98 research outputs found
STRATEGY FOR ASSESSING IMPACTS OF THYROID DISRUPTING CHEMICALS IN TELEOSTEANS
Peer reviewe
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
Thyroid dysfunction in sea bass (Dicentrarchus labrax): Underlying mechanisms and effects of polychlorinated biphenyls on thyroid hormone physiology and metabolism
peer reviewedaudience: researcher, professional, student, popularization, otherThe current study examines the effect of subchronic exposure to a mixture of Aroclor standards on thyroid hormone physiology and metabolism in juvenile sea bass. The contaminant mixture was formulated to reflect the persistent organic pollution to which the European sea bass population could conceivably be exposed (0.3, 0.6 and 1.0 g 7PCBs per g food pellets) and higher (10 g 7PCBs per g food pellets). After 120 days of exposure, histomorphometry of thyroid tissue, muscular thyroid hormone concentration and activity of enzymes involved in metabolism of thyroid hormones were assessed. Mean concentrations of 8, 86, 142, 214 and 2279 ng g−1 ww ( 7 ICES PCB congeners) were determined after 120 days exposure. The results show that the effects of PCB exposures on the thyroid system are dose-dependent. Exposure to environmentally relevant doses of PCB (0.3–1.0 g 7PCBs per g food pellets) induced a larger variability of the follicle diameter and stimulated hepatic T4 outer ring deiodinase. Muscular thyroid hormone levels
were preserved thanks to the PCB induced changes in T4 dynamics. At 10 times higher concentrations (10 g 7PCBs per g food pellets) an important depression of T3 and T4 levels could be observed which are apparently caused by degenerative histological changes in the thyroid tissue
Methods, fluxes and sources of gas phase alkyl nitrates in the coastal air
The daily and seasonal atmospheric concentrations, deposition fluxes and emission sources of a few C3-C9 gaseous alkyl nitrates (ANs) at the Belgian coast (De Haan) on the Southern North Sea were determined. An adapted sampler design for low- and high-volume air-sampling, optimized sample extraction and clean-up, as well as identification and quantification of ANs in air samples by means of gas chromatography mass spectrometry, are reported. The total concentrations of ANs ranged from 0.03 to 85 pptv and consisted primarily of the nitro-butane and nitro-pentane isomers. Air mass backward trajectories were calculated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to determine the influence of main air masses on AN levels in the air. The shorter chain ANs have been the most abundant in the Atlantic/Channel/UK air masses, while longer chain ANs prevailed in continental air. The overall mean N fluxes of the ANs were slightly higher for summer than those for winter-spring, although their contributions to the total nitrogen flux were low. High correlations between AN and HNO2 levels were observed during winter/spring. During summer, the shorter chain ANs correlated well with precipitation. Source apportionment by means of principal component analysis indicated that most of the gas phase ANs could be attributed to traffic/combustion, secondary photochemical formation and biomass burning, although marine sources may also have been present and a contributing factor. © 2014 Springer International Publishing Switzerland
Daily intake of OCPs, PCBs and PBDEs from food consumption and indoor dust ingestion in Romania
Brominated flame retardants: analytical, toxicological and environmental aspects
Brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs) and tetrabromobisphenol-A (TBBP-A), have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injury and property damage. Recently. concern for this emerging class of chemicals has risen because of their occurrence in the environment and in human biota. Here we briefly review scientific issues related to analytical, toxicological and environmental aspects of these BFRs and discuss data gaps
Estimation of daily intake of organohalogenated contaminants from food consumption and indoor dust ingestion in Romania
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