Application of Multiple Occupational Health Risk Assessment Models for Metal Fumes in Welding Process.

Welding fumes have an important role to create the adverse health effects. So, the aim of this study was to use of multiple occupational health risk assessment models for metal fumes in welding process. This cross-sectional study was conducted among welding workers. Sampling of heavy metals such as Sn, Zn, Al, Fe, Cd, Pb, Cu, Mn, Ni, Cr, and As was provided based on the National Institute for Occupational Safety and Health (NIOSH) method 7300 and analyzed by inductively coupled plasma mass spectroscopy (ICP-MS). Risk assessment was managed by four methods including Malaysia's method, Control of Substances Hazardous to Health Essentials (COSHH model), Chinese OHRA standard (GBZ/T 298-2017), and EPA method. Also, Monte Carlo simulation was used to examine the uncertainties by using the Crystal Ball tool. To compare the models, the risk levels of each model were converted into the risk ratio and the SPSS 22.0 software was used to the statistical analysis. The consistency of the two occupational health risk assessment models was examined by Cohen's Kappa. Risk ration was the highest level for Cr (VI) fumes in all models. Also, carcinogenic risk was unacceptable for all examined fumes. Moreover, non-carcinogenic risk was the highest (HI > 1) for As fumes. Mont Carlo simulations suggested that exposure time (ET) had a significant effect on the risk. Also, there was a good consistency between Malaysia method/GBZ/T 298-2017 and COSHH model/GBZ/T 298-2017. Therefore, it is recommended that the engineering and administrative controls should be provided to reduce exposure.

Cancer risk assessment of exposure to asbestos during old building demolition.

BACKGROUND: Years ago, the use of asbestos in construction materials was common. Although asbestos has been recently banned in many countries, exposure to asbestos during old building demolition is not unexpected. OBJECTIVE: The aim of this study is to assess the concentration of exposure to asbestos and estimate its cancer risk among old building demolition workers. METHODS: In this study, personal air samples were collected during building demolition. The number of asbestos fibers in collected samples were determined according to the NIOSH-7400 standard method. Chemical compositions of fibers were assessed using scanning electron microscopy (SEM). The carcinogenic risk of exposure to asbestos was determined based on the recommended United State Environmental Protection Agency (USEPA) method and Monte-Carlo simulation used to estimate the probability of cancer. RESULTS: Chemical analysis confirmed the presence of asbestos in collected air samples, and 67% of counted fibers were asbestos. In a number of buildings, workers had exposed to asbestos that was higher than occupational exposure limit (0.10 f/ml). Results of cancer risk estimation showed that cancer risk were considerable among workers. CONCLUSION: Implementation of asbestos risk management program such as separation of asbestos containing material, personal protective equipment's and use of wet method in demolition could minimize asbestos exposure during old building demolition.

Risk Assessment of Silicosis and Lung Cancer Mortality associated with Occupational Exposure to Crystalline Silica in Iran.

BACKGROUND: Exposure to crystalline silica has long been identified to be associated with lung diseases. Therefore, the present study aimed to assess the risk of silicosis and lung cancer associated with occupational exposure to crystalline silica in Iran. STUDY DESIGN: It is a systematic review study. METHODS: Different databases were searched, and the Cochrane method was used for the systematic review. Thereafter, cumulative exposure to crystalline silica (mg/m3-y) was calculated in every industry. The relative risk of death from silicosis was performed using Mannetje's method. Based on the geometric mean of exposure, the lung cancer risk of exposure to crystalline silica was also calculated. RESULTS: As evidenced by the results, worker's exposure to silica ranged from a geometric mean of 0.0212- 0.2689 mg/m3 (Recommended standard by the American Conference of Governmental Industrial Hygienists (ACGIH) was 0.025 mg/m3), which is generally higher than the occupational exposure limit recommended by National Institute for Occupational Safety and Health (NIOSH), ACGIH, and occupational exposure limits. The relative risk of silicosis was in the range of 1 to 14 per 1000 people, and the risk of lung cancer in workers ranged from 13-137 per 1000 people. CONCLUSION: Since workers are at considerable risk of cancer due to exposure to silica in Iran, exposure control programs need to be implemented in workplaces to decrease the concentration of silica.

Lung Cancer and Pleural Mesothelioma Risk Assessment for the General Population Exposed to Asbestos in Different Regions of Tehran, Iran.

BACKGROUND: Asbestos is a natural fiber leading to health risks like chronic lung diseases. The current study aimed to estimate pleural mesothelioma and lung cancer risk for population exposure to asbestos in Tehran, Iran. STUDY DESIGN: A cross-sectional study. METHODS: According to the annual report of Air Quality Control Company (AQCC), from 2011-2020, carcinogenic risk and mesothelioma were assessed based on the Environmental Protection Agency (EPA) method using the Monte Carlo simulation (MCS). The relative risk (RR) of mortality cancer was calculated based on Camus and colleagues' model. Moreover, mesothelioma risk was estimated by Bourgault and colleagues' model. RESULTS: The mean concentration and health risk of asbestos in ambient air generally reduced from 2011 to 2020. The highest mortality risk for lung cancer was 8.4 per 100000 persons in 2011 and reduced to 1.8 in 2017. For mesothelioma, the corresponding values were 8.96 per 100000 persons in 2011 and reduced to 1.92 in 2017. CONCLUSION: The findings of this study could be helpful to health policymakers in the management of asbestos risk.

Evaluating the airborne asbestos dispersion in enclosed parking lots in Iran.

Each time a car's brakes are used, asbestos is dispersed in the air. Breathing the air in enclosed parking lots can expose people working in these places to asbestos. This study aimed to evaluate the airborne asbestos dispersion in enclosed parking lots. In this study, 35 air samples were collected from six enclosed parking lots in Tabriz City. The samples were analyzed quantitatively by phase contrast microscopy (PCM) and qualitatively by a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray analyzer. The mean of fiber concentrations was found 0.155 ± 0.069 PCM f/cc. The SEM data demonstrated that the fibers consisted of synthetic fibers (69.57%) and asbestos (30.43%). Fiber concentrations in many enclosed parking lots in the city were higher than the threshold limit value-time weighted average of the American Conference of Governmental Industrial Hygienists and Occupational Exposure Limits of Iran. However, further investigations are needed to clarify asbestos exposure in such places.

Health Risk Assessment of Occupational Exposure to Hexavalent Chromium in Iranian Workplaces: a Meta-analysis Study.

Occupational exposure to hexavalent chromium (Cr+6) has reported in different industries. The Cr6+ has the carcinogenic and non-carcinogenic effects. The aim of this study was to provide a meta-analysis and health risk assessment of occupational exposure to Cr6+ in Iranian workplaces. Databases including Scopus, Web of Sciences (WOS), and Scientific Information Database (SID), as a national database, were searched from 2000 to February 2021. The related studies to occupational exposure to Cr6+ were selected by Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Lung cancer and non-cancer risk (nasal mucosal irritation, atrophy, and perforation) of Cr6+ were estimated by Environmental Protection Agency (EPA) method, based on the Monte Carlo simulation (MCS). Also, the results of spirometry and biomonitoring of previous studies were reviewed. We found 14 articles based on inclusion criteria. Pooled concentration of Cr6+ was estimated 0.037 ± 0.002 mg/m3 which was higher than the recommended exposure limit by the ACGIH (0.002 mg/m3). The mean lung cancer risk was estimated to be 5.49E-2, which was considerable risk. In the Cr6+-exposed workers, all parameters of pulmonary function had decreased. The level of Cr6+ in urinary and blood samples was higher than threshold limit. Results indicated that exposure to Cr6+ and its health risk were more than recommended exposure limit. The results of present study could be helpful for health policy maker to control exposure to Cr6+ in workplaces.

Toxicity risks of occupational exposure in 3D printing and bioprinting industries: A systematic review.

3-Dimensional (3D) printing and bioprinting are the new technologies. In 3D printing, synthetic polymers such as acrylonitrile, butadiene, and styrene, polylactic acid, nylon, and some metals are used as feedstocks. During 3D printing, volatile organic compounds (VOCs) and nanoparticles can be released. In the bioprinting process, natural polymers are most commonly used. All of these materials have direct and indirect toxic effects in exposed people. Therefore, the aim of this study was to provide a comprehensive review of toxicity risks due to occupational exposure to pollutants in the 3D printing and bioprinting industries. The Cochrane review method was used as a guideline for systematic review. Articles were searched in the databases including PubMed, Scopus, Web of Science, and Google Scholar. This systematic review showed that VOCs and ultra-fine particles are often released in fused deposition modeling and selective laser sintering, respectively. Asthma, chronic obstructive pulmonary disease, allergic rhinitis, and DNA damage were observed in occupational exposure to synthetic polymers. Metal nanoparticles can induce adverse health effects on the respiratory and nervous systems. This study emphasized the need to further study the toxicity of 3D printing and bioprinting-induced air pollutants. Also, consideration of safety and health principles is necessary in 3D printing and bioprinting workplaces.

8-Hydroxy-2'-deoxyguanosine (8-OHdG) as a biomarker of oxidative DNA damage induced by occupational exposure to nanomaterials: a systematic review.

In nuclear and mitochondrial DNA, 8-hydroxy-2'-deoxyguanosine (8-OHdG) is one of the predominant forms of reactive oxygen species (ROSs) lesions, which commonly used as a biomarker for oxidative stress. Studies showed that the different nanomaterials can induce toxicity by ROSs in human body. So, this study is going to review the studies about oxidative DNA damage caused by occupational exposure to nanomaterials, using 8-OHdG biomarker.Systematic review was managed based on Cochrane systematic review guideline. Literature search was conducted in scientific databases with the main terms of "biomarkers," "biological markers," combined with "occupational exposure" and "nanomaterials." All papers in the field of occupational exposure to nanomaterials until 2020 December were included. To evaluate the quality and bias of studies, GRADE method (Grading of Recommendations, Assessment, Development, and Evaluation) was used.Two hundred twenty-six studies were primarily achieved. By considering the inclusion criteria, overall 8 articles were selected. The majority of the studies were classified as the moderate quality studies (six studies). Also, the study-level bias was critical. This review shows that there is a significant relationship between job title and amount of produced nanomaterials and the existence of 8-OHdG. Also, the levels of 8-OHdG can be measured in urine, blood, and inhalation samples by instrumental procedures.Oxidative damages are an important threat for workers exposed to nanomaterial. Blood and EBC 8-OHdG level can be introduced as a biomarker for metal nanomaterials, but urinary 8-OHdG needs to be taken with caution. So, it is recommended that evaluation not be solely based on one biomarker.