[Determination of toxicological indexes of carbon nanotubes and Chrysotile according to invitro cytotoxicity on Human Lung epithelium cells]

In this study the cytotoxicity to human epithelial lung cells of single-walled carbon nanotubes, multi-walled carbon nanotubes and chrysotile was compared based on the following cytotoxicity indices: no observable adverse effect concentration [NOAEC], inhibitory concentration 50 [IC50], and Total Lethal Concentration [TLC]. Human epithelial lung cells were exposed to different concentrations [1 to 1500 micro g/ml] of carbon nanotubes and chrysotile for 6 and 24 hours. Cytotoxicity was assessed using the MTT assay. NOAEC, IC50, and TLC idices were determined by probit analysis. The results showed statistically significant correlations [p<0.001] between cytoxicity and exposure concentration in the case of all the three compounds. The NOAEC and IC50 indices were lowest for the multi-walled carbon nanotubes, while the single-walled carbon nanotubes showed the lowest TLC index. Cytotoxicity of multi-walled carbon nanotubes at low concentrations was higher than that of single-walled carbon nanotubes and chrysotile. This would mean that exposure to this compound occurs at low concentrations. Thus, cytotoxicity of multi-walled carbon nanotubes is a cause for concern. It can be concluded, then, that, like chrysotile fibers, crabon nanotubes are also considerably toxic to human epithelial lung cells

[Determining service life of respirator cartridge using a simple and practical method: case study in a car manufacturing industry]

For ensuring about proper performance of air-purifying respirators in providing protection against workplace contaminates, it is necessary to change the respirator cartridges before the end of their service life. The aim of this study was determination of service life of organic vapor cartridges using a simple and practical method in a spray painting booth of a car manufacturing industry. NIOSH Multi Vapor software was used for estimating service life of respirator cartridges based on workplace conditions and cartridge specifications. Efficiency of determined service life was investigated using an apparatus for field testing of cartridges in the workplace. The result showed that existing schedule for changing the respirator cartridges is not effective and no longer provide adequate protection for sprayers against organic contaminants while working in a painting booth. It is necessary to change the cartridges before their estimated service life [every 4 hours]. NIOSH Multi Vapor has acceptable efficiency for determining respirator cartridges service life and could be used as a simple and practical method in the workplace. This software could be used as a simple and practical method in the workplace. Moreover, Service life estimated by this software was confirmed by cartridge field test apparatus

[Evaluation of change schedule of organic vapor respirator cartridges in a petrochemical industry]

In the absence of End of Service Life Indicator [ESLI], a cartridge change schedule should be established for ensuring that cartridges are changed before their end of service life. The aim of this study was determining the efficiency of respirator change schedule and presenting a suitable schedule for changing the cartridges before their end of service life in a petrochemical complex. Required information for change criteria, number and time between changing the cartridges were gathered through the existing records in the industry. Also the highest values of measured environmental conditions were used as a worse case condition for estimation of service life of cartridges. Technical data and specification of used cartridges in the industry were collected through the cartridges manufactures. Manufacturer's service life software was used for estimation of cartridge service life and 10% of threshold limit values were considered for estimation of breakthrough time of cartridges. The results show that there is no effective change schedule for respirator cartridges in the studied industry. Also there was a significant difference between current schedule and developed schedule for changing the respirators in the studied industry. Relying on odor thresholds and other warning properties solely as the basis for changing respirator chemical cartridges is not allowed and a change out schedule should be developed base on workplace conditions and specification of respirator cartridges

Presence of atrazine in the biological samples of cattle and its consequence adversity in human health

Cattle can be considered as an important source for herbicides through nutrition. Therefore, herbicide residue in animal products is a potential human exposure to herbicides causing public health problems in human life. Triazines are a group of herbicides primarily used to control broadleaf weeds in corn and other feed ingredients and are considered as possible human carcinogens. To evaluate trace residue of these pollutants molecular imprinted solid phase extraction [MISPE] method has been developed, using biological samples. Blood samples were taken from the jugular vein of 45 Holstein cows in 3 commercial dairy farms in Khuzestan Province, Iran. Urine samples were also taken from the cows. The mean +/- SD concentrations of atrazine in serum and urine samples of the study group [0.739 +/- 0.567 ppm and 1.389 +/- 0.633 ppm, respectively] were higher [P < 0.05] than the concentrations in serum and urine samples of the control group [0.002 +/- 0.005 ppm and 0.012 +/- 0.026 ppm, respectively]. Atrazine in the feed ingredients ingested by cattle could be transferred into the biological samples and consequently can be considered as a potential hazard for the public health

[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

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

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

[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

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

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

Potential transmission of human fascioliasis through traditional local foods, in Northern Iran

Ingestion of infective metacercariae, attached to watercress or other various species of water and terrestrial plants, has been implicated as the main source of human contamination by fasciolid flukes. Presence of several species of aromatic wild grown plants, which are eaten fresh on the table or used for preparation of some plant-made foods [Delar, mixture of salt and ground local plants, as a paste and Zeitoon-Parvardeh, olives in walnut sauce, as an appetizer] have been suggested to play a role in human contamination in the endemic zone of fascioliasis, in Gilan province, northern Iran. The aim of the present study was to evaluate the impact of ingredients using for preparation of these local foods on viability and infectivity of liver fluke metacercariae. Metacercariae for this study were obtained by experimental infections of Lymnaea gedrosiana, collected from Bandar Anzali endemic zone. The viability and infectivity of metacercariae kept in Zeitoon-Parvardeh and Delar was checked by microscopical analyses and animal infection assays. The results indicate the possibility of human contamination following consumption of these traditional foods when prepared with fresh vegetables presenting attached metacercariae

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

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

Fluoride compounds and their biological effects in aluminum potroom

Respiratory system disorders occur in aluminum potroom workers despite pre-employment medical examinations. The aims of this study were to measure fluoride and its compounds in the potroom workplace atmosphere as well as workers' breathing zone air, examine the blood eozinophile cells count in the workers exposed to the fluoride compounds, and evaluate the respiratory symptoms and dysfunctions caused during the occupational exposure in potroom workers. To achieve these objectives, a study was carried out in 10 workplaces [potrooms] of Aluminum Producing Plants in Arak city located at Central Iran. Through this study, the data obtained from 160 workers [100 cases and 60 controls] were statically processed. The selected controls were matched for age, year of starting employment, smoking habit, and body mass index [BMI]. The total fluoride compounds concentration of potroom, mean concentration of workers' breathing zone air at different job positions were measured showed high concentration compared to the Threshold Limit Value-Time Weighted Average [TLV-TWA]. The incidence of respiratory symptoms, the number of blood eozinophile, and WBC counts were higher than normal range in case group. During this study, the susceptible aluminum potroom workers to occupational asthma were also identified. Through this study, it was concluded that, workers employing in the potroom in aluminum industries are at risk for respiratory disorders and a continuous workplace monitoring is needed to evaluate workers exposures

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