Annals Of Work Exposures and Health最新文献

Background: Since the 1980s, lung fibre burden analysis has been used in reconstructing past exposure to asbestos and in estimating the dose-response relationship for asbestos-related cancers.

Objective: The objective of this study was to evaluate the validity (sensitivity and specificity) of the reference values proposed by the Helsinki Consensus Documents in 1997 and 2014 to assign asbestos exposure.

Methods: Counts of asbestos bodies (AB) and amphibole asbestos fibres (AAF) in dry lung tissue samples performed by the ARPA Electron Microscopy Laboratory in Milan from 2009 to 2020 have been used to assess the discriminating performance between asbestos exposure and background exposure. For each sample/individual, we retrieved information on disease diagnosis and on asbestos exposure at work or in other settings. We calculated sensitivity and specificity using either Helsinki criteria (1000+ AB or 1,000,000+ AAF >1 µm per gram of dry lung tissue) or different optimal statistical cut-points chosen on the basis of three statistical methods.

Results: From the original list of 822 samples, we selected samples from 563 individuals with information on disease (325 with mesothelioma, 158 with lung cancer, 24 with asbestosis or pleural plaques, and 56 without asbestos-related diseases) and with information on asbestos exposure. The number of subjects with a history of asbestos exposure was 507, 478 occupationally exposed and 29 with familiar or environmental exposure. The 56 individuals without asbestos-related diseases (of whom 53 were included in a previous publication on background asbestos exposure) were taken as "unexposed." The estimated (rounded) optimal cut-points were 600 AB and 300,000 AAF with all three statistical methods. The Helsinki criteria had very good specificity (1 for AB and 0.95 for AAF), and good sensitivity (0.89) for AB, while sensitivity was quite low for AAF (0.67, implying one third of false negatives). The optimal statistical cut-points showed higher sensitivity for AB (0.94) and much better sensitivity for AAF (0.85). In sub-analyses, we found that the Helsinki criteria had good/sufficient sensitivity only among 249 highly exposed shipyard workers, not among 258 individuals with lower exposure; the optimal statistical cut-points yielded higher sensitivity, especially in lower-exposed individuals.

Conclusions: Based on a large sample size, we have shown good sensitivity for AB but very low sensitivity for AAF using Helsinki criteria for the attribution of exposure to asbestos. We propose to adopt lower values (600 AB or 300,000 AAF), because they would avoid a large proportion of false negatives. We remind that lung fibre burden analysis should be viewed as a complement (not a substitute) for a carefully collected lifetime job history.

Endotoxins are components of the outer membrane of bacteria that can become airborne during aerosol-generating work activities and cause adverse effects on workers' health. Filtration is the sampling method recommended by the EN 14031 standard for endotoxin measurements in workplace atmospheres. However, there are still differences in terms of practice regarding certain parameters of the measurement method. Thus, the storage of samples, the method of endotoxin extraction from the filter, and the type of filter are some parameters that still need to be studied to improve endotoxin recovery. For this purpose, laboratory experiments were performed based on 19 independent generations of an endotoxin aerosol coming from a suspension of 3 cultivable Gram-negative bacteria. Using a fix sampling time of 1 h, this experimental bioaerosol allow covering endotoxin concentrations from ~ 10 to ~ 104 EU/m3. Using the kinetic chromogenic LAL (Limulus Amebocyte Lysate) assay, our results show that a better recovery of endotoxins is achieved using 5 mL of pyrogen-free water compared to 10 mL, especially for glass fiber filters, with no change when the agitation time is reduced from 60 to 20 min. Except for polyvinylchloride, the type of filter (polycarbonate, Teflon, or glass fiber) does not have a great influence on the concentrations measured. However, PVC filters systematically gave a lower endotoxin concentration than the others. Finally, compared to the immediate processing of the cassette, storage of the samples at room temperature is possible for up to 8 d after sampling without altering the amount of endotoxin measured. These improvements make the results of the endotoxin concentration more robust and will help to make this measurement method more readily usable, especially with the simplification of the protocol steps and storage, providing a greater flexibility for analysts.

The inhalation of dust containing naturally occurring radioactive materials (NORM) associated with mining and mineral processing operations may lead to potential long-term health impacts, including cancer and chronic lung disease, due to alpha particle-emitting radionuclides. This study evaluates the effectiveness of air sampling strategies used to estimate radiation doses from NORM exposure, with a focus on the Western Australian minerals industry. The objectives were to review current sampling and analysis protocols, identify factors contributing to over- or underestimation of dose, and propose adjustments to improve intake assessments. A review of research and guidelines applicable to NORM dust exposure was conducted, and the sampling efficiency of the government-recommended 7-hole and IOM sample heads was compared, considering measured dust particle size distributions. Key inhalation-related parameters, including use of similar exposure group (SEG) mean concentrations, worker breathing rates, median dust particle size, and intake-to-dose conversion factors, were analysed to assess their influence on intake calculations. The findings indicate that use of the 7-hole sampler, currently recommended by local guidelines, may underestimate airborne radioactivity concentrations by 2-fold or more, primarily due to reduced sampling efficiency for larger particles. Standard default assumptions for breathing rates and aerosol characteristics used to convert the measured concentrations to intake and dose may further contribute to underestimation. This study recommends updating air sampling methods and dose assessment protocols to better align with workplace-specific exposure conditions and improve worker health protection in NORM industries.

Simultaneous sampling of diisocyanates and diamines is of great importance since occupational exposure to both diamines and diisocyanates may occur during production of the diisocyanates and polyurethane (PU) products or during thermal degradation of PU material. A methodology for the simultaneous collection and determination of diisocyanates and diamines using ASSET EZ4-ICA dry sampler (Supelco, PA, United States) was presented. The sampler was previously validated and is sold commercially for isocyanate detection. This work investigated to also include diamine determinations (specifically MDA and TDA) to enable a user-friendly approach, without the use of fragile glassware and solvents during sampling. In addition, a sampler based on the same design as the ASSET-sampler but with a modified impregnation with dibutyl amine (DBA) and sulfuric acid was also demonstrated. During sampling, isocyanates were collected and derivatized with DBA and the diamines were derivatized in a subsequent work-up procedure with ethyl chloroformate to form carbamate esters. For the ASSET-ICA sampler, no breakthrough was observed for 2,4'-MDA or 4,4'-MDA for sampling at 200 mL/min for up to 4 h (240 min). For 2,4-TDA and 2,6-TDA, no breakthrough was observed for up to 60 min of sampling. For the sampler with modified impregnation, no breakthrough of TDA was observed for up to 240 min of sampling. No losses were observed for the MDA isomers when storing the samplers in a refrigerator (8 °C) for up to 21 d after sampling. However, for the TDA isomers, minor losses could be observed after storage for 8 d. Storing the samplers in a freezer (-18 °C) or performing the addition of 500 µL of 3M sulphuric acid to the sampler filter media after sampling improved the stability of the TDA isomers during storage and no losses were observed for 21 d of storage. Also, for the sampler with modified impregnation, storage for up to 21 d could be made without any significant losses of TDA. Comparable concentrations were measured in ASSET-ICA samplers and in impinger-filter samples when sampling of a controlled test atmosphere was performed at different relative humidity (30% to 70% RH) and also during sampling of thermal degradation products from PU foam.

Crystalline silica was categorized by the International Agency for Research on Cancer as a known human carcinogen. Activities related to the processing of ceramic tiles, releasing crystalline silica, may vary considerably in terms of hours worked per day and days worked per week. This variability could be particularly high for craftsmen who process ceramic materials directly on-site during installation. The aim of this study is to measure the likely exposure to respirable crystalline silica (RCS) during ceramic tiles installation, evaluating the exposure to RCS of workers processing these tiles. Exposure assessments to RCS were conducted via both fixed-site and personal sampling for 2 working hours. The measured concentrations were calculated as 8-h time-weighted average (TWA) exposures, assuming no further RCS exposure in the time period. The permitted exposure time, not to exceed the occupational exposure limit (OEL) value, was then calculated also considering the assigned protection factor of selected respiratory protective equipment. The results of this study, considered as a worst-case simulation, show that, during the processing of ceramic tiles releasing RCS, the worker exposure can be very high (up to 240.9 µg/m3), exceedance of several OELs, including the European OEL of 100 µg/m³. Even working for a few hours a day, the RCS 8-h TWA OEL is likely to be exceeded. Inhaled exposure concentrations can be reduced by using appropriate respiratory protection, by a factor equal to 10 or 20. The assumption of this work was that (i) the cutting/grinding times are not always necessarily equal to 2 h and that (ii) these processes are not characterized by pre-established and continuous processing times. For these reasons, it is important to carefully evaluate the duration of exposure to RCS during the various tasks/activities performed, as these may vary depending on different factors.

Objectives: The aim was to estimate the prevalence and risk of respiratory symptoms among workers exposed to epoxy resin systems in the wind turbine industry.

Methods: We conducted a cross-sectional study including 180 epoxy-exposed production workers from two Danish wind turbine blade factories and 41 non-exposed office workers. Respiratory symptoms were defined as having two or more symptoms (i.e. wheezing in chest, waking up with chest tightness, shortness of breath, attack of coughing, or asthma attack) within the last 12 mo. Epoxy exposure was defined as exposure status (epoxy-exposed production worker or non-exposed office worker) and years of epoxy-exposure (years of employment as production worker). Epoxy skin sensitization status was obtained through a patch-test. The association between epoxy-exposure and respiratory symptoms was estimated using modified Poisson regression (prevalence ratio (PR)) adjusting for smoking and age.

Results: A total of 13.3% of the epoxy-exposed production workers and 4.9% of non-exposed office workers reported two or more respiratory symptoms (PRadj=1.8, 95% CI 0.4-9.5). For years of exposure, PRadj values were 1.2 (<1 yr), 1.0 (≥1-<5 yr), and 2.6 (≥5 yr). Higher PRadj were found among men. Epoxy-sensitized production workers had a PRadj of 0.4, while non-sensitized workers had a PRadj of 1.9, compared to non-exposed office workers.

Conclusion: Epoxy-exposed production workers showed a tendency to report respiratory symptoms more often than non-exposed office workers. However, we found no clear association between exposure duration and symptoms. Further studies are highly warranted to evaluate the potential association between epoxy exposure and respiratory symptoms.

Objectives: Many South African workers rely on respirators for protection from airborne hazards. To our knowledge, there is no public head and face anthropometric database for Black South African respirator users to inform the design of respirators for these individuals. The objective of our study was to determine the facial dimensions of Black South African respirator users using the 13 facial dimensions recommended by the United States National Institute for Occupational Safety and Health (NIOSH).

Methods: This was a descriptive and analytical cross-sectional study of Black South African respirator users working in Gauteng. Industries and companies known to use respirators in their operations were approached, and 693 participants between the ages of 18 to 65 were enrolled. Our study followed the methodology used in a NIOSH 2005 study that conducted a head and face anthropometric survey of US respirator users. Traditional measurement tools such as a tape measure, sliding caliper, spreading caliper, and pupillometer were used. Student's t-test was used to analyze data.

Results: The study found statistically significant differences between the facial dimensions of Black South African men and women respirator users and those of 3,000 Chinese respirator users studied in 2009 to develop a fit test panel. All the dimensions of males and females differed significantly, with the largest differences being in head circumference, neck circumference, and minimal frontal breadth. The majority of the facial dimensions of Black South Africans were also significantly different from the 3,997 American NIOSH 2007 fit test panel population, with only face width and nose protrusion not significantly different.

Conclusions: The mean values of Black South African facial dimensions differed significantly from those of the American and the Chinese populations. It may be that respirators designed and tested using the 2007 NIOSH and the 2009 Chinese fit test panels do not include dimensions representative of Black South Africans. Currently supplied respirators are likely to leave some Black South Africans unprotected due to poor fit.

This study investigated the compatibility of Tetrahydrofuran (THF) dissolution, following the procedures outlined in NIOSH Method 7500 and the similar OSHA ID-142 method, as a sample preparation technique for respirable crystalline silica (RCS) analysis in engineered stone materials compared to the muffle furnace (MF) ashing method. Our results revealed considerable variability in RCS content across different batches of engineered stone tested, underscoring the inherent material heterogeneity in engineered stone products. A statistically significant underestimation of RCS concentrations was observed when using THF dissolution for Stone A (polyester-based) samples collected on 47 mm polyvinyl chloride (PVC) filters, particularly at lower analyte loadings. In contrast, no statistically significant differences in RCS measurement were found between THF dissolution and MF ashing for the other 3 stone types, including one laboratory-synthetic material. The observed discrepancy in Stone A is likely attributed to the interaction of THF with its polyester resin binder, leading to swelling of the filter matrix and forming a non-volatile residue. This residue may physically entrap silica particles, hindering their complete recovery and subsequent quantification by X-ray diffraction (XRD). The suitability of THF processing as a sample preparation method is therefore highly dependent on the specific composition of the engineered stone. Based on these findings, MF ashing is recommended as the more reliable and universally applicable sample preparation method for engineered stone samples, especially those containing polyester resin binders. Caution should be exercised when considering THF dissolution for RCS analysis in engineered stones due to the potential for significant underestimation of actual RCS values, which could have implications for exposure assessments and regulatory compliance.

Objectives: Our aim was to explore the probable effectiveness of personal protective equipment (PPE) and environmental controls in protecting healthcare workers from Covid-19 infection using the Covid Exposure Model and Risk App (CEMRA), which estimates the risk of infection by various pathways.

Methods: We adapted a compartmental model of nine states within a hospital room to estimate virus transport and fate for contact and inhalation transmission from an infected patient, implemented using a discrete-time Markov-chain. Cough spray transmission was modeled separately, extrapolated to the expiratory volume, with a probability of the cough impacting the face in proportion to the surface area of the mucous membranes. Infectious profiles of patients observed in hospitals, constructed using information on salivary virus concentration, exhaled emissions and cough frequency, were categorized from "extremely low" to "extremely high" in seven steps. We parameterized the model using measurements made in three Scottish hospitals along with estimates from the literature. Seven interventions spanning PPE, engineering controls and administrative controls were applied to simulations of a health care worker working in a small room.

Results: Route of infection and to a lesser extent efficacy of controls depended on the infectiousness of the patient; inhalation was the main transmission route in scenarios from "extremely low" to "moderate" infectiousness. For these lower infectious profiles, the surgical mask, surgical mask combined with hand hygiene, and surgical mask, hand hygiene and surface disinfection showed between a 60% and 64% average reduction in risk compared with no intervention. The use of natural ventilation and an air purification device resulted in a modeled 71% to 77% reduction in risk. A healthcare worker wearing an FFP2 or FFP3 respirator, was associated with an 86% to 95% reduction in risk. Finally, a ventilated headboard or a powered respirator with hood showed between a 91% and 99% reduction in risk. For the "high" to "extremely high" infectious profiles the cough spray route predominated, although the modeled effectiveness of the interventions was similar to the lower infectious profiles.

Conclusion: The use of a flexible quantitative microbial risk assessment model can assess the likely reduction of risk of Covid-19 from workplace controls under various assumptions. Respirators and local ventilation were the most effective modeled interventions.

Background: Several authors have studied contamination of polycyclic aromatic hydrocarbons (PAHs) found on the outer gears of firefighters, but to our knowledge, none have investigated merino wool and mixed fibre undergarments used underneath the protective turnout gear. We therefore performed a comprehensive study regarding selected PAHs in pieces cut out from different areas of firefighter's sweaters and hood used in real fires and laundered after each use.

Method: Hoods (38) and sweaters (58) were donated by 3 fire departments and from these garments 558 pieces of fabric were cut out. Extracts of the fabric pieces were analysed by liquid chromatography with ultraviolet and fluorescence detection for 7 PAHs: anthracene, benzo[a]pyrene, chrysene, fluoranthene, naphthalene, phenanthrene, and pyrene. In addition, a small study was performed to examine the removal of PAHs from sweaters during laundry.

Results: Trace amounts of anthracene, benzo[a]pyrene, fluoranthene, and pyrene were detected both in merino wool and mixed fibre sweaters and hoods with highest concentrations for the hoods and lowest for the back of the sweaters. Highest concentration was found for the forehead position of the hoods. Significantly higher concentrations of PAHs were found in both hoods and sweaters containing the textile meta-aramid. Laundering reduced the amount of PAHs-in the sweaters but not completely.

Conclusion: Trace levels of benzo[a]pyrene and 3 other PAHs could be found in firefighters routine laundered undergarments. Cleaning reduced the PAH levels but not completely, and textiles with meta-aramid contained more PAHs than those without. Merino wool and mixed fibre undergarments are used in many countries and the results are valuable outside this study.