Fast analysis of decabrominated diphenyl ether using low-pressure gas chromatography electron-capture negative ionization mass spectrometry

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4-Amino-3,5-di-2-pyridyl-4H-1,2,4-triazole

In the crystal structure of the title compound, C12H10N6, the mol­ecules deviate slightly from planarity. The plane of the central triazole ring makes angles of 6.13 (9) and 3.28 (10)° with the pyridyl ring planes. Intra­molecular N—H⋯N inter­actions form six-membered closed rings. The crystal packing also shows weak C—H⋯π and C—H⋯N inter­actions

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

Assessment of the water soluble ionic species of suspended particulate matter, collected at a coastal spot, De Haan, Belgium

Chemical characterisation of suspended particulate matter (SPM) is very useful for broadening the knowledge concerning processes which are active in the atmosphere (e.g. Lin, 2002). Continental air-masses were found to contain high levels of anthropogenic emitted species, while these levels decreased when the influence changed to an oceanic atmosphere. The high levels of NH4 +, NO3 - and non-sea-salt (NSS) SO4 2- in the fine SPM fraction of continental air-masses (0.38, 0.15μg.N.m-3 and 0.59μg.m-3, respectively) stresses the importance of secondary aerosol formation as a source for SPM. The dominant appearances of Na+, Cl-, Mg2+ and Ca2+ in coarse maritime air masses show the presence of sea-salts and soil dust in the atmosphere at the coastal region. Neutralisation ratios higher than unity (1.20-1.59) for the fine SPM fraction suggested an excess of NH4 +, which was most probably present in the form of NH4Cl due neutralisation of HCl. The latter was formed in atmospheric reactions with sea-salt particles (Kadowaki, 1977), during which HCl escapes (0.13 and 0.58% lost sea-salt chloride for winter and summer, respectively). Correlation analysis showed that warm and dry summer conditions eliminated some influence of sea-salts on atmospheric processes, that where found to be active during winter. NSS SO4 2- was the dominant S-contributor in the fine fraction (83%). During winter, a total SOR value of 0.61 was reached, while summer gave a significant lower value (0.24). These values classified the sampling-site at the Belgian coast as a combined receptor-source area, accepting pollution from the continent and its local surroundings (Shaw and Rodhe, 1982)

Occurrence and profiles of PCBs and PBDEs in harbour seals and harbour porpoises from the southern North Sea

Harbour porpoises (Phocoena phocoen) and harbour seals (Phoca vitulina), two representative top coastal pollution. Concentrations of sum PCBs were 1-2 orders of magnitude higher than concentrations of sum PBDEs (with median values of 23.1 μg.g- lw (lipid weight) and 12.4 μ.g-1 lw for sum PCBs and 0.33 μ.g- lw and 0.76 μ.g-1 lw for sum PBDEs in harbour seals and harbour porpoises respectively) and were highly dependent of age group and gender. For both species, the highest PCB concentrations were observed in adult males as the result of accumulation for years and years, while the highest PBDE concentrations were measured in juveniles probably due to better developed metabolic capacities for these congeners with age in adults. Results for PCBs were higher than observations in harbour seals and porpoises from other areas, while results for PBDEs were comparable indicating that the North Sea is a highly contaminated area. Relative PCB and PBDE profiles were constructed to compare metabolic capacities between harbour seals and porpoises. A higher contribution of lower chlorinated and nonpersistent congeners, such as CB 52, CB 95, CB 101, CB 118 and CB 149 indicated that harbour porpoises are unable to metabolize these compounds. Similar to PCBs, higher contributions of other PBDEs than BDE 47 were observed in harbour porpoises, suggesting that this species has difficulties to metabolize these congeners. In contrast, harbour seals showed a higher ability to metabolize PCBs and PBDEs

STRATEGY FOR ASSESSING IMPACTS OF THYROID DISRUPTING CHEMICALS IN TELEOSTEANS

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Atmospheric nitrogen input into the North Sea: organic nutrient detection

The levels of gaseous organic nitrogen compounds (alkyl nitrates - ANs) together with identification of the possible sources of these compounds in the air were studied. Seasonal trends were investigated by conducting the sampling campaigns during the spring, summer and winter time. The air-mass backward trajectories (BWTs) were calculated for the sampling periods by Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model (Draxler and Rolph, 2003). These BWTs were considered for the determination of the influence of the Atlantic Ocean, the North Sea and the continent as possible sources of ANs. An adapted set-up for low and high volume samplings, extraction and minimized clean-up, identification and quantification capabilities resulting from the complementary use of GC-ECD and GC-MS methods is reported. The AN levels were found to be in the range of a few to 7400 pg.m-3 in the air. The AN fraction consisted of primarily the 2C4, C5 and C6 isomers, which contribute largely to the total AN level. The N-fluxes by ANs were more pronounced for the summer periods than for the winter/spring months, organic nitrates were the most abundant in the Atlantic/Channel/UK air-masses

Complete and incomplete spin transitions in 1D chain iron(II) compounds.

The synthesis and characterisation of two new octahedral iron(II) SCO coordination polymers [FeL1(bimm)] (1) and [FeL2(bppa)](MeOH)0.5 (2) (L1 = [3,30]-[1,2- phenylenebis-(iminomethylidyne)bis(4-phenyl-,4-butanedionato)(2-)-N,N0,O2,O20], L2 = [E,E]-[{diethyl 2,20-1,2- phenylenebis(iminomethylidyne)bis(3-oxo-3-phenylpropanato)}(2-)-N,N0,O3,O30], bimm = bis(1H-imidazol-1-yl)methane and bppa = 1,3-bis(pyridine-4-yl)propane) is presented. Results from X-ray structure analysis at different temperatures revealed in the case of 1 that the transition from a gradual to a cooperative SCO with a 5 K wide hysteresis is due to an increase of the short intermolecular contacts, which exceed a certain threshold for the cooperative effect. In the case of compound 2 an incomplete spin transition with a 4 K wide hysteresis was observed. The low temperature wMT product remains constant at a value typical for a mixed HS/LS state in stepwise spin transitions. A quantitative correlation between the cooperative effects of 12 monomer and polymer iron(II) SCO complexes and their structural properties derived from X-ray structure analysis, the so-called crystal contact index, CCI, is introduced