Internal exposure of Flemish teenagers to environmental pollutants: Results of the Flemish Environment and Health Study 2016-2020 (FLEHS IV).

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.

Circulating phthalates during critical illness in children are associated with long-term attention deficit: a study of a development and a validation cohort.

PURPOSE: Environmental phthalate exposure has been associated with attention deficit disorders in children. We hypothesized that in children treated in the pediatric intensive care unit (PICU), circulating phthalates leaching from indwelling medical devices contribute to their long-term attention deficit. METHODS: Circulating plasma concentrations of di(2-ethylhexyl)phthalate (DEHP) metabolites were quantified in 100 healthy children and 449 children who had been treated in PICU and were neurocognitively tested 4 years later. In a development patient cohort (N = 228), a multivariable bootstrap study identified stable thresholds of exposure to circulating DEHP metabolites above which there was an independent association with worse neurocognitive outcome. Subsequently, in a second patient cohort (N = 221), the observed independent associations were validated. RESULTS: Plasma concentrations of DEHP metabolites, which were virtually undetectable [0.029 (0.027-0.031) µmol/l] in healthy children, were 4.41 (3.76-5.06) µmol/l in critically ill children upon PICU admission (P < 0.001). Plasma DEHP metabolite concentrations decreased rapidly but remained 18 times higher until PICU discharge (P < 0.001). After adjusting for baseline risk factors and duration of PICU stay, and further for PICU complications and treatments, exceeding the potentially harmful threshold for exposure to circulating DEHP metabolites was independently associated with the attention deficit (all P ≤ 0.008) and impaired motor coordination (all P ≤ 0.02). The association with the attention deficit was confirmed in the validation cohort (all P ≤ 0.01). This phthalate exposure effect explained half of the attention deficit in post-PICU patients. CONCLUSIONS: Iatrogenic exposure to DEHP metabolites during intensive care was independently and robustly associated with the important attention deficit observed in children 4 years after critical illness. Clinicaltrials.gov identifier: NCT00214916.

Pivotal Role for the Visceral Fat Compartment in the Release of Persistent Organic Pollutants During Weight Loss.

CONTEXT: Polychlorinated biphenyls (PCBs), are implicated as potential endocrine disruptors and obesogens. These lipophilic substances are preferentially stored in the fat compartment and released into the circulation during weight loss. OBJECTIVE: The aim of this study was to examine the contribution of abdominal adiposity, and visceral adiposity in particular, to the increase of serum PCB levels during weight loss. MATERIALS AND METHODS: Fourty-five obese women were prospectively recruited. Twenty individuals received dietary counseling and 25 underwent bariatric surgery. Anthropometric data were collected and intra-abdominal adiposity was assessed by measurement computed tomography scanning of the abdominal fat compartment, delineating the visceral and subcutaneous compartment. Serum levels of 27 PCBs were determined and the sum of all PCBs (ΣPCBs) calculated. Follow-up measurements of anthropometric data, computed tomography scanning, and PCB levels were performed after 6 months in all patients. RESULTS: In patients who lost weight, serum ΣPCB levels displayed an increase after 6 months of approximately 50%. Both correlation and regression analysis, focusing on the relative contribution of the visceral vs the subcutaneous fat compartment, suggested that the increase in ΣPCB serum levels after 6 months of weight loss was more pronounced in patients losing relatively more visceral adipose tissue. This trend could be established in the diet-treated, but not the surgery-treated subgroup. CONCLUSION: Our study suggests that the contribution of PCBs released from the visceral fat compartment might be more pronounced compared with the subcutaneous fat compartment during weight loss. These findings are present in the entire study group whereas subanalysis of the diet vs surgery groups suggested the same effect in the diet group but failed to reach statistical significance in the surgery group. This suggests a possible weight-loss method-specific effect.

Detecting genome-wide gene transcription profiles associated with high pollution burden in the critically endangered European eel.

The European eel illustrates an example of a critically endangered fish species strongly affected by human stressors throughout its life cycle, in which pollution is considered to be one of the factors responsible for the decline of the stock. The objective of our study was to better understand the transcriptional response of European eels chronically exposed to pollutants in their natural environment. A total of 42 pre-migrating (silver) female eels from lowly, highly and extremely polluted environments in Belgium and, for comparative purposes, a lowly polluted habitat in Italy were measured for polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and brominated flame retardants (BFRs). Multipollutant level of bioaccumulation was linked to their genome-wide gene transcription using an eel-specific array of 14,913 annotated cDNAs. Shared responses to pollutant exposure were observed when comparing the highly polluted site in Belgium with the relatively clean sites in Belgium and Italy. First, an altered pattern of transcription of genes was associated with detoxification, with a novel European eel CYP3A gene and gluthatione S-transferase transcriptionally up-regulated. Second, an altered pattern of transcription of genes associated with the oxidative phosphorylation pathway, with the following genes involved in the generation of ATP being transcriptionally down-regulated in individuals from the highly polluted site: NADH dehydrogenase, succinate dehydrogenase, ubiquinol-cytochrome c reductase, cytochrome c oxidase and ATP synthase. Although we did not measure metabolism directly, seeing that the transcription level of many genes encoding enzymes involved in the mitochondrial respiratory chain and oxidative phosphorylation were down-regulated in the highly polluted site suggests that pollutants may have a significant effect on energy metabolism in these fish.