Inhalable Aerosol Fraction Research Articles

Aerosol Generation During Bronchoscopy.

Bronchoscopy is an aerosol-generating procedure and can place the health care providers at risk for exposure to viral pathogens. The pattern of aerosol generation during different aspects of bronchoscopy are poorly understood. The goal of this study is to characterize the pattern of aerosol generation during flexible and rigid bronchoscopy performed under moderate sedation or general anesthesia (GA). The inhalable mass concentration of aerosol generated during the procedures was measured continuously. The aerosol concentration in the endoscopy room at baseline and while the procedures were performed was measured. Procedures included flexible bronchoscopies with moderate sedation, flexible bronchoscopies performed through endotracheal tube under GA and rigid bronchoscopies under GA. Changes from the baseline were measured continuously during the bronchoscopy. Measurements obtained during the procedure were compared with the baseline reading. For flexible bronchoscopy under moderate sedation, the inhalable aerosol fraction was significantly higher (P=0.036) during atomization of lidocaine. For Flexible bronchoscopy through endotracheal tube, inhalable aerosol fraction was significantly higher (P<0.001) during intubation and extubation. For rigid bronchoscopy done under GA with jet ventilation, inhalable aerosol fraction was significantly higher during both the bronchoscopy (P=0.01) and recovery (P=0.012). Elevated levels of aerosol were generated during all aspects of bronchoscopy. However, atomization of lidocaine, intubation, extubation, and recovery generated the most aerosol.

Determining Potassium Bromate in the Inhalable Aerosol Fraction in Workplace Air with Ion Chromatography.

BackgroundThe article presents the results of studies performed in order to develop a new method of airborne potassium bromate(V) determination at workplaces.MethodsThe method is based on a collection of the inhalable fraction of potassium bromate(V) using the IOM Sampler, then extraction of bromates with deionized water and chromatographic analysis of the obtained solution. The analysis was performed using ion chromatography with conductometric detection. The tests were performed on a Dionex IonPac®AS22 analytic column (250 × 4 mm, 6 μm) with AG22 precolumn (50 × 4 mm 11 μm).ResultsThe method provides for potassium bromate(V) determination within the concentration range of 0.043 ÷ 0.88 mg/m3 for an air sample of 0.72 m3 in volume, i.e., 0.1–2 times the exposure limit value as proposed in Poland. The method was validated in accordance with PN-EN 482. The obtained validation data are as follows: measuring range: 3.1–63.4 μg/mL, limit of detection (LOD) = 0.018 μg/mL and limit of quantification (LOQ) = 0.053 μg/mL. The developed method has been tested in the work environment, on laboratory employees having contact with potassium bromate(V).ConclusionThe analytical method allowed the determination of the inhalable fraction of airborne potassium bromate(V) at workplaces and can be used to assess occupational exposure.

Evaluation of total and inhalable samplers for the collection of carbon nanotube and carbon nanofiber aerosols.

A growing number of carbon nanotubes and nanofibers (CNT/F) exposure and epidemiologic studies have utilized 25-mm and 37-mm open-faced cassettes (OFC) to assess the inhalable aerosol fraction. It has been previously established that the 37-mm OFC under-samples particles greater than 20 μm in diameter, but the size-selective characteristics of the 25-mm OFC have not yet been fully evaluated. This article describes an experimental study conducted to determine if the 25- and 37-mm OFCs performed with relative equivalence to a reference inhalable aerosol sampler when challenged with CNT/F particles. Side-by-side paired samples were collected within a small Venturi chamber using a 25-mm styrene OFC, 37-mm styrene OFC, 25-mm aluminum OFC, and Button Inhalable Aerosol Sampler. Three types of CNT/F materials and an Arizona road dust were used as challenge aerosols for the various sampler configurations. Repeated experiments were conducted for each sampler configuration and material. The OFC samplers operated at flow rates of 2 and 5 liters per minute. Results showed that the 25-mm OFC performed comparably to the Button Sampler when challenged with CNT/F aerosols, which was demonstrated in five of the six experimental scenarios with an average error of 20%. Overall, the results of this study indicate that the sampling efficiency of the 25- and 37-mm OFCs adequately followed the ISO/ACGIH/CEN inhalable sampling convention when challenged with CNT/F aerosols. Past exposure and epidemiologic studies that used these OFC samplers can directly compare their results to studies that have used other validated inhalable aerosol samplers.

Study of the occurrence of airborne Polycyclic Aromatic Hydrocarbons associated with respirable particles in two coastal cities at Eastern Mediterranean: Levels, source apportionment, and potential risk for human health

Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most hazardous substances in the environment. Although their occurrence and fate in the atmosphere of Eastern Mediterranean is well documented, there is limited information on PAH levels in the inhalable aerosol fraction. Additionally, to the best of our knowledge, there is lack of information on particulate matter with aerodynamic diameter equal or less than 2.5 and 10 μm (PM2.5/PM10)-bound PAH concentrations and sources in Cyprus. We therefore present the first study that i) determines the concentration levels of PAHs in the respirable and inhalable (PM2.5 and PM10) fraction of particulate matter; ii) identifies, quantifies, and compares PAH emission sources by applying two receptor models (Principal Components Analysis/Multiple Linear Regression Analysis, PCA/MLR; and UNMIX factorization), and iii) assesses their relative toxicity at two different coastal sites in Eastern Mediterranean (Island of Crete, Greece; and Cyprus). For this purpose, a total of 79 samples were collected in Heraklion (Island of Crete) and Limassol (Cyprus) during a 2-year sampling campaign between 2012 and 2014. Thirty five PAH members were identified and the total concentration (Σ35PAHs) levels in PM2.5 ranged between 0.15 and 9.19 ng/m3 in Heraklion; 0.12 and 3.91 ng/m3 (PM2.5), and 0.16 and 4.02 ng/m3 (PM10) in Limassol. PAH concentrations were the highest when air masses were passing over highly polluted areas, such as the eastern Balkan Peninsula/Adriatic Sea and northern Greece. The most abundant members at both sites were Benzo[b]fluoranthene (7–16%), Benzo[e]pyrene (8–11%), Indeno[1,2,3-cd]pyrene (10–18%) and Benzo[ghi]perylene (9–21%); as well as Anthranene (5–6%) and Coronene (9–11%) in Limassol. The major PAH emission sources obtained from the application of PCA/MLRA were gasoline and diesel/coal combustion sources, accounting for almost 60% and 40% of total contribution in Heraklion, while in Limassol both sources contributed nearly equally (51% and 49%, respectively). Similar findings were obtained using the UNMIX model. The lifetime incremental cancer risk (ILCR) due to both inhalation and ingestion exposure from particulate PAHs was well below the U.S. EPA regulatory threshold in both study areas.

Incorporation of dosimetry in the derivation of reference concentrations for ambient or workplace air: A conceptual approach

Dosimetric models are essential tools to refine inhalation risk assessments based on local respiratory effects. Dosimetric adjustments to account for differences in aerosol particle size and respiratory tract deposition and/or clearance among rodents, workers, and the general public can be applied to experimentally- and epidemiologically-determined points of departure (PODs) to calculate size-selected (e.g., PM10, inhalable aerosol fraction, respirable aerosol fraction) equivalent concentrations (e.g., HEC or human equivalent concentration; REC or rodent equivalent concentration). A modified POD (e.g., HEC) can then feed into existing frameworks for the derivation of occupational or ambient air concentration limits or reference concentrations. HECs that are expressed in terms of aerosol particle sizes experienced by humans but are derived from animal studies allow proper comparison of exposure levels and associated health effects in animals and humans. This can inform differences in responsiveness between animals and humans, based on the same deposited or retained doses and can also allow the use of both data sources in an integrated weight of evidence approach for hazard and risk assessment purposes. Whenever possible, default values should be replaced by substance-specific and target population-specific parameters. Assumptions and sources of uncertainty need to be clearly reported.

Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry.

The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette. Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers. The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios. The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the fractions.

Pulmonary function and serum pneumoproteins in professional ski waxers

Context: Professional ski waxers are exposed to particulate matter (PM) during work, but little is known about untoward pulmonary effects.Objectives: The aim was to study lung function and pneumoproteins in professional ski waxers before and during exposure to PM generated during ski waxing and ski preparation.Material and methods: Forty-five male professional ski waxers examined on an exposure-free day in the morning and at least 6 h later were re-examined during ski waxing 2 d later in a cross-shift study. Pulmonary function and gas diffusion capacity were measured and Clara cell protein 16 (CC-16), surfactant protein A and D (SP-A and SP-D), and C-reactive protein (CRP) were determined in serum. PM was collected by personal sampling.Results: The mean PM concentrations in the respirable and in the inhalable aerosol fraction in air samples collected during waxing were 3.1 mg/m3 and 6.2 mg/m3, respectively. The mid expiratory flow (MEF75%) was significantly lower during exposure. The concentrations of CRP increased significantly by more than 100% during ski waxing, and SP-D and CC-16 were significantly lower during the exposed day as compared with the non-exposed day. The results further suggest that SP-D and CC-16 in serum are affected by diurnal variations. No significant alterations were observed for the lung diffusion capacity.Discussion and conclusions: The results suggest that exposure to PM generated during ski waxing may induce pulmonary inflammation with reduced flow in small airways. The increased CRP concentrations indicate the induction of systemic inflammation in ski waxers during exposure.

Characterization and validation of sampling and analytical methods for mycotoxins in workplace air

Mycotoxins are produced by certain plant or foodstuff moulds under growing, transport or storage conditions. They are toxic for humans and animals, some are carcinogenic. Methods to monitor occupational exposure to seven of the most frequently occurring airborne mycotoxins have been characterized and validated. Experimental aerosols have been generated from naturally contaminated particles for sampler evaluation. Air samples were collected on foam pads, using the CIP 10 personal aerosol sampler with its inhalable health-related aerosol fraction selector. The samples were subsequently solvent extracted from the sampling media, cleaned using immunoaffinity (IA) columns and analyzed by liquid chromatography with fluorescence detection. Ochratoxin A (OTA) or fumonisin and aflatoxin derivatives were detected and quantified. The quantification limits were 0.015 ng m(-3) OTA, 1 ng m(-3) fumonisins or 0.5 pg m(-3) aflatoxins, with a minimum dust concentration level of 1 mg m(-3) and a 4800 L air volume sampling. The methods were successfully applied to field measurements, which confirmed that workers could be exposed when handling contaminated materials. It was observed that airborne particles may be more contaminated than the bulk material itself. The validated methods have measuring ranges fully adapted to the concentrations found in the workplace. Their performance meets the general requirements laid down for chemical agent measurement procedures, with an expanded uncertainty less than 50% for most mycotoxins. The analytical uncertainty, comprised between 14 and 24%, was quite satisfactory given the low mycotoxin amounts, when compared to the food benchmarks. The methods are now user-friendly enough to be adopted for personal workplace sampling. They will later allow for mycotoxin occupational risk assessment, as only very few quantitative data have been available till now.

Occupational exposure to beryllium in primary aluminium production

Alumina used in the production of primary aluminium contains Be which partly vaporises from the cryolite bath into the workroom atmosphere. Since Be may be toxic at lower exposure levels than previously thought, the personal exposure to Be among workers in 7 Norwegian primary smelters has been assessed. In total, 480 personal Respicon® virtual impactor full shift air samples have been collected during 2 sampling campaigns and analysed for water soluble Be, Al and Na using inductively coupled plasma optical emission spectrometry. In addition, water soluble F(-) has been measured by ion chromatography. The Be air concentrations in the inhalable, thoracic and respirable aerosol fractions have been calculated. The Be concentrations in the inhalable aerosol fraction vary between the different smelters. The highest GM concentration of Be in the inhalable fraction (122 ng m(-3), n = 30) was measured in the prebake pot room of a smelter using predominantly Jamaican alumina where also the highest individual air concentration of 270 ng m(-3) of Be was identified. The relative distribution of Be in the different aerosol fractions was fairly constant with the mean Be amount for the two sampling campaigns between 44-49% in the thoracic fraction expressed as % of the inhalable amount. Linear regression analysis shows a high correlation between water soluble Be, Al, F and Na describing an average measured chemical bulk composition of the water soluble thoracic fraction as Na(5.7)Al(3.1)F(18). Be is likely to be present as traces in this particulate matter by replacing Al atoms in the condensed fluorides and/or as a major element in a nanoparticle sized fluoride. Thus, the major amount of Be present in the work room atmosphere of Al smelter pot rooms will predominantly be present in combination with substantial amounts of water soluble Al, F and Na.

Workplace aerosol mass concentration measurement using optical particle counters

Direct-reading aerosol measurement usually uses the optical properties of airborne particles to detect and measure particle concentration. In the case of occupational hygiene, mass concentration measurement is often required. Two aerosol monitoring methods are based on the principle of light scattering: optical particle counting (OPC) and photometry. The former analyses the light scattered by a single particle, the latter by a cloud of particles. Both methods need calibration to transform the quantity of scattered light detected into particle concentration. Photometers are simpler to use and can be directly calibrated to measure mass concentration. However, their response varies not only with aerosol concentration but also with particle size distribution, which frequently contributes to biased measurement. Optical particle counters directly measure the particle number concentration and particle size that allows assessment of the particle mass provided the particles are spherical and of known density. An integrating algorithm is used to calculate the mass concentration of any conventional health-related aerosol fraction. The concentrations calculated thus have been compared with simultaneous measurements by conventional gravimetric sampling to check the possibility of field OPC calibration with real workplace aerosols with a view to further monitoring particle mass concentration. Aerosol concentrations were measured in the food industry using the OPC GRIMM® 1.108 and the CIP 10-Inhalable and CIP 10-Respirable (ARELCO®) aerosol samplers while meat sausages were being brushed and coated with calcium carbonate. Previously, the original OPC inlet had been adapted to sample inhalable aerosol. A mixed aerosol of calcium carbonate and fungi spores was present in the workplace. The OPC particle-size distribution and an estimated average particle density of both aerosol components were used to calculate the mass concentration. The inhalable and respirable aerosol fractions calculated from the OPC data are closely correlated with the results of the particle size-selective sampling using the CIP 10. Furthermore, the OPC data allow calculation of the thoracic fraction of workplace aerosol (not measured by sampling), which is interesting in the presence of allergenic particles like fungi spores. The results also show that the modified COP inlet adequately samples inhalable aerosol in the range of workplace particle-size distribution.

Performance Study of Personal Inhalable Aerosol Samplers at Ultra-Low Wind Speeds

The assessment of personal inhalable aerosol samplers in a controlled laboratory setting has not previously been carried out at the ultra-low wind speed conditions that represent most modern workplaces. There is currently some concern about whether the existing inhalable aerosol convention is appropriate at these low wind speeds and an alternative has been suggested. It was therefore important to assess the performance of the most common personal samplers used to collect the inhalable aerosol fraction, especially those that were designed to match the original curve. The experimental set-up involved use of a hybrid ultra-low speed wind tunnel/calm air chamber and a rotating, heating breathing mannequin to measure the inhalable fraction of aerosol exposure. The samplers that were tested included the Institute of Occupational Medicine (IOM), Button, and GSP inhalable samplers as well as the closed-face cassette sampler that has been (and still is) widely used by occupational hygienists in many countries. The results showed that, down to ∼0.2 m s(-1), the samplers matched the current inhalability criterion relatively well but were significantly greater than this at the lowest wind speed tested. Overall, there was a significant effect of wind speed on sampling efficiency, with lower wind speeds clearly associated with an increase in sampling efficiency.

Combined scanning electron microscopy and image analysis to investigate airborne submicron particles: A comparison between personal samplers

The main objectives of this study were: (i) to compare commonly used personal samplers and verify their collection efficiency with regards to submicron particles; (ii) to investigate how the submicron particles deposit onto the filter surface in order to assess the homogeneity of the deposition; (iii) to estimate the biases which could affect results when number concentration values have to be determined by particle counting. A method based on image analysis (IA) and scanning electron microscopy (SEM) is developed and adopted to investigate a large numbers of particles. Four different personal samplers were tested: the IOM sampler, the Button sampler and the German GSP for the inhalable aerosol fraction; the PEM sampler for the thoracic aerosol fraction. In order to investigate how particles distribute on the filters surface, the area of each filter was virtually divided into circular concentric areas or deposition zones (DZ). Results from different DZ of the same filter were compared. Uniformity of deposition was mostly observed for three of the four tested samplers. A significant radial distribution was observed only for the GSP sampler. The major homogeneity was found for the Button sampler. In order to estimate the relative collection efficiency between samplers, particles number concentrations determined by particle counting were compared. The GSP sampler provided the greatest concentrations but also the greatest variability. The PEM sampler provided the lowest concentrations. The homogeneity of particle deposition on the filter surface mostly affected results when counting is performed on localized areas of the filter.

High efficiency CIP 10-I personal inhalable aerosol sampler

The CIP 10 personal aerosol sampler was first developed by Courbon for sampling the respirable fraction of mining dust. This respirable aerosol sampler was further improved by Fabries, then selectors for sampling thoracic and inhalable aerosols were designed. Kenny et al. evaluated the particle-size dependent sampling efficiency of the inhalable version in a large-scale wind tunnel using a life-size dummy. The authors found that the overall sampling efficiency decreases more rapidly than the CEN-ISO-ACGIH target efficiency curve. Görner and Witschger measured the aspiration efficiency of the CIP 10 omni-directional inlet. They found that the aspiration efficiency was high enough for inhalable aerosol sampling. This result led to the conclusion that the low sampling efficiency is due to some internal losses of the aspirated particles before they reach the final sampling stage, namely the CIP 10 rotating filter. Based on the assumption that the inhalable particles are selected at selector aspiration level, an experimental research project was conducted to improve particle transmission to the collection stage of the sampler. Two different inhalable selectors were designed by Görner and tested in a laboratory wind tunnel. The transmission efficiency of both models was measured by Roger following an experimental protocol described by Witschger. The T-shaped air flow circuit was finally adopted to draw the aspirated particles into the final collection stage of the CIP 10. Actually, in this selector, the almost horizontally aspirated particles should be conducted vertically to the rotating cup. In two previous prototypes, particles could be deposited in certain places by inertia (where the aerosol was forced to deviate drastically) or by sedimentation (where the aerosol decelerated). The aerodynamic behaviour of the adopted solution causes the particles to accelerate radially between two horizontal plates before they enter a vertical tube. This acceleration avoids the particles being deposited on the lower horizontal plate. At the beginning of the vertical tubing, the mutually opposing particle trajectories limit particle wall deposition by virtual impaction effect. The inner selector walls are polished to avoid particles being stopped by eventual surface asperities. Particle size-dependent sampling efficiency was measured in the laboratory wind tunnel. The experimental aerosol was composed of polydisperse glass micro-spheres. The size analysis of the particles collected was done by the Coulter Counter technique. The transmission efficiency (reciprocal to wall losses) was found to be close to 100 % for the entire range of particle sizes, and indicated no particle loss. The overall sampling efficiency was measured using a rotating bluff body at an external wind speed of 1 m/s. The rotating bluff body represents a scaled torso of an operator. The "high efficiency" CIP 10-I (I for inhalable) responds fairly well to the conventional CEN-ISO-ACGIH criteria for sampling the inhalable health-related aerosol fraction.

Distribution of metals between inhalable and respirable fractions of welding fumes generated in gas metal arc welding

Respirable and inhalable fractions of welding fumes were collected in a welding plant, where corrosion resistant steel (X8CrNi1810) was welded with gas metal arc welding (GMAW). Welding fumes were sampled with 'fixed point' sampling technique applying different sampling heads: Institute of Occupational Medicine (IOM) sampler and conical inhalable sampler (CIS) for the inhalable aerosol fraction and the Higgins–Dewell (HD) cyclone for the respirable aerosol fraction. The 'water soluble' and the total concentrations of Fe, Mn, Cr, Ni and Cr(VI) were determined after water extraction and microwave assisted digestion applying inductively coupled plasma quadrupole mass spectrometry (Q-ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and UV visible spectrophotometry. The amounts of 'water soluble' metal components in the respirable aerosol fraction were 60–97% of their amounts in the inhalable fraction. These rates were 64–94% in the case of the total metal concentrations, while the respirable Cr(VI) was 1˙6-fold higher than inhalable Cr(VI). These findings suggest that from toxicological point of view the measurements of the chemical composition and size distribution of the particles formed during a welding process have high importance.

Maternal nickel exposure and congenital musculoskeletal defects

To investigate whether women occupationally exposed to nickel in early pregnancy are at elevated risk of delivering a newborn with a malformation or deformation of the musculoskeletal system (ICD-10: Q65-Q79). Data about the newborn, maternal occupation and workplace were obtained using the Kola Birth Register (KBR). Each record in the KBR was assigned a categorical nickel (Ni) exposure rating according to the occupation the delivering woman had at the time of becoming pregnant. This was achieved by using as a guideline the water-soluble Ni subfraction of the inhalable aerosol fraction obtained by personal monitoring for nickel- and copper-refinery workers or/and measured urinary-Ni concentrations. The reference population was delivering women from the source population with background exposure level. In total, the study population consisted of 22,965 births. Three hundred and four infants (13.3/1,000 births; 95% confidence interval (CI): 11.9-14.7) were diagnosed with isolated musculoskeletal defect(s) at birth. The adjusted odds ratio for the association between the maternal exposure to Ni and this outcome was 0.96 (95% CI: 0.76-1.21) per unit increase in exposure category. The incidence of defects in the musculoskeletal system at birth was high, especially for feet deformities, but we found no effect of maternal exposure to water-soluble Ni on the risk of delivering a newborn with a defect. However, the incidence among women working in the copper refinery was higher than in the other employment groups.

Spontaneous abortions among nickel-exposed female refinery workers

A case-control study to investigate whether women employed in nickel-exposed work areas in early pregnancy are at elevated risk of spontaneous abortion (SA). Data about pregnancy outcome and maternal factors were obtained about each delivery and SA from women in selected work places. Each pregnancy record was assigned a categorical nickel (Ni) exposure rating according to the women's occupations at pregnancy onset. The guidelines were the water-soluble Ni subfraction of the inhalable aerosol fraction obtained by personal monitoring for nickel- and copper-refinery workers or/and measured urinary-Ni concentrations. The unadjusted odds ratio for the association between the maternal exposure to Ni and an SA for Ni-exposed women was 1.38 (95% confidence interval: 1.04–1.84), and the adjusted was 1.14 (0.95–1.37). In conclusion, there was no statistical association between maternal occupational exposure to water-soluble Ni in early pregnancy and the risk of self-reported SA. The findings do not exclude the possibility of a weak excess risk, or a risk in the first weeks of pregnancy.

Relationships Between Inhalable, Thoracic, and Respirable Aerosols of Metalworking Fluids

The aim of the study described in this companion paper was to assesses relationships among inhalable, thoracic, and respirable aerosol fractions of metalworking fluids. A RespiCon sampler, which simultaneously collects all three fractions, was used at four Ontario plants to collect 37 samples of 120 to 400 min duration. The ratios of the slopes of the lines of a regression model forced through the origin between inhalable and thoracic, inhalable and respirable, and thoracic and respirable were 1.38, 1.51, and 1.13, respectively. These ratios would be useful in assessing metalworking fluid airborne exposure data based on different aerosol fractions and for interpreting occupational exposure standards based on different fractions.

Comparison of different sampling heads applied for investigation of welding fume

Welding fume samples were collected in two Hungarian welding plants, where different types of steels were welded with metal active gas (MAG) welding. Welding fumes were sampled with “fixed point” and personal sampling techniques applying different sampling heads: Institute of Occupational Medicine (IOM) sampler and conical inhalable sampler (CIS) for the inhalable aerosol fraction and the Higgins-Dewell (HD) cyclone for the respirable fraction. When sampled, the welding fume samples were digested with the mixture of nitric acid and hydrogen peroxide in a closed vessel microwave digestion system. The Cr, Mn, Ni and Co contents of the solutions were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Iron was analysed only by the ICP-AES method. Metal concentrations of the workplace air were calculated for the three samplers, and the results were compared to each other. The differences of the metal concentrations determined by the different inhalable sampling heads, which were paired during the sampling, proved not to be significant. Therefore, the IOM and CIS heads can be equally used for the sampling of welding fume. Finally, the distributions of metals were determined between the inhalable and respirable fractions. Metal concentrations in the respirable aerosol fraction were 57–98% of the concentrations in the inhalable fraction. These high rates of metals in the respirable aerosol call the attention to the increased health risk of the welding fume.

Genital malformations in newborns of female nickel-refinery workers

This study investigated whether pregnant women employed in nickel-exposed work areas are at elevated risk of delivering a newborn with a genital malformation. In this register-based cohort study, data about pregnancy outcome and occupation were obtained using the Kola Birth Registry. Each record in the Registry was assigned a categorical nickel exposure rating according to the occupation the delivering woman had at the time of becoming pregnant, using, as guidelines, the water-soluble nickel subfraction of the inhalable aerosol fraction obtained by personal monitoring for nickel-refinery workers or the measured urinary nickel concentrations. The reference population comprised delivering women from Moncegorsk with a background exposure level. The association of the outcome with the assigned exposure ratings was analyzed in a logistic regression model, adjusted for parity, maternal malformation, exposure to solvents, and infection in early pregnancy. The odds ratio for nickel-exposed women delivering a newborn with a genital malformation was 0.81 [95% confidence interval (95% CI) 0.52-1.26], and that for an undescended testicle was 0.76 (95% CI 0.40-1.47). In this study no negative effect of maternal exposure to water-soluble nickel was found on the risk of delivering a newborn with malformations of the genital organs. The results should be interpreted with caution since there were few cases in the higher exposure groups. The findings do not exclude the possibility of an effect on the risk of other congenital malformations and adverse outcomes (including reduced fertility).

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).