Dietary exposure to dioxin-like compounds in three age groups: results from the Flemish environment and health study

PCDD/Fs and PCBs in Baltic fish - Recent data, risk for consumers

This study determines the levels of PCDD/Fs and PCBs in Baltic fish caught in ICES areas 24, 25, and 26, and the related risk for fish consumers in relation to the newly established Tolerable Weekly Intake dose (TWI) (2 pg WHO-TEQ kg -^-1 body weight). The total PCDD/F/DL-PCBs toxic equivalents in the fish muscle ranged from 0.12 to 10.34 pg WHO-TEQ g - ^-1 wet weight. Salmon muscles contained the highest average concentration and cod the lowest, below 0.5 pg WHO-TEQ g - ^-1 wet weight of total TEQ. The average intake of PCDD/F/DL-PCBs (portion of fish 200 g) was 91-2420% of the TWI for children, and 30-799% of the TWI for adults. It appears that despite the decreased levels of PCDD/F and PCBs in Baltic fish, in relation to the newly established TWI dose, this decrease is not enough to make the Baltic fish safe for frequent consumers.

Farmed Fish as a Source of Dioxins and PCBs for Polish Consumers

Introduction

This paper reports polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF), and polychlorinated biphenyl (PCB) concentrations in fish collected from Polish and Vietnamese farms and the related risk for consumers.

Material and Methods

Altogether, 160 samples were analysed using an isotope dilution technique with high-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS). To characterise the potential health risk associated with PCDD/F and dioxin-like polychlorinated biphenyl (DL-PCB) intake, doses ingested in two 100 g portions of fish by adults and children were calculated and expressed as the percentage of the tolerable weekly intake (TWI) newly established by the EFSA in November 2018 at 2 pg WHO-TEQ kg^-1 b.w.

Results

Generally, levels in fish muscles were low in relation to maximum limits (4), being in the range of 0.02-3.98 pg WHO-TEQ g^-1 wet weight (w.w.) for PCDD/F/DL-PCBs and 0.05-24.94 ng g^-1 w.w. for NDL-PCBs. The highest concentration was found in eel muscles. The least polluted were pangas and zanders and the levels were at the limits of quantification. Consumption of two portions of fish per week results in intakes of 9- 866% TWI by children and 4-286% TWI by adults.

Conclusion

Frequent consumption of some species (for example eel and bream) can pose a health risk to vulnerable consumers and especially children and pregnant women.

Serum dioxin levels and sperm DNA methylation age: Findings in Vietnam war veterans exposed to Agent Orange

Exposure to dioxin, a known endocrine disruptor and carcinogen, is associated with poor reproductive outcomes. Yet, few studies have explored the role of DNA methylation in these relationships. Utilizing a publicly available dataset from 37 male Air Force Health Study participants exposed to dioxin-contaminated Agent Orange during the Vietnam war, we cross-sectionally examined the relationship of serum dioxin levels with a novel DNA methylation-based measure of sperm age (DNAm-agesperm). DNAm-agesperm was calculated using CpG sites on the Illumina HumanMethylation450 BeadChip. We estimated associations of dioxin levels with DNAm-agesperm using linear regression models adjusted for chronological age, body mass index, and smoking status. Chronological age was highly correlated with DNAmagesperm (r = 0.80). In fully-adjusted linear models, a one percent increase in serum dioxin levels was significantly associated with a 0.0126-year (i.e. 4.6-day) increase in DNAm-agesperm (95%CI: 0.003, 0.022, p = 0.01). Further analyses demonstrated significant negative associations of dioxin levels (β = -0.0005, 95%CI: -0.0010, 0.00004, P = 0.03) and DNAm-agesperm (β = -0.02, 95%CI: -0.04, -0.001, P = 0.03) with methylation levels of FOXK2 - a gene previously reported to be hypomethylated in infertile men. In sum, we demonstrate associations of dioxin with increased methylation aging of sperm. DNAm-agesperm may provide utility for understanding how dioxin levels impact sperm health and potentially male reproductive capacity in human population studies. Moreover, our pilot study contributes further evidence that some environmental toxicants are associated with methylation aging. Additional studies are necessary to confirm these findings, and better characterize dioxin and sperm methylation relationships with male reproductive health.

Mapping polychlorinated dibenzo-p-dioxins/dibenzofurans in soils around Pugu municipal dump site in Dar es Salaam, Tanzania: Implications on dermal and soil ingestion exposure for people in the peripheral

Experimental data on the contribution of a dump site in Tanzania as a point source of the 17 possible congeners of PCDD/Fs to the environment is presented. Dry and wet season samples were collected around Pugu municipal dump site followed by GCxGC-TOFMS analysis. The dominant congeners were OctaCDD, 1,2,3,4,6,7,8-HepCDF; 1,2,3,4,6,7,8-HeptaCDD and 1,2,4,7-PeCDD. The concentrations of the congeners expressed as TEQ WHO₂₀₀₅ ranged from 11.69 to 48.97 pg/g with a mean of 29.44 pg/g for the dry season and TEQ WHO₂₀₀₅ 4.13-85.82 pg/g with a mean of 41.51 pg/g for the wet season. These levels were speculated high enough to accumulate in free-range chickens and cause harmful effects to humans that consumed them especially residents around Pugu dump site. Exposure of people to PCDD/Fs through dermal absorption and soil ingestion were estimated using the VLIER-HUMAAN Mathematical model. Exposure through dermal absorption was estimated to be 1.2 × 10^-4 and 9.8 × 10^-6 ng TEQ/kg day for children and adults respectively while through soil ingestion via consumption of contaminated foods and other sources was 0.0045 and 0.27 ng TEQ/kg day for children and adults respectively. These values however were well below the WHO tolerable daily intake. Generally, there was no significant variation for total PCDD/Fs in the dry and wet season (α = 0.08). Strong positive correlation (r = 0.94) between total PCDD/Fs and organic matter content was observed during the wet season.

Genome-Wide Transcriptional Analysis Reveals Novel AhR Targets That Regulate Dendritic Cell Function during Influenza A Virus Infection

Activation of the ligand inducible aryl hydrocarbon receptor (AhR) during primary influenza A virus infection diminishes host responses by negatively regulating the ability of dendritic cells (DC) to prime naive CD8⁺ T cells, which reduces the generation of CTL. However, AhR-regulated genes and signaling pathways in DCs are not fully known. In this study, we used unbiased gene expression profiling to identify differentially expressed genes and signaling pathways in DCs that are modulated by AhR activation in vivo. Using the prototype AhR agonist TCDD, we identified the lectin receptor Cd209a (DC-SIGN) and chemokine Ccl17 as novel AhR target genes. We further show the percentage of DCs expressing CD209a on their surface was significantly decreased by AhR activation during infection. Whereas influenza A virus infection increased CCL17 protein levels in the lung and lung-draining lymph nodes, this was significantly reduced following AhR activation. Targeted excision of AhR in the hematopoietic compartment confirmed AhR is required for downregulation of CCL17 and CD209a. Loss of AhR's functional DNA-binding domain demonstrates that AhR activation alone is necessary but not sufficient to drive downregulation. AhR activation induced similar changes in gene expression in human monocyte-derived DCs. Analysis of the murine and human upstream regulatory regions of Cd209a and Ccl17 revealed a suite of potential transcription factor partners for AhR, which may coregulate these genes in vivo. This study highlights the breadth of AhR-regulated pathways within DCs, and that AhR likely interacts with other transcription factors to modulate DC functions during infection.

Monitoring polychlorinated dibenzo-p-dioxins/dibenzofurans and dioxin-like polychlorinated biphenyls in Africa since the implementation of the Stockholm Convention-an overview

Polychlorinated dibenzo-p-dioxin (PCDDs), polychlorinated dibenzofurans (PCDF), and dioxin-like polychlorinated biphenyl (dl-PCB) are groups of toxic compounds released into the environment as unintentional by-products of combustion. They persist, bioaccumulate through the food chain, and cause adverse health effects. This review attempts to collate available information on the release of PCDD/Fs and dl-PCBs and other critical data relevant to their monitoring in Africa during the existence of the Stockholm Convention (SC). Much as the implementation of the SC may be lagging, literature showed that there has been encouraging efforts that have been made with respect to PCDDs/Fs and dl-PCBs monitoring in Africa. Results from a global monitoring study showed that PCDD/Fs released to air in Africa stood at 18-532 fg WHO₉₈ TEQ/M³ while dl-PCBs were 7-278 fg WHO₉₈ TEQ/m³. In human milk, the total concentration of PCDD/Fs, i.e., WHO 2005 TEQ LB has been reported to range from 0.5 ng/g fat to 12 ng/g fat. Fourteen laboratories in Africa participated in inter-laboratory assessments of persistent organic pollutants (POPs) with two specifically for PCDD/Fs analysis. This shows that some efforts are being made to boost capacity in Africa. Levels of PCDDs/Fs and dl-PCBs in clay consumed by pregnant women have been reported in Cameroon, Democratic Republic of Congo (DRC), Nigeria, Zimbabwe, Ĉote d'Ivoire, and Uganda with a maximum concentration of 103 pg TEQ/g. This finding was very significant since women are the most impacted through exposure to POPs, a fact that is acknowledged by the SC.

Fish and seafood consumption during pregnancy and the risk of asthma and allergic rhinitis in childhood: a pooled analysis of 18 European and US birth cohorts

Background

It has been suggested that prenatal exposure to n-3 long-chain fatty acids protects against asthma and other allergy-related diseases later in childhood. The extent to which fish intake in pregnancy protects against child asthma and rhinitis symptoms remains unclear. We aimed to assess whether fish and seafood consumption in pregnancy is associated with childhood wheeze, asthma and allergic rhinitis.

Methods

We pooled individual data from 60 774 mother-child pairs participating in 18 European and US birth cohort studies. Information on wheeze, asthma and allergic rhinitis prevalence was collected using validated questionnaires. The time periods of interest were: infancy (0-2 years), preschool age (3-4 years), and school age (5-8 years). We used multivariable generalized models to assess associations of fish and seafood (other than fish) consumption during pregnancy with child respiratory outcomes in cohort-specific analyses, with subsequent random-effects meta-analyses.

Results

The median fish consumption during pregnancy ranged from 0.44 times/week in The Netherlands to 4.46 times/week in Spain. Maternal fish intake during pregnancy was not associated with offspring wheeze symptoms in any age group nor with the risk of child asthma [adjusted meta-analysis relative risk (RR) per 1-time/week = 1.01, 95% confidence interval 0.97-1.05)] and allergic rhinitis at school age (RR = 1.01, 0.99-1.03). These results were consistently found in further analyses by type of fish and seafood consumption and in sensitivity analyses.

Conclusion

We found no evidence supporting a protective association of fish and seafood consumption during pregnancy with offspring symptoms of wheeze, asthma and allergic rhinitis from infancy to mid childhood.

Accumulation of persistent organic pollutants in consumers of eel from polluted rivers compared to marketable eel

Globally, many river sediments are seriously contaminated with persistent organic pollutants (POPs) known to accumulate in aquatic food. In the Netherlands, toxicological risks of human exposure to dioxins and dioxin-like compounds led to a ban on eel fishing in the Rhine-Meuse delta. The aim of this study is to investigate differences in serum POP levels in consumers of eel from high-polluted areas and consumers of eel from low-polluted areas or aquaculture. In total 80 Dutch men were included, aged 40-70 years, with a habitual eel consumption of at least one portion (150 g) per month. Total levels of dioxins and dioxin-like compounds were measured in serum of all participants with the DR CALUX bioassay, validated with GC-MS. For a subgroup of 38 participants extensive POP measurements were performed. We revealed that consumption of eel from polluted rivers resulted in 2.5 and up to 10 times increased levels of dioxins and polychlorinated biphenyls (PCBs) respectively compared to controls. The highest PCB levels were detected for PCB 153, with a median level of 896 ng/g lipid and a maximum level of 5000 ng/g lipid in the high-exposed group. Furthermore, hydroxylated PCB metabolites (OH-PCBs: sum of 4-OH-CB107, 4-OH-CB146, 4'-OH-CB172, and 4-OH-CB187) were 8 times higher in men who consumed eel from polluted areas, and detected at levels (median 4.5 ng/g ww) reported to cause adverse health effects. Also, the majority of the perfluoroalkyl substances (PFASs) were significantly higher in consumers of eel from pullulated areas. In conclusion, this study is the first to reveal that (past) consumption of eel from polluted rivers resulted in high body burdens of dioxins, PCBs, OH-PCBs and PFASs. We confirmed the predictions made in a former risk assessment, and the high levels of dioxins and dioxin-like compounds as well as the OH-PCBs are of health concern.

Endocrine-disrupting polychlorinated biphenyls in metabolically healthy and unhealthy obese subjects before and after weight loss: difference at the start but not at the finish

BACKGROUND

A subset of obese individuals does not exhibit metabolically unfavorable features; this group is referred to as metabolically healthy obese (MHO). Serum concentrations of polychlorinated biphenyls (PCBs), which are chemicals with endocrine-disrupting properties, have been shown to be lower in MHO than in metabolically unhealthy obese (MUO).

OBJECTIVE

We studied PCB serum concentrations during and after weight loss and their relation with metabolic health.

DESIGN

We determined metabolic health features (weight, blood pressure, lipids, inflammation, and glucose metabolism) and serum PCB concentrations of 27 PCBs in a cohort of 184 overweight and obese subjects. Metabolic health was evaluated with the use of the criteria of the metabolic syndrome (MetS) [metabolic syndrome according to Adult Treatment Panel III criteria present (MetS+) or metabolic syndrome according to Adult Treatment Panel III criteria absent (MetS−)] or with extended criteria with inflammation and insulin resistance taken into account (MUO compared with MHO). Participants were treated with lifestyle counseling or bariatric surgery. A metabolic and toxicological re-evaluation was performed after 6 and 12 mo.

RESULTS

At baseline, serum ΣPCB concentrations were significantly higher in MUO than in MHO (ΣPCBs: 138 ±105 compared with 365 ± 481 ng/g lipid weight; P = 0.01) but not in MetS+ compared with MetS− subjects. No difference was detected in the percentage increase in PCB serum concentrations in MetS+ compared with MetS− subjects (median: 58% compared with 43% and 31% compared with 69% at 6 and 12 mo, respectively). The comparison of persistent with resolved MetS and MUO did not reveal any difference in ΣPCB concentration increments (median: 49% compared with 58% at 12 mo for MUO; P > 0.05). In a regression model with age, smoking, and body mass index corrected for, PCB serum concentrations at baseline were not predictive of the persistence or resolution of a metabolically unfavorable state.

CONCLUSION

Our study indicates that the increment in serum concentrations of PCBs does not differ according to metabolic health and does not seem to influence the beneficial metabolic health effects of weight loss. This study was registered at clinicaltrials.gov at NCT01778868.

CALUX bioassay: a cost-effective rapid screening technique for screening dioxins like compounds

Xenobiotic detection systems-chemically activated luciferase expression (XDS-CALUX) bioassay in determining the toxic equivalency (TEQ) of PCDD/Fs from contaminated sites reported in several papers has been discussed in this study. CALUX bioassay method has been validated by an effective combined column clean-up system followed by addition of samples to monolayer cell cultures of H1L6.1c3 cell line in 96 well plates. Cultures are then examined under microscope after 24 h incubation followed by rinsing with 75 μL phosphate buffer saline and 30 μL of cell culture lysis. The response is observed in the luminometer and expressed in relative light unit (RLUs). CALUX-TEQ is estimated from a TCDD standard curve for unknown samples. Quality control in CALUX is done by selecting the range of CALUX values falling in the center of the linear standard curve. For developing nations CALUX biossay can be used as a cost effective and rapid screening technique for screening xenobiotic compounds from the hotspots like open solid waste burning sites, informal e-waste recycling workshops and industrial zones where constant monitoring for such compounds is required.

Preliminary study on brominated dioxins/furans and hydroxylated/methoxylated PBDEs in Baltic cod (Gadus morhua) liver. Comparison to the levels of analogue chlorinated co-occurring pollutants

Low pg levels of PBDD/Fs in 0.8-38.9 pg g(-1) (fat) range (mean 14.2 pg g(-1)) observed in the tested cod liver samples were significantly lower than levels of their chlorinated analogues (25.1-95.9 range, 37.7 mean pg g(-1) fat). Brominated furans dominated the congener profile. Elevated levels of OH-/MeO-BDE were however observed with mean concentrations at 2769±1319 and 5441±2918 pg g(-1) (fat) respectively. The observed congener profiles with the predominance of 6-OH-BDE 47 and the relatively high proportion between the native and hydroxylated compounds indicate on natural origin of those compounds or at least presence of various exposure sources. A large fraction of studied samples did not comply with the currently standing EU regulations concerning PCBs and chlorinated dioxins (11%), especially as regards non-dioxin like PCBs (88%).

Trace metals in blood and urine of newborn/mother pairs, adolescents and adults of the Flemish population (2007-2011)

The Flemish Centre for Environment and Health started with human biomonitoring in 2002 (FLEHS I: 2002-2006). The main goal of the second human biomonitoring cycle (FLEHS II: 2007-2011), was to determine mean values for a large number of pollutants in a representative sample of the general Flemish population. Values for Cd and Pb were updated, and a group of previously undetermined metals and metalloids (As, Mn, Cu and Tl) were included in some of the age groups. In this human biomonitoring program, three different age groups of the general Flemish population were monitored: 255 newborns and their mothers, 210 adolescents aged 14-15, and 204 adults between 20 and 40 years old. Trace elements were determined in cord blood and maternal blood of the mothers, in blood and urine of adolescents and in urine of adults. Determinants of life-style and personal factors were taken into account. The levels of trace elements in cord blood and maternal blood were for most elements at the lower end of the range found in literature. For Pb, As and Tl, a strong correlation (respectively r=0.43, 0.55 and 0.33; p<0.05) was found between levels in cord blood (respectively 8.6, 0.54 and 0.017 μg/L) and maternal blood (11.1, 0.64 and 0.028 μg/L), indicating that they are transported via the placenta from mother to fetus. The levels found in the adolescents and adults were compared with results from international biomonitoring studies, and were found to be in the same ranges. With the exception of Pb, all trace elements increased with increasing age group population. Finally, the results also showed that the levels of Cd and Pb in blood for this campaign (e.g. for Pb 8.6 and 14.8 μg/L in neonates and adolescents respectively) were lower compared to the first campaign (e.g. for Pb 14.7 and 21.7 μg/L in neonates and adolescents respectively), indicating a decrease over time. However, differences in sampling strategies might partially explain this observed trend.

Maternal diet, prenatal exposure to dioxin-like compounds and birth outcomes in a European prospective mother-child study (NewGeneris)

Maternal diet can result in exposure to environmental contaminants including dioxins which may influence foetal growth. We investigated the association between maternal diet and birth outcomes by defining a dioxin-rich diet. We used validated food frequency questionnaires to assess the diet of pregnant women from Greece, Spain, United Kingdom, Denmark and Norway and estimated plasma dioxin-like activity by the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX®) bioassay in 604 maternal blood samples collected at delivery. We applied reduced rank regression to identify a dioxin-rich dietary pattern based on dioxin-like activity (DR-CALUX®) levels in maternal plasma, and calculated a dioxin-diet score as an estimate of adherence to this dietary pattern. In the five country population, dioxin-diet score was characterised by high consumption of red and white meat, lean and fatty fish, low-fat dairy and low consumption of salty snacks and high-fat cheese, during pregnancy. The upper tertile of the dioxin-diet score was associated with a change in birth weight of -121g (95% confidence intervals: -232, -10g) compared to the lower tertile after adjustment for confounders. A small non-significant reduction in gestational age was also observed (-1.4days, 95% CI: -3.8, 1.0days). Our results suggest that maternal diet might contribute to the exposure of the foetus to dioxins and dioxin-like compounds and may be related to reduced birth weight. More studies are needed to develop updated dietary guidelines for women of reproductive age, aiming to the reduction of dietary exposure to persistent organic pollutants as dioxins and dioxin-like compounds.

Dioxin and dl-PCB exposure from food: the German LExUKon project

Polychlorinated dibenzo-p-dioxin and -furan (PCDD/F) and dioxin-like polychlorinated biphenyl (dl-PCB) exposure from food were estimated using new food consumption data from the recent German food consumption survey (Nationale Verzehrsstudie II - NVS II). Based on these comprehensive data, information on the consumption of 545 individual food items by the German population was derived. Concentrations of dioxin-like compounds in food were compiled from the German Food Monitoring Programme (GFMP), the German Dioxin Database, other German authority programmes, European countries' authority programmes and the published literature covering the years 2000-2010. By multiplication with consumption data, estimates of intake from food were determined. The main food groups contributing most to the intake of the general public are dairy products (including milk), meat and fish (including seafood), followed - due to high consumption - by the main group vegetables. The combined intake of PCDD/F and dl-PCB (as toxic equivalents - TEQ) from food was estimated to be 2.11/1.53 pg kg(-1) bw and day and 3.56/2.85 pg kg(-1) bw and day (upper/lower bound) for average and high-end consumers, respectively. The estimated intake of average consumers is close to a reference value derived by the Scientific Committee on Food in 2001. Uncertainties in these estimates pertain to the influence of values below the limit of quantification (upper/lower bound ratio) and some foods not considered due to the lack of contamination data.

Screening for PCDD/Fs and dl-PCBs in local and imported food and feed products available across the State of Kuwait and assessment of dietary intake

A total of 318 local and imported meat, milk, eggs, fish, and animal feed samples collected in Kuwait were analyzed by cell-based reporter gene assay (Dioxin-Responsive Chemical Activated LUciferase gene eXpression DR-CALUX) for PCDD/Fs and dl-PCBs. The bioanalytical equivalents (BEQs) obtained by DR-CALUX bioassay were compared with the official maximum limits according to the European Commission (EC) regulations. Suspected and randomly chosen negative samples were analyzed by gas chromatography-high resolution mass spectrometry (GC-HRMS). The results showed that among suspected samples, one sample was confirmed to be non-compliant. The positive sample was of imported origin. The correlation coefficient of 0.98 between DR-CALUX and GC-HRMS was found. Moreover, the average daily intakes of PCDD/Fs and dl-PCBs for the Kuwaiti population were estimated. Results obtained in this study were discussed and compared with other published data.

A review of environmental fate, body burdens, and human health risk assessment of PCDD/Fs at two typical electronic waste recycling sites in China

This paper reviews the levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in different environmental media, human body burdens and health risk assessment results at e-waste recycling sites in China. To provide an indication of the seriousness of the pollution levels in the e-waste recycling sites in China, the data are compared with guidelines and available existing data for other areas. The comparison clearly shows that PCDD/Fs derived from the recycling processes lead to serious pollution in different environmental compartments (such as air, soil, sediment, dust and biota) and heavy body burdens. Of all kinds of e-waste recycling operations, open burning of e-waste and acid leaching activities are identified as the major sources of PCDD/Fs. Deriving from the published data, the estimated total exposure doses via dietary intake, inhalation, soil/dust ingestion and dermal contact are calculated for adults, children and breast-fed infants living in two major e-waste processing locations in China. The values ranged from 5.59 to 105.16 pg WHO-TEQ/kg bw/day, exceeding the tolerable daily intakes recommended by the WHO (1-4 pg WHO-TEQ/kg bw/day). Dietary intake is the most important exposure route for infants, children and adults living in these sites, contributing 60-99% of the total intakes. Inhalation is the second major exposure route, accounted for 12-30% of the total exposure doses of children and adults. In order to protect the environment and human health, there is an urgent need to control and monitor the informal e-waste recycling operations. Knowledge gaps, such as comprehensive dietary exposure data, epidemiological and clinical studies, body burdens of infants and children, and kinetics about PCDD/Fs partitions among different human tissues should be addressed.

Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans via fish consumption and dioxin-like activity in fish determined by H4IIE-luc bioassay

Dietary exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) via fish consumption in two major electronic (e) waste sites: Guiyu (GY), Guangdong Province and Taizhou (TZ), Zhejiang Province, and dioxin-like activity in fish determined by H4IIE-luc bioassay. In the present study, all fish were below EU's maximum allowable concentration in muscle of fish (4 pg WHO-TEQ/g wet wt), except crucian (4.28 pg WHO-TEQ/g wet wt) and silver carps (7.49 pg WHO-TEQ/g wet wt) collected from GY rivers. Moreover, the residual concentration in bighead carp collected from GY (2.15 pg WHO-TEQ/g wet wt) was close to the EU's action level (3 pg WHO-TEQ/g wet wt) which gives "early warning" to the competent authorities and operators to take measures to eliminate contamination. In addition, results indicated that the maximum human intake of PCDD/Fs via freshwater fish consumption in GY was 4.31 pg WHO-TEQ/kg bw/day, which exceeds the higher end of the tolerable daily intake recommended by the WHO, EC-SCF and JECFA (1-4, 2 and 2.3 pg WHO-TEQ/kg bw/day respectively). Furthermore, H4IIE-luc cell bioassay provides a very sensitive and cost-efficient screening tool for assessing the overall dioxin-like toxicity in the study, and is therefore valuable for high-throughput environmental monitoring studies.

Comparison of intake and systemic relative effect potencies of dioxin-like compounds in female mice after a single oral dose

BACKGROUND

Risk assessment for mixtures of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) is performed using the toxic equivalency factor (TEF) approach. These TEF values are derived mainly from relative effect potencies (REPs) linking an administered dose to an in vivo toxic or biological effect, resulting in "intake" TEFs. At present, there is insufficient data available to conclude that intake TEFs are also applicable for systemic concentrations (e.g., blood and tissues).

OBJECTIVE

We compared intake and systemic REPs of 1,2,3,7,8-pentachlorodibenzodioxin (PeCDD), 2,3,4,7,8-pentachlorodibenzofuran (4-PeCDF), 3,3',4,4',5-pentachlorobiphenyl (PCB-126), 2,3',4,4',5-pentachlorobiphenyl (PCB-118), and 2,3,3',4,4',5-hexachlorobiphenyl (PCB-156) in female C57BL/6 mice 3 days after a single oral dose.

METHODS

We calculated intake REPs and systemic REPs based on administered dose and liver, adipose, or plasma concentrations relative to TCDD. Hepatic cytochrome P450 1A1-associated ethoxyresorufin-O-deethylase (EROD) activity and gene expression of Cyp1a1, 1a2 and 1b1 in the liver and peripheral blood lymphocytes (PBLs) were used as biological end points.

RESULTS

We observed up to one order of magnitude difference between intake REPs and systemic REPs. Two different patterns were discerned. Compared with intake REPs, systemic REPs based on plasma or adipose levels were higher for PeCDD, 4-PeCDF, and PCB-126 but lower for the mono-ortho PCBs 118 and 156.

CONCLUSIONS

Based on these mouse data, the comparison between intake REPs and systemic REPs reveals significant congener-specific differences that warrants the development of systemic TEFs to calculate toxic equivalents (TEQs) in blood and body tissues.

Dietary intake of PCDD/Fs and dioxin-like PCBs from the Chinese total diet study in 2007

Concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in 96 food composite samples from eight varieties of food groups from the Chinese total diet study (TDS) in 2007. The concentrations of samples, expressed as WHO toxic equivalents (TEQ), ranged from 0.001 pg TEQ g(-1) to 0.85 pg TEQ g(-1) (fresh weight). Dietary intake of PCDD/Fs and dl-PCBs of 12 age/gender subgroups of the Chinese population subsequently estimated ranges from 15.4 pg TEQ kg(-1) bw month(-1) to 38.7 pg TEQ kg(-1) bw month(-1) for average population and from 68.5 pg TEQ kg(-1) bw month(-1) to 226.1 pg TEQ kg(-1) bw month(-1) for high consumers (the 97.5th percentile). Dietary exposure of children (mean: 32.5 pg TEQ kg(-1) bw month(-1)) is significantly higher than that of the adults (mean: 21.5 pg TEQ kg(-1) bw month(-1)) (p<0.01) presumably due to more food consumed by children relative to their body weight compared to adults. There is no difference of dietary exposure, expressed as pg TEQ kg(-1) bw, found between different genders. Across various regions in China, there are large differences of dietary exposure of adult population and pattern of contribution of food groups to total exposure due to different contamination level and food habits. Dietary exposures of average population of various subgroups were all below the PTMI recommended by JECFA, but those of higher consumers were found exceeding or comparable to the PTMI.

Polychlorobiphenyls and organochlorine pesticides in conventional and organic brands of milk: occurrence and dietary intake in the population of the Canary Islands (Spain)

The population of the Spanish archipelago of the Canary Islands has been studied in depth regarding its levels of contamination by organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs). Foodstuffs of animal origin, such as milk, are prominent contributors to the body burden of these contaminants. As this population presents one of the highest milk-intake in Spain and Europe, we evaluated the level of OCs and PCBs in 26 commercially available brands of milk (16 conventional and 10 organic brands) present in the market of these Islands, in order to estimate the relevance of milk as a source of these chemicals for the Canary population. Our findings showed that hexachlorobenzene, trans-chlordane, and PCB153 were present in almost all the samples with independence of the type of milk. For both types of milks, the concentration of OCs was very low, showing organic milks lower levels than conventional ones. As a consequence, the estimated daily intake for OCs was lower than the tolerable daily intake (TDI) established by International Agencies. The levels of PCBs in milk were also found to be very low, but, in this case, the situation was the opposite: there were higher levels of PCBs in organic than in conventional brands of milk. Unexpectedly, levels of dioxin-like PCBs (DL-PCBs) reached values higher than 25 pg WHO-TEQ g(-1) fat in percentile 75 for both types of milk indicating the existence of a number of brands of milk highly contaminated by these toxicants. Consequently, the population who consume the most contaminated milk brands could have estimated daily intakes well above the recommended TDI (2 pg WHO-TEQ kg(-1)b.w.d(-1)) established by European Union Authorities. These results are of concern if we consider the well known adverse health effects exerted by dioxin-like compounds.

Potential impact of fertilization practices on human dietary intake of dioxins in Belgium

Dioxins can enter the food chain at any stage, including crop fertilization. Therefore, we developed a simple method for estimating the introduction of dioxins in the food chain according to various fertilization practices. Using dioxin's contamination data taken from the literature, we estimated that fertilization accounts for approximately 20% of the dioxin inputs on agricultural soils at country scale. For the estimations at the field scale, 6 fertilization scenarios were considered: sludge, compost, digestate, manure, mineral fertilizers, and a common fertilization scenario that corresponds to an average situation in Belgium and combines mineral and organic fertilizers. According to our first estimations, mineral fertilizers, common fertilization practices or manure bring less than 1 ng TEQ/m² while atmospheric deposition or digestate bring between 1 and 3 ng TEQ/m² and sludge or compost bring more than 3 ng TEQ/m². The use of solid fertilizers could potentially increase the dioxin levels in the 30 cm agricultural soil layer by 0 to ~1.5% per year (up to ~9% for the 5 cm thick surface layer). For animals, the increase in dioxin ingestion linked to the fertilization practices is lower than 1% for most scenarios with the exception of the compost scenario. Increases in human dietary intake of dioxin are estimated to be lower than 1% for conventional rearing methods (i.e. grazing animals are reared outdoor while pigs and poultry are reared indoor). Spraying liquid fertilizers on meadows and fodder crops, even if very limited in practice, deserves much more attention because this application method could theoretically lead to higher dioxin's intake by livestock (from 6 to ~300%). Considering an average half-life of dioxins in soils of 13 years, it appears that the risks of accumulation in soils and in the food chain are negligible for the various fertilization scenarios.

Blood and urine levels of long half-life toxicants by nativity among immigrants to the United States

One's place of birth is a major determinant of his or her exposure to environmental toxicants. By understanding biological burdens of long half-life toxicants by race and nativity we can better understand geographic variation in toxicant distribution. We used the National Health and Nutrition Examination Survey (1999-2006) biomonitoring data to examine differences in blood and urine levels of long half-life environmental toxicants of foreign-born relative to US-born people by race/ethnicity. We log transformed blood and urine measures of 51 environmental toxicants. We then used "seemingly unrelated regression," a robust technique for making multiple comparisons across a group of variables with correlated error terms, to examine differences in blood and urine toxicants by nativity and race. We found that, compared to native-born Americans, the foreign-born are generally more likely to be exposed to metals (p<0.001) and organochlorine pesticides (p<0.001), but less likely to be exposed to dioxin-like compounds (p<0.001) or polyflourinated compounds (p<0.001). While levels of toxicants varied greatly by region of birth, US-born participants had consistently higher levels of dioxin-like compounds and polyflourinated compounds.

Obesity and persistent organic pollutants: possible obesogenic effect of organochlorine pesticides and polychlorinated biphenyls

Persistent organic pollutants (POPs) are endocrine-disrupting chemicals associated with the development of the metabolic syndrome and type 2 diabetes. In humans, little is known about their role in the potential origin of obesity. This study aims to assess the associations between serum levels of POPs and the prevalence of obesity in a cohort of obese and lean adult men and women. POP serum samples were investigated cross-sectionally in 98 obese and 47 lean participants, aged ≥18 years. Serum samples were analyzed for the presence of polychlorinated biphenyl (PCB) congeners 153, 138, 180, and 170 and for the organochlorine pesticides, dichloro-diphenyl-dichloroethylene (pp-DDE), and β-hexachlorocyclohexane (βHCH). We established a significant negative correlation between BMI, waist, fat mass percentage, total and subcutaneous abdominal adipose tissue, and serum levels of PCB 153, 180, 170, and the sumPCBs. For βHCH, we demonstrated a positive correlation with BMI, waist, fat mass percentage, and total and subcutaneous abdominal adipose tissue. PCBs 180, 170, and the sum of PCBs correlated significantly negative with homeostasis model assessment for insulin resistance (HOMA(IR)). βHCH correlated significantly positively with HOMA(IR). A strong correlation was established between all POP serum levels and age. We established a positive relationship between high serum levels of βHCH and BMI and HOMA(IR), whereas serum PCB levels were inversely correlated with BMI and HOMA(IR). Combined, these results suggest that the diabetogenic effect of low-dose exposure to POPs might be more complicated than a simple obesogenic effect.

Estrogenic and androgenic activities in total plasma measured with reporter-gene bioassays: relevant exposure measures for endocrine disruptors in epidemiologic studies?

Measurements of estrogenic and androgenic activities in total plasma with Chemically Activated LUciferase gene eXpression (CALUX®) bioassays could provide biologically relevant measures for exposure to endocrine disruptors in epidemiologic studies. The objective of this study was to explore the effects of a variety of sources of potential endocrine disruptors on estrogenic and androgenic activities in total plasma measured by CALUX®. Plasma samples and interview data on sources of potential endocrine disruptors were collected from 108 men with different exposures profiles. CALUX® measurements (BioDetection Services) involved human U2-OS cell lines controlled by the estrogen receptor alpha and the androgen receptor. Mean differences (beta) in 17β-estradiol equivalents (EEQs) and dihydrotestosterone equivalents (AEQs) between exposure groups were estimated using general linear models. Mean plasma AEQs and EEQs were 9.1×10(-1)ng/ml and 12.0pg/ml, respectively. Elevated AEQs were found in smokers (beta 1.9 (95%CI 0.1-3.6)×10(-1)ng/ml) and heavy drinkers (1.4 (0.2-3.1)×10(-1)ng/ml), and in men occupationally exposed to disinfectants (1.6 (0.3-3.5)×10(-1)ng/ml) or welding/soldering fumes (1.4 (-0.2-2.9)×10(-1)ng/ml). Occupational exposure to pesticides, disinfectants, and exhaust fumes seemed to be associated with increased plasma EEQs: 1.5 (-0.2-3.2)pg/ml, 2.1 (0.2-3.9)pg/ml, and 2.9 (0.6-5.2)pg/ml, respectively. Moderate to high plasma dioxin levels, measured in a subgroup by the dioxin-responsive CALUX®, were accompanied by a 20% increase in AEQs. This is the first study in which CALUX® was used to assess hormone activities in total plasma. Although the results are not yet readily interpretable, they indicate that these measurements can be valuable for epidemiologic studies on endocrine disruptors and give direction for further research.

Congener profile, occurrence and estimated dietary intake of dioxins and dioxin-like PCBs in foods marketed in the Region of Valencia (Spain)

During 2006-2008, a monitoring program was conducted on 29 target compounds, including PCDD/Fs and dl-PCBs, comprising 150 randomly collected individual food samples marketed in the Region of Valencia, Spain, grouped into 8 categories (vegetables, cereals, fats and oils, eggs, milk and dairy products, fish products, meat and meat products and fish oil). For PCDD/Fs, the highest frequency of detection corresponds to 1,2,3,4,6,7,8-HpCDD, OCDD, 2,3,4,7,8-PeCDF; and PCBs 118, 105 and 156 were the more frequent dl-PCBs. The food groups presenting higher contamination, expressed as toxic equivalents (WHO-TEQs), were fish oil (6.38 pg WHO-TEQ g(-1)fat), fish (1.21 pg WHO-TEQ g(-1)w.w.) and milk and dairy products (0.90 pg WHO-TEQ g(-1)fat). Of all analysed samples, only two fish oils presented levels higher than the EU limits for total WHO-TEQ. The average PCDD/Fs and dl-PCBs intakes were estimated as 2.86 pg WHO-TEQ kg(-1)b.w.d(-1) and 4.58 pg WHO-TEQ kg(-1)b.w.d(-1), for adults and children, respectively, using the deterministic method for chronic exposure. The main contributors to total intake for adults were fish (59%), milk and dairy products (19%), and fat and oils (9%). The average daily intake for adults (2.86 pg WHO-TEQ kg(-1)b.w.d(-1)) is within range of TDI recommended by the WHO (1-4 pg WHO-TEQ kg(-1)b.w.d(-1)), and slightly above the TWI and PTMI adopted by SCF and JECFA respectively.

Internal exposure to pollutants and sex hormone levels in Flemish male adolescents in a cross-sectional study: associations and dose-response relationships

Flanders is densely populated with much industry and intensive farming. Hormonal status of 14- to 15-year-old male adolescents was studied in relation to internal exposure to pollutants. A total of 887 participants were selected as a random sample of the adolescents residing in the study areas. Confounding factors and significant covariates were taken into account. Serum levels of testosterone, free testosterone and estradiol, and the aromatase index showed significant positive associations with serum levels of marker polychlorobiphenyls (sum of PCBs 138, 153, and 180) and of hexachlorobenzene (HCB) and a negative association with urinary cadmium concentration. Serum levels of estradiol also showed a positive association with serum levels of dichlorodiphenyldichloroethylene (DDE). A doubling of serum concentrations of marker PCBs and HCB and of urinary concentration of cadmium were, respectively, associated with an increase of 16.4% (P<0.00001) and 16.6% (P<0.001) and a decrease of 9.6% (P<0.001) in serum testosterone concentration. Similar findings were made after additional adjustment for concurrent exposures. Associations between biological effects and internal exposures were, in terms of the regression coefficient, often stronger at exposures below the median. Environmental exposures to pollutants resulting in "normal" levels of internal exposure were associated with quite substantial differences in hormone concentrations.

Internal exposure to pollutants and sex hormone levels in Flemish male adolescents in a cross-sectional study: associations and dose-response relationships

Flanders is densely populated with much industry and intensive farming. Hormonal status of 14- to 15-year-old male adolescents was studied in relation to internal exposure to pollutants. A total of 887 participants were selected as a random sample of the adolescents residing in the study areas. Confounding factors and significant covariates were taken into account. Serum levels of testosterone, free testosterone and estradiol, and the aromatase index showed significant positive associations with serum levels of marker polychlorobiphenyls (sum of PCBs 138, 153, and 180) and of hexachlorobenzene (HCB) and a negative association with urinary cadmium concentration. Serum levels of estradiol also showed a positive association with serum levels of dichlorodiphenyldichloroethylene (DDE). A doubling of serum concentrations of marker PCBs and HCB and of urinary concentration of cadmium were, respectively, associated with an increase of 16.4% (P<0.00001) and 16.6% (P<0.001) and a decrease of 9.6% (P<0.001) in serum testosterone concentration. Similar findings were made after additional adjustment for concurrent exposures. Associations between biological effects and internal exposures were, in terms of the regression coefficient, often stronger at exposures below the median. Environmental exposures to pollutants resulting in "normal" levels of internal exposure were associated with quite substantial differences in hormone concentrations.

Exposure assessment of dioxins and dioxin-like PCBs in pasteurised bovine milk using probabilistic modelling

Quantitative exposure assessment is a useful technique to investigate the risk from contaminants in the food chain. The objective of this study was to develop a probabilistic exposure assessment model for dioxins (PCDD/Fs) and dioxin-like PCBs (DL-PCBs) in pasteurised bovine milk. Mean dioxins and DL-PCBs (non-ortho and mono-ortho PCBs) concentrations (pg WHO-TEQ g(-1)) in bovine milk were estimated as 0.06 ± 0.07 pg WHO-TEQ g(-1) for dioxins and 0.08 ± 0.07 pg WHO-TEQ g(-1) for DL-PCBs using Monte Carlo simulation. The simulated model estimated mean exposure for dioxins was 0.19 ± 0.29 pg WHO-TEQ kg(-1)bw d(-1) and 0.14 ± 0.22 pg WHO-TEQ kg(-1) bw d(-1) and for DL-PCBs was 0.25 ± 0.30 pg WHO-TEQ kg(-1) bw d(-1) and 0.19 ± 0.22 pg WHO-TEQ kg(-1) bw d(-1) for men and women, respectively. This study showed that the mean dioxins and DL-PCBs exposure from consumption of pasteurised bovine milk is below the provisional maximum tolerable monthly intake of 70 pg TEQ kg(-1) bw month(-1) (equivalent of 2.3 pg TEQ kg(-1) bw d(-1)) recommended by the Joint FAO/WHO Expert Committee on Food Additives and Contaminants (JECFA). Results from this study also showed that the estimated dioxins and DL-PCBs concentration in pasteurised bovine milk is comparable to those reported in previous studies.

Opening the research agenda for selection of hot spots for human biomonitoring research in Belgium: a participatory research project

BACKGROUND

In order to select priority hotspots for environment and health research in Flanders (Belgium), an open procedure was organized. Environment and health hotspots are strong polluting point sources with possible health effects for residents living in the vicinity of the hot spot. The selection procedure was part of the work of the Flemish Centre of Expertise for Environment and Health, which investigates the relation between environmental pollution and human health. The project is funded and steered by the Flemish government.

METHODS

The involvement of other actors than merely experts is inspired by the 'analytical-deliberative' approach of the National Research Council in the United States and the extended peer community approach. These approaches stress the importance of involving different expert- and social perspectives in order to increase the knowledge base on complex issues. In the procedure used in the project a combination of expert and stakeholder input was essential. The final decision was supported by a multi-criteria analysis of expert assessment and stakeholder advice.

RESULTS

The endeavour was challenging from the start because of the complicated ambition of including a diversity of actors, potential hotspots, concerns and assessment criteria, but nevertheless the procedure proved its value in both structuring and informing the decision-making process. Moreover the process gained the support of most actors participating in the process, even though the final selection could not satisfy all preferences.

CONCLUSIONS

Opening the research agenda exemplifies the value of inter- and transdisciplinary cooperation as well as the need for a well-structured and negotiated procedure that combines relevant factors and actors with pragmatism. The value of such a process also needs to prove itself in practice after the procedure has been completed: the tension between an ambition of openness on the one hand and a more closed attitude amongst experts on the other will continue to play a role even after closure.

Depletion study of PCDD/Fs and dioxin-like PCBs concentrations in contaminated home-produced eggs: preliminary study

Dioxins (PCDD/Fs) and polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants. The contamination of food products with dioxins and PCBs is a well studied issue, because food is generally considered the major source of dioxin intake for humans. In Italy, the Regional Monitoring Plan (part of the national residue monitoring plan) used in the field for 2009 has also included the control of environmental pollutants in small egg producers. Following an irregular result, 12 laying hens were transferred into a laboratory controlled environment. Eggs were collected for 60 days and they were weekly analysed for the evaluation of dioxins, dioxin-like PCBs (DL-PCBs), and non-dioxin-like PCBs (NDL-PCBs, six congeners) levels. The dioxins and PCBs contents were determined, according to EPA methods, by gas chromatography ic determination coupled with high resolution mass spectrometry (HRGC-HRMS). The content of PCDD/Fs, DL-PCBs and NDL-PCBs was evaluated weekly by mean from week to week. The concentration of dioxins was lower than DL-PCBs (2.5 pg TEQ g(-1) of fat against 4.5 pg TEQ g(-1) of fat), but we observed the same depletion trend for both pollutants. On the opposite, NDL-PCBs had a different course: we noted there was an increase between weeks 6 and 7, but the mean levels remained very low (about 20 ng g(-1) of fat). The dioxins, and sum of dioxin and DL-PCBs concentration were below the fixed European limits (i.e. 3 pg TEQ g(-1) of fat for dioxins and 6 pg TEQ g(-1) of fat for sum of dioxins and DL-PCBs), beginning from the 3rd week of trial.

Internal exposure to pollutants and body size in Flemish adolescents and adults: associations and dose-response relationships

Flanders is densely populated with much industry and intensive farming. Body size of 14- to 15-year old adolescents and of adults aged 50-65 was studied in relation to internal exposure to pollutants. 1679 adolescents (887 boys and 792 girls), 775 men and 808 women were selected as a random sample of the population. Concentrations of pollutants in blood or urine were measured in accordance with quality control/quality assurance procedures. Self-assessment questionnaires provided information on personal and life-style factors. Height and weight of subjects were measured. Confounding factors and significant covariates were taken into account. For boys and girls, height and body mass index (BMI) showed a negative association with urinary concentration of cadmium and BMI also with serum concentration of hexachlorobenzene (HCB) and with the sum of serum concentrations of polychlorinated biphenyls (PCBs) 138, 153, and 180 (marker PCBs), whereas BMI showed a positive association with serum concentration of PCB 118. For boys, height showed a negative association with urinary concentration of 1-hydroxypyrene (1-OHP) and positive associations with serum concentrations of HCB and PCB 118. For adults no significant associations between internal exposure and height were observed. For men, BMI showed negative associations with urinary cadmium concentration and with serum levels of marker PCBs and positive associations with serum levels of HCB, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), PCB 118 and the dioxin fraction of dioxin-like activity. For women, BMI showed a negative association with urinary cadmium concentration, with blood lead concentration and with the concentration of marker PCBs in serum, and a positive association with serum concentrations of HCB, p,p'-DDE and PCB 118. Associations between biological effects and internal exposures were, in terms of the regression coefficient, often stronger at exposures below the median. Environmental exposures to pollutants resulting in "normal" levels of internal exposure were associated with quite substantial differences in body mass index.

Dietary intake of PCDD/Fs and dioxin-like PCBs of the Belgian population

The World Health Organization recommends assessing human exposure to contaminants on a regular basis. In order to assess the current dietary exposure of the Belgian adult population to PCDD/Fs and dioxin-like PCBs and to update exposure estimates of 2000-2001, a total diet study was designed. The mean dietary intake of PCDD/Fs and dioxin-like PCBs in the Belgian adult population in 2008 was estimated to be 0.72pgTEQkgbw(-1)d(-1) (middle bound concentrations, TEF of 1998) based on occurrence data of 2008 and national food consumption data of 2004. This value is clearly below the Tolerable Weekly Intake (TWI) of 14pgTEQkgbw(-1)week(-1) set by the Scientific Committee on Food of the European Commission and below the provisional tolerable monthly intake of 70pgTEQkgbw(-1)month(-1) set by the Joint FAO/WHO Expert Committee on Food Additives. Considering the cumulative distribution, the intake was less than 1pgTEQkgbw(-1)d(-1) for more than 80% of the population, and less than 2pgTEQkgbw(-1)d(-1) for the entire population. When using the 2005 TEF instead of the 1998 TEF, the mean dietary intake in the Belgian adult population was estimated to be 0.61pgTEQkgbw(-1)d(-1).

Availability and comparability of human biomonitoring data across Europe: a case-study on blood-lead levels

Recently, it has become clear that the complexity of environmental health issues requires an approach that takes into account the complexities, interdependencies and uncertainties of the real world. An urgent issue that has surfaced is the need for accurate tools to better describe exposure characterization to environmental chemicals. By including human biomonitoring (HBM) data, a greater precision in exposure and associated risk estimates and more accurate dose-response relationships may be achieved. A restricting issue still is the availability of reliable and comparable HBM data. The aim of the current study was twofold: (1) to find out whether it is practically feasible to collect raw, individual HBM data across Europe; and (2) to evaluate the comparability and use of these HBM data for environmental health impact assessment at a European scale. Blood-lead (B-Pb) was selected as the chemical of choice because of its long history as an environmental pollutant in HBM programs and its known public health relevance. Through literature search and identification of HBM experts across Europe, HBM programs that measured B-Pb were identified and asked to share individual data on age, gender and B-Pb levels. Following this request, more than 20,000 individual data points from 8 European countries were collected. Analysing these data made clear that it is difficult to use disparate data collections because of the inherent variability with respect to the gender and age of participants and calendar-years sampled. When these confounders were taken however, there was no additional variability in B-Pb distributions among different countries. It was concluded that while it is possible to collect HBM data from different sources across Europe, the need to get data from comparable (sub-)populations is essential for appropriate use and interpretation of HBM data for environmental health impact assessment.

Organochlorine and heavy metals in newborns: results from the Flemish Environment and Health Survey (FLEHS 2002-2006)

To collect regional information on internal levels of pollutants in humans in Flanders, 1196 mother-child pairs were systematically recruited in 2002-2003 via 25 maternities across Flanders. Cd, Pb, PCB congeners 118, 170, 138, 153 and 180, p,p'-DDE - a key metabolite of DDT- and hexachlorobenzene (HCB) were measured in cord blood or plasma. Cd was detected in 64% of the samples (geometric mean 0.21 microg/L cord blood). p,p'-DDE (110 ng/g plasma lipids) and Pb (14.7 microg/L blood), were measurable in nearly all samples. The individual PCB congeners could be detected in 40 to 81% of the newborns (138+153+180=64.4 ng/g plasma lipids). HCB (18.9 ng/g plasma lipids) and dioxin-like compounds measured by DR-CALUX(R) (23 pg CALUX-TEQ/g lipids) were above detection limit in more than 75% of the samples. Age and smoking habits of the mothers, did not influence the cord blood Pb and Cd levels. The organochlorines increased 4 to 9% per year of the mother's age (partial R(2)=0.05 to 0.22). Mothers had 2.6% less PCBs in cord blood (partial R(2)=0.02) for each unit increase in pre-pregnancy BMI. Season of delivery, breastfeeding previous children or consumption of local dairy products, were minor determinants. Up to 20% of the variability in organochlorine concentrations was explained by residence area. It was concluded that the place of birth in Flanders is an important determinant of the load of pollutants measured at the start of life. This underlines the validity of human biomonitoring on (relatively) small geographical scale.

Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay

Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g(-1) fat) in the following ascending order: pork (0.289 pg g(-1) fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g(-1) fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g(-1) wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1-4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and rapid screening of dioxin levels in food and human samples.

Association between dioxin concentrations in breast milk and food group intake in Vietnam

OBJECTIVES

To clarify the association between dioxin concentrations in breast milk and food group intake in herbicide-sprayed and nonsprayed areas in Vietnam.

METHODS

This survey was conducted in August 2007 in sprayed and nonsprayed areas, respectively. The interviews were performed using a questionnaire to obtain information on personal characteristics and usual dietary intake. Eighty mothers of sprayed area and 42 mothers of nonsprayed area participated in the study. Breast milk was analyzed for concentration of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

RESULTS

Multiple regression analysis showed that location (sprayed or nonsprayed area) has the highest association with the toxic equivalents (TEQ)-PCDDs, TEQ-PCDFs, and TEQ-Total rather than other factors. In the sprayed area, the adjusted R (2) values of regression were approximately 0.1. On the other hand, the adjusted R (2) values in the nonsprayed areas were higher than those in the sprayed area, i.e., between 0.2 and 0.3, and showed that there were significant associations with body mass index (BMI) in all models.

CONCLUSIONS

Dioxin exposure was less affected by usual dietary intake in the sprayed area than in the nonsprayed area in Vietnam. It was clear that past exposure rather than present dietary intake may affect present dioxin concentrations in breast milk in the sprayed area in Vietnam. This study suggests that present dioxin concentrations in breast milk were maintained by continuous past exposure even after 30-40 years had passed.

PCDD/Fs and dioxin-like PCBs in home-produced eggs from Belgium: levels, contamination sources and health risks

This paper discusses the dioxin TEQ levels as determined by the chemically activated luciferase gene expression assay (CALUX) and by HRGC-HRMS in eggs, soils, faeces and kitchen waste samples obtained in the CONTEGG study. The samples were collected in each Belgian province at private homes and in small gardens where chickens are held. The CALUX levels for eggs sampled in autumn were higher than the levels in eggs obtained at the same locations in spring (median values of 5.86 and 4.08 pg CALUX TEQ/g fat, respectively). The total WHO-TEQ levels in eggs, determined by HRGC-HRMS, ranged from 3.29 to 95.35 pg TEQ/g fat in autumn and from 1.50 to 64.79 pg TEQ/g fat in spring. In the soils on which the chickens forage, levels of 2.51-11.35 pg I-TEQ/g in autumn and 2.00-7.86 pg I-TEQ/g in spring were found. The congener pattern of PCDD/Fs in the eggs, soils and faeces was dominated by OCDD, in addition to 1,2,3,4,6,7,8-HeptaCDD, OCDF and 1,2,3,4,6,7,8-HeptaCDF. The predominant dioxin-like PCBs were PCB118, PCB 105 and PCB 156. The dioxin-like PCBs contributed on average 47%, 14% and 20% to the total WHO-TEQ in eggs, soils and faeces, respectively. Kitchen waste samples were very low-contaminated with dioxin-like compounds. The present results showed a good agreement between egg and soil TEQ levels for PCDD/Fs but not for dioxin-like PCBs. This study showed that current soil levels found in some private gardens do not lead to egg levels below the current EU maximal level of 6 pg total TEQ/g fat for dioxins and dioxin-like PCBs. The consumers of the analysed eggs attained 5-79% of the tolerable weekly intake (TWI) of 14 pg TEQ/kg bw for dioxins and dioxin-like PCBs by exposure to their home-produced eggs only.

Brominated flame retardants in Belgian home-produced eggs: levels and contamination sources

The extent and the sources of contamination with brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), in home-produced eggs from free-foraging chicken of Belgian private owners were investigated. Various factors, such as seasonal variability, exposure of chickens through diet (kitchen waste) and soil, and elimination of BFRs through eggs and faeces were assessed. PBDEs were more important than HBCD in terms of concentrations and detection frequency. Concentrations of PBDEs and HBCD in Belgian home-produced eggs were relatively low and comparable with reported levels from other European countries and the US. The concentrations of PBDEs (sum of 13 congeners, including BDE 209) ranged between not detected and 32 ng/g lipid weight (lw), with medians of 3.0 and <2.0 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively. When present, BDE 209 was the major PBDE congener (45% of sum PBDEs). When BDE 209 was not detected, the PBDE profile was composed of PentaBDE (BDE 99 and BDE 47), with, in some cases, higher contribution of OctaBDE (BDE 183 and BDE 153). HBCD was also detected (<0.4 and 2.9 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively), but at lower detection frequency. The highest HBCD value was 62 ng/g lw. The similarity between profiles and seasonal variations in the concentrations of BFRs in soil and eggs indicate that soil is an important source, but not the sole source, for eggs laid by free-foraging chicken. The contamination of eggs with PBDEs and HBCD appears to be of low concern for public health and the contribution of eggs to the total daily intake of PBDEs appears to be limited (10% for chicken owners and 5% for the average Belgian consumer).

Assessment of the chemical contamination in home-produced eggs in Belgium: general overview of the CONTEGG study

This overview paper describes a study conducted for the Belgian Federal Public Service of Health, Food Chain Safety and Environment during 2006-2007. Home-produced eggs from Belgian private owners of hens were included in a large study aiming to determine concentration levels of various environmental contaminants. By means of the analyses of soil samples and of kitchen waste samples, obtained from the same locations, an investigation towards the possible sources of contaminants was possible. Eggs, soils, faeces and kitchen waste samples were checked for the presence of dioxins, PCBs (including dioxin-like PCBs), organochlorine pesticides, trace elements, PAHs, brominated flame retardants and mycotoxins. The study design, sampling methodology and primary conclusions of the study are given. It was found that in some cases dioxin-like compounds were present at levels that are of concern for the health of the egg consumers. Therefore, measures to limit their contamination in eggs, produced by hens of private owners, were proposed and deserve further attention.

Dietary exposure to total and toxic arsenic in Belgium: importance of arsenic speciation in North Sea fish

Total and toxic (sum of As(III), As(V), monomethylarsenic (MMA), and dimethylarsenic (DMA)) As concentrations were assessed in 19 respectively 4 different fish and shellfish species from the North Sea. Following results were obtained: (i) for fish an average total As concentration of 12.8 microg/g ww and a P90 value of 30.6 microg/g ww; (ii) for shellfish an average total As concentration of 21.6 microg/g ww and a P90 value of 40.0 microg/g ww; (iii) for fish an average toxic As concentration of 0.132 microg/g ww and a P90 value of 0.232 microg/g ww; (iv) for shellfish an average toxic As concentration of 0.198 microg/g ww and a P90 value of 0.263 microg/g ww. For the Belgian consumer the average daily intake of total arsenic from fish, shellfish, fruit, and soft drinks (the main food carriers of As in Belgium) amounts to 285 microg/day with more than 95% coming from fish and shellfish, while for a high level consumer it amounts to 649 microg/day, more than twice the average value. Using the same daily consumption pattern for the selected food products as for total As, we find that the average daily intake of toxic As amounts to 5.8 microg/day, with a 50% contribution of fish and shellfish and the high level intake to 9.5 microg/day. When considering the FOA/WHO Expert Committee's recommendation for inorganic As intake of 2 microg/kg bw/day or 140 microg/day for a 70 kg person, the toxic dose in Belgium is thus an order of magnitude lower.

Determinants of polychlorinated aromatic hydrocarbons in serum in three age classes--Methodological implications for human biomonitoring

Human biomonitoring provides an integrated measure for individual exposure to environmental pollutants. Better insight in inter-individual variability of biomarkers of exposure may help in the interpretation of biomonitoring studies. The aim was to study the impact of outliers, determine the optimal unit for fat-soluble biomarkers in serum and quantify the major determinants for biomarkers of exposure to polychlorinated aromatic hydrocarbons (PCAHs) in three age groups. Data were obtained from the Flemish Environment and Health Study (2002-2006). Marker PCBs (sum of 138, 153, 180), hexachlorobenzene (HCB) and p,p'-DDE were measured in cord blood samples of 1196 newborns, in serum samples of 1679 adolescents (14-15 years) and 1583 adults (50-65 years). Exclusion of influential outliers in multiple linear regression models lead to models that are better applicable to the general population. In terms of adjusted R2, the regression model with the pollutant expressed in volume-based units and blood fat as a separate independent variable was superior compared to models with other units. We found highly consistent relationships between the serum concentration of PCAHs and blood fat, age, changes in body weight, animal fat in the diet, local vegetable consumption (HCB and p,p'-DDE only) and being breastfed as a baby (in adolescents only). The impact of sex and BMI differed by age. For biomarkers of persistent pollutants that reflect long-term exposure, the relation between the covariates and the biomarkers can be well quantified.

Bioanalytical characterization of dioxin-like activity in sewage sludge from Beijing, China

In this preliminary study, the bioanalytical characterization of dioxin-like activity in the sludge of all the nine municipal sewage treatment plants from Beijing city was studied using chemically activated luciferase gene expression (CALUX) assay. The influence of heating period in winter, sewage and sludge treatment processes on the occurrence of dioxin-like activity was also discussed. For the use of clean coal and natural gas, heating did not have significant influence on the occurrence level of PCDD/Fs and dioxin-like-PCBs in this study. Anaerobic-aerobic-anoxic sewage treatment process did not show a good performance in the reduction of dioxin-like activity which is useful in the removal of chemical oxygen demand (COD) and nitrogen. Anaerobic digestion of sludge increased the concentration of PCDD/Fs from 30.1 to 68.3pgCALUX-TEQg(-1)d.w., and total dioxin-like activity from 32.2 to 69.3pgCALUX-TEQg(-1)d.w. This cost-effective and quick test is useful for large developing countries like China in monitoring programs to obtain baseline data about the scale of contamination caused by dioxin-like activity. It is also a useful component in the monitoring capacity building of dioxins.

Human exposure to PCDDs, PCDFs and dioxin-like PCBs associated with seafood consumption in Korea from 2005 to 2007

Concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DLPCBs) were measured in 26 seafoods commonly consumed by the Korean population. The total toxic equivalent (TEQ) concentrations in seafood samples ranged from 0.01 to 6.76 pg TEQ/g wet wt, which were comparable with those found in other countries. The predominant congeners found in seafood samples were 2, 3, 4, 7, 8-PeCDF and 2, 3, 7, 8-TCDF for PCDD/Fs and PCB 118 for DLPCBs. Dietary intakes of PCDD/Fs and DLPCBs from seafood consumption were estimated for various age groups and gender in Korea. The dietary intake of PCDD/Fs and DLPCBs from seafood consumption for the general population was estimated to be 1.23 pg TEQ/kg bw/day, values that are in the range of those reported for other countries. Mackerel, tuna and hairtail contributed to the highest TEQ intakes, which collectively accounted for 66% of the total intake. Among the eight age groups investigated, 3-6 year old children had the highest TEQ exposure, followed by 50-64 years, 30-39 years and <2 years. Considering contributions of seafood consumption to the total dietary intake studies, the dietary TEQ intakes to the general population appear to be below the threshold values by international organizations. The present study may be useful for risk management for dioxins and dioxin-like contaminants in Korean seafood.

Reproducibility and relative validity of a semi-quantitative food frequency questionnaire designed for assessing the intake of dioxin-like contaminants

OBJECTIVE

The aim of this study was to assess the reproducibility and relative validity of a food frequency questionnaire (FFQ) designed to estimate the intake of dioxin-like contaminants.

METHOD

In total, 180 adults (50-65 years) completed the FFQ twice and 157 of them kept four times a 2-day estimated dietary record (EDR) spread over a year.

RESULTS

Spearman rank correlation coefficients varied between 0.58 and 0.67 for reproducibility, versus between 0.28 and 0.46 for validity for the different food groups under study. Exact agreement within quartiles was between 34% and 39%, only between 3% and 9% was grossly misclassified. The weighed kappa statistics indicated fair agreement between the two methods (0.29 for the total diet). The correction factors used had a relevant influence on the absolute estimated intake.

CONCLUSION

The FFQ presented here is a valuable tool for ranking individuals in the study population on the basis of estimated intake of dioxin-like contaminants. However, absolute intakes should be estimated without correction factors and interpreted with caution.