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The aim of this study was to determine factors influencing observed increased metal biomarkers of exposure levels in a group of 116 Quebec apprentice welders during a longitudinal follow-up of exposure. Analysis of 14 metals was carried out in hair, fingernail, and toenail samples taken from participants over the course of their welding curriculum at 6 different times. Personal and socio-demographic characteristics, lifestyle habits, and other potential confounding factors were documented by questionnaire. Multivariate linear mixed-effect models were used to assess main predictors of metal concentrations in each biological matrix including increasing time of exposure throughout the curriculum (defined as the repeated measure "time" variable"). Significant associations between repeated measure "time" variable and metal levels in hair, fingernails, and toenails were found for chromium, iron, manganese and nickel. Significant associations with "time" were also noted for arsenic levels in hair and fingernails, and for barium, cobalt and vanadium levels in fingernails and toenails. The repeated measure "time" variable, hence increasing time of exposure throughout the curriculum, was the predominant predictor of elevated biological metal levels. Reduced spaces and simultaneous activities such as oxyfuel-cutting and welding in the same welding room were suspected to contribute to higher metal levels. Age, ethnicity, and annual household income exerted an effect on metal levels and considered as confounders in the models. Variations observed in metal levels between hair and nails of apprentice welders also emphasized the relevance and importance of performing multi-matrix and multi-element biomonitoring to assess temporal variations in biological metal concentrations during welding curriculum. [ABSTRACT FROM AUTHOR]

Canada has recently invested in the large-scale exploitation of scandium oxide. However, there are no studies available to date to understand its toxicokinetics in the animal or human body, which is necessary to assess exposure and health risks. The aim of this research was to investigate the toxicokinetics of absorbed scandium oxide (Sc 2 O 3) using the rat as an experimental model. Male Sprague-Dawley rats were injected intravenously with 0.3 or 1 mg Sc 2 O 3 /kg body weight (bw). Blood and excreta (urine and feces) were collected sequentially during a 21-day period, and main organs (liver, spleen, lungs, kidneys, brain) were withdrawn at sacrifice on day 21. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the measurement of Sc element in the different samples. The mean residence time (MRT IV) calculated from the blood profile was 19.7 ± 5.9 h and 43.4 ± 24.6 h at the lower and higher doses, respectively. Highest tissue levels of Sc were found in the lungs and liver; respective lung values of 10.6 ± 6.2% and 3.4 ± 2.3% of the Sc dose were observed at the time of sacrifice while liver levels represented 8.9 ± 6.4% and 4.6 ± 1.1%. Elimination of Sc from the body was not complete after 21 days. Cumulative fecal excretion over the 21-day collection period represented 12.3 ± 1.3% and 5.9 ± 1.0% of the lower and higher Sc doses, respectively, and showed a significant effect of the dose on the excretion; only a small fraction of the Sc dose was recovered in urine (0.025 ± 0.016% and 0.011 ± 0.004% in total, respectively). In addition to an effect of the dose on the toxicokinetics, results highlight the importance of the lung as a site of accumulation and retention of Sc 2 O 3 , which raises the question of the risks of effects related to respiratory exposure in workers. The results also question the relevance of urine as a matrix for biological exposure monitoring. A more in-depth inhalation toxicokinetic study would be necessary. • Intravenously injected scandium oxide accumulates in lungs and liver mainly. • Excretion occurs mainly in feces and little is found in urine. • The dose impacts the toxicokinetics of scandium oxide. • Higher scandium oxide dose resulted in lower cumulative excretion rates. • Lung retention raises the question of risks related to respiratory exposure. [ABSTRACT FROM AUTHOR]

The massive increase in emissions of air pollutants due to economic and industrial growth in developing countries has made air quality a crucial health problem in this continent. Hence, it is somewhat critical to have a better knowledge on the air pollution in Sub-Saharan Africa countries. Three air pollution PM2.5 samples were also collected in two urban sites (i.e. Fann and Faidherbe) in Dakar (Senegal) and in a rural site near Dakar (i.e. Ngaparu). The two urban sites mainly differ in the type of used vehicles: in Fann, most of the traffic is made of buses, which are absent, in Faidherbe. The physicochemical characteristics of the three PM2.5 samples revealed their high heterogeneities and complexities, related to the multiple natural and anthropogenic emission sources. Results from 5-bromodeoxyuridine incorporation into DNA, mitochondrial dehydrogenase activity, and extracellular lactate dehydrogenase activity in PM2.5-exposed BEAS-2B cells suggested the exposure conditions (i.e. 3 and 12μg PM/cm² during 24, 48, and 72h) to further consider. The organic fractions (i.e. mainly PAHs) of the PM2.5 samples were able to induce a time and/or concentration-dependent gene expression of CYP1A1 and CYP1B1, and, to a lesser extent, NQO1. There was a time and/or dose-dependent increase of both the gene expression and/or protein secretion of inflammatory mediators (i.e. TNF-α, IL-1β, IL-6, and/or IL-8) in PM2.5-exposed BEAS-2B cells. In agreement with the physicochemical characterization, urban PM2.5 samples caused greater biological responses in BEAS-2B cells than the rural one. Variable concentrations of transition metals (i.e. Fe, Al, Pb, Mn, Zn) and organic compounds (i.e. PAHs) founded in the three PM2.5 samples might be firmly involved in a time- and/or dose-dependent toxicity, relying on inflammatory processes. [Copyright &y& Elsevier]

Objective: This study aimed to investigate the impact of batteries recycling on the health of women of Colobane and mechanics of Medina (Dakar, Senegal). Methods: Various biological indicators of lead impregnation were determined among exposed and non-exposed subjects. Thus, blood lead level was assessed by SSA, and the rate of erythrocyte zinc protoporphyrin (ZPP) and δ-aminolevulinic acid in urine (UAla) were, respectively, determined by fluorimetry and spectrophotometry. The levels of serum iron and hemoglobin were also measured by spectrophotometry. Air and soil were sampled for lead level determination by ICP/MS. Results: Atmospheric and soil concentrations of lead on the site of Colobane, which is more contaminated than the site of Medina, were 10.3 μg/m3 and 115 792 mg/kg, respectively. The biological data obtained revealed average blood lead levels of 131.08±32.87 μg/L in unexposed subjects and 546.55±185.24 μg/L in exposed ones, where the value is clearly above the standard of 300 μg/L fixed for professionals. The rates obtained for ZPP (12.28 ± 7.09 μg/g Hb) and urinary Ala (9.12 ± 7.52 mg/g creatinine) showed the degree of impregnation of mechanics and lead-collecting women. Conclusion: As part of the fight against lead poisoning, which often touches a socially disadvantaged population, a policy of eradication or lead poisoning risk management should be implemented in accordance with the laws in force at an international level. [ABSTRACT FROM AUTHOR]

This study focused on the generation of aerosols of titanium dioxide (TiO 2 ) nanoparticles (NPs) and their disposition kinetics in rats. Male Sprague-Dawley rats were exposed by inhalation to 15mg/m 3 of anatase TiO 2 NPs (∼20nm) during 6h. Rats were sacrificed at different time points over 14days following the onset of inhalation. Ti levels were quantified by ICP-MS in blood, tissues, and excreta. Oxidative damages were also monitored (MDA). Highest tissue levels of Ti were found in lungs; peak values were reached only at 48h followed by a progressive decrease over 14days, suggesting a persistence of NPs at the site-of-entry. Levels reached in blood, lymph nodes and other internal organs (including liver, kidney, spleen) were circa one order of magnitude lower than in lungs, but the profiles were indicative of a certain translocation to the systemic circulation. Large amounts were recovered in feces compared to urine, suggesting that inhaled NPs were eliminated mainly by mucociliary clearance and ingested. TiO 2 NPs also appeared to be partly transferred to olfactory bulbs and brain. MDA levels indicative of oxidative damage were significantly increased in lungs and blood at 24h but this was not clearly reflected at later times. Translocation and clearance rates of inhaled NPs under different realistic exposure conditions should be further documented., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)