Exposures In Occupational Settings Research Articles

Methods to assess dermal exposures in occupational settings: a scoping review.

The dermal exposure route is expected to become increasingly significant relative to total worker exposure as inhalational exposure limits continue to decrease. However, standardization of occupational exposure assessment methods and scientific consensus are needed. This is the first scoping review mapping the literature across all dermal exposure assessment methods and their targeted substances/chemicals in occupational settings. Eligibility criteria broadly included studies reporting any noninvasive dermal exposure assessment method in an occupational setting. The literature search (Web of Science and MEDLINE) was restricted to peer-reviewed, primary literature published in the last 20 years (2002-2022). Titles/abstracts were dual independently screened. Data charting was performed by a single reviewer using standard template. All stages were pilot tested. The JBI (formerly, the Joanna Briggs Institute) scoping review methods and PRISMA-ScR checklist (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) were used. In total, 493 articles were data charted and categorized by 4 study types: methods development (22%), exposure assessment (51%), health outcomes (21%), and controls assessment (6%). Fourteen types of dermal exposure assessment methods were charted with biomarkers (51%), dosimeters (21%), and qualitative assessments such as questionnaires or surveys (17%) most common. Seventeen different chemicals/substances were charted; pesticides (28%) and polycyclic aromatic hydrocarbons (PAHs) (22%) associated with crude oil products and combustion were most common. Mapping between substances and exposure assessment method categories, pesticide dosimeters (11%), and PAH biomarker studies (14%) were most reported. Literature gaps were identified for cleaning agents, hair dyes, glycol ether, N,N-dimethylformamide/N-methyl-2-pyrrolidone, dioxins, and bisphenol A. To foster scientific consensus, standardization across study reporting is needed for describing: (i) exposure assessment methods used, (ii) worker tasking/conditions, (iii) targeted substances and substance state, and (iv) targeted exposure routes. Overall, this review categorizes, maps, and defines the scope of literature for occupational dermal exposure assessment methods.

Public Health Risks, Dermatological Manifestations, and Environmental Justice Associated With Vinyl Chloride Exposure: Narrative Review.

Environmental vinyl chloride (VC) exposure may result in serious acute and chronic dermatological conditions. Because existing literature largely focuses on exposures in occupational settings, a gap persists in our understanding of the medical consequences of large-scale chemical spills. This study aims to examine the potential dermatological manifestations of VC exposure in the context of industrial spills and other environmental disasters and to highlight the public health and justice implications of such releases. In this narrative review, relevant evidence-based, peer-reviewed scientific sources, gray literature, and media reports were identified via searches of search PubMed and Google using predetermined keyword search terms related to VC, VC spills and releases, train derailment, cutaneous disease, public health, and vulnerable and marginalized populations. Contact dermatitis and frostbite may arise acutely, highlighting the importance of swift decontamination. Long-term manifestations from chronic VC exposure due to persistence in environmental reservoirs include Raynaud disease, sclerodermatous skin changes, acro-osteolysis, and cutaneous malignancies. The clinical severity of cutaneous manifestations is influenced by individual susceptibility as well as duration, intensity, and route of exposure. Additionally, chemical releases of VC more frequently impact Communities of Color and those of lower socioeconomic status, resulting in greater rates of exposure-related disease. With environmental release events of hazardous chemicals becoming increasingly common and because the skin has increased contact with environmental toxins relative to other organs, an urgent need exists for a greater understanding of the overall short- and long-term health impacts of large-scale, toxic exposures, underscoring the need for ongoing clinical vigilance. Dermatologists and public health officials should also aim to better understand the ways in which the disproportionate impacts of hazardous chemical exposures on lower-income and minority populations may exacerbate existing health disparities. Herein, we describe the health implications of toxic releases with particular consideration paid to marginalized and vulnerable populations. In addition to legal and regulatory frameworks, we advocate for improved public health measures, to not only mitigate the risk of environmental catastrophes in the future, but also ensure timely and effective responses to them.

Laboratory comparison of field portable X-ray fluorescence spectrometer (FP-XRF) and inductively coupled plasma mass spectrometry (ICP-MS) for determination of airborne metals in stainless steel welding fume

Welding fume is a common exposure in occupational settings. Gravimetric analysis for total particulate matter is common; however, the cost of laboratory analyses limits the availability of quantitative exposure assessment for welding fume metal constituents in occupational settings. We investigated whether a field portable X-ray fluorescence spectrometer (FP-XRF) could provide accurate estimates of personal exposures to metals common in welding fume (chromium, copper, manganese, nickel, vanadium, and zinc). The FP-XRF requires less training and is easier to deploy in many settings than traditional wet laboratory analyses. Filters were analyzed both by FP-XRF and inductively coupled plasma mass spectrometry (ICP-MS). We estimated the FP-XRF limit of detection for each metal and developed a correction factor accounting for the non-uniform deposition pattern on filter samples collected with an Institute of Medicine (IOM) inhalable particulate matter sampler. Strong linear correlation was observed for all metals (0.72<r < 0.96). The median percent bias for chromium and nickel was less than 15%. The linear slope between the two methods for some metals (copper, manganese, and zinc) was greater than 1, indicating that the FP-XRF overestimated metal mass (median percent bias for vanadium was the largest at 94%), but the linearity of the response suggests that appropriate correction factors could be developed.

Health risks of titanium dioxide (TiO2) dust exposure in occupational settings - A scoping review.

Titanium dioxide (TiO2) is an inorganic compound with many applications, for example in paint, sunscreen or as food coloring. There have been concerns regarding its safety and according to IARC, the existing evidence is not substantial enough to rule them out, leading to the substance being classified as possibly carcinogenic to humans (2B). This work aims to provide a comprehensible overview about epidemiological studies on occupational health risks and methodological aspects. A literature search was conducted in two databases (MEDLINE and Web of Science). The search focused on occupational exposure since this setting provides the highest amounts of TiO2 exposure. Of 443 unique search results, ten were included in this study, with publication dates ranging from 1988 to 2022. Seven of them are retrospective cohort studies and three have a case-control study design. Main outcomes of most studies were all-cause mortality and lung cancer mortality. For all-cause mortality, most cohort studies reported no association with TiO2 exposure. For lung cancer mortality, a significantly increased risk was found in a study population from Europe. The analysis results of working cohorts from the US comparing exposed workers' mortality rates with those of the general population were unobtrusive. However, one US cohort found an elevated mortality risk for all causes and lung cancer based on a reference population of company workers unexposed to TiO2. Case-control studies did not indicate an increased risk for cancer related to TiO2. Recent publications partly questioned the validity of those earlier findings, claiming insufficient confounder analysis, most notably for smoking, as well as the presence of the healthy worker effect, masking a potential health risk. In conclusion, the associations between occupational TiO2 exposure and mortality are unclear, but concerns regarding possible health risks recently re-emerged based on new analytical approaches, highlighting methodological difficulties that could have limited the inferential value of previously conducted studies.

Wood dust exposure and small cell lung cancer: a systematic review and meta-analysis.

Occupational exposure role on small cell lung cancer (SCLC) onset has been little studied. Wood dust has been recognized as a human carcinogen, and many occupations have high wood-dust exposure. The aim of this study was therefore to perform a systematic review and meta-analysis of the scientific literature to summarize and analyse the risks of wood dust-related occupations on development of SCLC, taking tobacco use into account. We conducted a literature search of PubMed, EMBASE, Web of Science and Cochrane using a predefined strategy and including case-control and cohort studies assessing occupational exposure to wood dust or wood dust-related occupations. To perform the meta-analysis, the odds ratio (OR) and 95% confidence interval (CI) of each of the studies were extracted. A random-effects model was fitted using the DerSimonian Laird method. Sensitivity and subgroup analyses were performed. Quality was assessed using the Office and Health Assessment and Translation (OHAT) for human and animal studies instrument. Eleven studies with a total of 2,368 SCLC cases and 357,179 controls were included. Overall, exposure to wood dust significantly increases risk of SCLC (RR = 1.41, 95% CI 1.11-1.80), with low heterogeneity between studies (I2 = 40%). The association was maintained in studies conducted on males (RR = 1.41, 95% CI 1.12-1.78) but not in those conducted on females/both sexes (RR = 1.37, 95% CI 0.35-3.44). Sensitivity analysis showed that none of the studies significantly modified the results. Our results support that exposure to wood-dust can increase the risk of SCLC. Although the level of evidence is low, there are strong arguments to recommend the implementation of effective control measures to reduce exposure in occupational settings, as a means of preventing SCLC. The results of this study support that exposure to wood-dust can increase the risk of developing small cell lung cancer. Determining the impact of occupational exposure on workers is essential to improve their individual protection and prevention. There is a strong case for recommending the implementation of control measures to reduce occupational exposure to wood dust, specifically for highly exposed occupations such as carpenters and sawmills, in order to prevent small cell lung cancer.

Occupational exposure to per- and polyfluoroalkyl substances: a scope review of the literature from 1980-2021.

Per- and polyfluoroalkyl substances (PFAS) comprise a large group of chemicals that have been integrated into a wide variety of industrial processes and consumer products since the 1950s. Due to their profuse usage and high persistence in human serum, understanding workplace exposures to PFAS is critical. We aimed to characterize the PFAS exposure profiles of relevant occupational populations, elucidate trends in the PFAS exposure characterization process, and identify major research gaps that remain within the occupational PFAS exposure literature. A systematic search of four literature databases for peer-reviewed articles published between 1980 and 2021 on PFAS exposure in occupational settings was conducted. Of the 2574 articles identified, 92 met the inclusion criteria. Fluorochemical workers were the target population in most early exposure assessment research; however, studies conducted within the last 10 years have evaluated a wider range of occupational populations and settings. The highest exposures were reported in fluorochemical workers, but, in comparison to reference populations, one or more PFAS were elevated in most workers and in most workplaces that were assessed. PFAS was most frequently assessed in worker serum using a discrete analytical panel of PFAS, with earlier studies restricted to a few long-alkyl chain PFAS while more recent studies have included more expansive panels due to more robust methods. Characterization of occupational exposure to PFAS is limited but expanding. Current analytical methods are not robust enough to fully capture the potential range of PFAS present across different workers and workplaces. While exposures to PFAS for certain occupational groups have been studied in detail, exposure information for other occupational groups with high potential for exposure are limited. This review highlights substantial findings and major research gaps within the occupational literature.

Evaluation of Risk and Uncertainty for Model-Predicted NOAELs of Engineered Nanomaterials Based on Dose-Response-Recovery Clusters

Abstract Experimental toxicology studies for the purposes of setting occupational exposure limits for aerosols have drawbacks including excessive time and cost which could be overcome or limited by the development of computational approaches. A quantitative, analytical relationship between the characteristics of emerging nanomaterials and related in vivo toxicity can be utilized to better assist in the subsequent mitigation of exposure toxicity by design. Predictive toxicity models can be used to categorize and define exposure limitations for emerging nanomaterials. Model-based no-observed-adverse-effect-level (NOAEL) predictions were derived for toxicologically distinct nanomaterial clusters, referred to as model-predicted no observed adverse effect levels (MP-NOAELs). The lowest range of MP-NOAELs for the polymorphonuclear neutrophil (PMN) response observed by carbon nanotubes (CNTs) was found to be 21–35 μg/kg (cluster “A”), indicating that the CNT belonging to cluster A showed the earliest signs of adverse effects. Only 25% of the MP-NOAEL values for the CNTs can be quantitatively defined at present. The lowest observed MP-NOAEL range for the metal oxide nanoparticles was Cobalt oxide nanoparticles (cluster III) for the macrophage (MAC) response at 54–189 μg/kg. Nearly 50% of the derived MP-NOAEL values for the metal oxide nanoparticles can be quantitatively defined based on current data. A sensitivity analysis of the MP-NOAEL derivation highlighted the dependency of the process on the shape and type of the fitted dose-response model, its parameters, dose selection and spacing, and the sample size analyzed.

Application of hybrid Shannon’s entropy – PROMEHTEE methods in weighing and prioritizing industrial noise control measures

There are various strategies to prevent and control of noise exposure in occupational settings. This study was aimed to use Shannon’s entropy – PROMEHTEE hybrid model for weighing and prioritizing noise control solutions in an oil refinery. At first, the sound pressure levels were measured based on the recommended standard of ISO 9612. Next, criteria and noise control strategies were determined using the Delphi technique. In the third stage, the weights of the criteria were computed using Shannon’s entropy method and in the last stage, the solutions were prioritized by the PROMEHTEE method. Based on the results of Shannon’s entropy method, criteria in the order of priority included executive cost (0.2710), noise reduction efficiency (0.2531), feasibility (0.2435), safety (0.1120), possible interference with other processes (0.1107) and up-to-datedness of the methods (0.091). Also, based on the results of the PROMEHTEE method, the best solutions were construction of acoustic enclosures for people exposed to noise with a weight of 0.5476, and Modification or change of the work process with a weight of −0.6905, respectively. Therefore, the Shannon’s entropy – PROMEHTEE hybrid method can be used as a credible scientific tool to select the most appropriate noise control solution in the industries.

Occupational exposure to formaldehyde and oxidative stress in Italian workers

Abstract Background Formaldehyde (FA) is an environmental pollutant widely used in several occupational settings. Beyond its carcinogenic effect, FA can trigger inflammation by promoting reactive oxygen species formation in exposed subjects. The current study aims to investigate the association between air-FA exposure and systemic oxidative stress induction in specific working environments. Methods We accounted for three different scenarios of air-FA exposure by including a sample of pathologists and nurses from operating theatres (n = 185), traffic police officers (n = 154) and wood-workers (n = 127), who participated as volunteers. Exposure to air-FA was assessed by passive air-samplers (Radiello®) and oxidative stress was quantified by 15-F2t-IsoP urinary biomarker (ELISA). A piecewise linear regression model was performed to analyse oxidative stress variation in response to air-FA exposure. Results Overall, 466 subjects (45 ± 9 years) were included in the study, 53% were females. None significant changes of ln(15-F2t-IsoP) were observed before a specific exposure breakpoint of 4.729 (air-FA = 113 µg/m3). Beyond the breakpoint, ln(15-F2t-IsoP) showed a 1.5 increase (p &amp;lt; 0.0001), independently from age and sex. Interestingly, while age did not affect oxidative stress levels nor before neither beyond the breakpoint, sex determined an increase of ln(15-F2t-IsoP) only before the breakpoint (+0.62, p &amp;lt; 0.0001). Conclusions Currently, the most precautionary regulatory limit of air-FA exposure in occupational settings is 0.1 ppm (TLW-TVA, i.e. 120 µg/m3). This limit is recommended to protect for eyes and upper respiratory tract irritation. However, our results highlighted that slightly lower exposures can induce a biological effect, which should deserve consideration from Primary Prevention perspective. Since oxidative stress may evolve in future diseases, it would be advisable considering to tailor the regulatory limits to such a pre-pathological condition rather symptoms onset. Key messages Occupational exposure to air-FA is able to induce systemic oxidative stress even below the regulatory limit, independently from age and sex. Future updates of the regulatory limits in force may consider pre-pathological conditions, such as oxidative stress, rather symptoms onset.

Intercomparison of Indoor and Outdoor Pollen Concentrations in Rural and Suburban Research Workplaces

Pollen exposure in occupational settings involves different categories of workers. In this paper the effects of diurnal pollen variations have been evaluated in two sites characterized by different vegetation and urbanization: the suburban site of Tor Vergata (TV) and the rural site of Monte Porzio Catone (MPC). Aerobiological and meteorological monitoring was performed in the two sites during the winter of 2017. The data analysis focuses on the comparison between pollen concentrations observed in relation to meteorological variables. In general, it can be stated that the indoor and outdoor dynamics for MPC and TV are different, with the outdoor concentration of pollen for MPC always higher than for TV, in accordance with significant presence of vegetation. The high nocturnal peaks detected in MPC and completely absent in TV could be caused by the presence of particular conditions of stagnation combined with greater emissions from the pollen sources. Furthermore the higher I/O ratio observed during the working hours in TV compared to MPC could be ascribed to the workers’ behavior. Exposure to pollen can be responsible for several health effects and the knowledge of its level can be useful to improve the evaluation and management of this biological risk.

Application of Hybrid Shannon's Entropy – PROMEHTEE Methods for Weighing and Prioritizing Noise Control Solutions in an Iranian Oil Refinery

Background: There have been numerous control strategies employed to prevent the very physiological and psychological impacts of noise exposure in occupational settings. The present study aims to use the Shannon's entropy – PROMEHTEE hybrid model to weigh and prioritize noise control solutions in an oil refinery.   Methods: This study was performed in four stages. At first, the sound pressure levels were measured and determined according to the recommended standard of ISO 9612. Next, criteria and sound control strategies were determined using the Delphi technique. In the third stage, the weights of the criteria were determined using the Shannon's entropy method and in the last stage, the solutions were prioritized using the PROMEHTEE method. Result: According to Shannon's entropy method, criteria were sorted by the priority order of cost-effectiveness (0.2710), efficiency in reducing the noise (0.2531), executability (0.2435), safety (0.1120), process interference (0.1107) and up-to-dateness of the methods (0.091). Also, according to the PROMEHTEE method, the best solution was determined to be building a noise chamber with a weight of 0.5476, and modification or change of the work process was ranked last with a weight of -0.6905. Conclusion: The Shannon's entropy – PROMEHTEE hybrid method introduced in this study can be used as a credible scientific tool and solution to select the most appropriate noise control solution in the oil industry and other industries in which a choice of noise control technique is felt as a necessity.

A Health Surveillance Study of Workers Employed at a Copper Smelter-Effects of Long-Term Exposure to Copper on Lung Function Using Spirometric Data.

Significantly lower permissible occupational exposure limits for copper dust are being discussed in Europe and other jurisdictions. However, little data are published on exposures in occupational settings and copper-specific effects in humans. Hence, a health surveillance study was performed among workers employed at a copper smelter between 1972 and 2018. Possible effects of long-term exposures to dust containing copper on lung function were assessed. Specifically, declines in forced expiratory volume in 1 second (FEV1) were compared between a copper-exposed and control group. Cumulative copper exposures were derived from historical airborne monitoring data. FEV1 declines among exposed and control never smokers were similar to a typical age-dependent decline of 29 mL/y. The study findings indicate that cumulative inhalable copper dust exposure averaging 4.61 mg/m3-years over an exposure duration of ∼22 years is not associated with adverse effects on lung function.

Investigating Multi-Mycotoxin Exposure in Occupational Settings: A Biomonitoring and Airborne Measurement Approach.

Investigating workplace exposure to mycotoxins is of the utmost importance in supporting the implementation of preventive measures for workers. The aim of this study was to provide tools for measuring mycotoxins in urine and airborne samples. A multi-class mycotoxin method was developed in urine for the determination of aflatoxin B1, aflatoxin M1, ochratoxin A, ochratoxin α, deoxynivalenol, zearalenone, α-zearalenol, β-zearalenol, fumonisin B1, HT2-toxin and T2-toxin. Analysis was based on liquid chromatography–high resolution mass spectrometry. Sample pre-treatments included enzymatic digestion and an online or offline sample clean-up step. The method was validated according to the European Medicines Agency guidance procedures. In order to estimate external exposure, air samples collected with a CIP 10 (Capteur Individuel de Particules 10) personal dust sampler were analyzed for the quantification of up to ten mycotoxins, including aflatoxins, ochratoxin A, deoxynivalenol, zearalenone, fumonisin B1 and HT-2 toxin and T-2 toxin. The method was validated according to standards for workplace exposure to chemical and biological agents EN 482. Both methods, biomonitoring and airborne mycotoxin measurement, showed good analytical performances. They were successfully applied in a small pilot study to assess mycotoxin contamination in workers during cleaning of a grain elevator. We demonstrated that this approach was suitable for investigating occupational exposure to mycotoxins.

First trimester pesticide-related exposure behaviors and NNNS scores in infants from the SAWASDEE birth cohort

Background: Prenatal pesticide exposures have been associated with adverse neurodevelopmental outcomes in several studies. A prospective birth cohort, the Study of Asian Women and their Offspring’s Development and Environmental Exposures (SAWASDEE) evaluated the association between self-reported pesticide exposure behaviors during early pregnancy and neurodevelopment in infants. We examined behaviors associated with pesticide exposures in occupational settings to further understand potential sources of prenatal pesticide exposure and the implications for neurobehavioral outcomes in infants. Methods: Pregnant women working in agricultural settings provided information on pesticide-related exposures through detailed questionnaires. We investigated their pesticide-related exposure behaviors during the first trimester and their offspring’s neurobehavioral outcomes measured by the NICU Network Neurobehavioral Scales (NNNS). Results: Among those with first trimester exposure information, 272 women reported working since their last menstrual cycle. 58% of working women handled and applied fertilizers and 38% handled containers of pesticides. Common crop types were fruit (tangerines and/or longan; 44.41%) and rice (23.90%). Participants reported wearing long-sleeved shirts (84.93%), other protective clothing (boots, apron, waterproof pants; 67.28%) and face covers (i.e. scarf/handkerchief; 52.94%) for personal protection against pesticide exposures. For NNNS scale scores ranging from 1 to 9, average summary scores were 5.72±0.81 for attention, 3.69±0.54 for arousal, and 6.02±0.60 for regulation. Handling scores ranged between 0 and 1, and the average was 0.20±0.23. Maternal handling of pesticide containers did not increase infant’s OR of having poorer attention (crude OR: 1.06; 95% CI: 0.41, 2.69) or arousal scores (crude OR: 1.02, 95% CI: 0.49, 2.13). However, working with tangerines during the first trimester increased infant’s OR of having poorer handling scores (crude OR: 3.62; 95% CI: 1.44, 9.11). Conclusions: Prenatal pesticide-related behaviors in agricultural settings can lead to poorer neurobehavioral outcomes in the offspring, as demonstrated with the standardized NNNS summary scores.

The effects of genotype × phenotype interactions on silver nanoparticle toxicity in organotypic cultures of murine tracheal epithelial cells

Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. Previous studies have identified AgNP toxicity in airway epithelial cells, but no in vitro studies to date have used organotypic cultures as a high-content in vitro model of the conducting airway to characterize the effects of interactions between host genetic and acquired factors, or gene × phenotype interactions (G × P), on AgNP toxicity. In the present study, we derived organotypic cultures from primary murine tracheal epithelial cells (MTEC) to characterize nominal and dosimetric dose-response relationships for AgNPs with a gold core on barrier dysfunction, glutathione (GSH) depletion, reactive oxygen species (ROS) production, lipid peroxidation, and cytotoxicity across two genotypes (A/J and C57BL/6J mice), two phenotypes (‘Normal’ and ‘Type 2 [T2]-Skewed’), and two exposures (an acute exposure of 24 h and a subacute exposure of 4 h, every other day, over 5 days [5 × 4 h]). We characterized the ‘T2-Skewed’ phenotype as an in vitro model of chronic respiratory diseases, which was marked by increased sensitivity to AgNP-induced barrier dysfunction, GSH depletion, ROS production, lipid peroxidation, and cytotoxicity, suggesting that asthmatics are a sensitive population to AgNP exposures in occupational settings. This also suggests that exposure limits, which should be based upon the most sensitive population, should be derived using in vitro and in vivo models of chronic respiratory diseases. This study highlights the importance of considering dosimetry as well as G × P effects when screening and prioritizing potential respiratory toxicants. Such in vitro studies can be used to inform regulatory policy aimed at special protections for all populations.

The Effects of Genotype × Phenotype Interactions on Transcriptional Response to Silver Nanoparticle Toxicity in Organotypic Cultures of Murine Tracheal Epithelial Cells.

The airway epithelium is critical for maintaining innate and adaptive immune responses, and occupational exposures that disrupt its immune homeostasis may initiate and amplify airway inflammation. In our previous study, we demonstrated that silver nanoparticles (AgNP), which are engineered nanomaterials used in multiple applications but primarily in the manufacturing of many antimicrobial products, induce toxicity in organotypic cultures derived from murine tracheal epithelial cells (MTEC), and those differentiated toward a "Type 2 [T2]-Skewed" phenotype experienced an increased sensitivity to AgNP toxicity, suggesting that asthmatics could be a sensitive population to AgNP exposures in occupational settings. However, the mechanistic basis for this genotype × phenotype (G × P) interaction has yet to be defined. In this study, we conducted transcriptional profiling using RNA-sequencing to predict the enrichment of specific canonical pathways and upstream transcriptional regulators to assist in defining a mechanistic basis for G × P effects on AgNP toxicity. Organotypic cultures were derived from MTEC across 2 genetically inbred mouse strains (A/J and C57BL/6J mice), 2 phenotypes ("Normal" and "T2-Skewed"), and 1 AgNP exposure (an acute 24 h exposure) to characterize G × P effects on transcriptional response to AgNP toxicity. The "T2-Skewed" phenotype was marked by increased pro-inflammatory T17 responses to AgNP toxicity, which are significant predictors of neutrophilic/difficult-to-control asthma and suggests that asthmatics could be a sensitive population to AgNP exposures in occupational settings. This study highlights the importance of considering G × P effects when identifying these sensitive populations, whose underlying genetics or diseases could directly modify their response to AgNP exposures.

Development of a Job-Exposure Matrix for Assessment of Occupational Exposure to High-Frequency Electromagnetic Fields (3 kHz-300 GHz).

The aim of this work was to build a job-exposure matrix (JEM) using an international coding system and covering the non-thermal intermediate frequency (IF) (3-100 kHz, named IFELF), thermal IF (100 kHz-10 MHz, named IFRF), and radiofrequency (RF) (>10 MHz) bands. Detailed occupational data were collected in a large population-based case-control study, INTEROCC, with occupations coded into the International Standard Classification of Occupations system 1988 (ISCO88). The subjects' occupational source-based ancillary information was combined with an existing source-exposure matrix and the reference levels of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for occupational exposure to calculate estimates of level (L) of exposure to electric (E) and magnetic (H) fields by ISCO88 code and frequency band as ICNIRP ratios (IFELF) or squared ratios (IFRF and RF). Estimates of exposure probability (P) were obtained by dividing the number of exposed subjects by the total number of subjects available per job title. With 36 011 job histories collected, 468 ISCO88 (four-digit) codes were included in the JEM, of which 62.4% are exposed to RF, IFRF, and/or IFELF. As a reference, P values for RF E-fields ranged from 0.3 to 65.0% with a median of 5.1%. L values for RF E-fields (ICNIRP squared ratio) ranged from 6.94 × 10-11 to 33.97 with a median of 0.61. The methodology used allowed the development of a JEM for high-frequency electromagnetic fields containing exposure estimates for the largest number of occupations to date. Although the validity of this JEM is limited by the small number of available observations for some codes, this JEM may be useful for epidemiological studies and occupational health management programs assessing high-frequency electromagnetic field exposure in occupational settings.

Airway exposure to TiO2 nanoparticles and quartz and effects on sperm counts and testosterone levels in male mice

Several types of engineered nanoparticles (ENP) have been shown to adversely affect male reproduction in rodent studies, but the airway route of exposure has been little investigated. This precludes adequate risk assessment of ENP exposure in occupational settings. Titanium dioxide nanoparticles (TiO2 NP) have been shown to affect total sperm count in adult male mice after intravenous and oral administration. This study aimed to investigate whether also airway exposure would affect sperm counts in male mice. Mature C57BL/6J mice were intratracheally instilled with 63 μg of rutile nanosized TiO2, once weekly for seven weeks. Respirable α-quartz (SRM1878a) was included at a similar dose level as a positive control for pulmonary inflammation. BALF cell composition showed neutrophil granulocyte influx as indication of pulmonary inflammation in animals exposed to TiO2 NP and α-quartz, but none of the particle exposures affected weight of testes or the epididymis, sperm counts or plasma testosterone when assessed at termination of the study.

The Effects of Gene × Environment Interactions on Silver Nanoparticle Toxicity in the Respiratory System.

Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. AgNP toxicity in the respiratory system is well characterized, but few in vitro or in vivo studies have evaluated the effects of interactions between host genetic and acquired factors or gene × environment interactions (G × E) on AgNP toxicity in the respiratory system. The primary goal of this article is to review host genetic and acquired factors identified across in vitro and in vivo studies and prioritize those necessary for defining exposure limits to protect all populations. The impact of these exposures and the work being done to address the current limited protections are also discussed. Future research on G × E effects on AgNP toxicity is warranted and will assist with informing regulatory or recommended exposure limits that enforce special protections for all populations to AgNP exposures in occupational settings.

Ultraviolet Radiation Albedo and Reflectance in Review: The Influence to Ultraviolet Exposure in Occupational Settings.

Ultraviolet (UV) albedo and UV reflectance are defined, compared and contrasted, to explain their roles and place in studies focusing on UV radiation and exposure measurements, in the context of localised albedo measurement and human UV exposure studies. This review recommends that the term UV albedo be used when investigating natural horizontal surfaces when the albedo is not known to change significantly over time. The term UV reflectance should be mostly used for non-natural surfaces and non-horizontal measurements and will change with respect to the geometry of the irradiances reflected and received, and due to the intrinsic nature of the surface itself. UV albedo measurements made in the literature have been compiled, in both broadband and spectral UV albedo measurements. Broadband measurements have been tabulated and spectral UV measurements have been displayed visually. The methodology of measurements is briefly discussed. Finally, studies that consider how high albedo or reflectance sites influence UV exposure are reviewed. It was concluded that there is currently no known relationship between the albedo or reflectance of a surface and the resulting influence it has on individual UV exposure. This presents an opportunity for researchers to continue exploring the influence of reflective UV surfaces.