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The Flemish Environment and Health Study (FLEHS) collects information on internal exposure to a broad range of environmental chemicals in the general population in Flanders, the Northern region of Belgium. The aim is to establish biomonitoring exposure distributions for the general population in support of public health and environmental policy, environmental risk assessment and risk management decisions. In 2017-2018, urine and blood samples were collected from 428 teenagers by a stratified clustered two stage randomized design. Samples were analyzed for a broad range of biomarkers related to exposure to chlorinated and newer pesticides, brominated and organophosphate flame retardants (BFR/OPFR), polychlorinated biphenyls (PCBs), bisphenols, phthalates and alternative plasticizers, per-and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), benzene, metals and trace elements. The geometric mean levels and percentiles of the distribution were estimated for each biomarker, for the whole study population and following stratification for sex, the household educational attainment and the residence area's urbanicity. Geometric means of biomarkers of lead, dichlorodiphenyltrichloroethane (DDT), PCBs, PAHs, regulated phthalates and bisphenol A (BPA) were lower than in the previous FLEHS cycles. Most biomarker levels were below health-based guidance values (HB-GVs). However, HB-GVs of urinary arsenic, blood lead, blood cadmium, sum of serum perfluorooctane sulfonate (PFOS) and perfluoro-1-hexanesulfonate (PFHxS) and the urinary pyrethroid metabolite (3-PBA) were exceeded in respectively 25%, 12%, 39.5%, 10% and 22% of the teenagers. These results suggest that the levels of exposure in the Flemish population to some environmental chemicals might be of concern. At the same time, we noticed that biomarkers for BPA substitutes, metabolites of OPFRs, an expanded list of PFAS, glyphosate and its metabolite could be measured in substantial proportions of participants. Interpretation of these levels in a health-risk context remains uncertain as HB-GVs are lacking. Household educational attainment and residential urbanicity were significant exposure determinants for many biomarkers and could influence specific biomarker levels up to 70% as shown by multiple regression analysis. The research consortium also took care of the broader external communication of results with participants, policy makers, professional groups and civil society organizations. Our study demonstrated that teenagers are exposed to a wide range of chemicals, it demonstrates the success of public policies to reduce exposure but also points to concern and further priorities and needs for follow up. [ABSTRACT FROM AUTHOR]

Pesticides are among the most widely used chemicals thus contributing to a global contamination of the environment. Studies in North America and Europe have reported ambient air concentrations of Currently Used Pesticides in rural and urban locations as well as in remote areas. Monitoring pesticides in air is required for a better understanding of human exposure through inhalation and to assess potential health effects related to this exposure pathway. In this study, 46 pesticides were analyzed in ambient air in sampling stations distributed over Wallonia during a year, from May 2015 to May 2016. Different typologies were defined for sampling sites (remote areas, urban sites, agricultural sites, livestock area, and sites with other professional uses). Ambient air was sampled for 14 days with an active air sampler at a flow rate of 4 m³/h. Quartz filters and PUF/XAD-2/PUF cartridges were used to sample both gas and particulate phase pesticides. On the 46 pesticides studied, 6 insecticides, 18 herbicides and 18 fungicides were detected. Herbicides were measured in 68.3% of samples throughout the year, whereas fungicides and insecticides were measured in 62.6% and 13.2% of the samples, respectively. The highest mean concentrations for all pesticides were measured in spring-summer, whereas few pesticides were measured at low concentrations in winter. Six pesticides were measured in the remote sampling station at lower concentrations than in all other sites highlighting volatility of these pesticides. The highest number of different pesticides and the highest concentrations were measured in agricultural stations, where uses of plant protection products are higher. Finally, less volatile pesticides were only detected near application areas and at low concentrations. Together, these results provide better insight on the spatial and temporal variations of pesticides concentrations in ambient air, which were related to pesticides uses as well to atmospheric volatility and persistence., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Childhood exposure to endocrine-disrupting chemicals (EDCs), either alone or in mixtures, may affect metabolic outcomes, yet existing evidence remains inconclusive. In our study of 372 adolescents from the Flemish Environment and Health Study (FLEHS IV, 2017-2018), we measured 40 known and suspected EDCs and assessed metabolic outcomes, including body mass index z -score (zBMI), abdominal obesity (AO), total cholesterol (TC), and triglycerides (TG). We applied Bayesian kernel machine regression (BKMR) and Bayesian penalized horseshoe regression for variable selection and then built multivariate generalized propensity score (mvGPS) models to provide an overview of the effects of selected EDCs on metabolic outcomes. As a result, BKMR and horseshoe together identified five EDCs associated with zBMI, three with AO, three with TC, and five with TG. Through mvGPS analysis, monoiso-butyl phthalate (MIBP), polychlorinated biphenyl (PCB-170), and hexachlorobenzene (HCB) each showed an inverse association with zBMI, as did PCB-170 with AO. Copper (Cu) was associated with higher TC and TG, except in boys where it was linked to lower TG. Additionally, monoethyl phthalate (MEP) and monobenzyl phthalate (MBzP) were associated with higher TG. To conclude, our findings support the association between certain chemicals (Cu, MEP, and MBzP) and elevated lipid levels, aligning with prior studies. Further investigation is needed for sex-specific effects.

Prenatal exposure to metabolism-disrupting chemicals (MDCs) has been linked to birth weight, but the molecular mechanisms remain largely unknown. In this study, we investigated gene expressions and biological pathways underlying the associations between MDCs and birth weight, using microarray transcriptomics, in a Belgian birth cohort. Whole cord blood measurements of dichlorodiphenyldichloroethylene ( p,p' -DDE), polychlorinated biphenyls 153 (PCB-153), perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and transcriptome profiling were conducted in 192 mother-child pairs. A workflow including a transcriptome-wide association study, pathway enrichment analysis with a meet-in-the-middle approach, and mediation analysis was performed to characterize the biological pathways and intermediate gene expressions of the MDC-birth weight relationship. Among 26,170 transcriptomic features, we successfully annotated five overlapping metabolism-related gene expressions associated with both an MDC and birth weight, comprising BCAT2 , IVD , SLC25a16 , HAS3 , and MBOAT2 . We found 11 overlapping pathways, and they are mostly related to genetic information processing. We found no evidence of any significant mediating effect. In conclusion, this exploratory study provides insights into transcriptome perturbations that may be involved in MDC-induced altered birth weight.

Given the many public health and environmental impacts associated with the use of pesticides, comprehensive pesticide application data are a high priority for environmental and health professionals, government agencies, and community groups in Wallonia (Belgium). In that context, geographic information system (GIS) approaches for mapping estimates of agricultural pesticide use were developed in the present study. Data on pesticide application rates and high-resolution annual datasets of the geographic distribution of crops were used to complete this analysis in Wallonia over the period 2015-2017. The method was implemented in Python in order to allow easy update and improvements of maps, or to segment maps by individual pesticides, chemical groups of pesticides (e.g. insecticides, herbicides), etc. Linked databases were created to classify, select, and possibly weight AIs according to specific requests and criteria. The results provide a first map of agricultural pesticide use in Wallonia, which depicts the best picture up to now of their geographic distribution. Maps of fungicides, herbicides, and plant growth regulators showed quite similar spatial patterns as the map of the combination of all pesticides. In contrast, the insecticide map showed a specific pattern related almost exclusively to dwarf-tree orchards in some municipalities in northern Wallonia. This research work is a preliminary result on the spatial characterization of agricultural pesticide use in Wallonia and give a valuable basis for research and environmental health actions in Belgium. Forthcoming developments will focus on exposure characterization to agricultural pesticides using GIS models. Using this information, policymakers will able to detect potential priority zones and take action to check and reduce agricultural pesticide loads in the environment., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Exposure to air pollution during pregnancy has been associated with adverse pregnancy outcomes in studies worldwide, other studies have described beneficial effects of residential greenspace on pregnancy outcomes. The biological mechanisms that underlie these associations are incompletely understood. A biological stress response, which implies release of cortisol, may underlie associations of air pollution exposure and access to neighborhood greenspaces with health., Methods: We explored residential exposure to air pollution and residential access to neighborhood greenspaces in relation to hair cortisol concentrations of participants in a prospective pregnancy cohort study in Flanders, Belgium. Hair samples were collected at the end of the second pregnancy trimester (n = 133) and shortly after delivery (n = 81). Cortisol concentrations were measured in 3-cm scalp-near hair sections, to reflect second and third pregnancy trimester cortisol secretion. We estimated long-term (3 months before sampling) residential exposure to fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ) and black carbon (BC), assessed residential distance to major roads and residential access to neighborhood greenspaces (NHGS). Associations between residential exposures and hair cortisol concentrations were studied using linear regression models while adjusting for season of sampling., Results: Three-month mean residential NO 2 and BC concentrations were positively associated with third pregnancy trimester hair cortisol concentrations (p = 0.008 and p = 0.017). Access to a large NHGS (10 ha or more within 800 m from residence) was negatively associated with third trimester hair cortisol concentrations (p = 0.019). Access to a large NHGS significantly moderated the association between residential proximity to major roads and second trimester hair cortisol concentrations (p = 0.021). Residential distance to major roads was negatively associated with second trimester hair cortisol concentrations of participants without access to a large NHGS (p = 0.003). The association was not significant for participants with access to a large NHGS. The moderation tended towards significance in the third pregnancy trimester (p < 0.10)., Conclusions: Our findings suggest a positive association between long-term residential exposure to air pollution and biological stress during pregnancy, residential access to neighborhood greenspaces may moderate the association. Further research is needed to confirm our results., Trial Registration: The IPANEMA study is registered under number  NCT02592005 at clinicaltrials.gov .

In spring 2016, a study was carried out to characterize currently used pesticide (CUP) exposure among children living in Wallonia (Belgium). Pesticides were measured in both first morning urine voids of 258 children aged from 9 to 12 years and in ambient air collected close to the children's schools. Out of the 46 pesticides measured in the air, 19 were detected with frequencies varying between 11 % and 100 %, and mean levels ranging from <0.04 to 2.37 ng/m³. Only 3 parent pesticides were found in 1-10% of the urine samples, while all the metabolites analyzed were positively detected at least once. The captan metabolite (THPI) was quantified in 23.5 % of the samples, while 3,5,6-trichloro-2-pyridinol (chlopryrifos metabolite) was detected in all urines with levels ranging from 0.36-38.96 μg/l. 3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (t-DCCA) and diethylphosphate were the most abundant pyrethroid metabolites and dialkylphosphate measured. The air inhalation was demonstrated to be a minor route of exposure for the selected CUPs. Statistical regressions highlighted predictors of exposure for some pesticides such like consumption of grey bread, presence of carpets at home or indoor use of pesticides, although no clear source was identified for most of them., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2020 Elsevier B.V. All rights reserved.)

In response to the Walloon Environment and Health Program, the Scientific Institute of Public Services (ISSeP) developed an integrated approach of environmental exposure assessment in the Walloon region, Belgium. The study presents an index-based approach to estimate the multiple environmental burdens at regional level and detailed local resolution. Indicators are based on environmental measurements of pollutants in ambient air and soil, and on stressors for citizens related to noise and radon. These indicators were mapped as proportions to obtain an accurate comparison between spatial units. In order to indicate the need for intervention, environmental indicators are calculated as the proportion of areas where the level of detrimental environmental factors exceeds threshold values from WHO guidelines and Walloon legal threshold values. In parallel, a spatial web tool based on GIS was developed to enable a flexible and weighted combination of the normalized indicators by computing the resulting composite index online. This interactive web tool designed for policy makers and experts eases the spatial analysis of results in order to identify geographic areas where hotspot exposures are a potential risk to human health. The next steps of this work aim to integrate more environmental indicators (stressors and benefits) and some sociodemographic and health indicators in order to detect vulnerable populations. A holistic assessment is essential to inform environmental justice debates and to ensure a health conducive equal environment. Finally, this environmental health tool will support decision makers focus resources and programs to improve the environmental health of Walloons living in areas disproportionately burdened by multiple sources of pollution.

Background: Recent lead (Pb) exposure reduction strategies enabled to lower children's blood lead levels (B-Pb) worldwide. This study reports the estimated intelligence gain and social cost savings attributable to recent exposure reduction based on reported B-Pb levels observed in adolescents sampled within the framework of the Flemish Environment and Health Studies (FLEHS, Belgium), i.e. in 2003-2004 (FLEHSI), in 2008-2009 (FLEHSII), and in 2013-2014 (FLEHSIII)., Methods: Intelligence Quotient (IQ) loss per 100,000 individuals - attributable to B-Pb above 20 μg/L - was estimated based on widely accepted dose response functions between children's B-Pb and IQ (- 1.88 IQ points for a duplication in B-Pb from 20 μg/L onwards; 95% Confidence Interval (CI): - 1.16;-2.59) and B-Pb exposure distribution parameters of FLEHS studies. The results were translated to the Flemish population of 15-year-olds. Given a 3-year time gap between subsequent sampling periods, the exposure distribution of each study was assumed 3 years prior to the study as well. Economic impact was estimated based on expected decrease in lifetime earnings (€ 19,464 per decreasing IQ point in 2018)., Results: The percentage of the adolescent population exceeding a B-Pb of 20 μg/L decreased from 57% (FLEHSI) to 23% (FLEHSII), and even further to 2.5% (FLEHSIII). The estimated IQ loss per 100,000 individuals was 94,280 (95% CI: 58,427-130,138) in FLEHSI, 14,993 (95% CI: 9289-20,695) in FLEHSII, and 976 (95% CI: 604-1347) in FLEHSIII. This translates into a total loss of 378,962 (95%CI: 234,840-523,091) IQ points within the Flemish population of 15-year-olds between 2000 and 2014. Assuming that current exposure levels do not reincrease, the expected IQ loss during the subsequent period of 15 years is estimated to be maximally 10,275 (95%CI: 6363-14,182) points., Conclusions: 7176 (95%CI: 4447-9905) million € of social cost savings were achieved by Pb reduction strategies in Flanders over 15 years. If current exposure levels further reduce to B-Pb below 20 μg/L for the whole population, social cost savings may increase up to 7376 (95%CI: 4571-10,181) million €. Given the relatively low lead contamination in Flanders, the global impact of ongoing reduction strategies is expected to be tremendous.