Immunotoxicity induced by occupational inhalation exposure to waste anesthetic gases: a historical cohort study.

This study was undertaken to ascertain whether long-term occupational exposure to inhalational anesthetic, was associated with any significant alteration in the parameters of immune function. Materials and methods: This was a historical cohort study in which 30 male participants with at least one year of work experience in the operating room at the time of the study and 30 unexposed referent subjects were investigated. Exposure levels were quantified by measuring the urinary concentrations of nitrous oxide (N2O), isoflurane, and sevoflurane gases by headspace gas chromatography-mass spectrometry. Serum concentrations of interleukin-4 (IL-4), Th2-type cytokines, and interferon-gamma (IFN-γ) were measured by the ELISA method. Additionally, an automated hematology analyzer was used for the white blood cell count and white blood cell differential test. The data were analyzed using SPSS software for Windows version 21. Results: Mean urinary concentrations of N2O, isoflurane, and sevoflurane were found to be 211.57±75.15, 4.06±0.96, and 19.51±12.96  ppb, respectively. In simplistic statistical data analysis, significant differences were noted between exposed and control groups as far as the mean serum cytokines levels (IFN-γ, IL-4) were concerned. Furthermore, after adjusting for important confounders, statistical analysis showed that the IFN-γ, IL-4, and the ratio of IFN-γ/IL-4 were significantly higher in the exposed group than in the referent subjects. Conclusion: These findings provide corroborative evidence to further substantiate the contention that exposure to anesthetics agents (N2O, isoflurane, and sevoflurane) is associated with subtle, subclinical, prepathological changes in the parameters of immune function. The long-term ramification of these changes requires further investigation.

Assessment of respiratory exposure to cypermethrin among farmers and farm workers of Shiraz, Iran.

Cypermethrin, a member of the synthetic pyrethroids group, is a popular insecticide used to eliminate a broad range of common bugs in agricultural lands and households. However, studies of farmers' exposure to this insecticide are limited. The present study aimed to measure the respiratory exposure to cypermethrin among farmers and farm workers of Shiraz, as one of the biggest cities in Fars province, Iran. Totally, nine target regions were selected, where 42 individual samples were taken using XAD-2 sorbents and were analyzed by gas chromatography-electron capture detector (GC-ECD). This is the first study on farmers' exposure to insecticides during spraying in Iran. The average concentration of cypermethrin vapor in farmers' respiratory area during spraying was 0.982 ± 0.421 mg/m3, which was lower than the permitted threshold value for cypermethrin recommended by the Occupational Safety and Health Administration (OSHA). The mean time-weighted average (TWA) was also evaluated in two distinct occupational groups (tree operators and field operators). The exposure was significantly higher in tree operators than in field operators. A direct correlation was also found between the height of the workers and the amount of cypermethrin (Spearman's r = 0.555). Findings support that farm workers' respiratory exposure to cypermethrin was within the permissible range, but this situation cannot guarantee workers' safety. Total respiratory exposure and skin exposure studies are recommended in future research.

Erratum to: Toxic responses of the liver and kidneys following occupational exposure to anesthetic gases.

[This corrects the article on p. 418 in vol. 19, PMID: 32327960.].

Low-level Eexposure to lead dust in unusual work schedules and hematologic, renal, and hepatic parameters.

BACKGROUND: Many workers are exposed to lead dust in lead-­zinc mines. Exposure to this heavy toxic metal and its compounds can cause irreversible adverse health effects. OBJECTIVE: To assess possible hematotoxic, nephrotoxic, and hepatotoxic potentials of low levels of lead in a group of mine workers exposed to this heavy metal in an unusual work schedule. METHODS: A total of 73 exposed and 70 non-exposed employees were interviewed. Demographic data, and occupational and medical history of the employees were obtained by questionnaires. Air monitoring was performed to determine the workers' time-weighted average (TWA) exposure to lead dust. The threshold limit value (TLV) for lead was adjusted for unusual work schedules according to the model developed by the University of Montreal and the Institute de Recherche en Sante et en Securite du Travail (IRSST). Blood samples were collected for complete blood count, liver and kidney function tests. Data were analyzed using version 21.0 of the SPSS software. RESULTS: The TWA exposure of workers was 24 µg/m3. On average, the worker's exposure to lead dust did not exceed the 8-h OSHA and ACGIH TLV-TWA of 50 µg/m3. Significant associations were found only between exposure to lead and platelet count, red cell distribution width, total protein, and albumin. CONCLUSIONS: Exposure to low levels of lead dust in unusual work schedules was not associated with overt hematotoxicity, hepatotoxicity or nephrotoxicity. However, mild, sub-clinical, pre-pathologic significant changes were noted in some blood parameters of the exposed employees as compared with their referent counterparts.

Respiratory symptoms and lung functional impairments associated with occupational exposure to poultry house pollutants.

This study aimed to assess respiratory symptoms and the pulmonary function test (PFT) in a group of poultry workers. The prevalence of respiratory symptoms was determined. Airborne concentrations of total and repairable dusts exceeded the threshold limit values. Gram-positive cocci and Cladosporium were the dominant genera of bacteria and fungi, respectively. The prevalence of respiratory symptoms was significantly higher in the exposed subjects. Mean baseline values of forced expiratory volume (FEV1), FEV1 to forced vital capacity (FVC) ratio (FEV1/FVC) and peak expiratory flow (PEF) were significantly lower in the exposed group. Significant cross-shift decrements were noted in vital capacity (VC), FVC, FEV1, PEF and FEV1/FVC of the exposed subjects. A dominant pattern of lung function abnormality was found to be obstructive. Exposure to poultry pollutants may result in a significant increase in the prevalence of respiratory symptoms as well as both acute reversible and chronic irreversible decrements in the PFT.

Association between genotoxic properties of inhalation anesthetics and oxidative stress biomarkers.

Exposure to inhalation anesthetics (IAs) has been associated with DNA damage as reflected in the increased frequency of micronuclei (MN) and chromosomal aberrations (CAs). The present study was undertaken to ascertain whether there was any correlation between increased MN and CA and the extent of oxidative stress as well as the antioxidant status of a group of operating room personnel exposed to a mixture of IAs, including nitrous oxide, isoflurane, and sevoflurane. In this cross-sectional study, 60 operating room personnel (exposed group) in whom the frequencies of MN and CA had already been shown to be significantly higher than those of a referent group, as well as 60 unexposed nurses, were studied. Venous blood samples were taken from all participants, and malondialdehyde (MDA) levels as an index of oxidative stress (OS) and the activity of superoxide dismutase (SOD) and levels of total antioxidant capacity (TAC) as indices of antioxidant status were measured. The level of TAC (1.76 ± 0.59 mM vs. 2.13 ± 0.64 mM, p = 0.001) and the activity of SOD (11.22 ± 5.11 U/ml vs. 13.36 ± 4.12 U/ml, p = 0.01) were significantly lower, while the mean value of MDA was significantly higher (2.46 ± 0.66 µM vs. 2.19 ± 0.68 µM, p = 0.03) in the exposed group than in the nonexposed group. After adjusting for potential confounders, there were statistically significant associations between exposure to IAs, gender, SOD, and TAC with MN frequency and between exposure to IAs and SOD with numbers of CA. The findings of the present study indicated that exposure to IAs was associated with OS, and this, in turn, may be causally linked with DNA damage.

Toxic responses of the liver and kidneys following occupational exposure to anesthetic gases.

This study was undertaken to determine whether exposure of operating room personnel to inhalation anesthetics, including nitrous oxide, isoflurane, and sevoflurane was associated with any hepatotoxic or nephrotoxic changes. Fifty-two operating room personnel and 52 non-exposed subjects were studied. A questionnaire pertaining to demographic characteristics and medical history of participants was completed. Fasting blood samples were taken from all subjects to measure the functional parameters of kidneys and liver. Biological monitoring was also performed to detect the urinary concentration of IAs. Urinary concentrations of nitrous oxide, isoflurane, and sevoflurane were found to be 175.8 ± 77.52, 4.95 ± 3.43, and 15.0 3± 16.06 ppm, respectively. The mean levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma-glutamyltransferase, Alpha-glutathione-S-transferase, as well as the serum levels of kidney injury molecule-1, creatinine and calcium were significantly higher in the exposed group. Statistically significant associations were observed between exposure to inhalation anesthetics and the mean levels of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase, serum creatinine, kidney injury molecule-1, and calcium. Under the exposure scenario described in the present study, occupational exposure to inhalation anesthetics was associated with subtle, subclinical, pre-pathologic changes in the parameters of liver and kidneys. Additionally, Alpha-glutathione-S-transferase and kidney injury molecule-1 were found to be sensitive markers for early detection of subclinical changes in the parameters of kidney and liver function in subjects who are exposed to inhalation anesthetics.

Effects of Low-level Occupational Exposure to Ammonia on Hematological Parameters and Kidney Function.

BACKGROUND: Many workers, particularly those working in manufacture of fertilizers, explosives, rubber, pesticides, textiles, and employees of petrochemical industries are exposed to ammonia in their workplaces. Toxic responses of hematopoietic system and kidney following occupational exposure to this chemical have not been thoroughly investigated. OBJECTIVE: To determine the relationship between long-term occupational exposure to low levels of ammonia and hematological parameters and kidney function. METHODS: In this cross-sectional study, 119 randomly selected, male petrochemical workers and 131 office employees (comparison group) were examined. Urine and blood samples were taken from all participants for urinalysis, complete blood count (CBC), serum calcium level, and blood urea nitrogen (BUN) and plasma creatinine. Personal, environmental, and peak ammonia exposure were also measured. RESULTS: The median personal, environmental, and peak occupational exposure to ammonia were 0.23, 0.16, and 65.50 mg/m3, respectively, among the exposed group. No significant difference was observed between the exposed and unexposed participants in terms of hematological parameters and urinalysis. Conversely, calcium and BUN, while within the normal range, were significantly higher in the exposed than in the comparison group. CONCLUSION: Occupational exposure to low atmospheric concentrations of ammonia was associated with subtle, sub-clinical, pre-pathologic changes in kidney function. Possible longterm consequences and ramifications of these effects require further investigation.

Genotoxicity of inhalational anesthetics and its relationship with the polymorphisms of GSTT1, GSTM1, and GSTP1 genes.

Due to their wide applications, concern exists regarding possible genotoxic effects of inhalational anesthetics (IAs) among operating room personnel. This study was undertaken to examine genotoxic properties of co-exposure to nitrous oxide, sevoflurane, and isoflurane on induction of micronucleus (MN) and chromosomal aberrations (CAs) and to determine whether any associations exist between polymorphisms of GST genes and the level of genomic damage measured by MN and CAs assays. Sixty operating room personnel and 60 unexposed referent nurses were studied. The workers' exposure to the IAs was determined. DNA damage was evaluated by MN and CAs assays. Additionally, the GSTM1, GSTT1, and GSTP1 polymorphisms were detected. The mean concentrations of nitrous oxide, isoflurane, and sevoflurane were found to be 850.92 ± 919.78, 2.40 ± 0.86, and 0.18 ± 0.14 ppm, respectively. The frequency of MN and CAs in the exposed group was significantly higher than that of the non-exposed group. The frequency of MN was significantly higher in referent nurses with null GSTT1, compared to referent nurses with positive GSTT1. The frequency of MN was significantly higher in exposed individuals carrying the combined genotype of GSTT1 (-), GSTM1 (-), and GSTP1 AG as compared with subjects carrying a combination of GSTT1 (+), GSTM1 (+), and GSTP1 AA. Statistically significant associations were noted between exposure to the IAs, gender, and the combination of the three GSTs genotypes with MN frequency. These findings indicate that inhalation exposure to IAs induces genotoxic response and the polymorphisms of GSTs genes might modulate the effect of exposure to IAs on MN.

Early, Subclinical Hematological Changes Associated with Occupational Exposure to High Levels of Nitrous Oxide.

This study was undertaken to determine whether exposure of operating room personnel to inhalation anesthetics, nitrous oxide, isoflurane, and sevoflurane was associated with any hematological changes. This historical cohort study was performed in 2018 at a large public hospital in Shiraz, where 52 operating room personnel and 52 administrative staff were investigated. The blood sample was taken from all individuals for Complete Blood Count. Furthermore, demographic information was collected through questionnaires. Mean atmospheric concentrations of nitrous oxide, isoflurane, and sevoflurane, to which subjects were exposed, were 850.92, 2.40, and 0.18 ppm, respectively. The hematological parameters were within the normal range in both groups. However, the mean values of hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and red blood cell count in the exposed group were significantly lower than the control group. No significant differences were noted between the two groups as far as other hematological factors were concerned. These findings provide circumstantial evidence to further substantiate the notion that occupational exposure to inhalation anesthetics, under the exposure scenario explained in this study, is associated with subtle, subclinical, prepathologic hematological changes. Long-term consequence and ramifications of these effects require further investigation. The range of exposure levels to anesthetic gases in operating rooms.

Respiratory and Dermal Symptoms and Raised Serum Concentrations of Biomarkers of Oxidative Stress among Pesticide Retailers.

BACKGROUND: Recently concern has been raised regarding possible health effects resulting from exposure of a group of pesticide retailers to chemicals they handle. OBJECTIVE: To investigate the prevalence of respiratory and dermal symptoms, as well as biomarkers of oxidative stress, among pesticide retailers and to compare them with those of an unexposed comparison group. METHODS: 70 male pesticide retailers and 64 male construction workers (served as the comparison group) were investigated. Blood samples were taken from all participants to assess the biomarkers of oxidative stress. A data sheet and the European Community Respiratory Health Survey II questionnaire were used to determine the prevalence of dermal and respiratory disorders, respectively. RESULTS: After adjusting for age, weight, height, education level, job tenure, average daily work, presence of family history of respiratory diseases, marital status, smoking status, and number of cigarettes smoked per day, we found that wheezing (OR 4.07, 95% CI 1.17 to 14.17), cough (OR 3.38, 95% CI 1.15 to 9.98), and mucus hypersecretion (OR 3.66, 95% CI 1.45 to 9.05) were significantly more prevalent among pesticide retailers compared with the comparison group. The prevalence of tingling and dryness of skin exposed individuals was significantly higher than unexposed participants. The mean serum concentrations of glutathione and malondialdehyde in the exposed group were significantly higher than those in the comparison group. CONCLUSION: Occupational exposure to low doses of a mixture of pesticides by retailers was associated with increased prevalence of dermal and respiratory symptoms as well as raised concentrations of biomarkers of oxidative stress.

Functional disorders of the lung and symptoms of respiratory disease associated with occupational inhalation exposure to wood dust in Iran.

OBJECTIVES: The possible adverse respiratory effects of airborne pollutants in sawmills have not been thoroughly investigated in Iran. Additionally, the extent to which workers are exposed to this organic dust and its associated bioaerosols has not been extensively quantified. Likewise, the predominant bacterial and fungal species associated with wood dust have not been characterized. The present study was undertaken to address these issues. METHODS: One hundred male individuals exposed to wood dust and 100 unexposed male subjects were investigated. They completed a standardized respiratory symptom questionnaire and underwent spirometry testing. Additionally, airborne concentrations of respirable and inhalable dust particles, bacteria, and fungi were measured. RESULTS: The mean concentrations of inhalable and respirable dust particles, bacteria, and fungi were found to be 2.44, 6.76 mg/m3 , 756.38, and 299.15 colony-forming units/m3 , respectively. The predominant Gram-negative bacteria in the sawmills included the Pseudomonadaceae, Klebsiella pneumoniae, and Rhinoscleromatis spp., and the predominant fungi consisted of the zygomycetes and Aspergillus spp. Respiratory symptoms were significantly more prevalent among exposed workers. Significant cross-shift decrements were noted in some pulmonary function parameters. Similarly, pre-shift spirometry results indicated that some pulmonary function parameters were significantly lower in the exposed group. CONCLUSIONS: Exposure to wood dust and its bioaerosols was associated with significantly higher prevalence of respiratory symptoms and both acute (i.e., partially reversible) and chronic (i.e., irreversible) decrements in the functional capacity of the lung. Additionally, the characterized bioaerosols did not differ significantly from those isolated in other parts of the world.

Ventilatory disorders associated with occupational inhalation exposure to nitrogen trihydride (ammonia).

Respiratory effects of long term exposure to low levels of ammonia have not been thoroughly investigated. In this cross sectional study, 124 male subjects (67 high exposed and 57 low exposed), occupationally exposed to low levels of ammonia and 120 male referent individuals were investigated. Airborne concentrations of ammonia were measured and subjects underwent spirometry tests prior to and at end of their daily work shift. Average concentrations of ammonia in the breathing zones of the high and low exposed employees were found to be 1.35 ± 4.59 and 0.29 ± 0.31 ppm, respectively. Additionally, mean baseline values of some parameters of pulmonary function such as Vital Capacity (VC) and Forced Expiratory Volume in the first second (FEV1) in the high exposed group were significantly lower than those of referent individuals. Similarly, significant reversible cross shift decrements were noted in FEV1, VC and Forced Vital Capacity (FVC) of exposed employees. These findings indicate that exposure to low levels of ammonia is associated with significant chronic irreversible and acute reversible decrements in the lungs' functional capacity.

Effects of Genetic Polymorphism on Susceptibility to Nephrotoxic Properties of BTEXs Compounds.

OBJECTIVE: The aim of this study was to ascertain whether genetic polymorphism affects susceptibility of individuals to nephrotoxic potentials of benzene, toluene, ethyl-benzene, and xylenes (BTEXs). METHODS: Fifty BTEXs exposed workers with one or more abnormal parameter of kidney function and 232 referent subjects, with similar exposure history, free from any abnormal kidney parameters were investigated. Atmospheric concentrations of BTEXs were measured. In addition, genetic polymorphisms were determined by multiplex polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP). RESULTS: The frequencies of GSTP1 Ile-Val/Val-Val, null GSTT1, and null GSTT1/GSTM1 genotypes and mean values of blood urea nitrogen and plasma creatinine were significantly higher, while average glomerular filtration rate was significantly lower in cases than in referent subjects. CONCLUSION: These findings indicate that individuals carrying null GSTT1 or null GSTT1/GSTM1 are more susceptible to nephrotoxic properties of BTEXs compounds.

Evaluation of hematological and biochemical parameters of pesticide retailers following occupational exposure to a mixture of pesticides.

AIMS: This study was undertaken to ascertain whether light occupational exposure to pesticides by retailers might be associated with any liver, kidney, nervous system dysfunction or hematological abnormalities. MAIN METHODS: In this cross-sectional study, 70 male pesticide retailers (cases) and 64 male subjects, randomly selected from the constructions workers of city council contractors, as the referent group, were investigated. Urine and blood samples were taken from all subjects for urine analysis, hematological and biochemical parameters. Data analysis was conducted through SPSS v.19 using t-test and chi-square test. KEY FINDINGS: The results of urine analysis showed that the frequency of abnormal urine tests was significantly higher in cases than in referent individuals. Similarly, the results of CBC showed that the mean values of monocyte, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and platelet distribution width were significantly lower, and mean corpuscular hemoglobin concentration and red blood cell distribution width were significantly higher in retailers. No significant differences were found for other parameters. SIGNIFICANCE: These findings indicate that an association exists between exposure to pesticides by retailers and early subtle and sub-clinical changes in the urine tests and hematological parameters. Engineering measures are recommended to eliminate exposure to pesticides and to prevent its associated outcomes.

Occupational exposure to extremely low frequency magnetic fields and risk of Alzheimer disease: A systematic review and meta-analysis.

INTRODUCTION: Occupational exposure to extremely low frequency magnetic fields (ELF-MF) occurs in many occupations such as welders, electric utility workers, train drivers and sewing machine operators. There is some evidence suggesting ELF-MF exposure to be a risk factor for Alzheimer's disease (AD). The current study aims at systematically reviewing the literature and conducting a meta-analysis to evaluate the risk of AD amongst workers exposed to ELF-MF. METHODS: Bibliographic databases were searched including PubMed, EMBASE, Cochrane Library, and Web of Science in November 2017. Risk of bias was assessed in the all included studies. Pooled estimates were obtained using random-effects meta-analysis. In addition, sources of heterogeneity between studies and publication bias were explored. RESULTS: In total, 20 articles met the inclusion criteria. The pooled results suggest an increased risk of AD (RR: 1.63; 95% CI: 1.35, 1.96). Higher risk estimates were obtained from case-control studies (OR: 1.80; 95% CI: 1.40, 2.32) than from cohort studies (RR: 1.42; 95% CI: 1.08, 1.87). A moderate to high heterogeneity (I2 = 61.0%) and indication for publication bias (Egger test: p <  0.001) were found. CONCLUSION: The results suggested that occupational exposure to ELF-MF might increase the risk of AD. However, this suggestion should be interpreted with caution given the moderate to high heterogeneity and indication for publication bias.

Association between polymorphism of GSTP1, GSTT1, GSTM1 and CYP2E1 genes and susceptibility to benzene-induced hematotoxicity.

Occupational exposure to benzene has been associated with leukemia, anemia, leukopenia, and thrombocytopenia. Genetic susceptibility to benzene toxicity in humans may be related to variations in benzene metabolizing genes. The main objective of this study was to ascertain whether polymorphism of GSTP1, GSTM1, GSTT1 and CYP2E1 genes might influence susceptibility to the adverse effects of benzene among employees of a petrochemical plant. In this cross-sectional study, 124 employees of a petrochemical plant who had been occupationally exposed to benzene and had one or more abnormal hematological parameter (cases) and 184 subjects with a similar exposure scenario, free from any abnormal hematological parameters (referent) were studied. Atmospheric concentrations of benzene were measured and GSTM1 and GSTT1 genotypes were evaluated using the multiplex polymerase chain reaction (PCR) technique. Additionally, GSTP1 and CYP2E1 genotypes were determined by PCR- restriction fragment length polymorphism (PCR-RFLP). The frequency of null GSTT1 genotype in cases was significantly higher than that of referent group (32.3 vs. 18.5%, OR 2.1, 95% CI 1.23-3.56, p = 0.004). The mean value of platelets in subjects with null GSTT1 genotype was significantly lower than that of individuals with positive GSTT1 genotype (p = 0.015). Conversely, the mean value of leukocytes was significantly higher in subjects with null GSTM1 genotype as compared to those with positive GSTM1 genotype (p = 0.026). Logistic regression analysis showed that, subjects with null GSTT1 genotype had a significantly higher risk for hematological disorders, as compared to those with positive GSTT1 genotype (OR 2.1, 95% CI 1.23-3.56). Moreover, subjects with both null GSTT1 and GSTM1 genotypes had a significantly higher risk for hematological disorders as compared to subjects with positive GSTT1 and GSTM1 genotypes (OR 2.35, 95% CI 1.14-4.8). The results of this study showed that, individuals carrying null GSTT1 or both null STT1 and GSTM1 genotypes had a higher risk and were more susceptible to benzene-induced hematological disorders.

Exposure to Cooking Fumes and Acute Reversible Decrement in Lung Functional Capacity.

BACKGROUND: Being exposed to cooking fumes, kitchen workers are occupationally at risk of multiple respiratory hazards. No conclusive evidence exists as to whether occupational exposure to these fumes is associated with acute and chronic pulmonary effects and symptoms of respiratory diseases. OBJECTIVE: To quantify the exposure levels and evaluate possible chronic and acute pulmonary effects associated with exposure to cooking fumes. METHODS: In this cross-sectional study, 60 kitchen workers exposed to cooking fumes and 60 unexposed employees were investigated. The prevalence of respiratory symptoms among these groups was determined through completion of a standard questionnaire. Pulmonary function parameters were also measured before and after participants' work shift. Moreover, air samples were collected and analyzed to quantify their aldehyde, particle, and volatile organic contents. RESULTS: The mean airborne concentrations of formaldehyde, acetaldehyde, and acrolein was 0.45 (SD 0.41), 0.13 (0.1), and 1.56 (0.41) mg/m3, respectively. The mean atmospheric concentrations of PM1, PM2.5, PM7, PM10, and total volatile organic compounds (TVOCs) was 3.31 (2.6), 12.21 (5.9), 44.16 (16.6), 57 (21.55) µg/m3, and 1.31 (1.11) mg/m3, respectively. All respiratory symptoms were significantly (p<0.05) more prevalent in exposed group. No significant difference was noted between the pre-shift mean of spirometry parameters of exposed and unexposed group. However, exposed workers showed cross-shift decrease in most spirometry parameters, significantly lower than the pre-shift values and those of the comparison group. CONCLUSION: Exposure to cooking fumes is associated with a significant increase in the prevalence of respiratory symptoms as well as acute reversible decrease in lung functional capacity.

The Effect of Exposure to Low Levels of Chlorine Gas on the Pulmonary Function and Symptoms in a Chloralkali Unit.

BACKGROUND: The present study was undertaken to ascertain whether (or not) long term occupational exposure to low (sub-TLV levels) atmospheric concentrations of chlorine gas was associated with any significant decrements in the parameters of pulmonary function and/or  increased prevalence of respiratory symptoms. METHODS: In this retrospective cohort study that was performed in 2012, 54 workers of a local chloralkali unit and 38 non-exposed office staff were enrolled and compared. Atmospheric concentrations of chlorine gas were measured by numerous sampling with gas detector tubes. Data on respiratory symptoms were gathered using a standard questionnaire. Furthermore, spirometry test was performed for subjects both prior to and at the end of shift. RESULTS: Mean atmospheric concentration of chlorine gas was 0.27 ±0.05 ppm that was lower than the existing TLV value for this toxic irritant gas. Symptoms of respiratory diseases were significantly more frequent among exposed subjects than in referent individuals. Additionally, mean values of most parameters of pulmonary function including FEV1 (P=0.031), FEV1/FVC ratio (P=0.003) and PEF (P=0.005) were significantly lower than their corresponding values for unexposed subjects. Additional cross shift decrements were also noted in some lung functional capacities, although changes were not statistically significant. CONCLUSIONS: Exposure to sub-TLV levels of chlorine gas is associated with statistically significant decrements in the parameters of pulmonary function as well as increased prevalence of respiratory symptoms.