Reactions between mercury vapor and chlorine gas at occupational exposure levels

AbstractAir force ground crew personnel are potentially exposed to fuels and lubricants, as raw materials, vapours and combustion exhaust emissions, during operation and maintenance of aircrafts. This study investigated exposure levels and biomarkers of effects for employees at a Danish air force military base. We enrolled self-reported healthy and non-smoking employees (n = 79) and grouped them by exposure based on job function, considered to be potentially exposed (aircraft engineers, crew chiefs, fuel operators and munition specialists) or as reference group with minimal occupational exposure (avionics and office workers). We measured exposure levels to polycyclic aromatic hydrocarbons (PAHs) and organophosphate esters (OPEs) by silicone bands and skin wipes (PAHs only) as well as urinary excretion of PAH metabolites (OH-PAHs). Additionally, we assessed exposure levels of ultrafine particles (UFPs) in the breathing zone for specific job functions. As biomarkers of effect, we assessed lung function, plasma levels of acute phase inflammatory markers, and genetic damage levels in peripheral blood cells. Exposure levels of total PAHs, OPEs and OH-PAHs did not differ between exposure groups or job functions, with low correlations between PAHs in different matrices. Among the measured job functions, the UFP levels were higher for the crew chiefs. The exposure level of the PAH fluorene was significantly higher for the exposed group than the reference group (15.9 ± 23.7 ng/g per 24 h vs 5.28 ± 7.87 ng/g per 24 h, p = 0.007), as was the OPE triphenyl phosphate (305 ± 606 vs 19.7 ± 33.8 ng/g per 24 h, p = 0.011). The OPE tris(1,3-dichlor-2-propyl)phosphate had a higher mean in the exposed group (60.7 ± 135 ng/g per 24 h) compared to the reference group (8.89 ± 15.7 ng/g per 24 h) but did not reach significance. No evidence of effects for biomarkers of systemic inflammation, genetic damage or lung function was found. Overall, our biomonitoring study show limited evidence of occupational exposure of air force ground crew personnel to UFPs, PAHs and OPEs. Furthermore, the OH-PAHs and the assessed biomarkers of early biological effects did not differ between exposed and reference groups.

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Effect of occupational exposure to elemental mercury in the amalgam on thymulin hormone production among dental staff

Toxicology and Industrial Health ◽

10.1177/0748233709105270 ◽

2009 ◽

Vol 25 (3) ◽

pp. 159-167 ◽

Cited By ~ 9

Author(s):

SA Farahat ◽

LA Rashed ◽

NH Zawilla ◽

SM Farouk

Keyword(s):

Nitric Oxide ◽

Occupational Exposure ◽

Blood Level ◽

Body Burden ◽

Elemental Mercury ◽

Mercury Vapor ◽

Dental Amalgam ◽

Thymus Gland ◽

Hygiene Measures ◽

Dental Staff

Occupational exposure of dental staff to elemental mercury vapor released from dental amalgam is an issue of concern because of the possible immunological and neurological adverse outcomes. Recently, studies have reported that inorganic mercury induces immunosuppression by decreasing the production of thymus gland hormone (thymulin). This study aimed at investigating mercury body burden in dental staff and the relation of this burden to the potential impact of mercury on thymus gland hormone level (thymulin). Besides, the work aimed at verifying mercury effect on nitric oxide synthetase as a possible mechanism of its immunotoxicity. The study population consisted of a group of dental staff ( n = 39) [21 dentists and 18 nurses] and a matched control group ( n = 42). Each individual was subjected to detailed occupational and medical history taking and to estimation of urinary mercury (U-Hg) and blood mercury (B-Hg) as indicators of mercury body burden and exposure, respectively. Measurement of total thymulin hormone blood level, and plasma level of nitrite and nitrate (indicators of nitric oxide) was also done. The study showed a significantly increased U-Hg and B-Hg levels in the dental staff compared to their controls. This elevation of mercury body burden was associated with significant reduction in thymulin hormone blood level and nitric oxide parameters. These results were more evident in the group of nurses compared to the dentists. In conclusion, our results show that dentists and dental nurses have significant exposure to mercury vapor and point to the negative impact of mercury on thymus gland functions and confirm the implication that the nitric oxide pathway is a possible mechanism for this impact. Moreover, the study raises attention to the importance of hygiene measures in reduction of exposure to mercury vapor released from dental amalgam.

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

Toxicology and Industrial Health ◽

10.1177/0748233719851697 ◽

2019 ◽

Vol 35 (6) ◽

pp. 424-430 ◽

Cited By ~ 2

Author(s):

Rezvan Zendehdel ◽

Il Je Yu ◽

Behnam Hajipour-Verdom ◽

Zahra Panjali

Keyword(s):

Dna Damage ◽

Occupational Exposure ◽

Low Frequency ◽

International Agency ◽

Tail Moment ◽

Limit Values ◽

Strand Breaks ◽

Extremely Low Frequency ◽

Exposed Population ◽

Exposure Levels

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.

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Occupational exposure to mercury vapor in a compact fluorescent lamp factory: Evaluation of personal, ambient air, and biological monitoring

Toxicology and Industrial Health ◽

10.1177/0748233719831531 ◽

2019 ◽

Vol 35 (4) ◽

pp. 304-313 ◽

Cited By ~ 3

Author(s):

Ebrahim Darvishi ◽

Mohammad Javad Assari ◽

Maryam Farhadian ◽

Ebrahim Chavoshi ◽

Hamid Reza Ehsani

Keyword(s):

Occupational Exposure ◽

Light Emitting Diode ◽

Mercury Level ◽

Mercury Vapor ◽

Ambient Air ◽

Cross Sectional Study ◽

Cross Sectional ◽

Air Samples ◽

The Mean ◽

Occupational Exposure To Mercury

Compact fluorescent lamps (CFLs) have become a popular lighting choice in recent years despite the good performance of light-emitting diode (LED) lamps. The CFLs that have been produced recently contain 1.5–3.5 mg Hg/lamp. There is evidence that even low doses of mercury are toxic. This study aimed to assess occupational exposure to mercury vapor in workers of a CFLs factory by determining mercury levels in personal and ambient air samples and urine of workers. This cross-sectional study was conducted on 59 workers in a CFLs factory in Iran. Personal and ambient air sampling of mercury vapor levels (MVLs) was performed during a workday. In total, 10 personal samples and 10 ambient air samples of mercury vapor were collected simultaneously from different units of the factory. Urine samples were collected before the work shift. Samples were analyzed using a cold-vapor atomic absorption spectrophotometer (CVAAS). The mean of the MVLs in the personal and ambient air samples was 14.78 ± 5.76 and 67.10 ± 59.37 µg.m−3, respectively. The highest MVL was measured for the production line supervisor (25 µg.m−3). There was a significant correlation between the MVLs in the ambient air and personal samples ( r = 0.84, p = 0.005). The mean urinary mercury level (UML) was 13.85 ± 13.14 µg/g creatinine. The UML of 86.4% workers was below the 20 µg/g creatinine recommended by the Centre of Environmental and Occupational Health in Iran. There were significant differences between the UMLs in different areas of the factory ( p = 0.041). Lamp breakage was an important determinant of exposure to mercury vapor; hence, effective programs to control mercury vapor are essential in the CFLs industry.

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