This paper describes a new extraction technique with needles and a sorbent based on carbon nanotubes to analyze trace amounts of three isomers of xylenes in aqueous samples. In this research, results have been compared with one commercial sorbent. The synthesized sorbent was prepared using sol-gel technology and was packed into 20 gauge needles, and the same size needle was used for packing the commercial sorbent. In the extraction process, a purge and trap sampling methodology is developed, so purging and trapping cycles were performed by a sampling pump. Optimized conditions for standard xylene samples have been obtained, and eight urine samples from workers that were exposed to xylene in the workplace were collected and analyzed. Experimental parameters such as limits of detection and quantification were investigated, and these two parameters were <1 μg/L.

Background: Exposure to the evaporated gases during the welding process has short-or long-term effects on welders' health. Assessment of the risk by identifying and determining the chemical risk rating might be a useful tool for the experts in industrial hygiene. Objectives: The present study aimed at evaluating the exposure of welders to welding gases in seven welding types in the Steel Industry. Methods: The present study was conducted in one of the factories of the steel industry in 2017. Seven types of welding were studied including SMAW-E7018, SMAW-E730, MIG, MAG, PAW, SAW, and GTAW. Sampling from the NO, NO2, CO, CO2, and O3 was done via directreading instruments. To assess the health risk of exposure, the used approach was the one proposed by the division of occupational safety and health of the labor department of Singapore. Results: Findings of the present study revealed that the average range of welders' exposure to NO, NO2, CO, CO2, and O3 gases in various welding processes was 30 -50, 2456 -5000, 2 -12, 3.5 -6, and 0.16 -0.5 parts per million (ppm). Maximum and minimum concentrations of exposure to each of the gases were observed in MIG and PAW welding processes, respectively. The results of risk assessment showed that ozone and nitrogen dioxide had a very high-risk rating and nitrogen monoxide had a rank of "negligible" in all types of welding. Among the different types of welding, the most and the least risks of welding types were in MIG and PAW welding, respectively. Conclusions: MIG welders have a high occupational exposure to various types of welding gases. Use of control measures such as installing a local ventilation system, workplace air monitoring, implementing appropriate respiratory protection, and training the workers are recommended for safety of the welders.

Background Musculoskeletal symptoms often occur in more than one anatomical site. The present study aimed to define specific patterns of multisite musculoskeletal disorders and examine how these patterns are related to common psychological problems. Methods Using the data from an interview-based health survey of 358 samples of the industrial manufacturing male employees, we derived major patterns of musculoskeletal complaints using latent class analysis and investigated its association with psychological problems score extracted from depression, anxiety, and stress measured by Depression/Anxiety/Stress Scale (DASS-21). Musculoskeletal disorders were assessed by Nordic Musculoskeletal Questionnaire (NMQ). The statistical analysis was carried out by Mplus 8. Results Complaints in the lower back (42.1%) and neck (30.7%) had the highest prevalence, and in the hip (15.0%) and ankle (12.2%) the lowest. Three major patterns of musculoskeletal disorders were extracted using latent class analysis. Class 1 (12.9%) was characterized by a high rate of complaints in upper musculoskeletal sites, such as the neck, shoulder, and joints; class 2 (38.2%) was identified by a higher rate of complaints in the lower and upper back; and class 3 (48.9%) was marked by low rates of complaints in all musculoskeletal sites. After adjustment for confounding variables and specifying class 3 as the reference, it turned out that there was a statistically significant association between the psychological problems score and the chance of being in class 1 (OR = 2.47, 95% CI 1.66–3.68), but not a significant association with the chance of being in class 2 (OR = 1.51, 95% CI 0.83–2.72). Conclusion Musculoskeletal disorders can be summarized in the latent class-derived patterns in the adult study population and provide additional prognostics. Common psychological problems are significantly associated with the type of musculoskeletal disorder patterns. The findings in this study could be useful for dealing with prevention and treatment programs.

BACKGROUND: Welding pollutants have potentially dangerous effects on the health of welders. Analysis of exposure risks is an appropriate method for industrial hygiene occupational exposure. OBJECTIVE: The present study aimed to determine the concentrations of exposure and risk evaluation of welders to fumes and gases in three common types of welding including Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW). METHODS: This cross-sectional study was carried out at a steel company. Samples were taken from manganese, chromium and nickel fumes with NIOSH 7300 method and for NO, NO2, CO and O3 gases using direct reading instruments. SQRCA method was used to assess the level of exposure risk. RESULTS: Our study showed that the highest and lowest concentrations of exposure to gases were observed in MIG and GTAW welding, respectively. Also, the highest and lowest concentrations of exposure to metals were observed in SMAW and GTAW processes, respectively. Mean exposure to M, Cr and Ni metals was 2.302, 3.195, and 1.241 mg/m3, respectively. Also, mean exposure to CO, NO, NO2 and O3 was 43.05, 27.88, 4.30, and 0.41 ppm, respectively. Results of risk analysis showed that O3, NO2 and Cr had high and very high risk levels in all welding processes. CONCLUSIONS: MIG and SMAW welders have a high occupational exposure to metal and toxic gases in welding. Preventive measures such as assessment of workplace air, installation of the ventilation systems, and providing appropriate respiratory protection devices for welders should be taken.

Received: August 2017, Accepted: September 2017 Background: Hazardous chemical agents in the welding operation are a mixture of metal fumes and toxic gases, the inhalation of which causes adverse health effects among welders. The emission of gases in the workplace is a logical cause for concern regarding the potential development of respiratory disease. The aim of the present study was to determine the concentration values of gases discharged during arc welding and perform risk assessment through semi-quantitative chemical risk assessment (SQCRA) method. Materials and Methods:This cross-sectional study was conducted in an Iranian steel mill on the 3 processes of plasma arc welding (PAW), submerged arc welding (SAW), and gas tungsten arc welding (GTAW). Direct reading instruments were used for sampling of carbon dioxide (CO 2 ), carbon monoxide (CO), nitrogen monoxide (NO), nitrogen dioxide (NO 2 ), and ozone (O 3 ). SQCRA method was used for risk assessment of gases. Results: The concentrations of O 3 (0.356 ppm), CO (41.642 ppm), NO (6.357 ppm), and NO 2 (4.871 ppm) were found to exceed their threshold limit values (TLVs), while the concentrations of CO 2 (3879.285 ppm) were below its TLV. The maximum exposure concentration of all gases, except CO 2 , was observed in SAW. SQCRA method showed that among the gases, the highest and least risk rating was related to ozone and nitrogen monoxide, respectively. The risk rating for CO 2 , CO, and NO 2 was low, high, and very high, respectively. Conclusions: In this study, exposure values were higher than the threshold limit values-time weighted average (TLV-TWA) and the results of risk assessment showed that control engineering should be applied and the use of respiratory protective equipment (RPE) should be made mandatory for welders especially in SAW, PAW, and GTAW processes.

Received: November 2016, Accepted : February 2017 Background: The use of chemicals is essential in education resulting in exposure to these pollutant in a variety of chemical and research laboratories. Chemical contaminants in chemical laboratories are in different forms and chemical exposure risk assessment is important for choosing appropriate controls in protecting the health of operators, experts and students. For risk assessment in chemical exposures, several techniques were introduced that their use should be assessed. This research was done with the aim to introduce the most appropriate technique in chemical risk assessment by using three chemical risk assessment techniques. Materials and Methods: This was a descriptive research done in one chemical laboratory. This research had been defined in several stages: in the first phase, the list of solid and liquid chemicals were prepared and full physicochemical properties of substances as well as toxicity and health risk of them were collected. Finally Chemical Risk Management Self-Assessment Model (Chem-SAM), University Of Wollingong (UOW) risk assessment and semi-quantitative risk assessment method (SQRA) methods were used and compared. Results: There was significant difference between SQRA methods and UOW technique while no significant difference was observed between SQRA methods and Chem-SAM model. Conclusions: All three techniques are simple, but the results were similar in SQRA methods and Chem-SAM model, so these two methods can be replaced in chemical risk assessment. In order to control the identified risks, this research has recommended programs, control measures, improving local exhaust ventilation systems, personal protective equipment and training of personnel.

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