Burton's Line on the Gum Seen in Lead Poisoning Among Petroleum Refinery Workers in Kirkuk City, Iraq: A Case Series.

Lead poisoning is a serious occupational health risk, especially for those who work in fields where lead-containing products are frequently exposed, including petroleum refining. Three cases of lead poisoning among employees of the petroleum refinery in Kirkuk City, Iraq, have been presented in this case series, emphasizing the clinical significance of Burton's line (blue-purplish line or gingival pigmentation) on the gums as an indication of lead toxicity. Patients presented with typical gingival margin darkening along with symptoms like fatigue, headaches, abdominal pain, and neurological impairments. Subsequent laboratory analysis confirmed that all three patients had increased blood lead levels, which ranged from 30 to 43 µg/dL (normal range <10 µg/dL). In the process of refining petroleum, lead can be inhaled, ingested, or come into direct touch with lead-containing items. Burton's line identification is essential for prompt diagnosis and intervention. This case series highlights the importance of taking preventative action to lessen the risks of lead exposure and protect the well-being and safety of employees of petroleum refineries. Healthcare providers should be vigilant, and strict safety protocols, worker education, and regular monitoring are all essential.

Evaluation the cytotoxic effect of Fe3O4@Glu-Gingerol on lung adenocarcinoma cell line (A549) with biological mechanisms.

The use of nanotechnology products with supermagnetic properties for targeted delivery of drugs has gained attention recently. Due to the anticancer features of Gingerol, the major phenolic compound from Ginger, this study aims to prepare Fe3O4@Glucose-Gingerol nanoparticles (NPs) and investigate their anticancer potential in a lung adenocarcinoma cell line. The physical and chemical features of the nanoparticles were investigated by FT-IR, XRD, zeta potential, DLS, EDS mapping, VSM, and electron microscope imaging. Cytotoxic effects of the nanoparticles for the A549 (lung adenocarcinoma) and MRC-5 (normal) cell lines was investigated by MTT assay. Furthermore, the effects of Fe3O4@Glucose-Gingerol nanoparticles on the expression of the CASP8, BAX, and BCL2 genes and the activity of Caspase 3 were characterized. The flow cytometry assay (annexin V/PI) was employed to find out the percentage of apoptotic cells. The Fe3O4@Glu-Gingerol NPs were spherical (42-67 nm), without elemental impurity, and with surface charge, DLS size, and magnetic saturation of -47.7 mV, 154 nm, and 35 emu/g, respectively. Fe3O4@Glu-Gingerol NPs showed a remarkable greater toxicity in the A549 cells than normal cell line with the 50 % inhibition concentration (IC50) of 190 and 554 µg/mL, respectively. Treatment of lung adenocarcinoma cells with the Fe3O4@Glu-Gingerol NPs led to an increase in cell apoptosis from 4.6 to 39.48 %. Also, the CASP8 and BAX genes were upregulated by 2.49 and 2.8 folds, respectively, while a downregulation by 0.75 folds was noticed for the BCL2. Moreover, apoptotic features were observed in Fe3O4@Glu-Gingerol NPs treated cells by Hoechst staining, and activation of Caspase 3 by 2.8 folds. This study revealed that the Fe3O4@Glu-Gingerol NPs have antiproliferative effects on the lung adenocarcinoma cell line by activation of intrinsic and extrinsic apoptosis that is a promising feature in cancer treatment.

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.

Testicular histopathology in rats co-exposed to heat and psychological stressors.

Objectives: The present study aimed to investigate the effect of co-exposure to heat and psychological stressors on testicular tissue as one of the major male reproductive organs in rats. Methods: Forty adult male Wistar rats were divided into four groups of 10 animals each. The first group was exposed to heat stress (Temperature Humidity Index: 57.75 ± 3), the second group was exposed to three psychological stressors including strobe light ultrasonic sound, and tilting cage, and the third group was co-exposed to both heat and psychological stress daily. The order of exposure to various psychological stressors was randomized. Following the last day of the 40 -day exposure, the rats were euthanized and their testicular tissues were fixed in Bouin's solution. Moreover, a tissue processor, a microtome as well as hematoxylin, and eosin staining were used for tissue preparation. Results: The co-exposure to psychological and heat stress can cause negative testis histopathological changes including spermatid retention, degeneration of round spermatids and spermatocytes, degeneration and depletion of elongated Spermatid, Sertoli cell status, tubular degeneration/atrophy, Leydig cell atrophy, tubular dilatation, re-tubular dilation, and sclerosis status in a number of rats. Moreover, the histopathological changes were higher in the group exposed to heat stress compared with those exposed to psychological stress. Conclusions: Although exposure to either stressor alone can affect testicular tissue as part of the reproductive system, co-exposure to both stressors may result in an increased risk of adverse effects on testicular tissue.

Preparation of Photocatalytic TiO2-Polyacrylonitrile Nanofibers for Filtration of Airborne Microorganisms.

Background: We aimed to investigate the efficiency of neat polyacrylonitrile (PAN) nanofibers and photocatalytic PAN/TiO2 nanofibers for removal of airborne microorganisms. Methods: Nanofibers were fabricated from 16 wt% of PAN dissolved in dimethyl formamide through the electrospinning technique. The efficiency of media for removal of Staphylococcus epidermidis and Bacillus subtilis was investigated at different conditions such as face velocity, relative humidity, air temperature and UVC radiation intensity. as face velocity (0.1 and 0.3 m/s), relative humidity (35±5% and 60±5%), air temperature (22±3 °C and 30±3 °C) and the UVC radiation intensity (dark, 1±0.09 mW/cm2 and 1.8±0.07 mW/cm2) using air sampling from upstream and downstream of media by cascade impactor containing blood agar culture medium. Results: The mean diameter of electrospun fibers and coefficient of variation were 194 nm and 15%, respectively. The amount of immobilized TiO2 on the filter was 620±6.56 mg/m2. Photocatalytic nanofiber filter media presented the best performance for removal of airborne B. subtilis at 60±5% relative humidity, 0.1 m/s face velocity, air temperature 22 °C, and 1.8 ± 0.07 mW/cm2 UVC radiation. Conclusion: The filtration efficiency of photocatalytic media was significantly higher than neat ones. Lower efficiency of media was found in the higher air velocity for all bioaerosols. High UVC radiation intensity increased filtration efficiency. Moreover, the increase in air temperature and relative humidity (except for TiO2-coated media under UVC radiation) did not significantly affect the filtration efficiency of all media.

Assessment of semen quality of taxi drivers exposed to whole body vibration.

Whole body vibration (WBV) is a recognized occupational hazard for many workers such as drivers and operators of heavy and light machinery and exposure to it is accompanied by physical and mental repercussions. Only the limited studies have been done on the effects of vibration exposure on reproductive indices, however vibration exposure has been indicated as being a hazardous agents with the potential of being able to directly affect the reproductive system. Considering the importance of infertility, the present study was conducted with the aim of investigating semen quality among taxi drivers in Tehran and determine the effect of exposure to WBV on sperm parameters. The study population consisted of 70 taxi drivers and 70 office employee who attended infertility clinics for diagnostic purposes in the past year. The participants had to meet the entry criteria of the study while also being willing to recruit. Data was collected in the form of demographic questionnaires and general health questionnaires as well as sperm analysis conducted in an infertility clinic according to standard laboratory guidelines. The 8-hour time-weighted average (TWA) exposure to of WBV in automobile was measured as per ISO 2631-1. The TWA exposure to WBV among the taxi drivers and office employees were 0.697 ± 0.13 m/s2 and 0.068 ± 0.09 m/s2 respectively (P < 0.05). A statistically significant difference in total sperm count, progressive motility, non-progressive motility and total motility was observed between the taxi drivers and the office employees (P < 0.05). According to the univariate analysis of variance, exposure to WBV had negative effect on sperm concentration, progressive motility and normal morphology (P > 0.05); moreover exposure to WBV resulted in the larger effect size (B) on sperm parameters than the demographic variables (P > 0.05). Being taxi drivers increase the chance of the decreased semen quality (P > 0.05). It is difficult to draw definitive conclusions regarding the effects of WBV while intervening factors exist, such as psychological stressors, quality of sleep, background issues as well as environmental factors such as chemical pollutants (heavy metals) or ergonomic factors (body posture and working while sitting down).

UV protection properties of workwear fabrics coated with TiO2 nanoparticles.

The main purpose of this study was to evaluate the ultraviolet protective factor (UPF) of fabrics coated with TiO2 nanoparticles made using an in-situ synthesis method and more accurately assess the intrinsic properties of the textile. The cotton-polyester twill fabric (70-30%) (246.67 g/m2) was coated in-situ with TiO2 nanoparticles. In-situ coating is conducted in 4 steps; washing the fabrics, preparation of nanoparticles, injecting the nanoparticles into fabrics, and drying the fabric after coating. The scanning electron microscope (SEM) and X-ray diffraction (XRD), FTIR spectrometer, dynamic light scattering (DLS) and UV-Vis spectrophotometer were used to analyse the data of the coating and UPF results. Also, four standards such as ASTM D737, ISIRI 8332, ISIRI 4199, and ISIRI 567 were used for analyzing the intrinsic properties of a textile. The results of SEM, XRD and DLS altogether confirmed the in-situ formation of nanoparticles onto textile fibers. Moreover, the UPF value of the uncoated and coated fabrics was 3.67 and 55.82, respectively. It was shown that the in-situ deposition of TiO2 nanoparticles on fabric can provide adequate protection against UVR. Also, the results of analyzing the intrinsic properties of the textile showed that there were no significant differences in the intrinsic properties between the coated and uncoated fabrics. Based on the results, it can be concluded that the UV protective properties of workwear fabrics can be improved by coating TiO2 nanoparticles on them without any effect on the cooling effect of perspiration evaporation.

Effect of anthropometric and demographic factors on musculoskeletal disorders in nurses' aides.

BACKGROUND: Nurses' aides usually face various stressors, making them prone to musculoskeletal disorders (MSDs). OBJECTIVE: This study evaluates the effect of ergonomic and anthropometric indices, postural risk, and demographic variables on MSDs in nurses' aides. METHODS: Demographic variables, anthropometric dimensions, postural risk level (RL), and related percentiles of 75 nurses' aides were examined using Quick Exposure Check (QEC) software, caliper, and body map questionnaire. Pearson correlation coefficient, univariate and multivariate tests were used to analyze the data. RESULTS: The results showed that the RL of QEC in both groups of males and females was 73.67±22.34 (RL = 4) and 65.34±18.38 (RL = 3), respectively. The level of MSDs in the lumbar, thigh, and leg areas was higher than in other areas. Also, increasing age and work experience, and BMI were significantly associated with increasing disorders in the hands, wrists, and shoulders, respectively (P < 0.05). The results showed that an increase in some anthropometric indices such as body height, buttock, knee, popliteal height, abdomen depth, standing grip access limit, sitting grip access limit increased disorders in the hands and wrists. Also, MSDs were predicted in different areas of the nurses' aides' bodies using regression models, which was significant in the hands, wrists, elbows, legs, and shoulders (P < 0.05). CONCLUSIONS: The results showed that there was a significant difference between male and female nurses in most aspects of anthropometry and the risk level of QEC. Therefore, it is necessary to pay attention to anthropometric dimensions, and demographic diversity to design tools and workstations.

Development and validation of assessment tool of knowledge, attitude, and practice of outdoor workers regarding heat stress.

BACKGROUND: Improving the level of knowledge, attitude and practices of workers exposed to heat stress using a suitable tool can be a cheap and effective method. This requires the consideration of personal, environmental and social factors, which, the PRECEDE model is highly applicable for. Thus, the aim of the present study is the development of a tool assessment for measuring the knowledge, attitude and practices of workers in outdoor occupations regarding heat stress exposure using the PRECEDE model. METHODS: In the present study, a tool was designed and constructed using the PRECEDE model by analyzing the relevant literature and expert opinion. The face validity of the tool was determined based on the opinion of ten experts with experience in the field of occupational weather conditions. The content validity of the tool was determined using the Content Validity Ratio (CVR) and the Content Validity Index (CVI). Cronbach's alpha reliability coefficient was used to determine the reliability of the tool's internal consistency. SPSS version 23 was used for statistical analysis. RESULTS: A PRECEDE based questionnaire was designed with a total of 55 questions consisting of predisposing factors (28 questions for knowledge and 14 questions for attitude), enabling factors (5 questions), reinforcing factors (3 questions) and preventive behaviors (5 questions). The Content Validity Index (CVI) of all questions was above 0.79. The Content Validity Ratio (CVR) of all questions was above 0.62 (Lawshe method). The Cronbach's alpha reliability coefficient of all PRECEDE domains were above the 0.7 acceptable value. Based on the results obtained, all 55 questions were approved and thus the content validity and reliability of this tool was deemed acceptable. CONCLUSION: Considering the reliability and validity of this tool, its application is recommended in all health and safety inspections within various industries for measuring the heat stress knowledge, attitude and practices of workers engaged in outdoor occupations and also for presenting suitable solutions or preventive measures.

The Influence of Vitamin E and Omega-3 Fatty Acids on Reproductive Health Indices Among Male Workers Exposed to Electromagnetic Fields.

The present study aims to investigate the effects of using the supplementation of vitamin E and Omega 3 fatty acids on reproductive indices among workers in an automobile parts manufacturing plant. The effect of exposure to electromagnetic fields on certain sex hormones and sperm parameters will also be assessed. The participants were deployed into four groups as per the double-blind block randomization method. Semen parameters and sex hormones of the participants were analyzed before and after 3-month consumption of supplements. The level of workers' exposure to low-frequency magnetic and electrical fields was measured through the recommendation of National Institute for Occupational Safety and Health. Univariate analysis of variance indicated that exposure to electric fields had a statistically significant effect on sperm count, morphology, and motility. The simultaneous consumption of vitamin E + Omega 3 had a statistically significant effect on sperm morphology and motility.

Effect of Co-exposure to Heat and Psychological Stressors on Sperm DNA and Semen Parameters.

The present study aims to investigate the effects of co-exposure to heat and psychological stress on sperm DNA and semen parameters among male rats. The study was conducted on 40 healthy adult male Wistar rats. The rats were randomly categorized into four groups of same size consisting of a control group, a heat stress, psychological and co-exposure groups. The heat stress group was exposed to a temperature of 36 °C at 20% relative humidity. The psychological stress exposure group was subjected to three stressors including exposure to strobe light, noise and tilting cage. According the results,the co-exposure group had lower mean sperm parameters including sperm count (17.22 ± 4.22 106/ml), motility (42.63 ± 12.95 %), viability (48.50 ± 23.25 %), normal morphology (56 ± 7.5%), progressive motility (11.61 ± 7.81%), non-progressive motility (31.18 ± 7.77%), curvilinear velocity (24.11 ± 3.81 µm/s) and straight-line velocity (3.2 ± 1.4 µm/s) when compared with those of the other groups (P = 0.001). Mean sperm immobility (57.36 ± 12.95%) and non-progressive motility (37.93 ± 11.15%) in the co-exposure group was higher compared to the other groups (P = 0.001 and P = 0.333, respectively). Assessment of damage to sperm DNA revealed that the heat exposure group had a higher percentage of sperm DNA damage (9.44 ± 6.80 %) compared to others (P = 0.185). In case of all of exposure scenario, the chance that the semen quality decreased compared to the control group has been increased. In general the combined stress had a greater significant effect on sperm parameters compared to other exposure groups, except for DNA damage.

The effects of combined exposure to road traffic noise and whole body vibration on types of attention among men.

BACKGROUND: Noise and vibration are considered as harmful physical agents in the environment which have adverse effects on cognitive performance. One of the occupations at risk is driving, where there is a possibility of simultaneous exposure to road traffic noise and whole body vibration (WBV) transferred through the vehicle. This study aims to assess the effects of single and combined exposure to road traffic noise and WBV on different types of attention in men. METHODS: The experiment was conducted on 24 men in 4 steps, executed on each participant inside an acoustic room. After recording a number of various attention scores at background conditions (27 dBA noise, no vibration) the participants were given single and combined exposure to noise levels at 55 and 85 dBA and vibration frequencies of 0.65 and 0.95 m/s2. RESULTS: As for combined exposure to noise and vibration, increasing vibration acceleration and noise levels at the same time compared to background condition caused a rise in the score of all visual attention types among groups exposed to low vibration acceleration and those exposed to medium acceleration and low noise. Nevertheless, when noise level and vibration acceleration is increased at the same time compared to background, auditory attention type scores mostly fell among groups with similar vibration accelerations. CONCLUSIONS: Overall, single and combined exposure to environmental stressors under investigation had a predominantly negative effect on auditory attention while the effects on visual attention were inconclusive. Definitive conclusions however require further systematic and comprehensive experiments.

Feasibility study on the application of electrospun nanofiber webs for the air sampling of crystalline silica.

The aim of the present study was to first fabricate an electrospun PVC nanofiber web and then assess its applicability in sampling and measuring the concentration of airborne crystalline silica by comparing analysis results with a commercial PVC membrane filter under different ranges of airborne silica concentration. A filtration performance comparison was also made between an electrospun PVC web with nano-sized fibers and a commercial PVC membrane filter. Overall, the measured concentration of silica by the electrospun webs was 1.022 times higher than that of the commercial PVC filter in all studied ranges of silica concentration and the nanofiber media had higher filtration efficiency and lower pressure drop compared to the PVC membrane filter. This can be considered to be due to the lower fiber diameter and greater porosity (obtained from the 2D SEM image) of the electrospun nanofiber webs. This makes them suited for air pollutant sampling and determining its airborne concentration.

Comprehensive analysis and investigation of accident/occupational disease responsibility rates: A case study for accidental CO poisoning.

One of the major problems of courts and insurance companies is the lack of a proper technique to determine the rate of responsibility of the parties involved in the accident. The aim of this study was to determine the Accident/Occupational Diseases Responsibility Rates (AOD RR) for complex events. Accordingly, a case study of a complex accident of carbon monoxide (CO) poisoning was selected and Occupational Accident Tree Analysis (OATA) and Occupational Accident Component Analysis (OACA) techniques, which were solely used to investigate occupational accidents, were used with the new names Accident/Occupational Disease Tree Analysis (AOD TA) and Accident/Occupational Disease Component Analysis (AOD CA) to evaluate their applicability to investigate non-occupational accidents and occupational diseases. For this purpose, causes of CO penetration to victims' room was assessed using gas tracking methods. Finally, Fuzzy Accident/Occupational Disease Tree/Component Analysis (FAOD TA and FAOD CA) techniques were developed and used for determining AOD RR in fuzzy environment. The results showed that the AOD RR obtained by AOD TA and AOD CA based on the average of experts' personal opinions and consensus between experts, and AOD TA and AOD CA in a fuzzy environment were close to each other, with the power terminal and the power cable crossing route being the main routes of transmission and penetration of CO to the victims' room. Also, the owner, contractor, tenant, and serviceman were responsible for the CO poisoning of victims. It can be concluded that any hole, crack, or fission in the building can result in CO penetration to the individuals' living rooms, and gas tracking in early winter, especially in older buildings, plays a very significant role in preventing residents' poisoning. Further, due to the uncertainty of AOD TA and AOD CA techniques, it is recommended to use FAOD TA and FAOD CA techniques for increasing the accuracy of the results. This will enhance the court and insurance companies' trust in the opinions of accident investigation experts, decrease delays in the proceedings, and prevent any violation of the individual rights.

Comparison of mice' sperm parameters exposed to some hazardous physical agents.

The present study was aimed to compare the effects of exposure to noise, vibration, lighting, and microwave on male mice' sperm parameters. The mice were randomly assigned to five groups of eight, which comprised of the unexposed group and exposure groups including the lighting (1000 lux), noise (100 dB(A)), vibration (acceleration of 1.2 m/s2) and microwave (power density of 5 watts). The exposure groups were subjected to the four agents for 8 hours a day, 5 days a week during a 2-week period. Semen analysis were done according to World Health Organization guidelines. The highest significant mean difference in sperm count (-1.35×106/mL) had being observed between the microwave group and the control one (P=0.001). The highest difference in immotile percent (25.88 %) had being observed between the noise group and the control one (P=0.001). The highest difference in normal morphology (-27.06 %) observed between the lighting exposure group and the control group (P=0.001). The four agents can cause changes in different sperm parameters, however for definite conclusion; more laboratory and field studies are required. In total, exposure to microwave has had the greatest effect on sperm count and exposure to light has had the greatest effect on normal morphology and non-progressive motility. Moreover, exposure to noise has had the greatest effect on progressive motility and immotile percent, respectively.

Relationship between occupational exposure to whole-body vibration and noise with sex hormone levels: An empirical assessment in an automobile parts manufacturing plant.

The present study investigated the relationship between occupational exposure to noise and whole-body vibration (WBV) with the levels of sex hormones in an automobile parts manufacturing plant. The level of workers' exposure (n = 162) to each of the mentioned stressors was measured through standard methods, and the time-weighted average of exposure was calculated for each person. In order to determine serum sex hormones (free testosterone, luteinizing hormone, and follicle-stimulating hormone), blood samples were taken from all participants after 8-10 h of fasting between 7 and 9 am and then the blood samples were analyzed by an enzyme-linked immunosorbent assay method. In general, regarding testosterone as the main male sex hormone, only 49% of the participants were in the normal range. In a total of three sections, the lowest mean testosterone levels were observed in the third exposure group (WBV > 1.93 m/s2; noise >92.69 dB) of the studied stressor; however, only the difference in testosterone levels between the three different groups of exposure to noise was statistically significant (p = 0.001). The relationship between demographic variables and levels of noise and WBV exposure with sex hormones was not linear and only the relationship between noise exposure and testosterone levels was statistically significant (R = -0.201, p = 0.013). According to the results of logistic regression, the WBV had the greatest effect on testosterone levels. However, according to the results of the correlation test, only the relationship between noise exposure and testosterone levels was statistically significant.

The combined effect of industrial noise type, level and frequency characteristics on hand motor skills: A lab trial study.

BACKGROUND: The study aimed to assess the interactive effects of industrial noise type, level and frequency characteristics on hand motor skills using the Minnesota Manual Dexterity Test and the Hand Tool Dexterity Test. METHODS: A total of ten nonsmoking male volunteers with normal hearing and vision were selected for this study. The study followed a full 3×3×2 factorial design. Independent variables were noise type (steady, intermittent and fluctuating), noise level (75, 85 and 95 dBA) and frequency characteristics ("roar" <2000 Hz and "hiss" >2000 Hz). RESULTS: For Minnesota Manual Dexterity Test, the lowest speed is related to steady hiss noise at 75 dBA and the highest speed is related to fluctuating roar noise at 95 dBA. The speed is being significantly affected by the frequency characteristic (P = 0.041) and noise type (P = 0.025). The effect of hiss noise on speed is greater than roar noise (P = 0.038). There is a significant difference (P = 0.035) between continuous noise and fluctuating noise. For the Hand Tool Dexterity Test, the lowest speed is related to fluctuating hiss noise at 95 dBA and the highest speed is related to steady roar noise at 95 dBA. The speed is being significantly affected by the frequency characteristic (P = 0.002), noise type (P = 0.0001) and noise level (P = 0.005). The effect of hiss noise on response variable to be greater than roar noise (P = 0.008). There is a significant difference (P = 0.0001) between steady noise and the two other types of noise, and also there is a significant difference between 75 dBA and 85 dBA level (P = 0.003). CONCLUSIONS: The results showed that on hand motor skills, speed response was influenced by three characteristics: the type of noise, frequency characteristics and noise level. Also, the effect of the hiss noise was more than the roar noise.

Assessment of sexual hormones in foundry workers exposed to heat stress and electromagnetic fields.

The presence of hazardous agents in workplaces has raised concerns regarding their possible impacts on male reproductive system. The present study investigated the individual and combined effects of exposure to heat stress and electromagnetic fields with low-frequency characteristics on the levels of sex hormones in two foundry sections (Aluminum and Cast Iron) of an automobile parts manufacturing plant. The level of workers' exposure (n = 110) to each of the mentioned stressors, was measured through standard methods and for each person and the time-weighted average (TWA) of exposure was calculated. The participants of each sections were classified into separate exposure groups based on the 33rd and 66th percentile of the level of to heat stress and electromagnetic fields exposure. In order to determine serum sex hormones, blood samples were taken from all participants between 7-9 am and then the blood samples were analyzed by ELISA method. In total of two sections, the lowest mean testosterone levels was observed in the third exposure group of the electromagnetic fields (magnetic field>1.40 µT; electric field >0.42 V/m), however, the mean difference in testosterone levels between the three different groups of exposure wasn't statistically significant (P > 0.05). According to the results of Logistic Regression, the electric field had the greatest effect on testosterone levels as the main male hormone. Drawing a definitive conclusion regarding the effects of each harmful physical hazards is difficult due to the existence of psychological stressors and other environmental stressors such as chemical pollution, ergonomic hazards and other physical stressors.