Semi-quantitative health risk assessment of heavy metal dust exposure among nail technicians using the SQRA technique and Monte Carlo simulation.

Nail technology, including the application of artificial nails and nail care, is a developing sector of the global beauty industry. Nail technicians are exposed to a variety of chemical substances through inhalation, as they spend extended periods of time in close proximity to these materials. This study aimed to evaluate the semi-quantitative health risk of dust-containing heavy metals among nail technicians. This analytical descriptive study employed the risk assessment method provided by the Singapore Occupational Health Department to evaluate the health hazards of lead, cadmium, nickel, chromium, and manganese. Dust samples from nail filing were collected from the respiratory zone of 20 nail technicians following the NIOSH 7300 method. The samples were analyzed using ICP-OES instrumentation. Monte Carlo simulation was utilized to characterize the risk and its uncertainties. Manganese and cadmium had the highest and lowest mean concentrations, respectively. The risk scores of the metals ranked from highest to lowest were as follows: Ni>Cr>Cd>Mn>Pb. All five metals had risk rankings below 2.8, signifying a minimal risk level. Sensitivity analysis using Spearman's correlation coefficient demonstrated a positive relationship between concentration, daily hours of exposure, and the number of workdays per week with the risk score (RR) and exposure level (ER). Conversely, the variable of weekly working hours (W) showed a negative correlation with these parameters. Despite the low-risk level of the examined metals, continuous exposure and potential long-term effects on nail technicians warrant preventive measures. Recommendations include implementing local exhaust ventilation systems, using table fans, establishing work-rest cycles, wearing N95 dust masks, and using reputable and high-quality nail polishes.

The association between blood, urine, respiratory, neurobehavioral parameters and occupational exposure to organophosphorus pesticides: a cross-sectional study among formulators.

Background: Organophosphate (OP) pesticides are one of the most extensively used chemical compounds all over the world. Objective: The aim of this study is to determine whether occupational exposure of the formulators to the OP pesticides, under normal working conditions, is associated with any hematotoxic, hepatotoxic, nephrotoxic, neurotoxic, and respirotoxic responses among them. Methods: 28 OP formulation plant workers and 17 office workers participated in this cross-sectional study as the exposed and control groups, respectively. Blood and urine samples were collected to measure hematological, biochemical, and urinalysis parameters. American thoracic society questionnaire and spirometry tests were employed to assess the function of their respiratory system. Q16 questionnaire was also used to investigate the prevalence of neurobehavioral symptoms. The data were analyzed by SPSS v.22 software using Kolmogorov-Smirnov, T-test, Mann-Whitney U, Chi-square, Fisher, Pearson, and Spearman tests. Results: No statistically significant difference was found in hematological, biochemical, urinalysis (except in specific gravity), spirometry parameters, as well as respiratory and neurobehavioral symptoms between the exposed and the control groups. For the exposed group, however, the means of spirometry parameters were significantly lower among the smokers. Conclusions: In this study, the expected adverse health effects due to exposure to OP pesticides were not observed among the formulators; however, the risk of developing respiratory dysfunction was found to be more considerable among smoker subjects than the non-smoker ones. Further investigations are required to determine whether formulators' occupational exposures to OP pesticides result in certain adverse health effects.

Effects of prenatal exposure to chrysotile asbestos on hippocampal neurogenesis and long-term behavioral changes in adult male rat offspring.

Prenatal development is a critical period of life that many environmental pollutants have been suggested to influence fetal growth. Nevertheless, there are still a few investigations into the prenatal exposure to chrysotile asbestos and its neurodevelopmental and behavioral outcome in offspring. In this study, twenty-eight pregnant Wistar rats were divided into four groups and received three-times repeated intraperitoneal injections of normal saline, chrysotile, ascorbic acid and the combination of chrysotile and ascorbic acid on gestational days 11, 14 and 17. The maternal serum levels of malondialdehyde (MDA) and prooxidant-antioxidant balance (PAB) and hippocampal MDA content in adult male offspring were measured. At postnatal day (PND) 60, elevated plus maze was performed to determine anxiety-like behavior, also depression-like behavior was examined using a forced swim test at PND 61- 62. Thereafter, the quantitative analysis of Ki-67, NeuN and GFAP positive cells in the hippocampal dentate gyrus were studied by immunostaining. Our data showed that prenatal exposure to chrysotile increased the maternal serum level of MDA and PAB as well as hippocampal MDA content in adult male offspring, also increased the depression- and anxiety-like behaviors of adult male offspring and decreased the hippocampal Ki-67+, NeuN+ and GFAP+ cells in dantate gyrus of adult male offspring. However, co-administration of ascorbic acid and chrysotile decreased hippocampal lipid peroxidation and increased the Ki-67+, NeuN+ and GFAP+ cells in adult male offspring. In summary, these results indicated that oxidative stress induced by prenatal exposure to chrysotile, lead to the long-lasting decrease of the hippocampal cell proliferation and neuronal differentiation as well as astrogliosis of adult male offspring that exhibit more depression- and anxiety-like behaviors in adulthood and co-treatment of ascorbic acid with chrysotile asbestos attenuated the changes.

Determining the effect of worker exposure conditions on the risk of hearing loss in noisy industrial workroom using Cox proportional hazard model.

In noisy workrooms, exposure conditions such as noise level, exposure duration and use of hearing protection devices are contributory factors to hearing loss. The aim of this study was to determine the effect of exposure conditions on the risk of hearing loss using the Cox model. Seventy workers, employed in a press workshop, were selected to study their hearing threshold using an audiometric test. Their noise exposure histories also were analyzed. The results of the Cox model showed that the job type, smoking and the use of protection devices were effective to induce hearing loss. The relative risk of hearing loss in smokers was 1.1 times of non-smokers The relative risk of hearing loss in workers with the intermittent use of protection devices was 3.3 times those who used these devices continuously. The Cox model could analyze the effect of exposure conditions on hearing loss and provides useful information for managers in order to improve hearing conservation programs.