Journal of Occupational and Environmental Hygiene最新文献

Eyewash stations are an essential component of laboratory safety programs, providing first aid in case of ocular exposure to hazardous materials. However, the presence of microbial contamination in these devices poses a potential risk of ocular infection to laboratory employees. This cross-sectional study aimed to evaluate the microbial quality and performance of 40 eyewash stations fixed in 10 buildings in a laboratory setting. Water quality parameters, including temperature, pH, turbidity, and the presence of Acanthamoeba spp., were measured at various time points (first draw, after 2 min of flushing, and 15 min flushing) from samples collected from each of the 40 eyewash stations. Performance and operational data were also measured according to the American National Standards Institute (ANSI)/International Safety Equipment Association (ISEA) Z358.1-2014 standard. Our results showed variable compliance with this standard across measures of physical condition, performance, access, and maintenance. Out of the 147 water samples collected (130 eyewash samples, 17 building reference samples), 28 samples were suspected to contain Acanthamoeba spp. or other free-living amoeba based on initial testing. Further analysis using polymerase chain reaction (PCR) confirmed the presence of Acanthamoeba spp. in 5 out of 28 samples. The results of this study provide insights into the potential risk of ocular infections associated with using eyewash stations and provide the basis for the recommendations on maintenance protocols to minimize the risk of microbial contamination.

The development of low-cost research equipment is crucial for enhancing accessibility in scientific research, particularly in the field of respiratory disease transmission. This study presents a novel, customizable cough simulator designed for ad-hoc studies that require precise control over ejection velocity and aerosol size. Constructed from off-the-shelf parts and 3D-printed components, this programmable, piston-driven simulator offers an affordable solution for researchers. Its performance has been validated, demonstrating suitability for evaluating fluid flow and monitoring ejected particles that correspond to the velocities of mouth breathing and coughing. Potential applications for this device include assessments of aerosol ventilation, disinfection, and the efficacy of personal protective equipment, all of which contribute to advancing scientific understanding and public health outcomes.

The ongoing resurgence of severe Coal Workers' Pneumoconiosis in the US has been linked to overexposure to respirable crystalline silica (RCS, which is predominantly present as quartz and regulated as such). Capabilities that enable more frequent RCS monitoring are highly sought. Recent developments include field-based quartz analysis of traditional filter samples-collected on polyvinyl chloride (PVC) filters-using portable Fourier Transform Infrared spectroscopy (FTIR). However, most respirable dust samples in US coal mines are collected with a continuous personal dust monitor (CPDM) that enables real-time tracking of total respirable dust mass concentration. FTIR cannot directly analyze the collected dust sample due to the materials and construction of the sampling substrate. To address this issue, a simple three-step method was envisioned wherein the dust could be recovered into a suspension, redeposited onto a PVC filter using a syringe filter apparatus, and then analyzed by FTIR. The current study was conducted to develop the redeposition and analysis steps. It specifically considers the issues of the PVC filter size and deposition pattern yielded by typical filtration apparatuses and the FTIR scanning locations to establish a model that predicts quartz mass from the spectral data. Of the options tested here, the following combination was found to be optimal: 25-mm PVC filter with dust deposition using an inline syringe filter holder (which yields a "wheel and spoke" pattern), and FTIR analysis at four center-offset locations (90° apart, 8-mm from the center) from which the spectral data were averaged. Under these conditions, the predicted quartz mass on filters with respirable dust deposited from one of two geologic source materials (i.e., representing real coal mine silica sources) was observed to have a standard error of 0.011 mg (11 µg) for samples with an expected quartz mass of less than 0.150 mg (which equated to a total sample mass of less than about 1.5 mg). For samples with higher expected quartz masses, standard error increased, suggesting that dust deposition becomes less uniform with increasing total sample mass.

Engineered stone countertops, popularly known as quartz or artificial stone countertops, have gained significant attraction due to their durability and aesthetic appeal. However, due to their high crystalline silica content, the fabrication of these countertops poses severe health risks to workers, as evidenced by numerous global cases of silicosis. The study aimed to assess occupational exposure to respirable crystalline silica (RCS) among fabricators in Chicago and characterize the elemental composition and physical properties of engineered stone dust. Eight professional fabricators from two local stone workshops were recruited for the study. The exposure levels to RCS were assessed using the NIOSH 7500 method. Bulk dust samples were collected on-site, and the elemental composition of the dust was analyzed using X-ray fluorescence (XRF) and reported in stoichiometric oxide units. A set of real-time air monitors was used to measure particle size distribution, particulate matter (PM) concentrations, and ambient conditions in the workplace. A questionnaire was administered, and worker activities were recorded during the visits. Workers were found to be overexposed to respirable quartz in their workplaces, with time-weighted averaged (TWA) concentrations ranging from 11 to 203 µg/m³, with a median concentration of 90 µg/m³. Seven samples (78%) exceeded the 50 µg/m³ TWA-8 hr occupational exposure limit for RCS. Engineered stone dust samples contain much higher silica content compared to natural stone dust (30%), with silica percentages ranging from 56% to 95%. Over 90% of the particles (90.3-98.7%) emitted from activities involving small hand tools were of size less than 2.5 µm. The use of respiratory protection was not observed during the visits. The study offers firsthand insights into the engineered stone fabrication industry. The findings reveal a combination of risk factors: elevated RCS concentrations, very high silica content in engineered stone, and a high prevalence of fine particles. These factors collectively pose significant health risks to workers that are unequaled in comparison to most other industries. The findings underscore the urgent need for regulatory measures to better protect workers' health in the engineered stone fabrication sector.

A significant portion of the work of developing and validating methods for volatile organic compound (VOC) sampling in workplace atmospheres involves the use of laboratory-generated atmospheres. The sample variability was evaluated from the dynamic atmosphere generation system used for VOC atmosphere generation and sampling. Characterization of the bias and variability of samples was done for a variety of atmospheres containing neat n-heptane and mixtures of VOCs sampled on activated coconut shell charcoal. Estimates of sampling variability ranged from 2% for neat n-heptane to 12% for a component in the 10 VOC mix. Sample variability increased for lower concentration samples and for mixtures of VOCs compared to single component atmospheres. This study can serve as a baseline for future atmosphere sampling experiments evaluating performance at lower concentrations and mixed VOC environments.

In public health, risk experts often define acceptable risk targets without community input. We developed a novel method for applying behavioral microeconomics to integrate individuals' risk preferences into risk assessment. To demonstrate this methodology, we explored a risk-risk tradeoff case scenario: increased asthma risk from increased cleaning and disinfection (C&D) and increased infection risk from decreased C&D for healthcare staff. Utilizing a risk-risk tradeoff (RRTO) framework, two datasets were informed with RRTO survey data describing the risks individuals would accept for one outcome to offset risk in another (i.e., "risk target"). A quantitative microbial risk assessment (QMRA) was deployed to output "critical concentrations," viral concentrations on surfaces that yield risk targets for a single contaminated surface touch and a work shift. Critical concentrations were over four orders of magnitude larger for single-touch scenarios. Critical concentrations across risk target datasets were similar. Using the RRTO framework to inform QMRA advances the incorporation of individuals' risk preferences in risk analyses outside economics.

Recently, the misuse of fentanyl and methamphetamine has increased in the United States. These drugs can be consumed via smoking a powder, which can subsequently contaminate air and surfaces with drug residue. With limited access to safe consumption sites, this misuse often occurs in public spaces such as public transit, leading to potential secondhand exposures among transit operators and riders. In the Pacific Northwest, transit operators have reported acute health symptoms and safety concerns regarding these drug exposures. Researchers conducted an exposure assessment, sampling air and surfaces for fentanyl and methamphetamine. A total of 78 air samples and 89 surface samples were collected on 11 buses and 19 train cars from four transit agencies in the Pacific Northwest. Fentanyl was detected above the limit of quantification (LOQ) in 25% of air samples (range of concentrations > LOQ: 0.002 to 0.14 µg/m³) and 38% of surface samples (range of concentrations > LOQ: 0.011 to 0.47 ng/cm²), while methamphetamine was detected in 100% of air samples (range: 0.003 to 2.32 µg/m³) and 98% of surface samples (range of concentrations > LOQ: 0.016 to 6.86 ng/cm²) The highest fentanyl air sample (0.14 µg/m³) was collected in the passenger area of a train for 4 hr, and would exceed the ACGIH^® 8-hr TWA TLV^® of 0.1 µg/m³ if conditions remained the same for the unsampled period. No surface samples exceed the ACGIH fentanyl surface level TLV (10 ng/cm²). The prevalence of fentanyl and methamphetamine on public transit highlights the need to protect transit operators from secondhand exposure and from the stress of witnessing and responding to smoking events. Future work is needed to evaluate the utility of engineering and administrative controls such as ventilation and cleaning upgrades in reducing exposures on transit, as well as the utility of training and increased workplace support for operators in addressing their health and well-being after observing or responding to drug use events.