Per Arne Drabløs

Ultrafine particles at workplaces of a primary aluminium smelter

The number concentration and size distribution of ultrafine particles in a Søderberg and a prebake potroom of an aluminium primary smelter have been measured using a scanning mobility particle spectrometer. The particle morphology was studied by transmission electron microscopy (TEM). The study shows the existence of elevated number concentrations of ultrafine particles in both potrooms. The main source of these particles is likely to be the process of anode changing. The ultrafine particles were measured directly at the source but could also be identified as episodes of high number concentrations in the general background air. Unlike the larger particles belonging to the 50-100 nm mode, the nanoparticle mode could not be detected in the TEM indicating that they may not be stable under the applied sampling conditions and/or the high vacuum in the instrument.

Plasma total homocysteine response to oral doses of folic acid and pyridoxine hydrochloride (vitamin B6) in healthy individuals. Oral doses of vitamin B6 reduce concentrations of serum folate

Plasma total homocysteine response was compared in four groups of healthy individuals given orally divided doses of vitamin supplementations for a duration of 5 weeks. The vitamin supplements; A, 0.3 mg folic acid; B, 120 mg vitamin B6; C, combination of 0.3 mg folic acid and 120 mg vitamin B6 or D, 0.6 mg folic acid reduced the concentrations of plasma total homocysteine 20, 17, 32 and 24%, respectively. However, the intergroup comparisons did not show a significant difference in the effects of vitamin supplements. Multivariate analysis with correction for differences in pre-supplement values indicated a significant effect of vitamin B6 supplementation on plasma total homocysteine and serum folate. Our data show that plasma total homocysteine concentrations are reduced with low to medium divided doses of folic acid alone or in combination with vitamin B6.

Characterization of individual aerosol particles in workroom air of aluminium smelter potrooms

Aerosol particles with aerodynamic diameters between 0.18 and 10 microm were collected in the workroom air of two aluminium smelter potrooms with different production processes (Soderberg and Prebake processes). Size, morphology and chemical composition of more than 2000 individual particles were determined by high resolution scanning electron microscopy and energy-dispersive X-ray microanalysis. Based on chemical composition and morphology, particles were classified into different groups. Particle groups with a relative abundance above 1%(by number) include aluminium oxides, cryolite, aluminium oxides-cryolite mixtures, soot, silicates and sea salt. In both production halls, mixtures of aluminium oxides and cryolite are the dominant particle group. Many particles have fluoride-containing surface coatings or show agglomerations of nanometer-sized fluoride-containing particles on their surface. The phase composition of approximately 100 particles was studied by transmission electron microscopy. According to selected area electron diffraction, sodium beta-alumina (NaAl(11)O(17)) is the dominant aluminium oxide and cryolite (Na(3)AlF(6)) the only sodium aluminium fluoride present. Implications of our findings for assessment of adverse health effects are discussed.

Serum Folate Is Significantly Correlated with Plasma Cysteine Concentrations in Healthy Industry Workers

Background: A low concentration of serum folate is associated with an increased risk of cardiovascular disease. Extracellular cysteine is involved in aging, cancer and cardiovascular disease. The relationship between serum folate and plasma cysteine is poorly understood. Therefore, we investigated this relationship in industry workers, whose health has economic implications. Methods: The concentration of serum folate was determined by the Access ImmunoAssay System Sanofi Pasteur. Plasma cysteine and homocysteine were measured by an ion-pair HPLC method. The concentrations of serum triglycerides were determined by an enzymatic colorimetric method. Results: We detected a positive correlation between the concentration of serum folate and plasma cysteine, whereas the concentration of serum folate was negatively correlated with plasma homocysteine and serum triglycerides. In a multiple regression analysis with adjustment for age, BMI and smoking, serum folate as the dependent variable exhibited a strong relationship with plasma cysteine, and a negative relationship with plasma homocysteine and serum triglycerides. Conclusion: We observed significant correlations between serum folate, plasma cysteine and serum triglyceride concentrations in industry workers, implying that folate may modulate key aspects of the body’s cysteine and lipid metabolism.

Absence of relation between sick leave caused by musculoskeletal disorders and exposure to magnetic fields in an aluminum plant

This is a study of the relationship between occupational exposure to magnetic fields in pot rooms and occurrence of sick leave caused by musculoskeletal disorders. The average exposure to static magnetic fields was 8 mT in the pot rooms. Ripple fields were recorded as well. A cohort of 342 exposed workers and 222 unexposed workers from the same electrolysis plant was retrospectively followed for 5 years. The reference group had a type of work similar to the exposed group except for the exposure to magnetic fields. The occurrence of sick leave and the diagnoses causing the sick leave were obtained from the Occupational Health Care Unit: these data were stored in their computer files. The data were complete. No relationship between the occurrence of sick leave caused by musculoskeletal disorders and exposure to magnetic fields was found. This was the case for both the annual number of periods of sick leave and the total number of days with sick leave. The results must be interpreted with caution due to limitations in the design and available data. Also, static magnetic fields constituted the major exposure, and the results may be different when related to work in other types of magnetic-field exposure.

Higher leukocyte subpopulation counts in healthy smoker industrial workers than in nonsmoker industrial workers: possible health consequences.

Objectives: Cigarette smoke contains free radicals, which cause injury to endothelial cells and oxidize bioactive components in the blood. Neutrophils, a subpopulation of leukocytes, contain the enzyme myeloperoxidase that mediates production of hypochlorous acid during oxidative stress. In this study, we investigated whether smoker industrial workers had significantly higher neutrophil counts than nonsmoker industrial workers. Design and Methods: We collected blood samples from 183 apparently healthy male and 30 female industrial workers. We obtained blood cell counts, measured the concentration of plasma aminothiols and determined the concentration of serum and erythrocyte folate and serum vitamin B12 in the samples. Results: Smoker industrial workers had significantly higher neutrophil, lymphocyte, monocyte, eosinophil and basophil counts than nonsmoker industrial workers (p < 0.0001, p < 0.0001, p < 0.0001, p < 0.0001 and p = 0.01, respectively). Mean corpuscular volume and mean corpuscular hemoglobin in smoker industrial workers were higher than in nonsmoker industrial workers (p = 0.001 and p = 0.03). Conclusion: Our study demonstrates that smoker industrial workers have higher neutrophil counts than nonsmoker industrial workers. Therefore, our observations suggest that smokers may become more easily prone to chronic inflammation than nonsmokers. About 84% of the study participants were male subjects; therefore, our findings may be more representative for men than women.

Hygroscopic properties of individual aerosol particles from aluminum smelter potrooms determined by environmental scanning electron microscopy

Aluminum is produced by electrolysis of alumina (Al2O3). To decrease the melting point cryolite (Na3AlF6) is added. At present, the Norwegian aluminum industry uses two different technologies to produce aluminum: the so called Soderberg and Prebake processes [1]. In both cases, particles with variable composition, several gases (for example hydrogen fluorides) and aromatic hydrocarbons (PAHs) are formed. Inhalation of these pollutants leads to adverse health effects for the workers. For better understanding of the toxicological relevance of the particulate matter present in the workrooms, individual particle analysis was performed. Special emphasis was placed on the hygroscopic properties of the different particles sampled in the potrooms, as the presence of thin water films or small droplets may provide an opportunity for hydrogen fluoride (HF) to be transported deep into the lung.