Authors:
Garaj-Vrhovac V, Gajski G, Pažanin S, Sarolić A, Domijan AM, Flajs D, Peraica M. Assessment of cytogenetic damage and oxidative stress in personnel occupationally exposed to the pulsed microwave radiation of marine radar equipment. Int J Hyg Environ Health. Sep 9, 2010. Ahead of print.

Introduction
The use of microwave radiation (MW) in occupational settings is growing. Despite extensive research, biological effects of MW are not completely understood. In particular, it is still unclear whether cells and DNA are the targets of this type of non-ionizing radiation. It is known that exposure to toxic substances and radiation leads to increased production of reactive oxygen species (ROS). The increase in ROS production leads to disturbance of oxidative balance in cells (oxidative stress), which may cause damage to macromolecules (such as DNA) and cell membranes. Malondialdehyde (MDA), a secondary product of lipid peroxidation, can be used as an indicator of cell membrane injury. A decrease in the level of glutathione (GSH), an antioxidant, can indicate exposure to oxidative stress. Comet assay and micronuclei test in peripheral blood lymphocytes are sensitive techniques for the assessment of DNA damage.

Objective
The objective of this study was “the assessment of cytogenetic damage and oxidative stress induced in workers occupationally exposed to pulsed MW while working in the vicinity of marine radar equipment.”

Methods
The exposed group included 29 workers (1 female and 28 male, average age 41.1 years, range 26-57 years; 38% smokers). The control group included 29 subjects (1 female and 28 male, average age 38.8 years, range 22-59 years; 50% smokers). Electromagnetic field strength was measured at marine radars’ operational frequencies of 3 GHz, 5.5 GHz and 9.4 GHz. These measurements were used for the estimation of exposure in terms of specific absorption rate (SAR).

Results and Interpretation
SAR values were several orders of magnitude lower than the limit of the International Commission on Non-Ionizing Radiation Protection (ICNRIP) (0.4 W/kg average SAR). There was a significant difference in comet assay parameters between the exposed and the control group suggesting, in the authors’ view, that “MW had an impact on DNA damage in peripheral blood lymphocytes of workers.” In addition, micronucleus test parameters were significantly increased in the exposed group as compared to the control. The concentration of glutathion was decreased and the concentration of MDA was increased in the exposed group as compared to the control group, suggesting oxidative stress in workers exposed to MW.

Conclusion

In the authors’ view, the results of this study “suggest that pulsed microwaves from working environment can be the cause of genetic and cell alterations and that oxidative stress can be one of the possible mechanisms of DNA and cell damage indicating that some biological effects are likely to occur even at low-level electromagnetic fields.”
 

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