Airway inflammation in iron ore miners exposed to dust and diesel exhaust.

The aim of the present study was to investigate if underground miners exposed to dust and diesel exhaust in an iron ore mine would show signs of airway inflammation as reflected in induced sputum. In total, 22 miners were studied, once after a holiday of at least 2 weeks and the second time after 3 months of regular work. Control subjects were 21 "white-collar" workers. All subjects completed a questionnaire regarding medical and occupational history, and underwent lung function testing and induced sputum collection. Total and differential cell counts and analyses of the fluid phase of the induced sputum were performed. Sampling of personal exposure to elemental carbon, nitrogen dioxide and inhalable dust was recorded. The average concentrations of inhalable dust, nitrogen dioxide and elemental carbon were 3.2 mg.m-3, 0.28 mg.m-3 and 27 microg.m-3, respectively. Miners had increased numbers of inflammatory cells, mainly alveolar macrophages and neutrophils, and increased concentrations of fibronectin, metalloproteinase-9 and interleukin-10 in induced sputum compared with controls. In conclusion, miners in an underground iron ore mine demonstrated persistent airway inflammation that was as pronounced after a 4-week holiday as after a 3-month period of work underground in the mine.

Different airway inflammatory responses in asthmatic and healthy humans exposed to diesel.

Particulate matter (PM) pollution adversely affects the airways, with asthmatic subjects thought to be especially sensitive. The authors hypothesised that exposure to diesel exhaust (DE), a major source of PM, would induce airway neutrophilia in healthy subjects, and that either these responses would be exaggerated in subjects with mild allergic asthma, or DE would exacerbate pre-existent allergic airways. Healthy and mild asthmatic subjects were exposed for 2 h to ambient levels of DE (particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) 108 microg x m(-3)) and lung function and airway inflammation were assessed. Both groups showed an increase in airway resistance of similar magnitude after DE exposure. Healthy subjects developed airway inflammation 6 h after DE exposure, with airways neutrophilia and lymphocytosis together with an increase in interleukin-8 (IL-8) protein in lavage fluid, increased IL-8 messenger ribonucleic acid expression in the bronchial mucosa and upregulation of the endothelial adhesion molecules. In asthmatic subjects, DE exposure did not induce a neutrophilic response or exacerbate their pre-existing eosinophilic airway inflammation. Epithelial staining for the cytokine IL-10 was increased after DE in the asthmatic group. Differential effects on the airways of healthy subjects and asthmatics of particles with a 50% cut-off aerodynamic diameter of 10 microm at concentrations below current World Health Organisation air quality standards have been observed in this study. Further work is required to elucidate the significance of these differential responses.

Comparison of self-assessment and expert assessment of occupational exposure to chemicals.

OBJECTIVES: Occupational assessments of chemical exposure are often inadequate because of difficulties in obtaining sufficient numbers of measurements by trained professionals (experts). The objective of this study was to determine whether workers can provide unbiased data via self-assessments of exposure facilitated by the use of simple passive monitors for personal sampling. METHODS: Untrained workers obtained personal measurements of their exposures to gaseous contaminants (terpenes in sawmills and styrene in reinforced plastics factories) with passive monitors and written instructions. To study the validity of the self-assessments, an occupational hygienist performed exposure measurements on the same occupational groups after the workers had obtained two or more measurements independently. The potential bias of the self-assessments was evaluated by comparing the self-assessments with the expert assessments in mixed-effects statistical models. RESULTS: A total of 153 terpene (97 self and 56 expert) and 216 styrene (159 self and 57 expert) measurements were obtained from four sawmills and six reinforced plastics factories, respectively. No significant differences in the geometric mean exposures were observed between the self-assessments and the expert assessments in 3 of 4 sawmills and 5 of 6 reinforced plastics factories (P > 0.10). The potential bias of the self-assessments of exposure ranged from less than 0.1% to 102% and was less than 17% in 9 of the 10 groups investigated. CONCLUSIONS: The results indicate that untrained, unsupervised workers are able to collect consistently unbiased exposure data by employing currently available passive monitors.

Diesel exhaust enhances airway responsiveness in asthmatic subjects.

Particulate matter (PM) pollution has been associated with negative health effects, including exacerbations of asthma following exposure to PM peaks. The aim of the present study was to investigate the effects of short-term exposure to diesel exhaust (DE) in asthmatics, by specifically addressing the effects on airway hyperresponsiveness, lung function and airway inflammation. Fourteen nonsmoking, atopic asthmatics with stable disease, on continuous treatment with inhaled corticosteroids, were included. All were hyperresponsive to methacholine. Each subject was exposed to DE (particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) 300 microg x m(-3)) and air during 1 h on two separate occasions. Lung function was measured before and immediately after the exposures. Sputum induction was performed 6 h, and methacholine inhalation test 24 h, after each exposure. Exposure to DE was associated with a significant increase in the degree of hyperresponsiveness, as compared to after air, of 0.97 doubling concentrations at 24 h after exposure (p < 0.001). DE also induced a significant increase in airway resistance (p=0.004) and in sputum levels of interleukin (IL)-6 (p=0.048). No changes were detected in sputum levels of methyl-histamine, eosinophil cationic protein, myeloperoxidase and IL-8. This study indicated that short-term exposure to diesel exhaust, equal to high ambient levels of particulate matter, is associated with adverse effects in asthmatic airways, even in the presence of inhaled corticosteroid therapy. The increase in airway responsiveness may provide an important link to epidemiological findings of exacerbations of asthma following exposure to particulate matter.

Characterization of chemical interferences in the determination of unsaturated aldehydes using aromatic hydrazine reagents and liquid chromatography.

A systematic investigation on interferences in the determination of unsaturated aldehydes and ketones using the 2,4-dinitrophenylhydrazine (DNPH) method is described. Acrolein, crotonaldehyde, methacrolein and 1-buten-3-one are derivatized with DNPH in the presence of an acidic catalyst to form the respective hydrazones. The unstable hydrazones react with excess reagent to form adducts. These are identified by high-performance liquid chromatography (HPLC)-mass spectrometry and spectroscopic techniques after cryogenic fraction collection of the adducts. The quantification of the unsaturated carbonyls with the DNPH method remains difficult. N-Methyl-4-hydrazino-7-nitrobenzofurazan (MNBDH) was used as an alternative reagent for this purpose. As with DNPH, the formation of a side product is observed. In contrast to DNPH, the alteration of the pH immediately after sampling leads to only one reaction product, which is stable and storable in solution at 4 degrees C for 2 days.

Determination of morpholine in air by derivatisation with 1-naphthylisothiocyanate and HPLC analysis.

A method for the determination of morpholine in air was developed. Samples were collected with adsorbent tubes containing XAD-2 resin coated with 1-naphthylisothiocyanate (NIT). The thiourea derivative formed was subsequently desorbed with acetonitrile and analysed by HPLC with UV detection. The recovery after gas phase spiking with morpholine (2.2-1570 micrograms) was 91% (86-100%) with a relative standard deviation of 5.5%. No effect on recovery from relative humidity or amount of morpholine was seen. The lowest level tested corresponded to 7 mg m-3 (1/10 threshold limit value) for a 15 min sampling period with a sampling rate of 20 ml min-1. Exposed NIT-coated XAD-2 tubes were stable at room temperature for at least 2 weeks.

Multivariate evaluation of factors influencing the performance of a formic acid biosensor for use in air monitoring.

A formic acid biosensor for air monitoring has been evaluated using chemometric methods. Using experimental design eleven factors that could influence the performance of the biosensor were examined. The response matrices consisted of six parameters (steady state currents at three different formic acid concentrations and response rates during changes in formic acid concentrations) describing the performance of the biosensor. The data were evaluated using a combination of principal component analysis (PCA) and multiple linear regression (MLR). To confirm the conclusions from the PCA-MLR partial least squares (PLS) was also used. The most important factor for the biosensor performance was found to be the enzyme concentration. Using the information from the chemometric analyses the optimum operation conditions for the biosensor were determined. The steady state currents were increased by 18-30% and the initial two response rates increased by 47-89% compared with a biosensor that had not been optimised.

Airway inflammation following exposure to diesel exhaust: a study of time kinetics using induced sputum.

The adverse health effects of particulate matter pollution are of increasing concern. In a recent bronchoscopic study in healthy volunteers, pronounced airway inflammation was detected following exposure to diesel exhaust (DE). The present study was conducted in order to evaluate the time kinetics of the inflammatory response following exposure to DE using induced sputum from healthy volunteers. Fifteen healthy nonsmoking volunteers were exposed to DE particles with a 50% cut-off aerodynamic diameter of 10 microm 300 microg x m(-3) and air for 1 h on two separate occasions. Sputum induction with hypertonic saline was performed 6 and 24 h after each exposure. Analyses of sputum differential cell counts and soluble protein concentrations were performed. Six hours after exposure to DE, a significant increase was found in the percentage of sputum neutrophils (37.7 versus 26.2% p=0.002) together with increases in the concentrations of interleukin-6 (12.0 versus 6.3 pg x mL(-1), p=0.006) and methylhistamine (0.11 versus 0.12 microg x L(-1), p=0.024). Irrespective of exposure, a significant increase was found in the percentage of sputum neutrophils at 24 as compared to 6 h, indicating that the procedure of sputum induction itself may change the composition of sputum. This study demonstrates that exposure to diesel exhaust induces inflammatory response in healthy human airways, represented by an early increase in interleukin-6 and methylhistamine concentration and the percentage of neutrophils. Induced sputum provides a safe tool for the investigation of the inflammatory effects of diesel exhaust, but care must be taken when interpreting results from repeated sputum inductions.

CYP1A1 and GSTM1 polymorphisms affect urinary 1-hydroxypyrene levels after PAH exposure.

Certain human biotransformation enzymes have been implicated in the formation and scavenging of the ultimate reactive metabolites, the diolepoxides, from polycyclic aromatic hydrocarbons (PAHs). In the present study, performed on aluminum smelter workers, we have analyzed airborne PAH, the pyrene metabolite 1-hydroxypyrene (1-OHP) in urine, and genotypes for biotransformation enzymes involved in PAH metabolism. The aim was to evaluate the correlation between external exposure and biomarkers of exposure and to investigate to what extent genetic polymorphism in metabolic enzymes can explain interindividual variation in urinary 1-OHP levels. DNA was prepared from blood samples from 98 potroom workers and 55 controls and altogether eight polymorphisms in the CYP1A1, mEH, GSTM1, GSTP1 and GSTT1 genes were analyzed. The 1-OHP excretion was found to correlate significantly (P 100-fold) and univariate and multivariate regression analyses were used to find the variables that could determine differences in excretion. The variation could, to some degree, be explained by differences in exposure to airborne particulate-associated PAHs, the use of personal respiratory protection devices, smoking habits and genetic polymorphisms in the cytochrome P450 1A1, GSTM1 and GSTT1 enzymes. The part of the variance that could be explained by differences in biotransformation genotypes seemed to be of the same order of magnitude as the variance explained by differences in exposure. In the control group as well as in the occupationally exposed group, the highest 1-OHP levels were observed in individuals carrying the CYP1A1 Ile/Val genotype who were also of the GSTM1 null genotype. The results show that urinary 1-OHP is a sensitive indicator of recent human exposure to PAHs and that it may also to some extent reflect the interindividual variation in susceptibility to PAHs.

Self-assessment of exposure--a pilot study of assessment of exposure to benzene in tank truck drivers.

Occupational hygienists or safety engineers perform exposure assessments, mostly with very little participation by the workers. The objective of our study is to involve the workers themselves in the assessment and measurement procedure, the self-assessment method (SAE). A pilot study has been carried out involving tank truck drivers at a company transporting gasoline. The drivers were supposed to decide themselves when, and how often, they wanted to measure benzene exposure by using diffusive samplers that were then sent by mail for analysis. After every measurement they received their own results in a personal document for interpretation. The company management also received a document, which summarized all the drivers' measurements. Expert measurements, with the same type of sampler, were also accomplished to evaluate the self-assessments. The geometric mean and the 95 percent confidence intervals of the measurements made by the drivers (29 measurements) was 0.17 (0.11-0.26), and by an occupational hygienist (8 measurements) 0.12 mg/m3 (0.04-0.37). The results show that the drivers technically can perform SAE. Interviews with the workers and the management indicated that some kind of organizational support within the company is needed to implement the method into the regular internal control of the working environment.

Efficiency of automotive cabin air filters to reduce acute health effects of diesel exhaust in human subjects.

OBJECTIVES: To evaluate the efficiency of different automotive cabin air filters to prevent penetration of components of diesel exhaust and thereby reduce biomedical effects in human subjects. Filtered air and unfiltered diluted diesel exhaust (DDE) were used as negative and positive controls, respectively, and were compared with exposure to DDE filtered with four different filter systems. METHODS: 32 Healthy non-smoking subjects (age 21-53) participated in the study. Each subject was exposed six times for 1 hour in a specially designed exposure chamber: once to air, once to unfiltered DDE, and once to DDE filtered with the four different cabin air filters. Particle concentrations during exposure to unfiltered DDE were kept at 300 micrograms/m3. Two of the filters were particle filters. The other two were particle filters combined with active charcoal filters that might reduce certain gaseous components. Subjective symptoms were recorded and nasal airway lavage (NAL), acoustic rhinometry, and lung function measurements were performed. RESULTS: The two particle filters decreased the concentrations of diesel exhaust particles by about half, but did not reduce the intensity of symptoms induced by exhaust. The combination of active charcoal filters and a particle filter significantly reduced the symptoms and discomfort caused by the diesel exhaust. The most noticable differences in efficacy between the filters were found in the reduction of detection of an unpleasant smell from the diesel exhaust. In this respect even the two charcoal filter combinations differed significantly. The efficacy to reduce symptoms may depend on the abilities of the filters investigated to reduce certain hydrocarbons. No acute effects on NAL, rhinometry, and lung function variables were found. CONCLUSIONS: This study has shown that the use of active charcoal filters, and a particle filter, clearly reduced the intensity of symptoms induced by diesel exhaust. Complementary studies on vehicle cabin air filters may result in further diminishing the biomedical effects of diesel exhaust in subjects exposed in traffic and workplaces.

Exposure to polycyclic aromatic hydrocarbons and genotoxic effects on nonsmoking Swedish road pavement workers.

OBJECTIVES: The objective of this study was to investigate exposure to polycyclic aromatic hydrocarbons (PAH) from asphalt fumes among Swedish road pavement workers and determine whether any effects could be detected with genotoxic tests. METHODS: The study included 28 nonsmoking road pavers and 30 nonsmoking referents. The concentration of PAH was determined in the breathing zone of the road pavers. 1-Hydroxypyrene was analyzed before and after shifts of asphalt work and during the afternoon for referents. Sister chromatid exchanges (SCE) and micronuclei (MN) were determined in peripheral lymphocytes. RESULTS: Several 3- or 4-ring PAH were found, and the analysis indicated that they occurred in bitumen fumes rather than in traffic fumes. The average total concentration of PAH was 2.3 (range 0.2-23.8) microg/m3. The concentration of 1-hydroxypyrene in urine was higher for the road pavers than for the referents, but there was no significant difference between the pre- and postshift values of the road pavers. The road pavers had no significant increase in SCE or MN. CONCLUSIONS: The study showed that Swedish road pavers have an increased exposure to PAH from bitumen fumes, but no genotoxic effects could be detected by SCE or MN tests.

Genotoxic exposures of potroom workers.

OBJECTIVES: Potroom workers in aluminum reduction plants have increased risks for bladder and lung cancer due to exposure from polycyclic aromatic hydrocarbons (PAH). In this study correlations between measures of the external, internal, and biological effective dose have been studied for PAH. METHODS: Venous blood samples were obtained from 98 male potroom workers and 55 unexposed male blue-collar workers, for the analysis of aromatic adducts to DNA (deoxyribonucleic acid) in lymphocytes, using the 32P-postlabeling technique. 1-Hydroxypyrene in urine was analyzed with high-pressure liquid chromatography. Personal sampling of both particulate and gas phase PAH was performed during a full workday for the potroom workers and for 5 referents. Individual PAH congeners were determined with liquid chromatographic-mass spectrometric and gas chromatographic-mass spectrometric techniques. RESULTS: The respiratory-zone airborne level of the sum of 22 particulate (median 13.2 micro/m3) and the 7 gas phase PAH-congeners (median 16.3 microg/m3) among the potroom workers was a hundred times higher than among the referents. The urinary concentration of 1-hydroxypyrene before work was 30 times higher for the potroom workers (median 3.43 micromol/mol creatinine) than for the referents. Most airborne PAH congeners correlated with the excretion of 1-hydroxypyrene in urine. The frequency of aromatic DNA adducts did not, however, differ between the potroom workers and the referents, and no correlation was found for 1-hydroxypyrene in urine. CONCLUSIONS: Despite an obvious occupational exposure to PAH, no increase in aromatic DNA adducts in lymphocytes was found among the potroom workers.

A diffusive sampling device for the determination of formaldehyde in air using N-methyl-4-hydrazino-7-nitrobenzofurazan (MNBDH) as reagent.

A new method utilizing the diffusive sampling of formaldehyde in air has been developed. Formaldehyde is sampled with the use of a glass fiber filter impregnated with N-methyl-4-hydrazino-7-nitrobenzofurazan (MNBDH) and phosphoric acid. The formaldehyde hydrazone formed is desorbed from the filter with acetonitrile and determined by high-performance liquid chromatography (HPLC) with UV/visible detection at 474 nm. The sampling rate was determined to be 24.7 mL min-1 with a relative standard deviation of 7% for 48 experiments. The measured sampling rates were not dependent on the formaldehyde concentration (0.1-1.0 mg m-3), sampling time (15-482 min) or relative humidity (20-85%). The detection limit was 70 micrograms m-3 for a 15 min sampling period and 2 micrograms m-3 for an 8 h sampling period.

Evaluation of two adsorbents for diffusive sampling and thermal desorption-gas chromatographic analysis of monoterpenes in air.

Tube type samplers with two different adsorbents, Chromosorb 106 and Tenax TA, were evaluated by laboratory experiments and field tests for simultaneous diffusive sampling of alpha-pinene, beta-pinene and delta 3-carene and subsequent thermal desorption-gas chromatographic analysis. No statistically significant effects of exposure time, concentrations of monoterpenes or relative humidity were found for samplers with Chromosorb 106 when running a factorial design, with the exception of the adsorption of delta 3-carene, for which some weak effects were noted. Samplers with Tenax TA were affected by the sampling time as well as the concentration for all terpenes, with a strong interaction effect between these two factors. The terpenes showed good storage stability on both adsorbents. No effect of back-diffusion was noted when using Chromosorb 106, while Tenax TA showed some back-diffusion effects. The uptake rates, in ml min-1, for the terpenes on Chromosorb 106 were 0.36 for alpha-pinene, 0.36 for beta-pinene and 0.40 for delta 3-carene. The corresponding average values on Tenax TA were 0.30 for alpha-pinene, 0.32 for beta-pinene and 0.38 for delta 3-carene. The field validation proved that diffusive sampling on Chromosorb 106 agreed well with pumped sampling on charcoal for stationary samples, while the personal samples indicated a discrepancy of 25% between Chromosorb 106 and charcoal samples. Tenax TA generally gave lower results than Chromosorb 106 in all field samples. Samplers packed with Chromosorb 106 could be used to monitor terpene levels in workplaces such as sawmills. The major advantages with this method are the sampling procedure, which is simple to perform compared to other techniques, the easily automated analysis procedure and the possibility to reuse the samplers.

Validation of a diffusive sampler for NO2.

A diffusive sampler for NO2, Willems badge, was validated in laboratory experiments and field tests. The collecting reagent for NO2 in the sampler is triethanolamine, and the analysis is based on a modified colorimetric method, the Saltzman method. The analysis was performed by a flow injection analysis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 ml min-1. There was no effect of NO2 concentration or relative humidity on sampling rate, and the influence of sampling time was found to be small. The detection limit was 4 micrograms m-3 for a 24 h sample. The capacity is high enough to allow sampling of 150 micrograms m-3 for 7 days, which is twice the recommended Swedish short-term (24 h) guideline value as a 98-percentile over 6 months. In field tests, the sampler performed well, even at wind speeds higher than 2 m s-1, and at low temperatures. The overall uncertainty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2-8 h in working environments.

Air sampling of fungal spores on filters. An investigation on passive sampling and viability.

In this study, glycerol was tested as a collection substrate for passive bioaerosol sampling. Filters (mixed cellulose acetate and nitrate) were soaked in glycerol and exposed for an aerosol from three different fungal species: Penicillum commune, Aspergillus versicolor and Paecilomyces variotii. The passive sampling method was compared with a closed-face polycarbonate filter sampling method. Exposure was performed in an exposure chamber. The total number of spores was determined by microscopic techniques, and the cultivable number was determined by cultivation on Malt Extract Agar dishes. The glycerol soaked filter demonstrated a good correlation with the closed-face sampler with regard to the total count. Spores stored in a pumped filter cassette were not affected by storage for up to 7 days. On the other hand, the culturability of the spores was markedly decreased after 1 day when stored on glycerol soaked filters.

Terpene exposure and respiratory effects among workers in Swedish joinery shops.

OBJECTIVES: Exposure to monoterpenes (alpha-pinene, beta-pinene and delta 3-carene) in joinery shops was studied in Sweden during the processing of Scot's pine, and the acute respiratory effects among the employees were evaluated. METHODS: A cross-sectional study of 38 workers was carried out in 4 joinery shops. The investigation included personal air sampling of monoterpenes, biological monitoring of metabolites of alpha-pinene in the workers' urine, interviews following a standardized questionnaire, and dynamic spirometry. RESULTS: The personal exposure to monoterpenes in the joinery shops was 10-214 mg/m3. The correlation (correlation coefficient = 0.69) between exposure to alpha-pinene and verbenols (metabolites from alpha-pinene) in urine was relatively good. No acute effects on forced vital capacity or forced expiratory volume during 1 s were detected. The workers had significantly reduced preshift lung function values when compared with the values of a local reference group, even when smokers and ex-smokers were excluded. CONCLUSIONS: Personal exposure to the monoterpenes alpha-pinene, and delta 3-carene in joinery shops may exceed the present Swedish occupational exposure limit of 150 mg/m3 during the winter season when workroom air is commonly recirculated. The determination of metabolites of alpha-pinene (verbenols) in urine can be used as an index of exposure to fumes released during wood-treating processes. The results from the lung function tests indicate chronic rather than acute reactions in the airways. The fact that there were no major changes in lung function over a workshift indicates chronic reaction in the airways.