Chemical Composition of Thoracic Dust at Workplaces During Cement Production.

OBJECTIVES: Cement belongs to the most used building materials. Clinker is the major constituent of cement, and it is believed that the strong increase of pH after hydration of clinker minerals is responsible for the observed decline in lung function of cement production workers. Information on clinker exposure at workplaces in the cement production industry is scarse. The aims of this study are to determine the chemical composition of thoracic dust and to quantify workplace exposure to clinker in cement production. METHODS: The elemental composition of 1250 personal thoracic samples collected at workplaces in 15 plants located in 8 different countries (Estonia, Greece, Italy, Norway, Sweden, Switzerland, Spain, Turkey) was determined by inductively coupled plasma optical emission spectrometry (ICP-OES), separately for water- and acid-soluble fraction. Positive matrix factorization (PMF) was used to determine the contribution of different sources to the dust composition and to quantify the clinker content in 1227 of the thoracic samples. In addition, 107 material samples were analysed to facilitate interpretation of the factors obtained by PMF. RESULTS: The median thoracic mass concentrations varied for individual plants between 0.28 and 3.5 mg/m3. PMF with 8 water-soluble and 10 insoluble (i.e., acid-soluble) element concentrations yielded a five-factor solution: Ca, K, Na sulfates; silicates; insoluble clinker; soluble clinker-rich; and soluble Ca-rich. The clinker content of the samples was calculated as sum of the insoluble clinker and soluble clinker-rich factors. The median clinker fraction of all samples was 45% (range 0-95%), and varied between 20% and 70% for individual plants. DISCUSSION: The 5-factor solution of PMF was selected on the basis of several mathematical parameters recommended in the literature as well as the mineralogical interpretability of the factors. In addition, interpretation of the factors was supported by the measured apparent solubility of Al, K, Si, Fe, and to a lesser extent Ca in material samples. The total clinker content obtained in the present study is considerably lower than estimates based on the Ca concentrations in a sample, and somewhat lower than estimates based on Si concentrations after selective leaching with a methanol/maleic acid mixture. The clinker abundance in workplace dust of one plant investigated in the present contribution was also estimated in a recent study by electron microscopy, and the good agreement between both studies gives confidence in the results of PMF. CONCLUSIONS: The clinker fraction in personal thoracic samples could be quantified from the chemical composition by positive matrix factorization. Our results allow for further epidemiological analyses of health effects in the cement production industry. As these estimates are more accurate for clinker exposure than aerosol mass, stronger associations with respiratory effects are expected if clinker is the main cause of these effects.

Elemental Carbon and Nitrogen Dioxide as Markers of Exposure to Diesel Exhaust in Selected Norwegian Industries.

Elemental carbon (EC) and nitrogen dioxide (NO2) in air as markers for diesel exhaust (DE) emission exposure were measured in selected work environments in Norway where diesel-powered engines are in use. Two hundred and ninety personal full-shift air samples were collected in primary aluminium production, underground and open-pit mining, road tunnel finishing, transport of ore, and among airport baggage handlers. EC was determined in the samples by a thermo-optical method, while NO2 was determined by ion chromatography. Highest EC air concentrations (geometric mean, GM) were found in aluminium smelters (GM = 45.5 µg m-3) followed by road tunnel finishing (GM = 37.8 µg m-3) and underground mining activities (GM = 18.9 µg m-3). Low EC air concentrations were measured for baggage handling at an international airport (GM = 2.7 µg m-3) and in an open-pit mine (GM = 1.2 µg m-3). Air concentrations of NO2 were similar in road tunnel finishing (GM = 128 µg m-3) and underground mining (GM = 108 µg m-3). Lower NO2 values were observed in open-pit mining (GM = 50 µg m-3), at the airport (GM = 37 µg m-3), and in the aluminium smelters (GM = 27 µg m-3). Highly significant (P < 0.001) positive correlations between NO2 and EC air concentrations in underground mining (r = 0.54) and road tunnel finishing (r = 0.71) indicate a common source of these pollutants. NO2 and EC were also correlated (P < 0.01) positively at the airport. However, due to the complex air chemistry and a potential contribution of various sources, the correlation between EC and NO2 cannot be regarded as unambiguous hint for a common source. The association between EC and NO2 was not of statistical significance in open-pit mining. In the aluminium smelters, EC and NO2 were negatively correlated, although not reaching statistical significance. The substantial differences in NO2/EC ratios across the investigated industries, ranging from around 0.2 in the primary aluminium production to around 25 during spring at the airport, clearly show that exposure to DE cannot be estimated based on NO2 concentrations, at least for outdoor environments. Results in the primary aluminium production suggest that the measured EC concentrations are related to DE emissions, although the NO2 concentrations were low. Further studies are required to assess the magnitude of exposure in primary aluminium production.

Multi-component assessment of worker exposures in a copper refinery. Part 2. Biological exposure indices for copper, nickel and cobalt.

Urinary copper (Cu), nickel (Ni) and cobalt (Co) concentrations were determined for 127 Cu refinery workers (40 females, 87 males), with values of the 95% upper confidence interval of the geometric mean in nmol per mmol creatinine of 89 (Ni), 42 (Cu) and 3.4 (Co) for electrorefinery workers. In the pyrometallurgical departments, the corresponding concentrations were 37 (Ni), 99 (Cu) and 11 (Co). Female workers had higher Co urinary concentrations than males (p< or = 0.05) while no gender difference was observed for Cu and Ni. Inter-elemental correlations were moderate to weak. Based on the inhalable aerosol levels reported previously for the same workers, the observed urinary Cu concentrations were considerably lower than expected, relative to Co and Ni. This is interpreted in terms of the current understanding of Cu homeostasis.

Multi-component assessment of worker exposures in a copper refinery. Part 1. Environmental monitoring.

The exposure characterisation described in this paper for 135 copper refinery workers (45 females, 90 males) focuses on the concentrations of copper, nickel and other trace elements in the inhalable aerosol fractions, as well as in the water-soluble and water-insoluble subfractions. Some information is also provided on the thoracic and respirable aerosol fractions. Further, results are presented for volatile hydrides of arsenic and selenium released in the copper purification steps of the electrorefining process. For the pyrometallurgical operations, a comparison of the geometric means for the inhalable aerosol fraction indicated that water-soluble copper levels were on average 19-fold higher compared to nickel (p < 0.001) and a significant association was evident between them (r = 0.87, p < 0.001); for the insoluble subfraction, the copper : nickel ratio was 12.5 (p < 0.001) and the inter-element correlation had r = 0.98 and p < 0.001. Although for the electrorefinery workers the relative inhalable concentrations of copper and nickel were not significantly different (p > 0.05), the corresponding inter-element associations were: slope of 7.7, r= 0.54, p < or =0.001 for the water-soluble subfraction and slope of 1.3, r = 0.71 and p < or =0.001 for the water-insoluble subfraction. On average, a good proportion of the inhalable copper and nickel were found in the thoracic (40%) and respirable (20%) aerosol fractions. Cobalt air concentrations were generally low with geometric means and 95% confidence intervals of 3.1 (2.4-4.2)microg m(-3) (pyrometallurgical workers) and 0.3 (0.4-0.5) microg m(-3)(electrorefinery workers). Similarly, the maximum concentrations of cadmium and lead were low, respectively 4 and 25 microg m(-3). Of the hydrides, tellurium and antimony could not be detected, but for the arsenic (arsine) and selenium hydrides measurable exposure occurred for almost all electrorefinery workers, although the levels were generally low at 0.2 microg m(-3).

Elements in placenta and pregnancy outcome in arctic and subarctic areas.

OBJECTIVES: This paper describes a comprehensive assessment of the association of concentrations of essential and toxic elements in maternal and neonatal body fluids and the placenta as predictors of birth weight and newborn body mass index (BMIC) for deliveries in northern Norway and Russia. STUDY DESIGN: A prospective cross-sectional study of delivering women and their outcomes from different locations in Russian and Norwegian arctic and sub-arctic areas. METHODS: Life-style information, blood, urine and placenta specimens were collected for 50 consecutive mother-infant pairs from hospital delivery departments in a total of six communities located in Finnmark, Norway, or the western arctic/subarctic regions of Russia. Questionnaire information was collected by individual interviews performed by trained health personnel. Pregnancy outcomes were verified by consulting medical records. Cadmium, copper, iron (as ferritin), nickel, lead, selenium and zinc were measured in maternal blood, serum or maternal urine: and in cord blood, or neonatal urine and placental tissue. Univariate and multivariate linear regression analysis and ANOVA were employed to explore associations between these clinical chemistry outcomes and birth weight and BMIC. RESULTS: A number of significant relationships were evident between: placental and maternal blood cadmium (p < 0.005); cord and maternal blood lead (p < 0.001); placental and maternal blood lead (p < 0.001); placental and cord-blood lead (p < 0.001); placental and maternal serum, or blood, selenium (p < 0.001); and placental and maternal serum copper (p < 0.001). Maternal body mass index (BMI), maternal age, placental lead, or maternal blood lead, and smoking were retained as predictors of birth weight and BMIC in the multivariate modelling. Birth weights in both countries were normally distributed. CONCLUSIONS: Maternal age and BMI as positive predictors of birth weight, and cigarette smoking and lead exposure as negative determinants, are discussed in terms of established evidence and recognized confounders, including maternal genetic factors, socio-economic status, socio-political change, life-style issues, prenatal care and nutrition. It is recommended that future work in societies undergoing socio-economic transition might best focus on preventive measures to improve neonatal health and development.