Assessment of welders exposure to carcinogen metals from manual metal arc welding in gas transmission pipelines, Iran

Welding can produce dangerous fumes containing various metals especially carcinogenic ones. Occupational exposure to welding fumes is associated with lung cancer. Therefore, welders in Gas Transmission Pipelines are known as a high-risk group. This study was designed to determinate the amounts of metals Cr, Ni, and Cd in breathing 2one and urine of welders and to assess the possibility of introducing urinary metals as a biomarker due to occupational exposure. In this cross sectional study, 94 individuals from Gas Transmission Pipelines welders, Iran, Borujen in 2011 were selected and classified into 3 groups including Welders, Back Welders and Assistances. The sampling procedures were performed according to NIOSH 7300 for total chromium, nickel, and cadmium and NIOSH

[Evaluation of submicron particle filtration efficiency of domestic and imported surgical masks]

Bioaerosols are one of the most important agents that cause post operating infections in hospitals. Surgical masks are recommended for prevention of bioaerosols transmition in operating rooms. This study aimed at evaluation of submicron particle filtration efficiency of domestic and imported surgical masks. In this cross sectional study, 5 types of surgical masks that have the most utilization in operating rooms of country's hospitals including domestic and imported surgical masks were tested. To evaluate all samples, the submicron particle filtration measurements were carried out based on ISIRI 6138 and American DOP standards. Filtration efficiency calculations and pressure drop measurements were performed and the results were analyzed using statistical tests. Results showed that particle filtration efficiency of domestic and imported masks were 56.130% [ +/- 10.7] and 31.906% [ +/- 7.062] respectively. Also, filtration efficiency in domestic masks were more than imported masks [P< 0.001]. Among all samples, Arman mask had the most filtration efficiency [66.5475% +/- 6.14951], where the least [27.8275% +/- 4.44152] filtration efficiency [P< 0.001] belongs to Blosom. The maximum mean of pressure drop in Arman mask [35 +/- 2. 58 Pa] and the least mean of pressure drop in Zist filter mask [11 +/- 1.82 Pa] were observed. According to the effect of filtration efficiency and pressure drop on general quality of mask, the quality factor of masks were also evaluated. Results showed that Zist filter mask had the most quality factor [0.068] while Blosom had the least quality factor [0.016]. This research showed that domestic surgical masks have a better quality toward imported surgical masks but can not obtained quality confirmed by standards, yet. To reduce respective infections and prevalence of diseases, it is recommended using filters with suitable physical characteristics and also carrying out test of surgical masks before supplying

Removal of airborne hexavalent chromium using alginate as a biosorbent

Airborne hexavalent chromium has been classified as a human respiratory carcinogen and long term exposure has been known to cause ulceration and perforation of the nasal septum, bronchitis, asthma, and liver and kidney damage. Chromium electroplating plants are the major sources of atmospheric chromium and packed-bed scrubbers are the common control devices used to reduce emission of chromic acid mist from electroplating bathes. The feasibility of a new method to remove this pollutant using alginate beads as a biomass derivative was investigated by one factor at a time approach and Taguchi experimental design. Polluted air with different chromium mist concentrations [10-5000 micro g/m3] was contacted to alginate beads [3.3-20 g/L], floating in distilled water with adjusted pH [3-7], using an impinger at different temperatures [20 and 35°C], and various velocities [1.2 and 2.4 m/s]. Although there were no statistical significant differences between factor levels, the higher ions removal efficiencies were achieved at lower levels of air velocities, pollution concentrations, higher levels of pHs, temperatures, and sorbent concentrations

[Influence of operational, technical and environmental factors on exposure of motor-vehicle painters to volatile organic solvents]

Considering the acute and chronic effects of organic solvents to which vehicle painters are exposed for long periods of time, their evaluation and control is crucial for protection of health of the employees. This study aimed to find the most influential factors on exposure to, and spreading pollution with, benzene, toluene, xylem, and etylebenzene [BTEX] in order to be able to choose the best control measures. In a motor-vehicle company the vehicle painting process was studied in detail and the solvents used in paints and in spreading organic solvent stations were identified. Based on the types and concentrations of the variables being studied, using the NIOSH method a total of 240 air samples were collected [5 samples for each variable and the respective controls] and analyzed. The SPSS version 11.5 was used for data analysis, the statistical tests being multi-regression and analysis of variance. Exposure to benzene in all occupational tasks, as well as to toluene in top coating and undercoating stations exceeded, while exposure to etylebenzene and xylene did not reach, the respective permitted exposure limits [p<0.05]. The most effective factors on exposure to all the four solvents were, in order of effectiveness, occupational task, gun type, and the type of paint sued [p<0.05]. The effects of the variables studies - occupational task, gun and paint types - on exposure to BTEX relate to differences in occupational task work load, the type of gun used, and the paint organic solvent formulation. The reason for the potentially high exposure to benzene is its presence as an impurity in the paint solvents. Thus, it is highly recommended that in the process of control and evaluation special attention be paid to these factors

[Risk assessment of welders' exposure to total fume in an automobile industry]

Risk assessment of Toxic or hazardous chemicals enables the Industrial Hygienists to make the appropriate decision in providing healthy work place. This project was conducted in an assembling plant, [4workshop] of an Automobile Industry in IRAN with 2 types of welding operations, including GMAW [CO[2] welding] and Spot resistance welding operations. Welders exposures were assessed via collecting 143 breathing zone air samples based on NIOSH 0500 method. Risk assessment was carried out using Singapore recommended method. Finding showed that the mean of welders exposure in GMAW and Spot resistance welding operations 5.61 +/- 5.78 and 2.38 +/- 2.15 mg/m[3], respectively [p<0.05]. The results showed that in GMAW welders had the high exposure in comparison with Spot resistance welders [p<0.05]. The findings also demonstrated that the risk rate of GMAW welders were high, while this rate for Spot resistance was low. More hygienic attention is needed for GTAW welders. Control approaches are required including effective engineering control, conduct air monitoring, biological monitoring training, adopt respiratory protection program, develop and implement safe and correct work procedures and finally reassess the risk after all the controls have been done

[Optimization of solid phase micro-extraction [SPME] for monitoring occupational exposure to ethyl benzene]

Analytical methods for volatile organic compounds [VOCs] in different samples need extraction of compounds by applying hazardous solvents. Solid phase micro-extraction [SPME] is a solvent-free equilibrium extraction method in which proper calibration can allow quantitative determinations of VOCs at a very good sensitivity without the use of any organic solvent. VOCs are generally present in urine only at trace levels therefore a sensitive procedure is needed for their trace determinations. Throughout this study headspace solid phase micro-extraction [HS-SPME] was followed by GC-FID for ethyl benzene in spiked urine was optimized. In this study the parameters influencing SPME and gas chromatography of ethyl benzene including extraction time temperature desorption temperature desorption time salt addition sample pH sample volume and sample agitation were investigated. Extraction procedure was performed at 30°C for 6 min using 0.2 gmL[-1] of NaCl in the sample solution. The sample volume and sample pH were optimized at 5 ml and 7 [neutral pH] respectively. Desorption of the ethyl benzene was carried out for 60 sec. at 250°C. The method was also validated with three different spiked urine samples and illustrated an appropriate reproducibility over six consecutive days as well as six within-day experiments. During this investigation parameters of accuracy linearity and detection limits of the procedure were also evaluated. The developed method of HS- SPME-GC-FID proved to be a simple convenient and practical procedure and was successfully used for measuring of ethyl benzene in spiked urine

Trace analysis of xylene in occupational exposures monitoring

Determination of organic pollutants usually requires extraction of the pollutants from samples, using hazardous solvent. Solid phase micro-extraction [SPME] is a solvent-free equilibrium extraction method, in which, proper calibration can allow quantitative measurements of organic pollutants at a very good sensitivity without the use of any organic solvent. Because individual VOCs are generally present in urine only at trace levels, a sensitive and accurate determination technique is essential. This study describes the optimization of headspace solid phase micro-extraction [HS-SPME] followed by gas chromatography equipped with flame ionization detector [GC-FID] for xylene in spiked urine. Through this investigation, the parameters affecting the extraction and GC determination of xylene, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were studied. An optimized headspace extraction was carried out at 30°C for 6 min in presence of 0.2 gml-1 of NaCl in the sample solution. Desorption of the xylene was carried out for 60 sec. at 250°C. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. In this study, the accuracy, linearity, and detection limits were also determined. The HS-SPME-GC-FID technique provided a relatively simple, convenient, practical procedure, which can be successfully applied for determination of xylene in spiked urine when an occupational exposure monitoring is required

Molecularly imprinted solid phase extraction for trace analysis of diazinon in drinking water

Amongst organophosphate pesticides, the one most widely used and common environmental contaminant is diazinon; thus methods for its trace analysis in environmental samples must be developed. Use of diazinon imprinted polymers such as sorbents in solid phase extraction, is a prominent and novel application area of molecular imprinted polymers. For diazinon extraction, high performance liquid chromatography analysis was demonstrated in this study. During optimization of the molecular imprinted solid phase extraction procedure for efficient solid phase extraction of diazinon, Plackett-Burman design was conducted. Eight experimental factors with critical influence on molecular imprinted solid phase extraction performance were selected, and 12 different experimental runs based on Plackett-Burman design were carried out. The applicability of diazinon imprinted polymers as the sorbent in solid phase extraction, presented obtained good recoveries of diazinon from LC-grade water. An increase in pH caused an increase in the recovery on molecular imprinted solid phase extraction. From these results, the optimal molecular imprinted solid phase extraction procedure was as follows: solid phase extraction packing with 100 mg diazinon imprinted polymers; conditioning with 5 mL of methanol and 6 mL of LC-grade water; sample loading containing diazinon [pH=10]; washing with 1 mL of LC-grade water, 1 mL LC- grade water containing 30% acetonitrile and 0.5 mL of acetonitrile, respectively; eluting with 1 mL of methanol containing 2% acetic acid. The percentage recoveries obtained by the optimized molecular imprinted solid phase extraction were more than 90% with drinking water spiked at different trace levels of diazinon. Generally speaking, the molecular imprinted solid phase extraction procedure and subsequent high performance liquid chromatography analysis can be a relatively fast and proper approach for qualitative and quantitative analysis of diazinon in drinking water

Monitoring of mandelic acid as a biomarker of environmental and occupational exposures to styrene

Styrene is an important constituent of widely used organic solvents in industries for production of various synthetic materials. The use of solid-phase extraction [SPE] has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquidliquid extraction. In this study, SPE has been optimized, regarding sample pH, sample concentration, sample flow rate, elution solvent, washing solvent, sample volume, elution volume, and sorbent mass. Through experimental evaluation, a strong anion exchange silica cartridge has been found successful in simplifying sample preparation. The present approach proved that, mandelic acid, as a urinary metabolite of styrene, could be retained on solid phase based on specific interaction. Further study was employed 10% acetic acid to extract the analyte from spiked urine and gave a clean sample. In this study, a high performance liquid chromatography, using reverse-phase column was used. The isocratic run was done at a constant flow rate of 0.85 ml/min, the mobile phase was water/methanol/acetic acid and an ultra violate detector was used, setting at 225 nm. At the developed conditions the extraction recovery was exceeded 98%. The factors were evaluated statically and also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments

Molecular imprinted solid phase extraction for determination of atrazine in environmental samples

Solid phase extraction is one of the major applications of molecularly imprinted polymers fields for clean-up of environmental and biological samples namely molecularly imprinted solid-phase extraction. In this study, solid phase extraction using the imprinted polymer has been optimized with the experimental design approach for a triazine herbicide, named atrazine with regard to the critical factors which influence the molecular imprinted solid phase extraction efficiency such as sample pH, concentration, flow-rate, volume, elution solvent, washing solvent and sorbent mass. Optimization methods that involve changing one factor at a time can be laborious. A novel approach for the optimization of imprinted solid-phase extraction using chemometrics is described. The factors were evaluated statistically and also validated with spiked water samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. Also, in order to the evaluate efficiency of the optimized molecularly imprinted solid-phase extraction protocols, enrichment capacity, reusability and cross-reactivity of cartridges have been also evaluated. Finally, selective molecularly imprinted solid-phase extraction of atrazine was successfully demonstrated with a recovery above 90% for spiked drinking water samples. It was concluded that the chemometrics is frequently employed for analytical method optimization and based on the obtained results, it is believed that the central composite design could prove beneficial for aiding the molecularly imprinted polymer and molecularly imprinted solid-phase extraction development

Optimization of sample preparation procedure for evaluation of occupational and environmental exposure to nickel

Nickel is an important constituent widely used in different industrial processes for production of various synthetic materials. For evaluation of workers' exposure to trace toxic metal of Ni [II], environmental and biological monitoring are essential processes, in which, preparation of samples is one of the most time-consuming and error-prone aspects prior to analysis. To evaluate factors influencing quantitative analysis scheme of nickel, solid phase extraction using mini columns filled with XAD-2 resin was optimized with regard to sample pH, ligand concentration, loading flow rate, elution solvent, sample volume [up to 500 ml], elution volume, amount of resins, and sample matrix interferences. Nickel ion was retained on solid sorbent and was eluted with followed by simple determination of analytes by using flame atomic absorption spectrometery. Obtained recoveries of metal ion were more than 92%. The amount of the analyte detected after simultaneous pre-concentration was basically in agreement with the added amounts. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. The developed method promised to be applicable for evaluation of other metal ions present in different environmental and occupational samples as suitable results were obtained for relative standard deviation [less than 10%]. This optimized method can be considered to be successful in simplifying sample preparation for trace residue analysis of Ni in different matrices for evaluation of both occupational and environmental exposures

[Design, construction and performance of chromium mist generator]

The chromium mist generator is an essential tool for research and for making evidence-based recommendations in evaluating air pollution and its control systems. The purpose of this study was to design and construct a homogeneous chromium mist generator and to look at the effects of factors such as sampling height and distance between samplers in side-by-side sampling on the chromium mist sampling method. First we developed a mist generator, using a chromium electroplating bath in pilot scale. Concentrations of CrO3 and sulfuric acid in plating solution were 125 g L-1 and 1.25 g L-1, respectively. To set up permanent air sampling locations, a Plexiglas cylindrical chamber [75 cm height, 55 cm i.d] was installed as the bath overhead. Sixty holes were made on the chamber in 3 rows [20 in each row]. The distance between rows and holes was 15 and 7.5 cm, respectively. Homogeneity and the related factors were studied using a side-by-side air sampling method. Forty-eight clusters of samples were collected on polyvinyl chloride [PVC] filters contained in sampling closed-face cassettes. Cassettes were located 35, 50, and 65 cm above the solution surface with < 7.5 and/or 7.5-15 cm distance between heads. All samples were analyzed by the NIOSH method 7600. ANOVA tests showed no significant differences between locations in side-by-side sampling [P=0.82] or between different sampling heights or sampler distances [P=0.86 and 0.86, respectively]. However, there were notable differences between means of coefficients of variation [CV] in various heights and distances. We conclude that the most chromium mist homogeneity could be obtained at a height of 50 cm from the bath solution surface and with a distance of < 7.5 cm between samplers

Solid phase microextraction for trace analysis of urinary benzene in environmental monitoring

Conventional analytical method for organic pollutants in water requires extraction of the pollutants, using hazardous solvent. Solid phase microextraction is a solvent free equilibrium extraction method, in which, proper calibration can allow quantitative determinations of organic pollutants at a very good sensitivity without the use of any organic solvent. Because individual volatile organic carbons are generally exposed environmentally and present in urine only at trace levels, a sensitive and accurate determination technique is essential. So, this study describes the optimization of headspace solid phase microextraction [HS-SPME] followed by GC-FID for benzene in spiked urine. Through this investigations, the parameters affecting the extraction and gas chromatographic determination of analytes, including extraction time, temperature, desorption temperature, desorption time, salt addition, sample pH, sample volume and sample agitation were studied. An optimized headspace extraction was carried out at 30°C for 6 min in the presence of 0.2 g/mL of NaCl in the sample solution. Desorption of the analytes was carried out for 60 sec. at 250°C. The optimized procedure was also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments. The accuracy, linearity, detection limits were also determined. The headspace solid phase microextraction, GC-FID technique provides a relatively simple, convenient, practical procedure, which was here successfully applied to determine benzene in spiked urine

Evaluation of urine mercury level of dentists in Tehran and its influencial factors

Dentists are exposed to mercury from dental amalgam in their routine occupational practice. Excess exposure to mercury is harmful and the measurement of mercury content of urine is a reliable and valid assessment of the level of mercury exposure from dental amalgam. The aim of this study was the measurement of urine mercury in dentists of Tehran and assessment of some possible related factors. This cross-sectional study was performed randomly on 211 dentists in all regions in Tehran city [center, north, south, west, and east] between 1381 and 1383. Dentists were asked to give a sample of urine in the day of visit and to complete a questionnaire consisting of variables such as age, working history, handling of amalgam, environmental parameters and general health situation. Urine samples were analyzed by cold vapour atomic absorption spectrophotometry. Data were analyzed by Kruskall Walis, Kendall and Mann Whitney tests, with p<0.05 as the limit of significance. The mean of urine mercury content in Tehran dentists was 3.1 [ +/- 3.95] microg/lit which was lower than the international TLV [Threshold Limit Value]. There was a significant relation between urine mercury level and working hours per day [P=0.006]. This relation was observed with working hours per week too [P=0.006]. In general dentists, there was a positive relation between urine mercury and age [0.008] as well as the practicing years [P=0.034]. A significant relation was found between urine mercury and the number of amalgam repairs and replacements in restorative specialists [p=0.039]. There was a significant relation between the number of amalgam fillings in the mouth and urine mercury in general practitioners [p=0.027]. The type of amalgam [predosed capsules or bulk powder] had a significant effect on the urine mercury content [P=0.001]. There was no significant relation between urine mercury and other variables of the study such as the squeezing of triturated amalgam, storage method of residual amalgam, method of storing mercury and office ventilation. Based on the results of this study, the mean urine mercury content of dentists of Tehran was below the international TLV. The use of precapsulated amalgams had significant effect on the urine mercury. Most of the dentists were working in public or semiprivate clinics, so it is concluded that the level of general hygiene and specially mercury hygiene in these centers seems to be acceptable

Removal of airborne hexavalent chromium mist using chitosan gel beads as a new control approach

Airborne hexavalent chromium is a known human respiratory carcinogen and allergen. Many workers are exposed to hexavalent chromium in various processes which chromium electroplating plants are the most common. In this study, the feasibility of a new control approach to remove this pollutant using chitosan beads as a biosorbent was investigated. Hexavalent chromium sorption was studied relative to pH, pollution concentration, sorbent concentration, temperature, and air velocity using one factor at a time approach and Taguchi experimental design. Polluted air with different chromium mist concentrations [10-5000 micro g/m[3]] was contacted to chitosan beads [3.3-20 g/L], floating in distilled water with adjusted pH [3-7], using an impinger at different temperatures [20 and 35 °C], and various velocities [1.12 and 2.24 m/s]. The ANOVA test result showed that, there were statistical significant differences between factor levels except optimized pH levels. The higher ions removal efficiencies were achieved at lower levels of air velocities, pollution concentrations, and higher levels of solution pH values, temperatures, and sorbent concentrations

Optimization of sample preparation for 1-hydroxypyrene as a major biomarker of exposure to PAHs prior to HPLC

Urinary 1-hydroxypuren [1-OHP] is commonly used as a major metabolite and biological indicator of the overall exposure to polycyclic aromatic hydrocarbons [PAHs]. For evaluation of human exposure to such compounds, biological monitoring is an essential process, in which, preparation of samples is one of the most time-consuming and error-prone aspects prior to chromatographic techniques. In this study, non classic form of liquid-liquid extraction [LLE] was optimized with regard to solvent type, solvent volume, extraction temperature, mixing type, and mixing duration. Through the extraction process, a mild temperature was used to keep the compound of interest as stable as possible. In this study, a high performance liquid chromatography, using reverse-phase column was used. The isocratic run was done at a constant flow rate of 0.8 ml/min, the mobile phase was methanol/water and a fluorescence detector was used, setting at 242 nm and 388 nm. At the developed conditions, the extraction recovery was exceeded 87.3%, achieving detection limit of 0.2 micro g/l. The factors were evaluated statically and the procedure was validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as experiments. It was concluded that, this optimized method could simplify sample preparation for trace residue analysis of PAHs metabolites

Optimization of SPE for analysis of mandelic acid as a biomarker of exposure to ethyl benzene

Ethyl benzene is an important constituent of widely used solvents in industries and laboratories, causing widespread environmental and industrial pollutions. For evaluation of occupational exposure to such pollutants, biological monitoring is an essential process, in which, preparation of environmental and biological samples is one of the most time-consuming and error-prone aspects prior to chromatographic techniques. The use of solid-phase extraction [SPE] has been grown and is a fertile technique of sample preparation as it provides better results than those of liquid-liquid extraction [LLE]. In this study, SPE using bonded silica has been optimized with regard to sample pH, sample concentration, elution solvent, elution volume, sorbent type, and sorbent mass. Through experimental evaluation, a strong anion exchange silica cartridge [SAX] has been found successful in simplifying sample preparation. The present approach proved that, mandelic acid could be retained on SAX sorbent based on specific interaction. Further study was employed using 10% acetic acid to extract the analyte from spiked urine and gave a clean sample for HPLC-UV system. In this study, a high performance liquid chromatography, using reverse-phase column was used. The isocratic run was done at a constant flow rate of 0.85 ml/min, the mobile phase was water/methanol/acetic acid and a UV detector was used, setting at 225 nm. At the developed conditions the extraction recovery was exceeded 98%. The factors were evaluated statically and also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments