DNA damage in workers exposed to mineral oils.

Mineral oils, untreated or mildly treated, have been classified in group 1 as a potential source of cancer by the International Agency for Research on Cancer (IARC). Although numerous studies have implicated metalworking fluids (MWFs) as human carcinogens, toxicology data regarding the mechanism of carcinogenicity are limited. This study is intended to examine the systemic effects of machining workers' exposure to MWFs. The potential toxicity of mineral oils was investigated in 65 lathe workers compared to controls (66 men). The occupational exposure was measured by the National Institute for Occupational Safety and Health (NIOSH) 5026. The DNA damage has been examined by the comet assay method. According to the field assessments, the time-weighted average (TWA) exposure to mineral oil mist was 7.67 ± 3.21 mg/m3. A comet assay of peripheral blood cells showed that tail length (TL) and olive moment (OM) were significantly higher in the exposed group (p < 0.05). A multiple logistic regression analysis revealed that, within subjects with over 10 years of exposure, the odds ratio of worker with high TL, percent of DNA in tail, OM, and tail moment (TM) were 1.68, 1.41, 1.71, and 2.71, respectively. DNA strand break in exposed workers was associated with higher exposure time in years. Mineral oil toxicity could be altered in the presence of by-products and impurities. For a better understanding of genotoxicity, further studies are required.

Human epithelial lung cell toxicity assessment of collected graphite particles from an iron casting industry (in vitro study).

Workers in the iron casting industries are exposed to various chemicals, especially graphite in furnace process. This study aims to investigate the toxic effects of graphite particles on human lung cells. Particle characteristics were confirmed by electron microscope and light scattering. Cell viability and oxidative stress markers were measured. The expression of oxidative repair genes, namely OGG1, MTH1, and ITPA, was evaluated. The average particle size was determined to be 172.1 ± 11.96 nm. The median inhibition concentration (IC50) of graphite particles was 46.75 µg/mL. Notably, 25 and 50 µg/mL concentrations resulted in significant GSH depletion and MDA production. The high concentration of graphite particles (200 µg/mL) led to OGG1 suppression and increased MTH1 expression. Based on these findings, graphite exposure may induce toxicity in human lung cells by increasing oxidative stress. Further research is necessary to fully understand the mechanisms underlying graphite toxicity.

Prediction of size-selective permitted daily exposures for mineral oil mist based on an in vitro study in different scenarios.

The incidence of DNA damage from exposure to specific types of metalworking fluids has been reported. In this research, size-selective permissible limits to prevent genotoxic damage in A549 cell lines exposed to two types of mineral oil were estimated for the first time using a benchmark dose approach and extrapolated to workers. The comet assay was performed based on Olive and Banath protocol to determine DNA damage. Then, the Benchmark Dose, the 95% lower bound confidence limit BMD, and the 95% upper-bound confidence limit BMD were determined using continuous response data. Finally, the four Benchmark Dose levels reported in the A549 cell line were extrapolated to the human population in occupational settings in two phases. This study showed when determining the permissible limits, the type used or unused, the type of injury, the organ affected in the body and the size of the particles should also be considered.

Cell toxicity assessment in co-treatment to metalworking fluids and vibration: an in vitro study of occupational exposure setting.

This study was designed to study dual risk of MWFs and vibration according to exposure simulation of selected industry. Air samples of two types MWFs were evaluated according to NIOSH 5026. Vibration acceleration exposure was assessed based on the ISO 8041:2005 standard. Cell treatment of both MWF air samples and vibration as the same as dual exposure to MWF airborne and vibration was assessed. There is a potency of nitrosamine formation in airborne samples of ethylamine containing MWF, while heterocyclic including bore is found in airborne bore containing MWF. DNA breaks caused by boron-containing MWF were higher than nitrosamine air samples. Oxidative stress production and chronic inflammation were highlighted in the response to cell treatments. The risk of cell toxicity in machining workers was evaluated at a level lower than the occupational exposure limit for MWFs and vibration.

Application of a novel exposure limit approach for co-exposure of chemicals: a field study by in-vitro design.

This study has suggested an occupational exposure limit (OEL) based on the co-exposure approach in an iron-foundry industry. Respirable dust was collected in an iron casting industry using the NIOSH 0600 method. The DNA damage was obtained by comet assay. The lower confidence interval of the benchmark dose (BMDL) was employed for exposure limit evaluation. The estimated BMDL of the cell line was extrapolated to human subjects. Based on the Hill model, a BMDL 1.65 µg for chemical mixture has been estimated for the A549 cell line. According to uncertainty factors, permitted daily exposure (PDE) was predicted in humans. However, PDE of 3.9 µg/m3 was specified as the time-weighted average limit for toxic respirable dust in the casting industry. In this study, OEL for active respirable dust in the casting industry has been proposed. The industry-based standard for active respirable dust has been proposed for better management of co-exposure.

Lung cell toxicity of co-exposure to airborne particulate matter and extremely low-frequency magnetic field.

Although the toxic effects of urban airborne particulate matter (PM) have been known on lung cells, there is less attention to co-exposure to PM and extremely low frequency magnetic (ELF-MF) in occupational settings. The present study investigated the influences of PM and ELF-MF co-exposure on toxicity in human lung cells (A549).In this case, total PM (TPM) was evaluated according to NIOSH-0500. The TPM SiO2 and metal contents were determined based on NIOSH-7602 and 7302, respectively. Besides, 900 mG ELF-MF exposure was simulated based on field measurements. The toxicity mechanisms were assessed by examining malondialdehyde, glutathione ratio, gene expression, and DNA strand breaks. Also, the toxicity indicators of the TPM samples were MDA generation, glutathione depletion, and DNA damage, and their impacts were analysed at doses below the LD50 (4 µg).In addition, gene expression of OGG1 and MTH1 was upregulated after TPM exposure at the lowest dose (2 µg). But ITPA was upregulated in the presence of ELF-MF. The co-exposure to TPM and ELF-MF decreased oxidative stress and DNA damage levels compared to a single exposure to TPM.Although the ELF-MF reduced toxicity in response to TPM, this reduction was not lower than the unexposed cells.

Release of Interleukin-1ß evaluation among mineral oil mist-exposed workers.

Exposure to aerosols has been found to be linked to respiratory impairment. Although the effects of both indoor and outdoor exposures to particulates have been extensively reported, exposures to mists are less studied. Herein, we reported a survey of mineral oil mist toxicity in an occupational exposure scenario. For the purpose of this study, 65 lathe workers of the metal processing industry, as mineral oil mist-exposed population, were studied. Thereafter, the participants' age, smoking habits and work experience were matched with those of the control workers (n = 65) who were not occupationally exposed to mist. Thereafter, air samples were evaluated from the breathing zone of the workers using NIOSH method 5026. Plasma Interleukin-1ß as a pro-inflammatory indicator was assessed in all the studied subjects. Mean ± standard deviation of mineral oil mist time-weighted average exposure in lathe workers was 7.10± 3.49 mg/m3. IL-1ß cytokine levels were significantly higher in the lathe groups compared to the control group. The mean level of Interleukin-1ß in the control subjects (2922 pg/L) was selected as the cut-off point of the inflammation effect. Based on this pro-inflammatory point, the results of monitoring showed that 60% of the exposed were affected. A Spearman correlation was also found between mineral oil mist exposure and inflammation in the affected subjects. Our findings highlighted the immunological potential of mineral oil mist in occupational exposure. Overall, the results of this study suggested that Interleukin-1ß evaluation in mineral oil mist exposure could be considered as both an acute and chronic inflammation marker.

Occupational exposure to metal-rich particulate matter modifies the expression of repair genes in foundry workers.

Foundry workers are exposed to numerous occupational health hazards, which may result in increased risk of cancer, respiratory disease, and other diseases. Oxidative stress is known to be involved in the pathogenesis of such diseases. The present study aimed to investigate the association between multiple occupational exposures in foundry workers and expression of deoxyribonucleic acid (DNA) repair genes as a biomarker of oxidative DNA damage. The study sample comprised 17 foundry workers and 27 matched control subjects. Expression of 8-oxoguanine DNA glycosylase-1 (OGG1), inosine triphosphate pyrophosphate (ITPA), and MutT homolog 1 (MTH1) in peripheral blood was examined using the real-time polymerase chain reaction method. Air sampling to determine exposure to metal-rich particulate matter and measurement of extremely low-frequency electromagnetic fields (ELF-EMFs) were conducted according to the National Institute for Occupational Safety and Health standard methods. Personal air sampling revealed that occupational exposure to particulate matter exceeded the threshold limit values (TLVs) in 76% of the workstations, whereas ELF-EMF exposure appeared to be lower than the TLV. ITPA was significantly upregulated in foundry workers compared with control subjects, whereas no significant difference was observed for OGG1 and MTH1. Moreover, ITPA was strongly and positively correlated with the concentration of metal-rich particulate matter in foundry workers. No significant correlation was found between ELF-EMF exposure and expression of DNA repair genes. DNA repair gene expression may be a sensitive biomarker for occupational exposures, which suggests an involvement of oxidative stress in metal-induced toxicity. Further studies are needed to determine the role of DNA repair gene expression in response to occupational/environmental hazards.

Inside-tube solid-phase microextraction as an interlink between solid-phase microextraction and needle device for n-hexane evaluation in air and urine headspace.

Monitoring the trace amount of chemicals in various samples remains a challenge. This study was conducted to develop a new solid-phase microextraction (SPME) system (inside-tube SPME) for trace analysis of n-hexane in air and urine matrix. The inside-tube SPME system was prepared based on the phase separation technique. A mixture of carbon aerogel and polystyrene was loaded inside the needle using methanol as the anti-solvent. The air matrix of n-hexane was prepared in a Tedlar bag, and n-hexane vapor was sampled at a flow rate of 0.1 L/min. Urine samples spiked with n-hexane were used to simulate the sampling method. The limit of detection using the inside-tube SPME was 0.0003 µg/sample with 2.5 mg of adsorbent, whereas that using the packed needle was 0.004 µg/sample with 5 mg of carbon aerogel. For n-hexane analysis, the day-to-day and within-day coefficient variation were lower than 1.37%, with recoveries over 98.41% achieved. The inside-tube SPME is an inter-link device between two sample preparation methods, namely, a needle trap device and an SPME system. The result of this study suggested the use of the inside-tube SPME containing carbon aerogel (adsorbent) as a simple and fast method with low cost for n-hexane evaluation.

A method development for bacterial quantification and qualification in occupational exposure.

Bacterial contamination occurs in different occupational exposures. Although the level of colony-forming units in airborne samples reveals bacterial exposure, the bacterial origin is not specified. We applied Fourier transform infrared spectroscopy to investigate bacterial species in airborne samples and validated bacterial evaluation in an occupational exposure. As a pilot study, airborn of nurses station (n=40) was assessed according to National Institute of Occupational Safety and Health 0800 method. Bacterial strain in all samples was evaluated by diagnosis gallery tests. Simultaneously, Fourier transform infrared spectroscopy of sampled bacteria was prepared and then classified by principal component analysis. Spectroscopy method was validated for Staphylococcus aureus quantification. For this aim, spectrum band area in different wavenumbers was evaluated for calibration curve plotting and extraction of validation parameters. The second derivatization of spectroscopy data in 1200 to 1500 cm-1 presented the best determination for gram-type discrimination by principal component analysis modeling. Moreover 900-1200 cm-1 region modeling finely differentiated gram-negative bacteria in airborne samples. Adding spectroscopy area band in 2850 and 2906 cm-1 was validated to assess the level of Staphylococcus aureus contamination. Results showed appropriate correlation between the Staphylococcus aureus level in airborne samples analyzed by commercial counting evaluation and Fourier transform infrared spectroscopy method. Fourier transform infrared spectroscopy is a functional technique for assessment of airborne quality in occupational exposure. This analysis was recommended as an alternative method for quantitative and qualitative analysis of bio-aerosols.

DNA effects of low level occupational exposure to extremely low frequency electromagnetic fields (50/60 Hz).

AIMS: Exposure to extremely low frequency magnetic fields (ELF-MF) occurs from natural and artificial sources. Although ELF-MF has been classified as a suspected humans carcinogen agent by the International Agency for Research on Cancer, little is known of the effects of ELF-MF at lower exposure levels of the recommended range. In the present study, DNA damage in the peripheral blood cells of power line workers was investigated. MATERIALS AND METHODS: Occupational exposure to ELF-MF in a power plant was measured using the National Institute for Occupational Safety and Health (NIOSH) manual. Single-strand breaks (SSBs) in DNA were evaluated in 29 male utility workers as the exposed population and 28 male support personnel as the control subjects using the comet assay. Effects of ELF-MF on subjects were evaluated using DNA percent in tails, tail length, olive length, and tail moment. RESULTS: Occupational exposure levels to ELF-MF in the utility workers were less than the threshold limit values (TLV) recommended by the American Conference of Government Industrial Hygienist (ACGIH). The median value of the magnetic field at the working sites was 0.85 µT. Induction of DNA damage was observed for the exposed workers compared with the controls. Olive length, tail moment, and tail DNA percent increased significantly (p < 0.05) in the utility workers. CONCLUSIONS: Exposure to ELF-MF at levels less than the ACGIH exposure limit can produce DNA strand breaks.

Development of a new method for biomonitoring of multiple metals in occupational exposure.

The assessment of co-exposure to several types of metal contamination poses a hurdle for occupational monitoring. Determination of elements in biological samples is an important way to evaluate occupational exposure. However, optimized methods for the extraction of multiple metals from biological samples have not been reported in recent studies. Therefore, solid-phase extraction (SPE) based on the functionalized nano-zeolite Y was suggested for the biomonitoring of metal co-exposure. SPE was conducted with ammonium pyrrolidine dithiocarbamate (APDC) surrounded by Triton X-100 micelles, which were loaded into the pores of nano-zeolite Y. In this study, SPE was optimized for pre-concentration of trace amounts of chromium (Cr), cadmium (Cd), and lead (Pb) in urine samples with respect to the pH, APDC concentration, elution condition, amount of functionalized nano-zeolite Y, and sample volume. This method has been successfully optimized for the extraction of the mentioned multiple metals with >97% efficiency and an acceptable reproducibility with a coefficient variation of <10%. This method could be used in the extraction of multiple metals in environmental and occupational exposure conditions. In this study, urine samples of welding workers were evaluated following this optimized method.

Analysis of formaldehyde and acrolein in the aqueous samples using a novel needle trap device containing nanoporous silica aerogel sorbent.

In this research, a needle trap device (NTD) packed with nanoporous silica aerogel as a sorbent was used as a new technique for sampling and analysis of formaldehyde and acrolein compounds in aqueous and urine samples. The obtained results were compared with those of the commercial sorbent Carboxen1000. Active sampling was used and a 21-G needle was applied for extraction of gas in the sample headspace. The optimization of experimental parameters like salt addition, temperature and desorption time was done and the performance of the NTD for the extraction of the compounds was evaluated. The optimum temperature and time of desorption were 280 °C and 2 min, respectively. The ranges of limit of detection, limit of quantification and relative standard deviation (RSD) were 0.01-0.03 µg L-1, 0.03-0.1 µg L-1 and 2.8-7.3%, respectively. It was found that the NTD containing nanoporous silica aerogel had a better performance. Thus, this technique can be applied as an effective and reliable method for sampling and analysis of aldehyde compounds from different biological matrices like urine, exhalation and so on.

Neurotoxicity effect of formaldehyde on occupational exposure and influence of individual susceptibility to some metabolism parameters.

Over the years, neurotoxicity and cognitive dysfunction have separately been associated with endogenous formaldehyde and reduction of acetylcholine signals. However, a limited number of studies have shown a relationship between cholinergic neurotransmitter and formaldehyde exposure. Therefore, the aim of this study was to assess the neurological effect on workers from melamine-dish preparation workshop, who were exposed to formaldehyde. A total of 35 formaldehyde-exposed workers were compared with 32 control employees from the food industry. Occupational exposure to formaldehyde was conducted using the National Institute of Occupational Safety and Health 3500 methods. Using the Ellman method, acetylcholinesterase (AChE) as a biomarker for neurotoxicity was analyzed in blood erythrocyte. The effects of alcohol dehydrogenase III (ADH3) and Mn-superoxide dismutase (Mn-SOD) polymorphism were used to survey the level of AChE activity. In this study, it was found that exposure to airborne formaldehyde increased from 0.024 to 0.74 ppm and the median personnel exposure was 0.057. Induction of AChE activity was observed in formaldehyde-exposed workers as compared with the control group (p < 0.01), while AChE activity increased in 64 % of the exposed subjects. Spearman's correlation (p < 0.02) was used to evaluate the association between AChE activity and occupational exposure to formaldehyde. Exposed subjects containing ADH32-2 genotype had higher AChE than others. The findings of this study suggest that the neurotoxic effect of formaldehyde depends on the AChE activity, which is affected by metabolism. It can be concluded that cholinergic signal reduction in cases of cognitive dysfunction could be associated with endogenous formaldehyde.

Development of a new method for sampling and monitoring oncology staff exposed to cyclophosphamide drug.

Treatment using cytotoxic drugs is considered to be the most common treatment for cancers. However, the widespread use of these drugs on the health status of the staff at the oncology department has become a great concern. Due to challenges of sampling and analysis of cytotoxic drugs, the aim of this study was to development a novel practical method called Needle trap devices (NTD) for sampling and analysis of personal exposure to cyclophosphamide drug. The sampler consisted of a stainless steel hyper needle gauge 21 of length 9 cm packed with Carboxen 1000 for adsorbing cyclophosphamide. A total of 41 samples of staff's air breathing zone in different wards of the oncology department were taken with the sampler. Samples were analyzed by gas chromatography coupled with electron capture detector (ECD). Linear range concentration was 212-1062 µg/m(3), and LOD and LOQ were 100 and 191 µg/m(3), respectively. The mean inter-day and intra-day coefficient variations for standards within linear range concentration were 8.9 and 4.8 %, respectively. Detectable levels of cyclophosphamide were measured in 31.7 % of air samples. The developed method is user-friendly, quick, and precise for sampling of airborne cyclophosphamide. The results showed that some staff of the oncology department were exposed to the carcinogenic drug and their health were at risk. Since carcinogens do not have a threshold and oncology staffs with their continuous exposure might be at risk, therefore, proper work practice and adequate control measures are essential to ensure their wellbeing.

Chemometrics models for assessment of oxidative stress risk in chrome-electroplating workers.

Oxidative stress is the main cause of hexavalant chromium-induced damage in chrome electroplating workers. The main goal of this study is toxicity analysis and the possibility of toxicity risk categorizing in the chrome electroplating workers based on oxidative stress parameters as prognostic variables. We assessed blood chromium levels and biomarkers of oxidative stress such as lipid peroxidation, thiol (SH) groups and antioxidant capacity of plasma. Data were subjected to principle component analysis (PCA) and artificial neuronal network (ANN) to obtain oxidative stress pattern for chrome electroplating workers. Blood chromium levels increased from 4.42 ppb to 10.6 ppb. Induction of oxidative stress was observed by increased in lipid peroxidation (22.38 ± 10.47 µM versus 14.74 ± 4.82 µM, p < 0.0008), decreased plasma antioxidant capacity (3.17 ± 1.35 µM versus 7.74 ± 4.45 µM, p < 0.0001) and plasma total thiol (SH groups) (0.21 ± 0.07 µM versus 0.45 ± 0.41 µM, p < 0.0042) in comparison to controls. Based on the oxidative parameters, two groups were identified by PCA methods. One category is workers with the risk of oxidative stress and second group is subjects with probable risk of oxidative stress induction. ANN methods can predict oxidative-risk category for assessment of toxicity induction in chrome electroplaters. The result showed multivariate modeling can be interpreted as the induced biochemical toxicity in the workers exposed to hexavalent chromium. Different occupation groups were assessed on the basis of risk level of oxidative stress which could further justify proceeding engineering control measures.

Urinary biomonitoring of fuel ether oxygenates using a needle trap device packed with a novel molecularly imprinted polymer surface modified Zeolite Y.

This study introduces an innovative needle trap device (NTD) featuring a molecularly imprinted polymer (MIP) surface-modified Zeolite Y. The developed NTD was integrated with gas chromatography-flame ionization detector (GC-FID) and employed for analysis of fuel ether oxygenates (methyl tert­butyl ether, MTBE, ethyl tert­butyl ether, ETBE, and tert­butyl formate, TBF) in urine samples. To optimize the key experimental variables including extraction temperature, extraction time, salt concentration, and stirring speed, a central composite design-response surface methodology (CCD-RSM) was employed. The optimal values for extraction in the study were found to be 51.2 °C extraction temperature, 46.2 min extraction time, 27 % salt concentration, and 620 rpm stirring speed. Under the optimized conditions, the calibration curves demonstrated excellent linearity within the range of 0.1-100 µg L-1, with correlation coefficients (R2) exceeding 0.99. The limits of detection (LODs) for MTBE, ETBE, and TBF were obtained 0.06, 0.08, and 0.09 µg L-1, respectively. Moreover, the limits of quantification (LOQs) for MTBE, ETBE, and TBF were obtained 0.18, 0.24, and 0.27 µg L-1, respectively. The enrichment factor was also found to be in the range of 98-129.The NTD-GC-FID procedure demonstrated a high extraction efficiency, making it a promising tool for urinary biomonitoring of fuel ether oxygenates with improved sensitivity and selectivity compared to current methods.

Comparative study of molecularly imprinted polymer surface modified magnetic silica aerogel, zeolite Y, and MIL-101(Cr) for dispersive solid phase extraction of fuel ether oxygenates in drinking water.

The study was performed in two phases. First, the polymerization was carried out upon three magnetized surfaces of silica aerogel, zeolite Y, and MIL-101(Cr). Then, optimal molecularly imprinted polymer and optimal extraction conditions were determined by the central composite design-response surface method. Subsequently, the validation parameters of dispersive solid-phase extraction based optimal molecularly imprinted polymer were examined for the extraction of the fuel ether oxygenates. The optimal conditions include the type of adsorbent: Zeolite-magnetic molecularly imprinted polymer, the amount of adsorbent: 40 mg, pH: 7.7, and absorption time: 24.8 min which was selected with desirability equal to 0.996. The calibration graphs were linear between 1 and 100 µg L-1, with good correlation coefficients. The limits of detection were found to be 0.64, 0. 4, and 0.34 µg L-1 for methyl tert-butyl ether, ethyl tert-butyl ether, and tert butyl formate, respectively. The method proved reliable for analyzing fuel ether oxygenates in drinking water.

Oxidative Stress Assessment of Noise Exposure in the Workers Using Hearing Protection in a Pressing Industry.

BACKGROUND AND OBJECTIVE: Exposure to noise by generation of free radicals causes oxidative stress in body. The aim of this study was the evaluation of oxidative stress in workers who have used hearing protection devices during working time. MATERIAL AND METHOD: Pressing workers (n=24) of a home appliance industry were studied using hearing protection devices to reduce noise exposure. Twenty two office staff (without exposure to noise) were considered as a control group. Two groups were matched for age, work experience and smoking. Exposure to noise was measured by dosimeter method at workstations. By obtaining 3 ml blood sample, Malondialdehyde levels, Thiol groups and total antioxidant capacity were evaluated in all subjects. RESULTS: Exposure to sound pressure level in pressing workers by considering the noise reduction factor of the earplug was observed in 77.65 dB with minimum 75.1 dB and Maximum 81.22 dB. Plasma thiol groups (0.076 (0.041-0.119) vs (0.110 (0.076-0.197), mmol/l P =0.0001) and total antioxidant capacity (361.33± 54.65 vs 414.14± 96.82, µmol/ml P = 0.026) in pressing workers significantly decreased than control group. Pearson correlation showed significant results between exposure to noise and oxidative stress parameters. CONCLUSION: Exposure to noise wave cause oxidative stress in different site of body. Oxidative stress is an intermediate way for different disease due to noise exposure. Reducing of noise exposure by earplug in pressing workers is not efficient protection for oxidative stress generation. Therefore, hearing protection devices are not a barrier to the harmful effects of noise in occupational exposure.

Health and Carcinogenic Risk Assessment of Exposure to by-Products of Photocatalytic Degradation of Toluene in a Spouted Bed Reactor with Porous and Non-Porous Draft Tube.

OBJECTIVE: This study was performed to assessment the health and carcinogenic risk of exposure to by-products of photocatalytic degradation of toluene in a spouted bed reactor Equipped with porous and non-porous draft tube. METHODS: For this purpose, titanium dioxide nanoparticles were used as photocatalysts and UV lamps as radiation sources. Degradation efficiency and CO2 selectivity were compared. By-products were also detected in three spouted bed reactors with and without a porous and non-porous draft tube. RESULT: The results revealed that the degradation efficiency of toluene in the spouted bed reactor without a draft tube was 30.75%. The insertion of porous and non-porous draft tubes in the spouted bed reactor increased the degradation efficiency up to 54.88% and 47.63%, respectively. Meantime, CO2 selectivity decreased from 100% to 50.8% within 180 min irradiation time in the spouted bed reactor without draft tube, while in the spouted bed reactors with porous and non-porous draft tube maintained at 89.85% and 84.35%, respectively. Toluene and four by-products with carcinogenic and non-carcinogenic risk of 0.002176 and 182.2, respectively, were detected in the spouted bed reactors without draft tube. However, no by-products with carcinogenic risk were found in the spouted bed reactor with porous and non-porous draft tube. CONCLUSION: photocatalytic degradation of toluene in a spouted bed reactor without a draft tube produces by-products with health and carcinogenic risks. The insertion of a porous and non-porous draft tube in spouted bed reactors provided mineralization more complete than spouted bed reactor without a draft tube by reducing the dead zone and providing appropriate contact between the toluene, photocatalyst, and UV. Therefore, prevent the formation of dangerous and carcinogenic by-products.