Human Biomonitoring Data Enables Evidence-Informed Policy to Reduce Internal Exposure to Persistent Organic Compounds: A Case Study.

Human biomonitoring (HBM) monitors levels of environmental pollutants in human samples, which often is a topic of concern for residents near industrially contaminated sites (ICSs). Around an ICS area in Menen (Belgium), including a (former) municipal waste incinerator and a metal recovery plant, increasing environmental concentrations of dioxins and polychlorinated biphenyls (PCBs) were observed, causing growing concern among residents and authorities. The local community succeeded in convincing the responsible authorities to investigate the problem and offer research funding. Persistent organic pollutants (POPs) were measured in two consecutive HBM studies (2002-2006 and 2010-2011), in the context of the Flemish Environment and Health Study (FLEHS), as well as in soil and locally produced food. Meanwhile, local authorities discouraged consumption of locally produced food in a delineated area of higher exposure risk. Ultimately, HBM and environmental data enabled tailored dietary recommendations. This article demonstrates the usefulness of HBM in documenting the body burdens of residents near the ICS, identifying exposure routes, evaluating remediating actions and providing information for tailored policy strategies aiding to further exposure reduction. It also highlights the role of the local stakeholders as an example of community-based participatory research and how such an approach can create societal support for research and policy.

Neonatal exposure to environmental pollutants and placental mitochondrial DNA content: A multi-pollutant approach.

BACKGROUND: Placental mitochondrial DNA (mtDNA) content can be indicative of oxidative damage to the placenta during fetal development and is responsive to external stressors. In utero exposure to environmental pollutants that may influence placental mtDNA needs further exploration. OBJECTIVES: We evaluated if placental mtDNA content is altered by environmental pollution in newborns and identified pollutants independently associated to alterations in placental mtDNA content. METHODS: mtDNA content was measured in placental tissue of 233 newborns. Four perfluoroalkyl compounds and nine organochlorine compounds were quantified in cord blood plasma samples and six toxic metals in whole cord blood. We first applied a LASSO (least absolute shrinkage and selection operator) penalized regression model to identify independent associations between environmental pollutants and placental mtDNA content, without penalization of several covariates. Then adjusted estimates were obtained using an ordinary least squares (OLS) regression model evaluating the pollutants' association with placental mtDNA content, adjusted for several covariates. RESULTS: Based on LASSO penalized regression, oxychlordane, p,p'-dichlorodiphenyldichloroethylene, ß-hexachlorocyclohexane, perfluorononanoic acid, arsenic, cadmium and thallium were identified to be independently associated with placental mtDNA content. The OLS model showed a higher placental mtDNA content of 2.71% (95% CI: 0.3 to 5.2%; p=0.03) and 1.41% (0.1 to 2.8%, p=0.04) for a 25% concentration increase of respectively cord blood ß-hexachlorocyclohexane and arsenic. For a 25% concentration increase of cord blood thallium, a 4.88% lower placental mtDNA content (95% CI: -9.1 to -0.5%, p=0.03) was observed. CONCLUSION: In a multi-pollutant approach, low fetal exposure levels of environmental organic and inorganic pollutants might compromise placental mitochondrial function as exemplified in this study by alterations in mtDNA content.

Metals, hormones and sexual maturation in Flemish adolescents in three cross-sectional studies (2002-2015).

Sex hormone levels and timing of sexual maturation are considered important markers for health status of adolescents in puberty, and previous research suggests they might be influenced by metal exposure. In three campaigns of the Flemish Environment and Health Study (FLEHS I 2002-2006; FLEHS II 2007-2011 and FLEHS III 2012-2015), data were collected on internal exposure to metals (Cd, Cu, Pb, Cr, Mn, Tl, Ni, Sb, Hg, As and As species) and sexual maturation in 2671 14-15years old adolescents. All metals were measured in blood and/or urine, except total- and methylmercury which were measured in hair samples. Sex hormone levels were measured in blood serum of adolescent males of the cohorts of FLEHS I and FLESH II. The use of a uniform methodology in successive campaigns allows to confirm associations between exposure and health in different cohorts and over time. Furthermore, mathematical and statistical density correction methods using creatinine or specific gravity were tested for urinary markers. Significant associations between sex hormones and maturity markers were observed in the FLEHS I and II campaigns, when both were assessed together. Regardless of the applied correction method, creatinine correction systematically introduced bias due to associations of creatinine with sex hormones and maturation markers, especially in adolescent males, while this is not the case for specific gravity. A series of exposure-response associations were found, but several involving Cd, Pb, As, Tl and Cu persisted in different FLEHS campaigns. The effects of Pb and Cu on luteinizing hormone, (free) testosterone, (free) oestradiol and maturation support a xenoestrogenic agonistic action on the feedback of oestradiol to the hypothalamus-pituitary-gonadal axis. Our results suggest that specific care should be taken when selecting urine density correction for investigating associations with hormonal and maturation markers in adolescent males. Furthermore, the possibility of xenoestrogenic effects of certain metals in environmentally exposed adolescents warrants further investigation.

Three cycles of human biomonitoring in Flanders - Time trends observed in the Flemish Environment and Health Study.

To follow time trends in exposure to environmental chemicals, three successive campaigns of the Flemish Environment and Health Study (FLEHS) have recruited and sampled in total 5825 participants between 2002 and 2014. Cord samples from newborns, urine and blood samples from 14 to 15 years old adolescents and from adults between 50 and 65 years old were analysed in geographical representative samples of the Flemish population. The data of the different campaigns were considered per age group and per biomarker after adjustment for predefined covariates to take into account differences in characteristics of the study populations over time. Geometric means were calculated. Multiple linear regression was used to evaluate time trends. The concentration of serum biomarkers for persistent organic pollutants (POPs), such as marker polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p'-DDE), the major metabolite of dichlorodiphenyltrichloroethane (DDT), and hexachlorobenzene (HCB) expressed per g lipid, decreased significantly with time. The levels of DDE in all age groups and those of PCBs in cord and adolescent serum samples were almost halved in a time period of ten years. HCB levels were reduced by a factor of 4 in adolescents and in adults. Mean serum concentrations of the more recently regulated perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were significantly lower in cord samples of 2013 compared to samples of 2007. The decline was more pronounced for PFOS than for PFOA. In the same period, mean metabolite levels of di-2-ethylhexyl phthalate (DEHP) and of di-n-butyl phthalate (DBP) decreased significantly in urine samples of adolescents with sharper declines for DEHP than for DBP. Cadmium and lead levels in cord and adolescent blood samples were significantly lower in the recent campaigns than 10 years before. Also the mean urinary cadmium level in adults was 35% lower compared to adult samples of 2002. Such favourable trends were not observed for arsenic and thallium measured in cord blood. Similar, the concentrations of 1-hydroxypyrene, a marker for exposure to polycyclic aromatic hydrocarbons (PAHs), was not lower in urine from adolescents sampled in 2013 compared to 2003. In contrast, concentrations of t,t'-muconic acid, a marker of benzene exposure, showed clearly reduced levels. The FLEHS program shows that concentrations of well-regulated chemicals especially traditional POPs and cadmium and lead are decreasing in the population of Flanders. Response to regulatory measures seems to happen rapid, since concentrations in humans of specific regulated perfluorinated compounds and phthalates were significantly reduced in five years time. Biomarker concentrations for arsenic, thallium, and polyaromatic hydrocarbons are not decreasing in this time span and further follow up is warranted.

Assessment of dioxin-like activity in PM10 air samples from an industrial location in Algeria, using the DRE-CALUX bioassay.

When compared to the European guidelines, PM10 (particulate matter up to 10-µm size) concentrations in Algeria are often exceeding the maximum limits, and in general, no information exists on the compounds bound on its surface. The objective of this study was to measure the dioxin-like activity of polychlorinated dibenzodioxines and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in the PM10 fraction at the Sour El Ghozlane cement plant in Algeria. PM10 samples (n = 23) were taken between 24 March and 15 April 2013, using a medium volume sampler and 47-mm PTFE filters. The 24-h samples were dried to determine the PM10 content and afterward extracted, cleaned up, and analyzed with the dioxin-responsive element-chemical-activated luciferase gene expression (DRE-CALUX) bioassay. Our results showed that the measured bioanalytical equivalents (BEQs) were similar to those in other international industrial sites worldwide. The PCDD/Fs and dioxin-like PCBs (dl-PCBs) were positively correlated (rho = 0.6, p = 0.002), indicating that they have similar sources. Furthermore, samples from March showed higher PCDD/F and dl-PCB BEQs and humidity but lower temperatures compared to samples from April, while there was no difference in the PM10 concentrations between the two months. These results reveal that PM10 alone is not a good proxy and that meteorological conditions are an important factor in assessing dioxin-like pollution in the atmosphere. It seems that, at present, there is no health hazard through direct airborne human exposure to dioxin-like pollutants in PM10 from this site. However, it is important to monitor these POPs for a longer period of time and also to gain more insight in their distribution between the particulate and gas phase in relation to meteorological conditions.

Metabolic targets of endocrine disrupting chemicals assessed by cord blood transcriptome profiling.

Early life exposure to endocrine disrupting chemicals (EDCs) has been frequently associated with impaired perinatal growth, an important risk factor for later onset of metabolic disorders. We analyzed whether the cord blood transcriptome showed early indications of alterations in metabolic processes in 195 human samples in relation to cord blood levels of dichlorodiphenyldichloroethylene (p,p'-DDE), polychlorinated biphenyl-153 (PCB-153), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS). Overall, 39 metabolically relevant transcription factors were significantly enriched (31 by p,p'-DDE, 10 by PCB-153, 8 by PFOA, and 2 by PFOS). These included the glucocorticoid receptor (p,p'-DDE and PCB-153) and the progesterone receptor (PFOA and PFOS). The 'insulin receptor signaling', 'acute phase response signaling', 'Interleukin(IL)-6 signaling', and 'prolactin signaling' pathways were significantly enriched in relation to p,p'-DDE. Transcriptional changes at birth suggest a role for specific metabolic targets as a link between prenatal EDC exposure and metabolic disorders later in life.

Assessment of estrogenic and androgenic activity in PM10 air samples from an urban, industrial and rural area in Flanders (Belgium) using the CALUX bioassay.

BACKGROUND: Endocrine disrupting chemicals represent a broad class of compounds, are widespread in the environment and can pose severe health effects. OBJECTIVES: The objective of this study was to investigate and compare the overall estrogen and androgen activating potential of PM10 air samples at an urban, rural and industrial location in Flanders, using a human in vitro cell bioassay. METHODS: PM10 samples were collected on glass fiber filters every six days between April 2013 and January 2014 using a high-volume sampler. Extraction was executed with a hexane/acetone mixture before analysis using a recombinant estrogen- or androgen responsive human carcinoma cell line. Results were expressed as bioanalytical equivalents (BEQs) per cubic meter of air. RESULTS: High fluctuations in estrogenic activity were observed during the entire sampling period, with median BEQs of 32.1, 35.9 and 31.1 fg E2-Eq m(-)³ in the industrial, urban and rural background area, respectively. Estrogenic activity was measured in 70% of the samples, while no androgenic activity was observed in any of the samples. The estrogenic activity in the industrial area was positively correlated with the airborne concentration of the sum of the non-carcinogenic PAHs pyrene and fluoranthene (rho=0.48; p<0.01) and the sum of the carcinogenic PAHs (rho=0.36; p=0.05). CONCLUSIONS: This study showed that no androgenic activity was present in PM10 and that although the median estrogenic activity was rather low and comparable in the three locations, high fluctuations in estrogenic response exist over time. While atmospheric PAHs contributed to the observed estrogenic response, especially in the industrial area, the chemicals responsible for the majority of estrogenic activity remain to be identified.

Investigating unmetabolized polycyclic aromatic hydrocarbons in adolescents' urine as biomarkers of environmental exposure.

Polycyclic aromatic hydrocarbons (PAHs) are of interest to human biomonitoring studies due to their carcinogenic potential. Traditionally metabolites of these compounds, like 1-hydroxypyrene, are monitored in urine, but recent methods allow the determination of the parent compounds in urine, which give additional information regarding sources and toxicity of PAHs. In order to assess the feasibility of incorporating these methods in a human biomonitoring study, the 16 USEPA parent PAHs were determined in 20 urine samples. These samples were obtained from 10 boys and 10 girls aged 14-16 years, participating in the third Flemish Environment and Health Study (Flanders, Belgium). Of these 16 parent PAHs, nine could be determined in more than 95% of the samples and three (including benzo(a)pyrene) in more than 50%. Several correlations were found between different PAHs, but not between pyrene and its metabolite 1-hydroxypyrene. Diagnostic PAH ratios in urine and air samples pointed towards combustion sources and are in line with the ratios in environmental samples. Benzo(a)pyrene, naphthalene and fluorene have the highest carcinogenic potential in our cohort, when using toxic equivalency factors. Some associations between PAH congeners and determinants of exposure were found, while fluorene and acenaphthylene were positively associated with thyroid hormone levels and benzo(a)pyrene showed a positive correlation with DNA damage by comet assay. These results confirm that parent PAHs in urine are useful as biomarkers of exposure in biomonitoring studies.

Optimization of a gas chromatography-mass spectrometry method with methyl chloroformate derivatization for quantification of amino acids in plant tissue.

Rapid, easy and reliable quantification of amino acids is crucial in research on plant amino acid metabolism and nutritional improvement of crops via enrichment of essential amino acids. A recently reported analysis method, based on solid phase extraction (SPE), derivatization with methyl chloroformate and gas chromatography-mass spectrometry was optimized and tested on three-week-old Arabidopsis thaliana leaf tissues. Optimization of the SPE cleanup yielded recovery rates of minimum 95% for all amino acids (except arginine). Variations in accuracy and precision did not exceed 12.5%, except for cysteine, histidine and tryptophane, which were excluded from analysis. Quantification of overlapping peaks for isoleucine/threonine and proline/asparagine was possible by selection of two specific fragment ions for each amino acid. Of the 16 selected amino acids, 14 were quantified successfully in at least 75% of the samples, while methionine and tyrosine were only quantifiable in 6% and 42%, respectively. A case study on the aspartate super pathway confirmed the applicability of the optimized method on wild type and genetically modified plants: external supplementation of methionine or lysine yielded a 146-fold or 27-fold increase in the respective absolute amino acid levels compared with the control treatment. Induced expression of dhdps-r1 (a mutated lysine biosynthesis gene encoding a feedback insensitive enzyme) caused an 83-fold increase in absolute lysine levels.

Assessment of estrogenic activity in PM10 air samples with the ERE-CALUX bioassay: Method optimization and implementation at an urban location in Flanders (Belgium).

Endocrine disrupting chemicals represent a broad class of compounds, are widespread in the environment and can pose severe health effects. The objective of this study was to investigate the overall estrogen activating potential of PM10 air samples at an urban location with high traffic incidence in Flanders, using a human in vitro cell bioassay. PM10 samples (n = 36) were collected on glass fiber filters every six days between April 2013 and January 2014 using a high-volume sampler. Extraction was executed with a hexane/acetone mixture before analysis using a recombinant estrogen-responsive human ovarian carcinoma (BG1Luc4E2) cell line. In addition, several samples and procedural blanks were extracted with ultra-pure ethanol or acetonitrile to compare extraction efficiencies. Results were expressed as bioanalytical equivalents (BEQs) in femtogram 17ß-estradiol equivalent (fg E2-Eq) per cubic meter of air. High fluctuations in estrogenic activity were observed during the entire sampling period, with mean and median BEQs of 50.7 and 35.9 fg E2-Eq m(-)(3), respectively. Estrogenic activity was measured in more than 70% of the samples and several sample extracts showed both high BEQs and high cytotoxicity, which could not be related to black carbon, PM10 or heavy metal concentrations. At this moment, it remains unclear which substances cause this toxicity, but comparison of results obtained with different extraction solvents indicated that acetone/hexane extracts contained more compounds that were cytotoxic and suppressive of responses than those extracted using ultra-pure ethanol. Although more research is needed, the use of a more polar extraction solvent seems to be advisable.

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.

Monitoring chlorinated persistent organic pollutants in adolescents in Flanders (Belgium): concentrations, trends and dose-effect relationships (FLEHS II).

BACKGROUND: In 2007, the second cycle of the Flemish human biomonitoring survey started, with a main focus on 14-15 year-old adolescents. OBJECTIVES: The main objectives were generating reference values for exposure markers, determining the pollution pressure in industrial hotspots and establishing dose-effect relationships between exposure to pollutants and hormone levels, sexual development, asthma and allergy, genotoxic and hematological markers. METHODS: Geometric means with 95% confidence intervals (CI) were calculated for a reference population of 200 14-15 year-old adolescents. Stepwise multiple regression analyses with correction for confounders and covariates were performed to establish dose-effect relationships. RESULTS: Geometric mean concentrations (with 95% CI) of 49.6 (45.7, 53.8), 70.8 (63.6, 78.8) and 8.34 (7.76, 8.97) n gg(-1) lipid for the sum of PCB 138, 153 and 180, p,p'-DDE and HCB were respectively 23%, 26% and 60% lower than those obtained five years earlier. Geometric mean concentrations of 108 (101, 114) and 32.1 (30.1, 34.2) pgCALUX-BEQg(-1) lipid were observed for the PCDD/Fs and dioxin-like PCBs, respectively. Multiple dose-effect relationships were observed between POPs and several effect markers, including positive (boys) and negative (girls) associations with data on sexual development and positive associations with asthma, animal allergy and free thyroxine (boys and girls). CONCLUSIONS: Our findings suggest that chlorinated POP concentrations are decreasing over time and that even relatively low concentrations are associated with biological effects.

Validity of parentally reported versus measured weight, length and waist in 7- to 9-year-old children for use in follow-up studies.

UNLABELLED: The aim of this prospective cohort study was to assess the validity of parentally reported anthropometric data compared to measured data in 7- to 9-year-old Flemish children especially for use in follow-up studies. The subjects were 116 Flemish children of a birth cohort recruited in the first Flemish Environment and Health Study (2002-2003). Data about anthropometric measures (waist circumference (WC), weight and length) were obtained by a postal parentally reported questionnaire and during a home visit. Our study showed that parents tend to overreport their child's WC and underreport the BMI, especially in children with large WC and high BMI. The median difference between measured and parentally reported WC was 1.6% of the median measured WC; for BMI, the median difference was 2.8% of the median measured BMI. Both for WC and BMI, we observed a good agreement between parentally reported values and measured values to classify children in the highest 10 and 20% of the study population. When classifying the children in 'overweight' and 'not overweight', there were less misclassifications when parentally reported WC was used compared to parentally reported BMI. CONCLUSIONS: Although there is a high agreement between parentally reported and measured WC, the parentally reported data must be used with reserve. Moreover, this study is the first to suggest that WC is a better indicator compared to BMI when parentally reported values are used to classify children.

Time-integrated monitoring of dioxin-like polychlorinated biphenyls (dl-PCBs) in aquatic environments using the ceramic toximeter and the CALUX bioassay.

Ceramic passive samplers or toximeters (packed with active carbon 1%, w/w, on celite), in combination with the CALUX bioassay have been used as a time-integrated monitoring technique for dissolved dioxin-like PCBs in urban and industrial wastewaters. The technique showed to be reliable during laboratory experiments: (1) PCB-126 amounts extracted from the passive samplers increased linearly with the time of exposure and (2) PCB-126 concentrations calculated from the amounts accumulated by the passive samplers were in agreement with their concentrations in the testing solution. Afterwards the toximeters were applied in the field. Two sampling sites located in Egypt were chosen: the Belbeis drainage canal, and the EMAK paper mill. A total of 18 ceramic toximeters were exposed to the wastewater in both sampling sites for a maximum period of 4 weeks. Two samplers were collected weekly from each site to monitor the increase in target analytes over time. Extracts were analyzed using the CALUX bioassay and the total dioxin-like PCB toxicity was reported for the aqueous phase (water column), as well as the solid phase (sediment and sludge) in both sampling sites. The time-weighted average concentration (TWA) of dl-PCBs in wastewater of the paper mill during the sampling period ranged between 7.1 and 9.1 pg-BEQL(-1), while that of the drainage canal ranged between 9.5 and 12.2 pg-BEQL(-1). The dl-PCBs in the fibrous sludge (paper mill) and bottom sediment (drainage canal) were 0.5 and 0.4 pg-BEQg(-1) dry-weight, respectively. The organic-carbon normalized partition coefficients between sediment and water (logKoc) for the paper mill and the canal were 2.4 and 4.3, respectively.

Time-integrated monitoring of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in urban and industrial wastewaters using a ceramic toximeter and the CALUX bioassay.

The ceramic toximeter as a passive sampler in combination with the CALUX bioassay was utilized as a time-integrated pollution-assessment technique for dioxin-like PCDD/Fs in wastewaters. Toximeters filled with XCARB and enclosed in stainless steel cages were submerged in wastewater of Belbeis drainage-canal and EMAK paper-mill, located in Egypt, for 28 days. Two samplers were removed every week from each site. Extracts from toximeters, from bottom-sediments, and from paper-mill sludge were analyzed by the CALUX. Results showed a regular increase in the amounts of PCDD/Fs trapped by the toximeters as sampling time increased. Time-weighted average concentrations (TWA) of PCDD/Fs in the wastewaters of the drainage-canal and paper-mill were 231 (214-281) and 26 (24.1-32.6) pg-BEQL(-1), respectively. Compared to literature data, this means a high pollution level for the drainage-canal water, while the pollution level in the paper-mill wastewater is similar to that reported for other paper mills. The PCDD/Fs levels in the drainage-canal bottom-sediments and in the paper-mill sludge were 8.3 and 14.6 pg-BEQg(-1) dry-weight, at the lower end of internationally reported values in similar compartments. The sampling rate of the tested toximeters for dissolved PCDD/Fs was about 3.6 mL d(-1). Sediment/water partitioning coefficient logKd of PCDD/Fs in the drainage-canal and the paper-mill was 1.42 and 2.70 respectively. The organic-carbon normalized partition coefficient logKoc was 4.17 and 3.19 respectively, and is lower than the reported values for other sites.

Health effects in the Flemish population in relation to low levels of mercury exposure: from organ to transcriptome level.

Due to possible health risks, quantification of mercury accumulation in humans was included in the Flemish biomonitoring programmes FLEHS I (2002-2006) and FLEHS II (2007-2011). The general objective of FLEHS I was to assess regional exposure levels in order to link possible differences in these internal exposure levels to different types of local environmental pressure. Therefore, Hg and MMHg (methylmercury) were only measured in pooled blood samples per region and per age class. In FLEHS II, mercury concentrations were measured in hair of each participant. About 200 adolescents and 250 mothers (reference group) and two times 200 adolescents (2 hotspots) were screened. The main objectives of the FLEHS II study were: (1) to determine reference levels of mercury in hair for Flanders; (2) to assess relations between mercury exposure and possible sources like fish consumption; (3) to assess dose-effect relations between mercury exposure and health effect markers. The results showed that mercury concentrations in the Flemish population were rather low compared to other studies. Mercury levels in the Flemish populations were strongly related to the age of the participants and consumption of fish. Significant negative associations were observed between mercury in hair and asthma, having received breast feeding as a newborn, age at menarche in girls, allergy for animals and free testosterone levels. Significant correlations were also observed between mercury in hair and genes JAK2, ARID4A, Hist1HA4L (boys) and HLAdrb5, PIAS2, MANN1B1, GIT and ABCA1 (girls).

Prenatal exposure to environmental contaminants and behavioural problems at age 7-8years.

Animal studies showed that the developing brain is particularly sensitive to chemical exposure. Human studies carried out in areas with high exposures have proven neurodevelopmental disorders in relation to e.g. lead and PCBs. Whether these chemicals are associated with behavioural problems in childhood at current environmental levels is not well known. Therefore, we assessed the association between prenatal exposure to lead, cadmium, PCBs, dioxin-like compounds, HCB and p,p'-DDE and behavioural problems in 7-8year old children. Prenatal exposure data were obtained from the Flemish mother-new-born cohort. Lead, cadmium, PCBs, dioxin-like compounds, HCB and p,p'-DDE were analysed in cord blood. When the child reached 7-8years, 270 mothers completed the Strengths and Difficulties Questionnaire assessing their children's behavioural health. We found that doubling the prenatal lead exposure (cord blood lead levels) was associated with a 3.43 times higher risk for hyperactivity in both boys and girls. In addition, total difficulties were 5.08 times more likely in the highest tertile for prenatal lead exposure compared to the lowest tertile. In girls, total difficulties were 4.92 more likely when doubling cord blood p,p'-DDE, whereas no significant association was found in boys. Further, we noted in boys a 1.53 times higher risk for emotional problems when doubling cord blood cadmium, whereas no significant association was found in girls. These results indicate that the presence of environmental contaminants influences the mental health of the next generation.

Neurobehavioral function and low-level exposure to brominated flame retardants in adolescents: a cross-sectional study.

BACKGROUND: Animal and in vitro studies demonstrated a neurotoxic potential of brominated flame retardants, a group of chemicals used in many household and commercial products to prevent fire. Although the first reports of detrimental neurobehavioral effects in rodents appeared more than ten years ago, human data are sparse. METHODS: As a part of a biomonitoring program for environmental health surveillance in Flanders, Belgium, we assessed the neurobehavioral function with the Neurobehavioral Evaluation System (NES-3), and collected blood samples in a group of high school students. Cross-sectional data on 515 adolescents (13.6-17 years of age) was available for the analysis. Multiple regression models accounting for potential confounders were used to investigate the associations between biomarkers of internal exposure to brominated flame retardants [serum levels of polybrominated diphenyl ether (PBDE) congeners 47, 99, 100, 153, 209, hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA)] and cognitive performance. In addition, we investigated the association between brominated flame retardants and serum levels of FT3, FT4, and TSH. RESULTS: A two-fold increase of the sum of serum PBDE's was associated with a decrease of the number of taps with the preferred-hand in the Finger Tapping test by 5.31 (95% CI: 0.56 to 10.05, p = 0.029). The effects of the individual PBDE congeners on the motor speed were consistent. Serum levels above the level of quantification were associated with an average decrease of FT3 level by 0.18 pg/mL (95% CI: 0.03 to 0.34, p = 0.020) for PBDE-99 and by 0.15 pg/mL (95% CI: 0.004 to 0.29, p = 0.045) for PBDE-100, compared with concentrations below the level of quantification. PBDE-47 level above the level of quantification was associated with an average increase of TSH levels by 10.1% (95% CI: 0.8% to 20.2%, p = 0.033), compared with concentrations below the level of quantification. We did not observe effects of PBDE's on neurobehavioral domains other than the motor function. HBCD and TBBPA did not show consistent associations with performance in the neurobehavioral tests. CONCLUSIONS: This study is one of few studies and so far the largest one investigating the neurobehavioral effects of brominated flame retardants in humans. Consistently with experimental animal data, PBDE exposure was associated with changes in the motor function and the serum levels of the thyroid hormones.

Dioxin analysis in water by using a passive sampler and CALUX bioassay.

Passive sampling of organic pollutants is a new trend in environmental monitoring and analysis. Passive samplers are being developed to overcome the drawbacks of the conventional snapshot sampling approach. The ceramic toximeter is a promising passive sampler for monitoring dioxin-contaminated surface and ground waters. It consists of an alumina cylinder lined with a thin coating of titania and a pore diameter of 0.05 µm. The cylinder serves as a diffusion barrier limiting the analyte transport to molecular diffusion only, as well as a container for a selective trapping material of a high capacity and affinity towards the chemical(s) of concern. The cylinder is closed from both sides with PTFE caps. The ceramic toximeter was filled with activated carbon as the trapping material and has been tested in vitro for the sampling of dioxin-contaminated water. In addition, the utilization of the CALUX bioassay technique for analyzing the trapped dioxin has greatly reduced the time and costs for dioxin scanning in aqueous media. Exposure times varied between 1 and 7 days in a solution of 1.35 ng-TCDDL(-1) (TCDD is 2,3,7,8-tetrachlorodibenzodioxin). The mean effective molecular diffusion coefficient of TCDD in the toximeter amounts to 11.9×10(-6)m(2)d(-1) while the minimum concentration detectable in an aquatic system after 30 days of exposure amounts to 0.89 pg-TCDDL(-1).

Concept of the Flemish human biomonitoring programme.

Since 2002 a human biomonitoring network has been established in Flanders (Belgium) as part of a programme on environmental health surveillance. The human biomonitoring network should support environmental health policy by identifying priorities for further action. The first cycle of the programme (2002-2006) confirmed the hypotheses that living in areas with different environmental pressure is reflected in different loads of environmental chemicals in the residents. In the second cycle of the programme (2007-2011) the number of environmental chemicals for which human biomonitoring data were obtained was expanded substantially. The goal of the Flemish programme is to use and translate the scientific results into policy actions. Its further orientation in the second cycle to human biomonitoring in hot spots and sensitive age groups or susceptible persons with underlying complications (e.g. persons with diabetes) are linked to these goals. Interaction with stakeholders is embedded in the programme emphasizing transparency of the choices that are made and direct communication. The Flemish human biomonitoring programme is organized centrally with major involvement of research partners from different disciplines which allows engrafting environmental health research on the programme. One of the major focuses is the question whether combinations of pollutants in the general population are associated with biological effects. The objective of this paper is to review and discuss the options that were taken in the human biomonitoring programme in order to achieve its goals.