may provide useful information for risk-benefit evaluation of formula- and breast-feeding.

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in common fish species in the Pearl River Delta area, China

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs) concentrations in 31 fish samples from 19 commonly consumed freshwater and saltwater species from the Pearl River Delta Area were analyzed. The PCDD/Fs dietary intake from fish for the local population was evaluated to provide a database for setting the national PCDD/F limits in fish for the People's Republic of China. The median concentration from the 31 fish samples was 1.27 pg/g wet weight for the total of PCDD/Fs, and the median WHO-TEQ was 0.26 pg/g wet weight, and ranged from 0.063 to 1.30 pg WHO-TEQ/g wet weight. The dominant contributors to the WHO-TEQ were 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF, which accounted for 38% and 28%, respectively. The dietary intake of PCDD/Fs from fish for local people was estimated to be 0.47 pg WHO-TEQ/kg bw x day. In view of the findings, the dietary of PCDD/Fs from other foods of animal origins in China should be studied in more detail as soon as possible in order that standards can be put forward to protect human health.

Dietary intake of dioxins and dioxin-like PCBs, due to the consumption of dairy products, fish/seafood and meat from Ismailia city, Egypt

Although dietary intake studies have been carried out extensively in most developed countries, to evaluate the health risks of PCDD/Fs and DL-PCBs, no data of this kind exists for Egypt. In this study, concentrations of PCDD/Fs and DL-PCBs were measured using HRGC/HRMS in the most contributing foodstuffs (dairy products, fish/seafood, and meat) randomly collected from Ismailia city, Egypt. The dietary intake of PCDD/Fs and DL-PCBs were subsequently determined, and compared with the most recent studies. To provide a primary estimation of the whole TEQ intake in Egypt if all the main food categories included, an estimation of the dietary intake (based on EU data) for some important and non-measured groups (cereals, vegetables/fruits, eggs and milk) was carried out. The calculated dietary intake based on the WHO assumption of 60 kg bw ranged from 3.69 to 4.0 pg WHO-TEQ/kg bw/day for PCDD/Fs and from, 6.04 to 6.68 pg WHO-TEQ/kg bw/day, if DL-PCBs were included. PCBs intake contributed about 40% of the total TEQ intake. Dairy products (mainly cheese) were the main contributor to the intake of PCDD/Fs (89%), while fish/seafood and meat have more or less the same percent share (5.4%). The dairy products contamination was the reason for our elevated dietary intake, as the content of PCDD/Fs and DL-PCBs is several times higher than in all the developed countries. The total intake (PCDD/Fs+DL-PCBs) due to consumption of dairy products, fish/seafood and meat, is close to that reported in EU countries at the beginning of 1980s, but much higher than all those mentioned in all the recent reports, and higher than the maximum WHO TDI of 4 pg TEQ/kg bw/day. A recalculation of the dietary intake to include not only our measured data but also the data for the non-measured groups, yielded a total intake in the range of 4.06-6.38 pg TEQ/kg bw/day for PCDD/Fs and a range of 6.59-9.98 pg TEQ/kg bw/day for total including PCBs. Results show that cereals and vegetables/fruits contribute significantly to PCDD/Fs TEQ intake in Egypt and play a more important role than fish/seafood and meat. This is the case even though the intake for cereals and vegetables/fruits based on EU data.

Current dietary exposure to polychlorodibenzo-p-dioxins, polychlorodibenzofurans, and dioxin-like polychlorobiphenyls in Italy

This study deals with an assessment of dietary exposure to polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs), and dioxin-like polychlorobiphenyls (DL-PCBs) for the Italian general population, obtained by combining data from a national food consumption survey with contamination concentrations of European foodstuffs available on the market. The distribution of PCDD, PCDF, and DL-PCB dietary intake(s) in the Italian population was investigated to assess to what extent the variability in dietary habits may cause higher exposures to the previously mentioned contaminants. Results indicate that the main contributions to total PCDD, PCDF, and DL-PCB intake are due to fish and fish products (44%) and to milk and dairy products (27%). The mean PCDD, PCDF, and DL-PCB intake (total toxic equivalents) via food was estimated 5.34, 3.37, and 2.28 pg World Health Organization (WHO)-TE/kg of body weight (kg-bw) per day for the three age groups 0-6 (breastfeeding excluded), 7-12, and 13-94 years old, respectively. The highest exposures due to variation in dietary habits are in general within a factor of 2-3. From the mean exposure estimated for the general population (adults), it can be inferred that a consistent part of it would exceed the tolerable daily intake of 2 pg WHO-TE/kg-bw adopted by the Scientific Committee on Food of the European Commission in 2001.

Structure-dependent Ah receptor agonist activities of chlorinated biphenylenes

Polychlorinated biphenylenes (PCBP) have been identified as combustion by-products that bind the aryl hydrocarbon receptor (AhR) and exhibit 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activity. This study investigates the Ah-responsiveness of 2,3,6,7-tetrachlorobiphenylene (2,3,6,7-CBP), 2,3,6-CBP, 2,3-CBP and 2-CBP in breast cancer cells. MCF-7 or ZR-75 cells were treated with different concentrations (1-100 nM) of the compounds alone to determine their activity as inducers of CYP1A1 protein expression or luciferase activity in cells transfected with a construct (pDRE(3)) containing three tandem dioxin responsive elements (DREs) linked to a luciferase reporter gene. In both assays, the order of potency was 2,3,6,7-CBP>2,3,6-CBP>2,3-CBP approximately 2-CBP, and 2,3,6,7-CBP and TCDD were equipotent. Similar results were also observed in an antiestrogenic assay in MCF-7 cells, confirming the high AhR agonist activity of 2,3,6,7-CBP in breast cancer cells.

Definition and GIS-based characterization of an integral risk index applied to a chemical/petrochemical area

A risk map of the chemical/petrochemical industrial area of Tarragona (Catalonia, Spain) was designed following a two-stage procedure. The first step was the creation of a ranking system (Hazard Index) for a number of different inorganic and organic pollutants: heavy metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated aromatic hydrocarbons (PAHs) by applying self-organizing maps (SOM) to persistence, bioaccumulation and toxicity properties of the chemicals. PCBs seemed to be the most hazardous compounds, while the light PAHs showed the minimum values. Subsequently, an Integral Risk Index was developed taking into account the Hazard Index and the concentrations of all pollutants in soil samples collected in the assessed area of Tarragona. Finally, a risk map was elaborated by representing the spatial distribution of the Integral Risk Index with a geographic information system (GIS). The results of the present study seem to indicate that the development of an integral risk map might be useful to help in making-decision processes concerning environmental pollutants.

Organochlorine compounds (PCBs, PCDDs and PCDFs) in seafish and seafood from the Spanish Atlantic Southwest Coast

Concentrations and congener specific profiles of PCDD/Fs and PCBs were determined in edible fish and seafood species from the Coast of Huelva, in the Spanish southwest Atlantic coast. Five fish species, namely wegde sole (Dicologoglossa cuneata), common sole (Solea vulgaris), white seabream (Diplodus sargus), sardine (Sardina pilchardus), angler fish (Lophius piscatorius), two shellfish species (Donax trunculus and Chamelea gallina), common cuttlefish (Sepia officinalis) and prawns (Parapenaeus longirostris), frequently found and consumed in the area were analysed. Concentrations ranged from 861 to 23787pg/g wet weight for total PCBs, while 2,3,7,8-PCDD/Fs showed concentrations ranging from 0.2 to 1.18pg/g wet weight. WHO-TEQ concentrations ranged from 0.038 to 0.186pg WHO-TEQ(PCDD/Fs)/g wet weight, values well below the maximum concentrations established by the EU. When non- and mono-ortho PCBs were included the values increased to a maximum of 0.99pg WHO-TEQ(PCDD/Fs+PCBs)/g wet weight. The PCB and PCDD/F accumulation pattern found in the samples analysed showed a distribution typically reported for marine samples, and no remarkable differences were found between species. The PCBs were the ones contributing with the highest percentage to the total TEQ content in most species studied. Concerning the seafood, specially prawns and shellfish, the opposite was observed and PCDD/Fs were found to contribute with a higher percentage than PCBs. The congener specific contribution to the TEQ showed PCB 126 followed by 1,2,3,7,8-PeCDD and 2,3,4,7,8-PeCDF as the most abundant ones.

Dioxin and dioxin-like PCB exposure of non-breastfed Dutch infants

The exposure of humans to PCDD/Fs (polychlorinated dibenzo-p-dioxins and dibenzofurans) and dioxin-like PCBs (dl-PCBs, i.e. polychlorinated non-ortho and mono-ortho biphenyls) occurs predominantly via the intake of food. Young children have a relatively high intake of these substances, due to their high food consumption per kilogram body weight. As the exposure of non-breastfed infants to these compounds has not been assessed before in The Netherlands, we studied the dietary intake of 17 PCDD/Fs and 11 dioxin-like PCBs in 188 Dutch non-breastfed infants between 4 and 13 months. The food intake of the infants was assessed by a 2-d food record. From these data PCDD/F and dioxin-like PCB intake was calculated using PCDD/F and dioxin-like PCB concentrations of food products sampled in 1998/1999 in The Netherlands. The long-term PCDD/F and dioxin-like PCB exposure of the infants was calculated using the statistical exposure model (STEM). For infants of 5 months the chronic exposure to PCDD/F and dioxin-like PCB was 1.1pg WHO-TEQ (toxic equivalents) per kilogram body weight (bw) per day (95th percentile: 1.7pg WHO-TEQ/kg bwxd), which mainly originated from infant formula and vegetables and increased to 2.3pg WHO-TEQ/kg bwxd (95th percentile 3.7pg WHO-TEQ/kg bwxd) for infants just over 1 year old eating the same food as their parents. The percentage of formula-fed infants with an exposure exceeding the TDI of 2pg WHO-TEQ/kg bwxd was 5% at 5 months, 49% at 9 months and 64% at 12 months.

Genetic polymorphisms in CYP1A1 and GSTM1 predispose humans to PCBs/PCDFs-induced skin lesions

INTRODUCTION

Polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) are ubiquitous persistent pollutants in humans. Whether people with different genotypes are with different susceptibility to these chemicals are unknown. In a group of people highly exposed to PCBs/PCDFs, we tested the hypothesis that genotypic polymorphisms affected susceptibility for development of skin manifestations.

METHODS

In 1979, approximately 2000 people in central Taiwan ingested cooking oil contaminated with PCBs/PCDFs. Skin disorder such as chloracne, abnormal nail, hyperkeratosis and skin allergy were found in PCBs/PCDFs exposed group. We recruited exposed and community background exposure subjects for blood testing and telephone-interview. Single nucleotide polymorphisms, AhR Arg554Lys, CYP1A1 Ile462Val, CYP1A1 T6235C, and GSTM1/T1 deletion, were determined. Occurrence of skin manifestations was compared among people with different genotypes while stratified by PCB exposure levels by logistic regression.

RESULTS

Data on exposure, medical history, and genotypes were obtained from 393 exposed and 181 background exposure groups. Skin manifestations including chloracne, allergy, abnormal nail, and hyperkeratosis were more prevalent in exposed people in a dose-related manner. Among highly exposed individuals, combined CYP1A1-MspI mutant genotype and GSTM1-null genotype were associated with increased risk of chloracne (odds ratio 2.8, 95% confidence interval 1.1-7.6). Among intermediately exposed individuals, GSTM1 null genotype was associated with skin allergy. AhR Arg554Lys genotype and GSTT1 null genotype were not related to susceptibility to skin manifestations in PCB/PCDF-exposed population.

CONCLUSION

CYP1A1 and GSTM1 genotypic polymorphisms might be related to the susceptibility to PCB/PCDF-induced skin manifestations.

PCB, PCDD and PCDF residues in fin and non-fin fish products from the Canadian retail market 2002

Fish products (n=129) available on the Canadian retail market were collected and analyzed for levels of PCBs, PCDDs and PCDFs during the spring of 2002. The collection included samples from eight fish groups (Arctic char, crab, mussels, oysters, salmon, shrimp, tilapia, trout) from the wild and those raised on fish farms, as available. Sample collection included both domestic and imported fish products, however, no significant difference in residue levels was observed between these groups of fish products. Salmon samples were found to contain the highest concentration of sigmaPCBs (geometric mean 12.9 ng/g wet weight), while crab samples had greatest sigmaPCDD/F levels (geometric mean 0.002 ng/g wet weight). The geometric mean of the total toxic equivalents (WHO-TEQ) ranged from 0.06 pg WHO-TEQ/g whole weight in farmed shrimp to 1.1 pg WHO-TEQ/g whole weight in farmed salmon samples. PCB 153, 138, 118 and 101 were the dominant congeners observed in fish product samples studied, while 1,2,3,7,8-pentachlorodibenzodioxin and 2,3,7,8-tetrachlorodibenzofuran contributed the most to total PCDD and PCDF loadings. Lipid content was positively correlated to sigmaPCB levels; however, no relationship between lipid content and sigmaPCDD/F concentrations was established. SigmaPCB levels were below the Canadian guideline value for PCBs in fish and fish products (2000 ng/g). Similarly, 2,3,7,8-TCDD levels in all fish products were below the Canadian guideline value (0.020 ng/g).

Polychlorinated dibenzo-p-dioxins, dibenzofurans and 'dioxin-like' PCBs in flue gas emissions from municipal waste management plants

The aim of this work is to give representative data on polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyl (PCBs) from stack gas emissions of an urban solid waste management plant which has to comply with the limit of 0.1 ng I-TEQ/Nm3. In particular, the study is focused on 29 target compounds, the seventeen 2,3,7,8-PCDDs/Fs, four non-ortho PCBs and eight mono-ortho PCBs which configure so-called 'dioxin-like' PCBs (DL-PCBs). To this end, emission measurements were performed during one year over the three operating combustion lines in a selected waste management plant. In general, accurate methodology allowed characterizing all target compounds in almost all the samples analyzed. In addition, a typical pattern for DL-PCBs is reported. The pattern presented PCB #118 to be the highest, nevertheless the figures demonstrated DL-PCBs contribution to the total TEQ around 3% being PCB #126 the most important congener due to its TEF of 0.1. Finally, remarkable differences were achieved in comparison with both environmental and biological samples such as soils, sediments, human milk or fish since these matrices may present DL-PCB contribution to the total TEQ up to 77%.

A dose-response study of the effects of prenatal and lactational exposure to TCDD on the immune response to influenza a virus

The goal of the current study was to evaluate the immune response to a common respiratory pathogen, influenza A virus, in mice exposed to increasing doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during development. Additionally, the treatment paradigm was designed to provide exposure throughout fetal and neonatal development, beginning on d 1 of gestation. To accomplish this, impregnated C57Bl/6 mice were treated with 0.25 microg/kg TCDD on d 0 and 7 of pregnancy, followed by 2 additional doses of 0.25, 1, or 5 microg/kg given on d 14 and postpartum d 2. The adult offspring were infected with influenza virus, and components of the adaptive and innate immune responses were evaluated. Our results show that developmental exposure to TCDD dose-responsively suppressed both the cell-mediated and antibody responses to influenza virus in female but not males. In contrast, TCDD exposure enhanced the innate immune responses in offspring of both sexes; specifically, neutrophilia and interferon (IFN) gamma levels in the lung were increased. These alterations in functional immunity did not result from overt toxicity to the immune organs, as developmental TCDD exposure did not alter the cellular composition of the thymus, spleen, or bone marrow. These findings extend our knowledge of the dose-responsive nature of immunological defects induced by developmental exposure to TCDD and offer insight regarding the dose required to alter the immune response to viral infection. Moreover, we demonstrate a clear dose at which no observable effects on immune function later in life were detected.

Environmental impact and human health risks of polychlorinated dibenzo-p-dioxins and dibenzofurans in the vicinity of a new hazardous waste incinerator: a case study

The purpose of this study was to assess the environmental impact of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the vicinity of a new hazardous waste incinerator (HWI) 4 years after regular operation of the facility. A double approach was carried out. The PCDD/F congener profiles corresponding to environmental samples, soil and herbage, collected before the HWI (baseline) and 4 years after starting regular operations, as well as PCDD/F profiles of air emission samples, were compared. The potential health risks (carcinogenic and noncarcinogenic) due to PCDD/F exposure were assessed for adults and children living in the neighborhood of the facility. Human exposure to PCDD/Fs was mainly due to dietary food intake. Comparisons between the PCDD/F congener profiles corresponding to the baseline and current surveys, as well as data concerning the human health risk assessment, indicate that the HWI in question does not cause additional risks to the environment orto the population living in the vicinity of the facility.

Health risks of dietary intake of environmental pollutants by elite sportsmen and sportswomen

The dietary intake of arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb), hexachlorobenzene (HCB), polychlorinated naphthalenes (PCNs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated diphenyl ethers (PCDEs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) by elite sportsmen and sportswomen of Catalonia, Spain, was assessed. In 2000, food samples were randomly acquired in various cities of Catalonia. Analysis of the above pollutants were determined according to the appropriate analytical techniques (ICP-MS, HRGC/HRMS, HPLC). In general terms, elite sportsmen and sportswomen showed a higher intake of Cd, Hg, Pb, HCB, PCNs, PCDD/Fs and PAHs than the general population, while it was lower for PCDEs (both sexes), and PCBs and PBDEs (women). According to the FAO/WHO provisional tolerable weekly intake (PTWI) for metals, the WHO tolerable daily intake (TDI) for HCB, and the US EPA's reference dose (RfD) for PAHs, the dietary intakes of environmental pollutants should not mean a potential toxic hazard. However, the WHO-TDI for PCDD/Fs and "dioxin-like" PCBs is exceeded in sportsmen. The current results indicate that the consumption of those food groups showing the highest contribution to the intake of these pollutants should be diminished. In relation to this, the reduction of the consumption of dairy products and cereals would be important.

Predicting toxicity equivalents in fish tissue

Toxicity equivalents is a measure of "dioxin-like" toxicity contributed by polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (dioxins), and polychlorinated dibenzofurans (furans). Calculation of toxicity equivalents require the use of analytical procedures that are expensive and slow, making them impractical for routine analysis. U.S. Environmental Protection Agency National Fish Tissue Study (2003) data were used to determine the most significant predictors of toxicity equivalents with multiple regression analysis. The strongest predictive model (P < 0.0001, R2 = 0.97) included five compounds (PCB-118; PCB-126; 2,3,7,8-TCDD; 1,2,3,6,7,8-HxCDD; 2,3,4,7,8-PeCDF). However, the required lower limit of detection for an analytical method measuring these congeners is 0.1 ppt and would not provide much benefit over the current analytical method. An alternative model (P < 0.0001, R2 = 0.68) that included three PCBs (PCB-138, PCB-153, PCB-118) would require a limit of detection of 1,000 ppt and be more practical. This research demonstrates that the measurement of selected compounds can be used to estimate toxicity equivalents and consequently serve as the impetus for the development of lower cost, rapid analytical methods for analysis of fish.

Maternal-fetal distribution and transfer of dioxins in pregnant women in Japan, and attempts to reduce maternal transfer with Chlorella (Chlorella pyrenoidosa) supplements

Dioxins can be transferred from mother to fetus via the placenta, or to nursing infants via breast milk, potentially causing developmental health problems in children. To assess pediatric health risks from dioxins, exposure of mothers and children to dioxins must be clarified. Methods of reducing maternal transfer of dioxins should also be investigated. Concentrations of 28 dioxin (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and co-planar polychlorinated biphenyls) congeners in blood, adipose tissue, breast milk, cord blood and placenta collected from 44 pregnant Japanese women were measured. In addition, to investigate potential reductions in maternal transfer of dioxins, 23 pregnant women were instructed to take Chlorella pyrenoidosa supplements during pregnancy. Correlations were observed between dioxin total toxic equivalents (total TEQ) in blood and total TEQ in adipose tissue (r=0.913, P<0.0001), breast milk (r=0.695, P=0.0007), and cord blood (r=0.759, P<0.0001). Dioxin levels transferred to fetuses and nursing infants reflect cumulative maternal concentrations of dioxins. A linear regression equation was introduced to predict total TEQ in breast milk and cord blood from dioxin levels in maternal blood, which should prove useful in evaluating fetal and infant risk of dioxin exposure. Total TEQ in cord blood were approximately 26% lower than in maternal blood (P<0.0001). The results of this study suggest that transplacental transfer differs depending on the dioxin congener. Total TEQ in breast milk were approximately 30% lower in the Chlorella group than in controls (P=0.0113). This finding suggests that maternal transfer of dioxins can be reduced using dietary measures such as Chlorella supplements.

A Weight-of-Evidence Analysis of the Cancer Dose-Response Characteristics of 2,3,7,8-Tetrachlorodibenzodioxin (TCDD)

Cancer risk assessment for TCDD and other compounds must focus on the cancer dose-response relationship and corresponding potency for the range of human doses before it can have relevance to the human exposure environment. Major differences of opinion exist over whether the dose-response curve for TCDD and other dioxin congeners is non-linear (incorporating a threshold dose region below which tumors are unlikely to be elicited) or linear (implying that any exposure has a statistical likelihood of causing cancer). The World Health Organization and others strongly support a non-linear dose-response relationship for TCDD and cancer, whereas USEPA characterizes the dose-response function as linear. This review critically summarizes the available information on TCDD dose-response relationship for cancer utilizing a weight-of-evidence approach. This assessment concludes that the available data support a non-linear dose-response relationship as being most likely and appropriate for human cancer risk assessment, i.e., the evidence suggests that a biological threshold exists in the dose-response. While proof of a threshold is not absolute, and never can be, the level of certainty for TCDD is substantial because of the concordance of many lines of evidence and the consistency of repeated observations pointing to non-linearity.

Oral tolerance

Multiple mechanisms of tolerance are induced by oral antigen. Low doses favor active suppression, whereas higher doses favor clonal anergy/deletion. Oral antigen induces T-helper 2 [interleukin (IL)-4/IL-10] and Th3 [transforming growth factor (TGF)-beta] T cells plus CD4+CD25+ regulatory cells and latency-associated peptide+ T cells. Induction of oral tolerance is enhanced by IL-4, IL-10, anti-IL-12, TGF-beta, cholera toxin B subunit, Flt-3 ligand, and anti-CD40 ligand. Oral (and nasal) antigen administration suppresses animal models of autoimmune diseases including experimental autoimmune encephalitis, uveitis, thyroiditis, myasthenia, arthritis, and diabetes in the non-obese diabetic (NOD) mouse, plus non-autoimmune diseases such as asthma, atherosclerosis, graft rejection, allergy, colitis, stroke, and models of Alzheimer's disease. Oral tolerance has been tested in human autoimmune diseases including multiple sclerosis (MS), arthritis, uveitis, and diabetes and in allergy, contact sensitivity to dinitrochlorobenzene (DNCB), and nickel allergy. Although positive results have been observed in phase II trials, no effect was observed in phase III trials of CII in rheumatoid arthritis or oral myelin and glatiramer acetate (GA) in MS. Large placebo effects were observed, and new trials of oral GA are underway. Oral insulin has recently been shown to delay onset of diabetes in at-risk populations, and confirmatory trials of oral insulin are being planned. Mucosal tolerance is an attractive approach for treatment of autoimmune and inflammatory diseases because of lack of toxicity, ease of administration over time, and antigen-specific mechanisms of action. The successful application of oral tolerance for the treatment of human diseases will depend on dose, developing immune markers to assess immunologic effects, route (nasal versus oral), formulation, mucosal adjuvants, combination therapy, and early therapy.

Biomarker measurements in a coastal fish-eating population environmentally exposed to organochlorines

The Lower North Shore region of the St. Lawrence River is home to a fish-eating population that displays an unusually high body burden of several organochlorines, including polychlorinated biphenyls (PCBs) and dioxin-like compounds (DLCs). We measured biomarkers indicative of liver enzyme induction and investigated the relationship with organochlorine body burden in adult volunteers from this population. We determined plasma concentrations of PCBs and chlorinated pesticides by high-resolution gas chromatography (HRGC) with electron capture detection. DLC concentrations were measured by the dioxin-receptor chemically activated luciferase expression (DR-CALUX) assay and in a subset of participants, by HRGC/high-resolution mass spectrometry. We measured cotinine, d-glucaric acid, and porphyrins in morning urine samples and determined liver CYP1A2 activity in vivo using the caffeine breath test. Neither DLC concentrations as measured by the DR-CALUX nor PCB-153 concentrations, the latter representing total PCB exposure, were correlated with biomarkers of effects. Smoking (morning urinary cotinine concentration) was positively related to CYP1A2 activity as measured by the caffeine breath test (p < 0.01). Liver CYP1A2 activity was in turn negatively correlated with PCB-105:PCB-153 and PCB-118:PCB-153 congener ratios (p < 0.05). Hence, despite the relatively high body burden of PCBs and DLCs in this population, only smoking had a significant correlation with biomarkers of hepatic enzyme induction. Our data are consistent with smoking-induced liver CYP1A2 activity altering heme metabolism and increasing the biotransformation of mono-ortho PCB congeners.

Persistent organochlorine compounds in human breast milk from mothers living in Penang and Kedah, Malaysia

This study determined the concentrations of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides, and tris(4-chlorophenyl) methane (TCPMe) in human breast milk samples collected in 2003 from primipara mothers living in Penang, Malaysia. OCs were detected in all the samples analyzed with DDTs, hexachlorocyclohexane isomers (HCHs), and PCBs as the major contaminants followed by chlordane compounds (CHLs), hexachlorobenzene (HCB), and TCPMe. The residue levels of DDTs, HCHs, and CHLs were comparable to or higher than those in general populations of other countries, whereas PCBs and HCB were relatively low. In addition, dioxins and related compounds were also detected with a range of dioxin equivalent concentrations from 3.4 to 24 pg-TEQs/g lipid wt. Levels of toxic equivalents (TEQs) were slightly higher than those in other developing countries but still much lower than those of industrialized nations. One donor mother contained a high TEQs level, equal to the mean value in human breast milk from Japan, implying that some of the residents in Malaysia may be exposed to specific pollution sources of dioxins and related compounds. No association was observed between OCs concentrations and maternal characteristics, which might be related to a limited number of samples, narrow range of age of the donor mothers, and/or other external factors. The recently identified endocrine disrupter, TCPMe, was also detected in all human breast milk samples of this study. A significant positive correlation was observed between TCPMe and DDTs, suggesting that technical DDT might be a source of TCPMe in Malaysia. The present study provides a useful baseline for future studies on the accumulations of OCs in the general population of Malaysia.

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.

Effects of a single dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin, given at post-puberty, in senescent mice

2,3,7,8-Tetrachlorodibenzo-p-dioxin is a well-known immunosuppressive environmental pollutant. TCDD interferes with physiological signaling of the arylhydrocarbon receptor, leading to cell-specific changes in gene transcription and cell differentiation. With respect to the immune system, the T-cell lineage and B-cell lineages are particularly affected. Although a single dose given to mice is excreted within weeks, these changes in differentiation may have long-term consequences for immune competence. We studied the effects of a single dose of TCDD given to young mice on some parameters of their immune system after they had aged almost to the end of their lifespan. Groups of 15 mice were given either 2.5 microg TCDD/kg b.w. or 25 microg TCDD/kg b.w. at the age of 8-12 weeks, and were analyzed between 16 and 21 months of age. Survival was equal in all groups. Blood glucose levels did not differ, and glucose tolerance after oral challenge was normal in old control mice and TCDD-exposed mice. No differences in the frequencies of B-cells, T-cells, or NK-cells were detectable. TCDD-exposed mice at both doses had a significantly higher titer of IgM compared to controls. Histological examination of pancreas, liver, kidney, spleen, and lungs yielded no differences, except for the lungs, where a significantly higher number of animals displayed activated BALT. In conclusion, our data suggest that a single dose of TCDD in young mice is correlated to activated secondary lymphoid tissues and high IgM titers. Both findings are congruent with a weakened immune system.

Biomonitoring of persistent organochlorine pesticides, PCDD/PCDFs and dioxin-like PCBs in blood of children from South West Germany (Baden-Wuerttemberg) from 1993 to 2003

In the context of a monitoring program, persistent organic pollutants (POPs) were quantified in the blood of 10 year old children at four different demographic regions in Baden-Wuerttemberg, a highly industrialised federal state in South West Germany. DDE, HCB, PCB 138, PCB 153 and PCB 180 were measured in 1996/1997, 1998/1999, 2000/2001 and 2002/2003 in individual samples of about 400 children per year. PCDD/PCDFs and some relevant coplanar PCBs were determined in pooled samples from children in seven cycles from 1993 to 2003. Blood concentrations of the investigated compounds decreased in that time period by a factor of 2-4 with the exception of most PCDFs. The concentrations of POPs in the blood of the children were distinctly lower than the concentrations reported for adults. Breast feeding was associated with about 30% higher median concentrations of DDE, HCB, PCBs and a 30% increase for mean PCDD/PCDF concentrations. Concerning demographic differences, significant lower concentrations of HCB, PCBs and PCDD/PCDFs could be seen in children from Mannheim compared to the region of Aulendorf. About 10-20% higher concentrations were found in boys compared to girls for HCB, indicator PCBs and PCDD/PCDFs. The pattern of non-ortho and mono-ortho PCBs in the blood of children was similar to the pattern reported for mother's milk, and PCB 126 and PCB 156 contributed about 70% to the toxicity of dioxin-like PCBs and about one-third to total TEQ including PCDD/PCDFs.

Recent advances in mass spectrometric measurement of dioxins

Past years, many efforts have been dedicated to the development of alternative analytical methods for the measurement of dioxins in various types of matrices. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are compounds that are present in samples at part-per-billion (ppb) or part-per-trillion (ppt) level. Their measurement requires the use of very sensitive analytical methods. Gas chromatography (GC) coupled to quadrupole ion storage mass spectrometry (QISTMS), fast GC (FGC) coupled to time-of-flight mass spectrometry (TOFMS) and comprehensive two-dimensional gas chromatography (GC x GC) coupled to TOFMS are the more promising tools challenging the reference GC high resolution mass spectrometry (HRMS) based on sector instruments. We report herein some of the advances we achieved in the past years in our laboratory on the development of alternative measurement methods for those compounds.

Enantiomeric separation of chiral polychlorinated biphenyls on β-cyclodextrin capillary columns by means of heart-cut multidimensional gas chromatography and comprehensive two-dimensional gas chromatography. Application to food samples

Three commercially available chiral capillary columns, Chirasil-Dex, BGB-176SE, and BGB-172, have been evaluated for the separation into enantiomers of the 19 chiral polychlorinated biphenyls (PCB) congeners stable at room temperature. The enantiomers of 15 chiral PCBs were, at least to some extent, separated using these beta-cyclodextrin based columns. Multidimensional techniques, such as heart-cut multi-dimensional gas chromatography (heart-cut MDGC) and comprehensive two-dimensional gas chromatography (GC x GC), were investigated for their ability to solve coelution problems with other PCBs present in commercial mixtures and real-life samples. Heart-cut MDGC improved the separation as compared to one-dimensional GC, and enantiomeric fractions of the investigated chiral PCBs could be determined free from interferences. However, limitations on the number of target compounds that can be transferred to the second column in a single run and, therefore, the time consumption, have led to the evaluation of GC x GC as an alternative for this type of analysis. With GC x GC, two column set-ups were tested, both having a chiral column as first-dimension column, and two different polar stationary phase columns in the second dimension. On using both column combinations, congeners 84, 91, 95, 132, 135, 136, 149, 174, and 176 could be determined free from coelutions with other PCBs. Results on the application of heart-cut MDGC to food samples such as milk and cheese are given, as well as the first results on the application of GC x GC to this type of samples.

Transforming growth factor-beta3 restores fusion in palatal shelves exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

The pollutant, 2,3,7,8-tetrachlorodibenzo-p-dioxin ("dioxin"), has been implicated in the etiology of a wide variety of human birth defects. In an effort to identify pharmacological blockers of dioxin-induced terata, we performed a histological and microscopic analysis of the developing murine palate that had been exposed to dioxin. In both in vivo and in vitro model systems, we observed that dioxin exposure leads to a reduction in the number of filopodial extensions at the medial epithelial edge of the developing palate. Given that this filopodial aberration is similar to the phenotype observed in Tgfbeta3 null mice, a mutant known to display a 100% incidence of cleft palate, we examined the interaction between TGFbeta3 and dioxin in palatal fusion. We found that that the addition of TGFbeta3 to an in vitro palate culture model prevented the dioxin-induced reduction in filopodial density. Moreover, TGFbeta3 exposure completely prevented the dioxin-induced block of palatal fusion in this system. Although these data do not point to a direct cellular or molecular mechanism for TGFbeta3 dioxin antagonism, these results do suggest that TGFbeta3 or stimulators of this signaling pathway hold potential as antidotes for dioxin-induced terata and that this opposing pharmacology may extend to additional toxicological endpoints.

Daily intake of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDFs) in foodstuffs consumed in Tarragona, Spain: a review of recent studies (2001-2003) on human PCDD/PCDF exposure through the diet

Concentrations of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) were measured in foodstuffs randomly acquired in various locations of Tarragona County (Catalonia, Spain) in September 2002. A total of 36 composite samples, belonging to various food groups (vegetables, fruits, meat and meat products, fish and seafood, cereals, pulses, milk, dairy products, eggs, and oils and fats) were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry. The dietary intake of PCDD/Fs was subsequently determined. For calculations, recent data on consumption of the selected food items were used. Total dietary intake of PCDD/Fs for the general population of Tarragona County was estimated to be 59.6 pg I-TEQ/day (63.8 pg WHO-TEQ/day). Fish and seafood (33.7%), oils and fats (15.3%), cereals (14.4%), and dairy products (13.7%) were the most important contributors to this intake. This PCDD/F intake is notably lower than the intake estimated in 1998 for the same geographical area, 210.1 pg I-TEQ/day. The current PCDD/F dietary intake is below the tolerable intake range of 1-4 pg TEQ/kg body weight/day established by the WHO in 1998. Finally, the current intake is compared with the dietary intakes of PCDD/Fs recently (2001-2003) reported for a number of regions and countries.