Using Evidence Integration Techniques in the Development of Health-Based Occupational Exposure Levels.

Development of toxicology-based criteria such as occupational exposure levels (OELs) are rarely straightforward. This process requires a rigorous review of the literature, searching for patterns in toxicity, biological plausibility, coherence, and dose-response relationships. Despite the direct applicability, human data are rarely used primarily because of imprecise exposure estimates, unknown influence of assumptions, and confounding factors. As a result, high reliance is often placed on laboratory animal data. Often, data from a single study is typically used to represent an entire database to extrapolate an OEL, even for data-rich compounds. Here we present a holistic framework for evaluating epidemiological, controlled in vivo, mechanistic/in vitro, and computational evidence that can be useful in deriving OELs. It begins with describing a documented review process of the literature, followed by sorting of data into either controlled laboratory in vivo, in silico/read-across, mechanistic/in vitro, or epidemiological/field data categories. Studies are then evaluated and qualified based on rigor, risk of bias, and applicability for point of departure development. Other data (eg, in vitro, in silico estimates, read-across data and mechanistic information, and data that failed to meet the former criteria) are used alongside qualified epidemiological exposure estimates to help inform points of departure or human-equivalent concentrations that are based on toxic end points. Bayesian benchmark dose methods are used to estimate points of departure and for estimating uncertainty factors (UFs) to develop preliminary OELs. These are then compared with epidemiological data to support the OEL and the use and magnitude of UFs, when appropriate.

[Determination of 1-chloro-2,3-epoxypropane in order to assess the working environment]. / Oznaczanie 1-chloro-2,3-epoksypropanu dla potrzeb oceny srodowiska pracy.

BACKGROUND: 1-Chloro-2,3-epoxypropane, known as epichlorohydrin (ECH), is a colorless liquid used in the production of epoxy resins, synthetic glycerine, elastomers, glycidyl ethers, surfactants, polyamide-epichlorohydrin resins and others. Epichlorohydrin may cause cancer. The aim of this study was to develop a new method for determining concentrations of ECH in workplace air in the range of 1/10-2 values of the maximum admissible concentration (MAC). MATERIAL AND METHODS: The paper presents a method for the determination of ECH in workplace air using a gas chromatograph coupled with a mass spectrometer (GC-MS). The developed method is based on the adsorption of ECH on an activated charcoal, extraction with acetone, and a chromatographic analysis of the resulting solution. RESULTS: The method developed makes it possible to determine ECH in the concentration range of 0.1-2 mg/m3, i.e., 1/10-2 values of MAC established in Poland. The limit of detection (LOD) is 0.24 µg/m3 and the limit of quantification (LOQ) is 0.71 µg/m3. CONCLUSIONS: The method is characterized by good precision and accuracy; it meets the requirements of the European standard PN-EN 482, and can be used by occupational hygiene laboratories to measure concentrations of ECH in workplace air, with a view to assessing workers' exposure to this substance. Med Pr. 2020;71(6):715-23.

On site comparison of the OSHA 42, Asset EZ4-NCO, Iso-Chek, DAN and CIP10 methods for measuring toluene diisocyanate (TDI) at a polyurethane foam factory.

Because of the semi-volatile nature of diisocyanates (being airborne in both physical vapor and particulate phases), their high reactivity and low occupational exposure limits, diisocyanate exposure evaluation has been challenging for industrial hygienists and laboratories. The objective of this study was to compare the toluene diisocyanate (2,4 and 2,6 isomers, TDI) concentration measured by five methods in a flexible polyurethane foam factory using different collection or derivatization approaches. The methods used were: OSHA 42 modified (filter, 1-(2-pyridyl)piperazine) (OSHA), Asset EZ4-NCO (denuder and filter, dibutylamine) (Asset), Iso-Chek (double-filter, 9-(N-methylaminomethyl) anthracene and 1,2-methoxyphenylpiperazine), DAN (filter, 1,8-diaminonaphthalene), and CIP10 (centrifugation, 1,2-methoxyphenylpiperazine). Particle real-time monitoring for concentration and size distribution was performed in parallel to improve the understanding of the potential bias between methods. The comparison study was performed over 3 days, providing 18 replicates for each of the 5 methods. Isocyanate concentrations collected for each sampling method were compared using linear mixed effect modeling. Compared to OSHA, which yielded the highest concentrations overall, the Asset and DAN methods provided the smallest biases (-29% (95% CI [-52;-6]) and -45% (95% CI [-67;-23]), respectively), while the CIP10 and Iso-Chek methods provided the largest biases (-82% (95% CI [-105;-66]) and -96% (95% CI [-118;-75]), respectively). The substantial bias of Iso-Chek and CIP10 seemed to be explained by the predominance of TDI in the form of sub-micron particles that were inadequately captured by these two methods due to their sampling principle, which are particle filtration without derivatizing agent and centrifugation respectively. Asset and DAN performance seemed to decrease as the sampling time increased. While DAN's bias could be related to a reagent deficiency on the filter, the disparities between OSHA and Asset, both considered as reference methods, highlight the fact that the mechanisms of collection, derivation and extraction do not seem to be completely controlled. Finally, an upward trend has been observed between concentrations of particles below 300 nm in size and concentration levels of TDI. It has also been observed that TDI levels increased with the TDI foam index produced at the facility.

Temporal trends in respirable dust and respirable quartz concentrations within the European industrial minerals sector over a 15-year period (2002-2016).

OBJECTIVES: Since 2000 the European Industrial Minerals Association's Dust Monitoring Programme (IMA-DMP) has systematically collected respirable dust and respirable quartz measurements from 35 companies producing industrial minerals. The IMA-DMP initiative allowed for estimating overall temporal trends in exposure concentrations for the years 2002-2016 and for presenting these trends by type of mineral produced, by jobs performed and by time of enrolment into the DMP. METHODS: Approximately 32 000 personal exposure measurements were collected during 29 sampling campaigns during a 15-year period (2002-2016). Temporal trends in respirable dust and respirable quartz concentrations were studied by using linear mixed effects models. RESULTS: Concentrations varied widely (up to three to four orders of magnitude). However, overall decreases in exposure levels were shown for the European minerals industry over the 15-year period. Statistically significant overall downward temporal trends of -9.0% and -3.9% per year were observed for respirable dust and respirable quartz, respectively. When analyses were stratified by time period, no downward trends (and even slight increasing concentrations) were observed between 2008 and 2012, most likely attributable to the recent global economic crisis. After this time period, downward trends became visible again. CONCLUSIONS: Consistent and statistically significant downward trends were found for both exposure to respirable dust and respirable quartz. These downward trends became less or even reversed during the years of the global economic crisis. To our knowledge, this is the first time that analyses of long-term temporal trends point at an effect of a global economic crisis on personal exposure concentrations of workers from sites across Europe.

Assessment of silica dust exposure profile in relation to prevalence of silicosis among Indian sandstone mine workers: Need for review of standards.

BACKGROUND: In Indian mines, the prescribed exposure limit (PEL) for free silica dust is 0.15 mg/m3 which is much higher than those of OSHA and the ACGIH. Because of the reporting of high numbers of silicosis cases among Indian sandstone mine workers, the present study was designed to assess the dust exposure profile of the workers and to substantiate correlation of silica exposure with radiographic findings of silicosis. METHODS: A cross-sectional study of 1012 workers actively engaged in sandstone mining was conducted. Chest x-rays were evaluated by the ILO Classification for the detection of pneumoconiosis. Representative 26 personal dust samples were collected using a personal dust sampler and free silica content estimated. RESULTS: Radiographs compatible with silicosis were seen in 12.3% of workers, of which about 90% were ILO category 1 & 2. Prevalence of abnormal profusion increased from 2.9% to 13.1% to 22% as work exposure increased from <10 to 11 to 20 to >20 years, respectively. In dust samples, the mean silica concentration was 0.12 mg/m3 with 70% samples below the prescribed standard of 0.15 mg/m3 . CONCLUSION: The study indicates that silica exposure below the prescribed limit in India is likely to be harmful. The PEL for crystalline silica in India of 0.15 mg/m3 is not adequately protective. Hence, there is an urgent need to reduce exposure to silica in these workplaces to prevent silicosis and to review the present standards as the government of India remains committed to the elimination of silicosis by 2030.

Chemical Pollution in Healing Spaces: The Decalogue of the Best Practices for Adequate Indoor Air Quality in Inpatient Rooms.

Indoor air quality (IAQ) is one of the main topics in which governments are focusing. In healthcare facilities, several studies have reported data analysis and case studies to improve users' health. Nowadays, although many studies have been conducted related to the biological and physical risks, the chemical risks have been less investigated and only in some specific functional areas of the hospitals. Starting from some systematic reviews and research works, this paper aims to list the best healthy practices for an adequate IAQ in inpatient wards. In particular, the decalogue lists the strategies related to chemical pollution, starting from design and management, with a focus on (a) localization of hospitals and inpatient rooms, (b) hospital room, (c) microclimatic parameters, (d) ventilation systems, (e) materials and finishing, (f) furniture and equipment, (g) cleaning products and activities, (h) maintenance and (i) management activities, and (l) users and workers. The multidisciplinary approach emphasizes the need for interdisciplinary knowledge and skills aimed to find solutions able to protect users' health status. The design and management decision-making, ranging from the adequate choices of construction site and hospital exposure, finishing materials, cleaning and maintenance activities, etc., which can affect the IAQ must be carried out based on scientific research and data analysis.

Improving Boston Nail Salon Indoor Air Quality Through Local Public Health Regulation, 2007-2019.

In 2011, following years of outreach and training, Boston, Massachusetts, enacted regulations to improve health and safety in nail salons. These were amended in 2013 to require mechanical ventilation, including dedicated exhaust for each manicure and pedicure station. As of June 2019, 185 of 190 salons have satisfied the regulatory requirements. Regulations can help ensure that environmental health benefits are widespread and that small businesses' investment in occupational health does not result in a competitive disadvantage.

Establishing a health-based recommended occupational exposure limit for nitrous oxide using experimental animal data - A systematic review protocol.

Nitrous oxide (N 2 O) is widely used as inhalation analgesic and anaesthetic in medical, paramedical, and veterinary practice. Previous evaluations resulted in classification of N 2 O as a possible risk factor for adverse reproductive health outcomes based on evidence from animal data. Available human data were considered inadequate, partly due to the possibility that other risk factors, such as co-exposures to other inhalation anaesthetics may have contributed to the adverse outcomes. As no substantial new human evidence has emerged since previous evaluations, this protocol describes a planned systematic review of the evidence obtained from animal studies. The aim is to assess the available evidence on the effects of N 2 O on reproductive and developmental outcomes in animals to inform a health-based recommended occupational exposure limit (OEL) for N 2 O. Comprehensive search strategies were designed to retrieve animal studies addressing N 2 O exposure from PubMed, EMBASE, and Web of Science. Screening of the studies retrieved will be performed by at least two independent reviewers, while discrepancies will be resolved by reaching consensus through repeated review and discussions. Articles will be included according to criteria specified in this protocol. Outcome data relevant for reproduction and development will be extracted and risk of bias will be assessed by two independent reviewers using the SYRCLE's risk of bias tool. Primary reproductive and developmental outcomes of interest will be the number of resorptions, malformations, and birth weight. We will focus on dose-response studies that allow to derive an OEL with the benchmark dose (BMD) approach. Adverse outcomes occurring at doses that are equivalent to the exposures occurring in human occupational settings will be particularly relevant for dose-response modelling. The proposed review has not been performed before. We will follow the procedures specified in this protocol. We will adhere to guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), adapted for animal studies. Ethical approval will not be required, as the review will use existing data available in the public domain.

Probabilistic risk assessment of occupational exposure to volatile organic compounds in the rendering plant of a poultry slaughterhouse.

In this study, occupational exposure to volatile organic compounds (VOCs) in the rendering plant of poultry slaughterhouse was determined and subsequently, carcinogen and non-carcinogenic risks were assessed using the US Environmental Protection Agency (USEPA). National Institute for Occupational Safety and Health (NIOSH) methods of 1501 and 1600 were used to measure VOCs in the breathing zone of the workers. Samples were analyzed by GC/MS. Carcinogenic and non-carcinogenic risks and sensitivity analysis were carried out using Monte Carlo simulations technique. The concentration of benzene and CS2 was higher than the occupational exposure limits (OEL). The hazard quotient (HQ) values for all measured compounds was more than 1, which indicating the high potential for non-carcinogenic risks. Furthermore, the calculated Lifetime Cancer Risks (LCR) for carcinogenic compounds revealed that cancer risk due to benzene is higher than the maximum acceptable level provided by USEPA (10-6). Based on the sensitivity analysis, the concentration and exposure frequency are the most important variable influencing both carcinogen and non-carcinogenic risks. Therefore, the concentration levels of the VOCs and exposure frequency should be controlled using engineering control measures.

Estimation of formaldehyde occupational exposure limit based on genetic damage in some Iranian exposed workers using benchmark dose method.

The present study evaluated an occupational exposure level for formaldehyde employing benchmark dose (BMD) approach. Dose-response relationship was determined by utilizing cumulative occupational exposure dose and DNA damage. Based on this goal, outcome of comet assay for some Iranian exposed people in occupational exposure individuals was used. In order to assess formaldehyde exposure, 53 occupationally exposed individuals selected from four melamine tableware workshops and 34 unexposed subjects as a control group were examined. The occupational exposure dose was carried out according to the NIOSH-3500 method, and the DNA damage was obtained by employing comet assay in peripheral blood cells. EPA Benchmark Dose Software was employed for calculating BMD and BMDL. Cumulative exposure dose of formaldehyde was between of 2.4 and 1972 mg. According to the findings of the current study, the induction of DNA damage in the exposed persons was increased tail length and tail moment (p < 0.001), when compared to controls. Finally, an acceptable dose-response relationship was obtained in three-category information between formaldehyde cumulative exposure doses and genetic toxicity. BMDL was 0.034 mg/m3 (0.028 ppm), corresponding to genetic damage of peripheral blood cells. It can be concluded that the occupational permissible limit in Iranian people could be at levels lower than OSHA standards.

Evaluation of airborne sensory irritants for setting exposure limits or guidelines: A systematic approach.

Sensory irritation of eyes and upper airways is an important endpoint for setting occupational exposure limits (OELs) and indoor air guidelines. Sensory irritants cause a painful burning, stinging and itching sensation. Controlled chamber studies are the "golden standard" for evaluations. Well conducted workplace studies offer another possibility. For generalization, the number of participants and their age, smoking, gender, and prior exposure, experience and mood has to be considered. Exposure assessments have to be reliable and exposure duration sufficiently long to establish time-response relationships. A potential confounding by odour has to be assessed. For workplace exposures, mixed exposure and healthy worker effects have to be evaluated. The "Alarie test" is the only validated animal bioassay for prediction of sensory irritation in humans. The mouse bioassay uses the trigeminal reflex-induced decrease in the respiratory rate. The 50% decrease (RD50) has been correlated with OELs set for sensory irritants; predicted OELs for sensory irritants are 0.03xRD50. Evaluation of the bioassay comprises the number of mice and the strain, the reliability of the exposure concentrations and exposure-response relationships, and the similar mode-of-action in mice and humans. These approaches can be used for quality assurance of reported data to set air quality guidelines.

The reciprocal calculation procedure for setting occupational exposure limits for hydrocarbon solvents: An update.

Hydrocarbon solvents are liquid hydrocarbon fractions, often with complex compositions. Due to the potential for human exposure, primarily to the more volatile solvents, substantial effort has been directed toward the development of occupational exposure recommendations. Because of the complex and variable nature of these substances, a proposed approach is to calculate occupational exposure levels (OELs) using an adaptation of the mixture formula developed by the ACGIH® in which "group guidance values" are assigned to similar constituents. This approach is supported by the results of toxicological studies of hydrocarbon solvents and their constituents which have shown that, with a few well-characterized exceptions, these substances have similar toxicological properties and produce additive effects. The objective of the present document is to summarize recommended revisions to the earlier proposals; these recommendations take into account recent toxicological information and changes in regulatory advice. Practical demonstrations on how to use these recommendations to develop occupational exposure advice in different situations (from simple complex solvents to blends of complex solvents) are also provided. Finally, a quantitative ideal gas method is proposed as a means of calculating occupational exposure limits for solvent blends in which, because the blended components have differing vapor pressures, there may be substantial differences between the liquid and vapor phase compositions.

[Studies on an efficient method for determining 3,3'-dimethylbenzidine in the workplace air]. / Badania nad skuteczna metoda oznaczania 3,3'-dimetylobenzydyny w powietrzu na stanowiskach pracy.

BACKGROUND: 3,3'-Dimethylbenzidene (DMB) is a substance classified into the group of carcinogens. The value of maximum admissible concentration for this substance in the workplace air is not specified in Poland. Bearing in mind that DMB is used in domestic companies there is a need to develop a sensitive method for determining 3,3'-dimethylbenzidine in the work environment. MATERIAL AND METHODS: The method consists in passing DMB-containing air through sulfuric acid-treated glass fiber filters, washing out the substance settled on the filter, using water and solution of sodium hydroxide, liquid-liquid extraction with toluene, replacing dissolvent with acetonitrile and analyzing the obtained solution. Studies were performed using high-performance liquid chromatography (HPLC) technique. An Agilent Technologies chromatograph, series 1200, with a diode-array detector (DAD) and a fluorescence detector (FLD) was used in the experiment. In the test, an Ultra C18 column of dimensions: 250×4.6 mm, particle diameter (dp) = 5 µm (Restek) was applied. RESULTS: The method is linear (r = 0.999) within the investigated working range of concentration 1.08-21.6 µg/ml, which is equivalent to air concentrations 2-40 µg/m3 for a 540 l air sample. The limit of detection (LOD) of quantification determination is 5.4 ng/ml and the limit of quantification (LOQ) - 16.19 ng/ml. CONCLUSIONS: The analytical method described in this paper allows for selective determination of 3,3'-dimethylbenzidine in the workplace air in the presence of 1,4-phenylenediamine, benzidine, aniline, 3,3'-dimethoxybenzidine, 2-nitrotoluene, 3,3'-dichlorobenzidine and azobenzene. The method is characterized by good precision and good accuracy, it also meets the criteria for procedures involving the measurement of chemical agents, listed in EN 482:2012.

Development of an occupational airborne chemical exposure matrix.

BACKGROUND: Population-based studies of the occupational contribution to chronic obstructive pulmonary disease generally rely on self-reported exposures to vapours, gases, dusts and fumes (VGDF), which are susceptible to misclassification. AIMS: To develop an airborne chemical job exposure matrix (ACE JEM) for use with the UK Standard Occupational Classification (SOC 2000) system. METHODS: We developed the ACE JEM in stages: (i) agreement of definitions, (ii) a binary assignation of exposed/not exposed to VGDF, fibres or mists (VGDFFiM), for each of the individual 353 SOC codes and (iii) assignation of levels of exposure (L; low, medium and high) and (iv) the proportion of workers (P) likely to be exposed in each code. We then expanded the estimated exposures to include biological dusts, mineral dusts, metals, diesel fumes and asthmagens. RESULTS: We assigned 186 (53%) of all SOC codes as exposed to at least one category of VGDFFiM, with 23% assigned as having medium or high exposure. We assigned over 68% of all codes as not being exposed to fibres, gases or mists. The most common exposure was to dusts (22% of codes with >50% exposed); 12% of codes were assigned exposure to fibres. We assigned higher percentages of the codes as exposed to diesel fumes (14%) compared with metals (8%). CONCLUSIONS: We developed an expert-derived JEM, using a strict set of a priori defined rules. The ACE JEM could also be applied to studies to assess risks of diseases where the main route of occupational exposure is via inhalation.

Occupational exposures among personnel working near combined burn pit and incinerator operations at Bagram Airfield, Afghanistan.

Occupational air samples were collected at Bagram Airfield Afghanistan for security forces (SF) stationed at the perimeter of the solid waste disposal facility that included a burn pit, air curtain destructors, and solid waste and medical waste incinerators. The objective of the investigation was to quantify inhalation exposures of workers near the disposal facility. Occupational air sample analytes included total particulates not otherwise specified (PNOS), respirable PNOS, acrolein and polyaromatic hydrocarbons (PAH). Exposures were measured for four SF job specialties. Thirty 12-hour shifts were monitored from November 2011 to March 2012. The geometric means for respirable particulate matter and PAH for all job specialties were below the 12-hour adjusted American Conference of Governmental Industrial Hygienists threshold limit value time weighted averages (TLV-TWA). The geometric mean of the respirable particulate matter 12-hour TWAs for the four job specialties ranged from 0.116 to 0.134 mg/m(3). One measurement collected at the tower (3.1 mg/m(3)) position exceeded the TLV-TWA. Naphthalene and pyrene were the only PAHs detected in multiple samples of the 18 PAHs analyzed. The geometric mean concentration for naphthalene was 9.39E-4 mg/m(3) and the maximum concentration was 0.0051 mg/m(3). The geometric mean of acrolein for the four job specialties ranged from 0.021 to 0.047 mg/m(3). There were four exceedances of the Occupational Safety and Health Administration 8-hour permissible exposure limit- time weighted average (PEL-TWA), respectively, ranging from 0.13 to 0.32 mg/m(3).

Estimation of the Human Extrathoracic Deposition Fraction of Inhaled Particles Using a Polyurethane Foam Collection Substrate in an IOM Sampler.

Extrathoracic deposition of inhaled particles (i.e., in the head and throat) is an important exposure route for many hazardous materials. Current best practices for exposure assessment of aerosols in the workplace involve particle size selective sampling methods based on particle penetration into the human respiratory tract (i.e., inhalable or respirable sampling). However, the International Organization for Standardization (ISO) has recently adopted particle deposition sampling conventions (ISO 13138), including conventions for extrathoracic (ET) deposition into the anterior nasal passage (ET1) and the posterior nasal and oral passages (ET2). For this study, polyurethane foam was used as a collection substrate inside an inhalable aerosol sampler to provide an estimate of extrathoracic particle deposition. Aerosols of fused aluminum oxide (five sizes, 4.9 µm-44.3 µm) were used as a test dust in a low speed (0.2 m/s) wind tunnel. Samplers were placed on a rotating mannequin inside the wind tunnel to simulate orientation-averaged personal sampling. Collection efficiency data for the foam insert matched well to the extrathoracic deposition convention for the particle sizes tested. The concept of using a foam insert to match a particle deposition sampling convention was explored in this study and shows promise for future use as a sampling device.