Journal of Health and Safety at Work

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Introduction: PAHs are organic compounds with benzenic rings that releas from hot asphalt as incomplete combusting. These compounds are one of the major concern in scientific societies, workplace and environment due to their stability, bioaccumulation, carcinogenic and mutagenic effects. Since asphalt workers are exposed to PAHs frequently in their job, in this study it was attempted to evaluate respiratory exposure of asphalt workers to PAHs in their breathing zone.

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Material and Method: In this study air samples of the asphalt workers were collected in accordance with the NIOSH 5506 method using PTFE filter and XAD-2 adsorbent. The ultrasonic bath and acetonithrile are used in order to extract the analytes from the filter and adsorbent. Also, the samples were analyzed by HPLC-UV.

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Result: In all samples, Finisher assistance and oilman with 1754.48 ng/m3 , 24.65 ng/m3 had maximum and minimum exposed to ∑PAH, respectively. Among the PAHs compounds, which asphalt workers exposed to, Naphtalene had the highest concentration. Among different asphalt workers tasks, screedman expoused to PAHs, had a significant difference.

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Conclusion: Evaluation of Polycyclic aromatic hydrocarbons concentrations in the breathing zone of asphalt workers indicated that exposure to these compounds were below the occupational exposure limits recommended by NIOSH, OSAH, ACGIH and Iranian OEL. Due to the highly carcinogenic potential of some of these compounds and absence of occupational exposure limits for these compounds, likes Chrysene and Benzo (a) Anthracene, it is strictly recommended to employ engineering controls and using suitable PPEs. This study also indicated that the exposure to PAHs in the most asphalt workers tasks had significant differences, and it can be due to proximity of the workers to the source of hot asphalt and also exposure to the exhaust gases that releasesd from the construction machinery.

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Introduction: Polycyclic Aromatic Hydrocarbons (PAHs) belong to one of the groups of persistent organic pollutants (POPs) which are the result of incomplete combustion of organic materials, volcanic eruptions and forest and agricultural fields’ fires in the environment. However, human factors are main source of these pollutions. Nowadays, these compounds are among the main concerns related to the pollutants which, can easily enter into the land and water systems. Absorption of aromatic hydrocarbons and poly-aromatic molecules on the surfaces of carbon nano-tubes (CNTs) have increased in recent years. In this study, absorption of phenanthrene (as a representative of aromatic hydrocarbons groups) on multi-walled carbon nano-tubes was investigated in organic environment.

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Material and Method: All experiments were performed in a laboratory environment with a temperature of 24±2.Different variables including the type of solvent, solvent volume, pH of the environment, the absorption time of optimal phenanthrene concentration, and the highest removal efficiency under optimized parameters were obtained. Samples were analyzed using HPLC.

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Result: Findings showed that methanol with the volume of 10 ml, and the absorption time of 1.5 hours and 1.3 ppm concentration had the maximum absorption efficiency. Environmental pH had no effect on the absorption efficiency.

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Conclusion: Multi-walled carbon nano-tubes have high absorption capacity for the absorption of phenanthrene. Moreover, in an organic environment, the level of phenanthrene absorption on multi-walled carbon nano-adsorbent was more than 90% and according to the material used was 92%. Day-to-day and within-day reproducibility confirmed the mentioned results.

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Introduction: Measurement of pesticides in biological matrices is become a serious challenge for researchers due to their very low concentration in different matrices. The aim of this study was to develop a new sample preparation method with high accuracy and validity and short retention time for determination of diazinon.
Material and Method: Dispersive liquid-liquid micro-extraction technique coupled with high performance liquid chromatography equipped with ultra violet detector was developed for trace extraction and determination of diazinon pesticide in human urine samples. One variable at a time method was used to optimize parameters affecting the diazinon extraction. Different parameters such as extraction solvent, disperser solvent, and volume of the extraction solvent, volume of the disperser solvent, centrifugation time and speed, salt addition, and sample pH were studied and optimized.
Result: Findings showed that optimal levels of these variables for diazinon pesticide were 150 μl of carbon tetrachloride as extraction solvent, 1.5 ml of methanol as dispersive solvent, pH of 6, 5 minutes centrifuge time at speed of 4000 rpm , 0% (w/v) salt addition. Correlation coefficient was 0.9965 indicating the linearity of a wide range of concentrations of the toxin. LOD and LOQ was calculated less than 0.7 and 5 µg L-1 respectively. The relative standard deviation for six replicate experiments in intra-day and inter-day at tree selected concentrations (50, 200 and 1000 µg L-1) was less than 4% that indicates the accuracy and precision of the optimized method. Enrichment factor and extraction recovery for diazinon were 245 and 99% respectively.
Conclusion: According to the results, dispersive liquid-liquid micro-extraction procedure was successfully developed for the extraction of diazinon from human urine samples. Compared to other extraction techniques, the proposed procedure had some advantages such as shorter extraction time, better reproducibility, and higher enrichment factor.

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Introduction: Toluene, benzene, xylene, and ethylbenzene (BTEX) belong to the class of monocyclic aromatic hydrocarbons and are identified as toxic volatile compounds due to their harmful properties. The reliable biomarkers for occupational exposure to these toxic compounds are hippuric acid (HA), trans,trans-muconic acid (tt-MA), mandelic acid (MA), and methylhippuric acid (MHA), which correlate with toluene, benzene, ethylbenzene, and xylene, respectively.
Material and Methods: A novel magnetized imine-linked covalent organic framework (Fe3O4@TFPA-Bd) was synthesized, marking its inaugural use as a sorbent in microextraction by packed sorbent (MEPS). The synthesis of Fe3O4@TFPA-Bd was executed in a straightforward and efficient manner, using Fe3O4 nanoparticles as the magnetic core and benzidine (Bd) and Tris (4-formyl phenyl) amine (TFPA) as the structural building blocks. This newly produced sorbent was tested for the microextraction of hippuric acid (HA), mandelic acid (MA), trans, trans-muconic acid (tt-MA), and m-methyl hippuric acid (m-MHA) from urine samples, which were then analyzed using high-performance liquid chromatography (HPLC). In order to optimize the extraction performance, parameters like sample volume, elution volume, extraction cycles, pH, and sample solution temperature were thoroughly adjusted. The synthesized adsorbent underwent thorough characterization via scanning and transmission electron microscopy (SEM and TEM), Fourier transforms infrared spectrometer (FTIR), and X-ray diffraction (XRD).
Results: The developed method showcased promising attributes: low detection limits (0.02 µg/ml for tt-MA, S/N=3), low quantification limits (0.06 µg/ml for tt-MA, S/N=10), a solid linear range (0.5-320 µg/ml for MA, R > 0.99), and commendable intra- and inter-day precision (2.4%-4.3% and 3.1%-7.8%, respectively) for volatile organic compound (VOC) biomarkers. Furthermore, the method demonstrated recoveries in the 81-87.5% range for spiked samples, indicating its practicality and effectiveness.
Conclusion: The developed procedure was suitable for the determination of BTEX biomarkers from urine samples and can be an alternative to previous methods.

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Introduction: Exposure to various chemicals can occur in the workplace. Polycyclic aromatic hydrocarbons (PAHs) are among these compounds. The aim of this study was to investigate the relationship between exposure to PAHs and urinary metabolites among built-up roofing installers.
Material and Methods: The current case-control study, conducted in 2021 in Ilam City, involved 35 built-up roofing workers as the case group and 15 non-exposed workers as the control group. In this study, in addition to the workers’ respiratory area, samples were taken from the urine to determine the amount of PAHs metabolites. HPLC was used to analyze the samples. The collected data were analyzed using SPSS software version 22.
Results: The mean concentrations of PAHs including naphthalene, phenanthrene, fluorne, pyrene, benzo(a)pyrene, benzo (ghi)perylene and indeno 1,2,3 cd pyrene were 440.26±80.07, 70.49±24.36, 15.18±5.98, 31.21±10.36, 2.15±1.41, 2.25±0.07 and 1.18±0.06 ng/m3, respectively, in respiratory area of the workers. Also, the average level of compounds 1- naphthol, 2- naphthol, 2-hydroxyfluorene, 3-hydroxyfluorne, 1-hydroxyfenanterol, 2+3-hydroxyfenanterol and 1- hydroxypyrene, present in the urine of the population, was obtained equal to 2±1.02, 6.03±2.5, 0.18±0.15, 0.14±0.1, 0.19±0.08, 0.04±0.02 and 0.34±0.26 μg/g creatinine, respectively. Statistical test showed that the values of these compounds were significantly different in the two groups (p <0.05).
Conclusion: Estimating the concentration of aromatic hydrocarbons in the respiratory area of built-up roofing workers showed the noticeable exposure to these compounds, although lower than the allowable limits. However, due to the high carcinogenic nature of these compounds, it is recommended to use appropriate personal protective equipment such as respirators and appropriate work outfits in addition to the technical strategies to combat the exposure.