| 1. |
- Gliga, Anda R., et al.
(författare)
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Mild steel welding is associated with alterations in circulating levels of cancer-related proteins
- 2019
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 93:12, s. 3535-3547
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Tidskriftsartikel (refereegranskat)abstract
- Welding fumes were recently classified as carcinogenic to humans and worldwide millions work as welders or perform welding operations. The purpose of this study was to identify new biomarkers of welding-induced carcinogenesis. We evaluated a panel of 91 putative cancer-related proteins in serum in a cohort of welders working with mild steel (n = 77) and controls (n = 94) from southern Sweden sampled on two occasions 6-year apart using a longitudinal analysis (linear mixed models). The significant results from the longitudinal analysis were tested for reproducibility in welders (n = 88) and controls (n = 69) sampled once during the same sampling period as timepoint 1 or timepoint 2 (linear regression models), i.e., in a cross-sectional setting. The models were adjusted for age, body-mass index, and use of snus. All study participants were non-smokers at recruitment. Exposure to welding fumes was assessed using questionnaires and respirable dust measurement in the breathing zone that was adjusted for personal respiratory protection equipment. The median respirable dust in welders was 0.7 (0.2–4.2) and 0.5 (0.1–1.9) mg/m3 at the first and second timepoints, respectively. We identified 14 cancer-related proteins that were differentially expressed in welders versus controls in the longitudinal analysis, out of which three were also differentially expressed in the cross-sectional analysis (cross-sectional group). Namely, syndecan 1 (SDC1), folate receptor 1 (FOLR1), and secreted protein acidic and cysteine rich (SPARC) were downregulated, in welders compared with controls. In addition, FOLR1 was negatively associated with years welding. Disease and function analysis indicated that the top proteins are related to lung cancer as well as cell invasion and migration. Our study indicates that moderate exposure to welding fumes is associated with changes in circulating levels of putative cancer-related proteins, out of which FOLR1 showed a clear dose–response relationship. It is, however, unclear to which extent these changes are adaptive or potential early biomarkers of cancer.
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| 2. |
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| 3. |
- Hedmer, Maria, et al.
(författare)
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Diesel Exhaust Exposure Assessment Among Tunnel Construction Workers—Correlations Between Nitrogen Dioxide, Respirable Elemental Carbon, and Particle Number
- 2017
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Ingår i: Annals of Work Exposures and Health. - : Oxford University Press (OUP). - 2398-7308 .- 2398-7316. ; 61:5, s. 539-553
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Occupational exposure to diesel exhaust is common due the widespread use of dieselpowered combustion engines. Diesel exhaust is chemically complex and consists of thousands of compounds present as gases and particulate matter. Both nitrogen dioxide (NO2) and elemental carbon(EC) have been used as markers for diesel exhaust exposure. Currently EC is regarded as the best surrogate of diesel exhaust. The objective was to quantify the occupational exposure to diesel exhaust in underground tunnel construction work using a multi-metric approach, and to investigate the correlations between NO2, respirable EC, respirable organic carbon (OC), respirable total carbon(TC), respirable dust (RD), and particle number. Also, the use of NO2 as a proxy for diesel exhaust was evaluated, how much of the variability in the diesel exhaust exposure was attributed to within and between individual factors and if there was a difference between expert and self-administered measurements of NO2. Methods: The personal exposure to diesel exhaust was assessed by expert supervised measurements of NO2, EC, OC, TC, RD and particle number in the breathing zones of underground tunnel workers. Stationary sampling of NO2, EC, OC, TC, RD, size-fractioned mass concentration, and particle number were conducted. The personal and stationary measurements were conducted on threeoccasions simultaneously. The workers measured their exposure by repeated self-administered measurements of NO2. The self-administered measurements were performed twice for each worker with at least one month lag between the samplings. Results: In the simultaneous sampling of diesel exhaust, the geometric mean (GM) concentration of NO2 and respirable EC were 72 μg m−3 (10th–90th percentile 34–140 μg m−3) and 2.6 μg m−3 (10th–90th percentile 1.6–7.3 μg m−3), respectively. The GM for OC and TC was 28 μg m−3 (10th–90th percentile 20–42 μg m−3) and 31 μg m−3 (10th–90th percentile 20–50 μg m−3), respectively. The GM for RD and particle number was 180 μg m−3 (10th–90th percentile 20–530 μg m−3) and 47 900 cm−3 (10th–90th percentile (27 500–94 100 cm−3), respectively. A significant correlation was found between NO2 and respirable EC [Spearman’s correlation r = 0.53 (P = 0.05)]. The within-worker variability of NO2 was 45.5% and the between-worker variability was 54.5%. The self-administered measured concentrations of NO2 (GM 70 μg m−3) did not statistically differ from the NO2 concentrations measured by an expert (P > 0.35).Conclusion: The diesel exhaust exposure in tunnel construction work was low. A significant correlation between NO2 and EC was observed. This indicates that NO2 could be used as a proxy for diesel exhaust in tunnel work if diesel exhaust is the only source of NO2 and if the ratio between EC and NO2 is known and constant. Passive sampling of NO2 is much easier and cheaper to perform compared with active sampling of EC. It is possible to utilize self-administered NO2 measurements in extreme and inaccessible work environments. This study adds support to continued use of NO2 as an exposure marker in combination with EC for diesel exhaust exposure. In tunnel construction work, the variability in the diesel exhaust exposure was high both between- and within-workers.
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| 4. |
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| 5. |
- Hossain, Bakhtiar, et al.
(författare)
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Exposure to welding fumes is associated with hypomethylation of the F2RL3 gene: a cardiovascular disease marker.
- 2015
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Ingår i: Occupational and Environmental Medicine. - : BMJ. - 1470-7926 .- 1351-0711. ; 72:12, s. 845-851
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Tidskriftsartikel (refereegranskat)abstract
- Welders are at risk for cardiovascular disease. Recent studies linked tobacco smoke exposure to hypomethylation of the F2RL3 (coagulation factor II (thrombin) receptor-like 3) gene, a marker for cardiovascular disease prognosis and mortality. However, whether welding fumes cause hypomethylation of F2RL3 remains unknown.
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| 6. |
- Li, Huiqi, et al.
(författare)
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A Cross-Sectional Study of the Cardiovascular Effects of Welding Fumes.
- 2015
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Occupational exposure to particulate air pollution has been associated with an increased risk of cardiovascular disease. However, the risk to welders working today remains unclear. We aimed to elucidate the cardiovascular effects of exposure to welding fumes. METHODS: In a cross-sectional study, structured interviews and biological sampling were conducted for 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal breathing zone sampling of respirable dust was performed. Blood pressure (BP) and endothelial function (using peripheral arterial tonometry) were measured. Plasma and serum samples were collected from peripheral blood for measurement of C-reactive protein, low-density lipoprotein, homocysteine, serum amyloid A, and cytokines. RESULTS: Welders were exposed to 10-fold higher levels of particles than controls. Welders had significantly higher BP compared to controls, an average of 5 mm Hg higher systolic and diastolic BP (P≤0.001). IL-8 was 3.4 ng/L higher in welders (P=0.010). Years working as a welder were significantly associated with increased BP (β=0.35, 95%CI 0.13 - 0.58, P=0.0024 for systolic BP; β=0.32, 95%CI 0.16 - 0.48, P<0.001 for diastolic BP, adjusted for BMI) but exposure to respirable dust was not associated with BP. No clear associations occurred between welding and endothelial function, or other effect markers. CONCLUSIONS: A modest increase in BP was found among welders compared to controls suggesting that low-to-moderate exposure to welding fumes remains a risk factor for cardiovascular disease.
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| 7. |
- Li, Huiqi, et al.
(författare)
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Oxidative stress, telomere shortening, and DNA methylation in relation to low-to-moderate occupational exposure to welding fumes.
- 2015
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Ingår i: Environmental and Molecular Mutagenesis. - : Wiley. - 1098-2280 .- 0893-6692. ; 56:8, s. 684-693
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Tidskriftsartikel (refereegranskat)abstract
- Evidence suggests that exposure to welding fumes is a risk factor for lung cancer. We examined relationships between low-to-moderate occupational exposure to particles from welding fumes and cancer-related biomarkers for oxidative stress, changes in telomere length, and alterations in DNA methylation. We enrolled 101 welders and 127 controls (all currently nonsmoking men) from southern Sweden. We performed personal sampling of respirable dust and measured 8-oxodG concentrations in urine using a simplified liquid chromatography tandem mass spectrometry method. Telomere length in peripheral blood was measured by quantitative polymerase chain reaction. Methylation status of 10 tumor suppressor genes was determined by methylation-sensitive high-resolution melting analysis. All analyses were adjusted for age, body mass index, previous smoking, passive smoking, current residence, and wood burning stove/boiler at home. Welders were exposed to respirable dust at 1.2 mg/m(3) (standard deviation, 3.3 mg/m(3) ; range, 0.1-19.3), whereas control exposures did not exceed 0.1 mg/m(3) (P < 0.001). Welders and controls did not differ in 8-oxodG levels (β = 1.2, P = 0.17) or relative telomere length (β = -0.053, P = 0.083) in adjusted models. Welders showed higher probability of adenomatous polyposis coli (APC) methylation in the unadjusted model (odds ratio = 14, P = 0.014), but this was not significant in the fully adjusted model (P = 0.052). Every working year as a welder was associated with 0.0066 units shorter telomeres (95% confidence interval -0.013 to -0.00053, P = 0.033). Although there were no clear associations between concentrations of respirable dust and the biomarkers, there were modest signs of associations between oxidative stress, telomere alterations, DNA methylation, and occupational exposure to low-to-moderate levels of particles. Environ. Mol. Mutagen., 2015. © 2015 Wiley Periodicals, Inc.
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| 8. |
- Ludvigsson, Linus, et al.
(författare)
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Carbon Nanotube Emissions from Arc Discharge Production: Classification of Particle Types with Electron Microscopy and Comparison with Direct Reading Techniques.
- 2016
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press (OUP). - 1475-3162 .- 0003-4878. ; 60:4, s. 493-512
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: An increased production and use of carbon nanotubes (CNTs) is occurring worldwide. In parallel, a growing concern is emerging on the adverse effects the unintentional inhalation of CNTs can have on humans. There is currently a debate regarding which exposure metrics and measurement strategies are the most relevant to investigate workplace exposures to CNTs. This study investigated workplace CNT emissions using a combination of time-integrated filter sampling for scanning electron microscopy (SEM) and direct reading aerosol instruments (DRIs). Material and Methods: Field measurements were performed during small-scale manufacturing of multiwalled carbon nanotubes using the arc discharge technique. Measurements with highly time- and size-resolved DRI techniques were carried out both in the emission and background (far-field) zones. Novel classifications and counting criteria were set up for the SEM method. Three classes of CNT-containing particles were defined: type 1: particles with aspect ratio length:width >3:1 (fibrous particles); type 2: particles without fibre characteristics but with high CNT content; and type 3: particles with visible embedded CNTs. Results: Offline sampling using SEM showed emissions of CNT-containing particles in 5 out of 11 work tasks. The particles were classified into the three classes, of which type 1, fibrous CNT particles contributed 37%. The concentration of all CNT-containing particles and the occurrence of the particle classes varied strongly between work tasks. Based on the emission measurements, it was assessed that more than 85% of the exposure originated from open handling of CNT powder during the Sieving, mechanical work-up, and packaging work task. The DRI measurements provided complementary information, which combined with SEM provided information on: (i) the background adjusted emission concentration from each work task in different particle size ranges, (ii) identification of the key procedures in each work task that lead to emission peaks, (iii) identification of emission events that affect the background, thereby leading to far-field exposure risks for workers other than the operator of the work task, and (iv) the fraction of particles emitted from each source that contains CNTs. Conclusions: There is an urgent need for a standardized/harmonized method for electron microscopy (EM) analysis of CNTs. The SEM method developed in this study can form the basis for such a harmonized protocol for the counting of CNTs. The size-resolved DRI techniques are commonly not specific enough to selective analysis of CNT-containing particles and thus cannot yet replace offline time-integrated filter sampling followed by SEM. A combination of EM and DRI techniques offers the most complete characterization of workplace emissions of CNTs today.
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| 9. |
- Xu, Yiyi, et al.
(författare)
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Occupational exposure to particles and mitochondrial DNA : Relevance for blood pressure
- 2017
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Ingår i: Environmental Health: A Global Access Science Source. - : Springer Science and Business Media LLC. - 1476-069X. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Particle exposure is a risk factor for cardiovascular diseases. Mitochondrial DNA (mtDNA) is a primary target for oxidative stress generated by particle exposure. We aimed to elucidate the effects of occupational exposure to particle-containing welding fumes on different biomarkers of mtDNA function, and in turn, explore if they modify the association between particle exposure and cardiovascular response, measured as blood pressure. Methods: We investigated 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal sampling of the welders’ exposure to respirable dust was performed during work hours (average sampling time: 6.8 h; range: 2.4-8.6 h) and blood pressure was measured once for each subject. We measured relative mtDNA copy number by quantitative PCR and methylation of the mitochondrial regulatory region D-loop and the tRNA encoding gene MT-TF by bisulfite-pyrosequencing. We calculated the relative number of unmethylated D-loop and MT-TF as markers of mtDNA function to explore the modification of mtDNA on the association between particle exposure and blood pressure. General linear models were used for statistical analyses. Results: Welders had higher mtDNA copy number (β = 0.11, p = 0.003) and lower DNA methylation of D-loop (β = −1.4, p = 0.002) and MT-TF (β = −1.5, p = 0.004) than controls. Higher mtDNA copy number was weakly associated with higher personal respirable dust exposure among welders with exposure level above 0.7 mg/m3 (β = 0.037, p = 0.054). MtDNA function modified the effect of welding fumes on blood pressure: welders with low mtDNA function had higher blood pressure than controls, while no such difference was found in the group with high mtDNA function. Conclusion: Increased mtDNA copy number and decreased D-loop and MT-TF methylation were associated with particle-containing welding fumes exposure, indicating exposure-related oxidative stress. The modification of mtDNA function on exposure-associated increase in blood pressure may represent a mitochondria-environment interaction.
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| 10. |
- Landberg, Hanna, et al.
(författare)
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Evaluating the Risk Assessment Approach of the REACH Legislation : A Case Study
- 2019
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Ingår i: Annals of Work Exposures and Health. - : Oxford University Press. - 2398-7308 .- 2398-7316. ; 63:1, s. 68-76
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Tidskriftsartikel (refereegranskat)abstract
- Risk assessments based on occupational exposure to chemicals have increased since REACH (European regulation on Registration, Evaluation, Authorization, and restriction of Chemicals) came into force. The European Chemicals Agency (ECHA) recommends that chemical exposure could be calculated using exposure models and that parameters used to calculate the exposure scenario (ES) should be communicated in extended safety data sheets (e-SDS) as workplace instructions which downstream users are obligated to follow. We aimed to evaluate REACH's risk assessment approach using the Stoffenmanager((R)) 6.1, the Advanced REACH Tool 1.5 (ART), and the European Centre for Ecotoxicology and Toxicology of Chemicals' targeted risk assessment (ECETOC TRA 3.1) exposure models. We observed 239 scenarios in three companies handling chemicals using 45 e-SDS. Risk characterization ratios (RCRs) were calculated by dividing estimated exposures by derived no-effect levels (DNELs). Observed RCRs were much lower than registered RCRs, indicating lower exposures. However, about 12% of the observed ES still had RCRs > 1, after adjustment for control measures and personal protections described in the ES, when using Stoffenmanager((R)). The ES with observed RCRs > 1 were the same by Stoffenmanager((R)) and ART, but not by ECETOC TRA. Stoffenmanager and ART identified 25 adjusted scenarios with RCR > 1, while ECETOC TRA gave RCR < 1 for the same scenarios. The ES with RCR > 1 were significantly associated to chemicals with higher vapour pressure and lower DNELs than ES with RCR < 1 by Stoffenmanager((R)). The correlations between observed and registered RCRs were lower than those between RCRs calculated from the different models themselves; ECETOC TRA had the lowest correlation with the registered ES. These results put in question the generic ES recommended under the REACH legislation. Downstream users may get better estimates by assessing their own ES, especially for chemicals with low DNELs and high vapour pressure.
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