Journal of Occupational and Environmental Hygiene最新文献

A job-exposure matrix (JEM) is a tool that can estimate diesel engine exhaust (DEE) exposures. JEMs based on expert judgment or measurement data are limited by the information available at the time of development. Over time, more information about hazardous exposures is understood through additional measurements and peer-reviewed publications. This study presents a systematic approach to updating an existing DEE JEM using published data to better reflect current scientific knowledge. The literature was searched for occupational exposure studies that measured DEE as elemental carbon (EC) between January 2010 and May 2022. Four-digit North American Industry Classification System (NAICS) 2002 and National Occupational Classification-Statistics (NOC-S) 2006 codes were assigned to each identified subgroup within the studies. EC exposures were categorized as low (0-10 µg/m³), moderate (10-20 µg/m³), or high (>20 µg/m³). Weighted arithmetic means were calculated for each industry-occupation intersection (IOI) identified in the literature. These means were used to adjust, or retain, the existing exposure level within the JEM cells using a decision tree based on the number of studies, workplace locations, and pooled sample size of the weighted mean. Concordance was measured between the updated JEM (Diesel Exhaust in Canada JEM (DEC-JEM)), the previous (existing) JEM, and the Canadian Job-Exposure Matrix (CANJEM). Thirty-seven studies were identified from the published literature reporting on 53 unique IOIs (20 NAICS and 34 NOC-S codes), including occupations in the mining, construction, and transportation industries. Exposure levels for 66% of identified IOIs increased, most in construction and mining. After the decision tree's results were expanded to the full DEC-JEM, the exposure level of 486 IOIs (12.5% of DEC-JEM) and 286,710 workers (15.8% of DEE-exposed workers) increased. There was a significant correlation between qualitative exposure levels in the updated DEC-JEM and CANJEM (Kendall's τ = 0.364, p < 0.001). This study describes a systematic approach to updating an existing JEM to incorporate new scientific knowledge. The updated DEC-JEM better reflects existing exposure knowledge in several industries, particularly construction. Future analyses include investigating its use as an exposure assessment tool in disease surveillance.

This study focuses on the semivolatile organic compound (SVOC) absorption through clothing and the skin. SVOCs are ubiquitous in daily life, in products like personal care items, plastics, and building materials. Understanding their permeation through the skin barrier is crucial for evaluating potential health risks of complete exposure. A PBPK model was developed to comprehend the dynamic interplay between SVOCs and human skin and to estimate tissue distribution throughout the body. The framework incorporated parameters such as skin permeability, physicochemical properties of the chemicals, and the impact of protective clothing and adsorbents. This model predicted the rate and extent of SVOC absorption under diverse scenarios. The PBPK predictions matched the experimental amount of mono-ethyl phthalate (MEP), a phthalate metabolite, when urine samples were collected for bare-skinned and clothed participants. Urine concentrations of MEP during a 6-hr exposure and for the next 48 hr show that clean clothing effectively decreased dermal uptake and the buildup of chemicals in the body. Additional removal of MEP was achieved through adsorption on activated carbon fabric. An increase in the maximum monolayer adsorption capacity or the Langmuir equilibrium constant further reduced the amount of MEP in the urine.

Exposure to silica dust presents a risk for the development of lung disease for stone carvers in Nakhon Ratchasima province, Thailand. This study aimed to develop a rapid prediction model for the assessment of silicosis risk among 243 stone carvers who were exposed to silica at work from August and October 2023 in Nakhon Ratchasima, Thailand. Demographic characteristics collected in questionnaires were work information; basic health information; health behavior data, including prevention and control of silicosis; knowledge; attitude; and practices for surveillance, prevention, and control of silicosis. Respirable crystalline silica (RCS) exposures were measured by conducting personal air sampling. Risk scores of silicosis were calculated and a rapid prediction model for assessment of silicosis risk among stone carvers was determined. It was found that 11 variables were significantly associated with silicosis risk scores (p < 0.05). However, it was demonstrated that only four significant influential variables, including the concentration of silica dust exposure (mg/m³), working hours per day, underlying diseases, and separation of residence from a workplace were acceptable for conducting a silicosis risk assessment using multiple regression analysis (R² = 0.675). This study indicated that a prediction model can be used for the assessment of silicosis risk among stone carvers. Therefore, the use of this prediction model is recommended to evaluate the risk associated with exposure to RCS of stone carvers in Nakhon Ratchasima province, Thailand due to its simplicity, accuracy, and time-saving attributes.

Exposure to biosolids in human waste handling occupations is associated with a risk for illness due to microbial infections. Although several years of exposure to biosolids might be hypothesized to be a prophylaxis against infection, the risks associated with infections from antibiotic-resistant organisms can also be a potential concern. Therefore, this study aimed to conduct a screening level risk assessment by deriving occupational exposure limits (OELs) characterizing the risks of adverse health effects among workers in human waste handling occupations with a focus on exposure to two pharmaceuticals commonly found in biosolids: ciprofloxacin (CIP) and azithromycin (AZ). Epidemiological and exposure studies of workers exposed to biosolids were identified through searches of major scientific databases. Screening OELs (sOELs) for these antibiotics were derived using a standardized methodology. The airborne concentrations of CIP and AZ antibiotics were determined using an exposure factors approach. The health-based exposure limits (i.e., sOELs) and the acceptable daily exposure (ADE) values for both of these antibiotics were derived as 80 μg/m³ and 12 μg/kg-day, respectively. An exposure factor approach suggested that inhalation route exposures to CIP and AZ are well below the sOELs and ADE daily doses, and likely too low to cause direct adverse health effects through antibiotic inhalation. A critical review of epidemiological studies on different occupations handling biosolids showed that the workers in industries with potential biosolids exposure have experienced an increased incidence of microbial-exposure-related illness. The health effects seen in the workers have been attributed to bacterial, viral, and protozoan infections. To the extent that bacteria are the pathogen of concern, it is not clear whether these bacteria are resistant to antibiotics commonly found in biosolids. It is also unclear whether the presence of antibiotics or antibiotic-resistant bacteria increases the susceptibility of these workers. Additional studies will provide more definitive estimates of inhalation and dermal exposures to CIP and AZ and could verify the exposure estimates in this study based on the literature and common exposure factors.

An occupational health study was conducted inside reinforced-concrete earth-covered munitions storage magazines (ECMs) at Fort Wingate Depot Activity (FWDA), a former military facility near Gallup, New Mexico. A two-phased approach was used: (1) HEPA vacuuming of bulk dust and (2) wipe sample verification post-vacuuming. Site-specific occupational health criteria were derived to evaluate potential risk from inhalation of bulk dust (Phase 1) and dermal contact of residual dust (Phase 2). In Phase 1, no explosives detections exceeded site-specific screening criteria. Any explosives detected, with or without criteria were carried forward into Phase 2. In Phase 2, no exceedances were noted for detected explosives with criterion. Using structure/reactivity characteristics within the explosives category, surrogates were assigned to the six (6) explosives without occupational health screening criteria. Based upon structural similarities within the analysis category, assignments of surrogates to explosives without criteria did not adversely impact the study conclusions. In Phase 1, lead was detected in bulk dust in all 35 igloos and all detections exceeded the applicable criterion for commercial/industrial workers. In Phase 2, all lead detections in wipe samples were below the wipe screening criteria. Study results indicated the ECM interiors posed no unacceptable dermal occupational risk for explosives or lead residues following bulk dust removal. High-efficiency particulate air (HEPA) filter vacuuming of interior bulk dust in ECMs at FWDA reduced occupational risk/hazard for exposure via inhalation and dermal contact for commercial/industrial worker activities under worst-case exposure conditions. Both phases of this sampling design are widely applicable, provided the site-specific assumptions made for this study are evaluated for suitability to another specific application and adjusted if needed.

Occupational exposure to particulate matter (PM) can result in multiple adverse health effects and should be minimized to protect workers' health. PM exposure at the workplace can be complex with many potential sources and fluctuations over time, making it difficult to control. Dynamic maps that visualize how PM is distributed throughout a workplace over time can help in gaining better insights into when and where exposure occurs. This study explored the use of spatiotemporal modeling followed by kriging for the development of dynamic PM concentration maps in an experimental setting and a workplace setting. Data was collected using personal low-cost PM sensors and an indoor location tracking system, mounted on a moving robot or worker. Maps were generated for an experimental study with one simulated robot worker and a workplace study with four workers. Cross-validation was performed to evaluate the performance and robustness of three types of spatiotemporal models (metric, separable, and summetric) and, as an additional external validation, model estimates were compared with measurements from sensors that were placed stationary in the laboratory or workplace. Spatiotemporal models and maps were generated for both the experimental and workplace studies, with average root mean squared error (RMSE) from 10-fold cross-validation ranging from 7-12 and 73-127 µg/m³, respectively. Workplace models were relatively more robust compared to the experimental study (relative SD ranging from 8-14% of the average RMSE vs. 27-56%, respectively), presumably due to the larger number of parallel measurements. Model estimates showed low to moderate fits compared to stationary sensor measurements (R² ranging from 0.1-0.5), indicating maps should be interpreted with caution and only used indicatively. Together, these findings show the feasibility of using spatiotemporal modeling for generating dynamic concentration maps based on personal data. The described method could be applied for exposure characterization within comparable study designs or can be expanded further, for example by developing real-time, location-based worker feedback systems, as efficient tools to visualize and communicate exposure risks.

Wildfires can negatively impact the health and well-being of wildland firefighters through a variety of exposure pathways. Many studies have measured acute health effects from occupational exposure to pollutants in wildfire smoke; however, research specifically examining cancer risks from exposure to carcinogens is limited. This review aimed to better understand cancer risk in this occupation by assessing the existing evidence of exposures and summarizing measured concentrations of carcinogens among wildland firefighters. A systematic search was conducted to identify scientific papers using the following databases: Medline(OVID), Embase(OVID), PsycINFO(OVID), Cochrane Library, CINAHL(EBSCOHost), EconLit(EBSCOHost), Scopus, Agricultural and Environmental Science Collect(ProQuest), and NIOSHTIC-2. Forty-nine papers were identified that met eligibility criteria. Across the papers, 31 carcinogens were identified and quantified using a variety of assessment methods. Papers measured particulate matter (N = 26), polycyclic aromatic hydrocarbons (N = 12), volatile organic compounds (N = 14), crystalline silica (N = 5), black carbon (N = 4), asbestos (N = 3), radionuclides (N = 7), and metals (N = 2). Most papers measured inhalation exposures through traditional air sampling methods, but a subset of exposures to polycyclic aromatic hydrocarbons (N = 8), as well as heavy metals (N = 1), were measured through urinary biomarkers and naphthalene was measured using dermal wipe samples (N = 2). Although the heterogeneity of exposure assessment methods made direct comparison of concentrations difficult, the papers provide consistent evidence that wildland firefighters are regularly exposed to carcinogens. All wildland fire personnel should continue to implement recommended mitigation strategies and support new mitigations to reduce exposure to carcinogens on the job.

Non-medical masks such as disposable non-medical, commercially produced cloth, and homemade masks are not regulated like surgical masks. Their performance, in terms of filtration efficiency and breathability, is variable and unreliable. This research provides a quantitative evaluation of various non-medical masks, assesses their fabrics' potential for the reduction of transmission of bioaerosols such as the SARS-CoV-2 virus, and compares them to surgical masks and N95 filtering facepiece respirators. Using a testing line with a NaCl challenge aerosol, four types of commercial reusable cloth masks, two types of disposable non-medical masks, three types of surgical or N95 masks, and seven types of commonly available materials were tested individually and in combinations. The testing line and procedure were adapted from the ASTM F2299-03: Standard Test Method for Determining the Initial Efficiency of Materials Used in Medical Face Masks to Penetration by Particulates Using Latex Spheres testing method used for testing surgical masks. Filtration efficiencies at 0.15 µm particle diameter at a face velocity of 25 cm/sec for commercial cloth masks, disposable non-medical masks, surgical masks, commercial mask combinations, and homemade combinations ranged from 16-29%, 39-76%, 91-97%, 51-95%, and 45-94%, respectively. The pressure drop results for the different masks and material combinations were all under 3 mm H₂O/cm² except for one material configuration. This study builds on other research that looks at individual materials and masks by testing combinations alongside the individual masks and materials. With proper layering, household materials can achieve the filtration efficiency and low pressure drop requirements of surgical masks. The filtration capabilities of disposable and cloth mask fabrics vary considerably meaning that they are not a reliable or consistent facemask option, regardless of fit.

Exposure to chlorine dioxide by staff working in a gnotobiotic mouse facility at an Australian research institute was measured to determine whether current controls were sufficient to ensure their exposure remains below the current Australian workplace exposure standard. A combination of workplace surveys, interviews with workers, and personal sampling was undertaken to understand the workplace, identify higher-risk tasks, and measure the concentration of chlorine dioxide in the air where the workers conduct routine tasks involving the use of a chlorine dioxide-based disinfectant. Personal sampling utilized the validated Occupational Safety and Health Administration (OSHA) method ID-202, with minor alterations. The tasks identified as being associated with higher airborne exposure to chlorine dioxide were the use of an atomizer to fill isolator ports with aerosolized disinfectant and the use of a disinfectant dunk tank to submerge and surface decontaminate objects. The current work practices in the gnotobiotic facility were found to be compliant with the current 8-hr time-weighted average (TWA) limit of 0.1 ppm (0.28 mg/m³) but were not compliant with the 15-min short-term exposure limit (STEL) of 0.3 ppm (0.83 mg/m³). Improvements in exposure controls, such as implementing the use of a fume cupboard (hood) or other local ventilation when activating the disinfectant solution and improving the utilization of respiratory protective equipment, are therefore required to meet the STEL, but it is recommended that such improvements are also aimed at meeting the proposed Peak limitation of 0.1 ppm that is expected to soon be adopted by Safe Work Australia, replacing the current TWA-8hr and STEL exposure standards.