Study type: Medical/biological study (observational study)

Microwave effects on the central nervous system - a study of radar mechanics med./bio.

By: Nilsson R, Hamnerius Y, Hansson Mild K, Hansson HA, Hjelmqvist E, Olanders S, Persson LI
Published in: Health Phys 1989; 56 (5): 777-779
Download citation in RIS format

Aim of study (acc. to author)

To determine whether radar mechanics and engineers occupationally exposed to microwave during recent decades exhibited signs indicating an effect on their central nervous system.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.3–10 GHz
Modulation type: pulsed
Exposure duration: repeated daily exposure
examination of men
-
Exposure 2: 2.45 GHz
Modulation type: pulsed
Exposure duration: repeated daily exposure, 4 h/day, for 12 or 2 days
animal study
Exposure 3: 2.45 GHz
Modulation type: CW
Exposure duration: repeated daily exposure, 4 h/day, for 12 days
animal study

Exposure 1

Main characteristics
Frequency 1.3–10 GHz
Type
Exposure duration repeated daily exposure
Additional info examination of men
Additional info 1.3 GHz, 3 GHz, and 10 GHz band
Modulation
Modulation type pulsed
Additional info

pulse durations of 0.1-10 µs and pulse rates between a few hundred and several thousand pps
Exposure setup
Exposure source
  • work at military radar installations
Parameters

No parameters are specified for this exposure.

Additional parameter details

Mean powers range from a few watts to several kilowatts. Peak intensities may be a hundred to a thousand times higher.

Measurement and calculation details

With aluminium covers around the magnetrons removed, exposure levels near some units, measured with an EMR monitor, exceeded 1 mW/cm². Near some of the older units, magnetic time derivatives due to high feeding currents were rather high, in one case even 350 T/s were measured.

Exposure 2

Main characteristics
Frequency 2.45 GHz
Type
Exposure duration repeated daily exposure, 4 h/day, for 12 or 2 days
Additional info animal study
Modulation
Modulation type pulsed
Exposure setup
Exposure source
  • not specified
Parameters
Measurand Value Type Method Mass Remarks
power density 10 mW/cm² - - - -
SAR 4.8 W/kg - - - 2.6-4.8 W/kg

Exposure 3

Main characteristics
Frequency 2.45 GHz
Type
Exposure duration repeated daily exposure, 4 h/day, for 12 days
Additional info animal study
Modulation
Modulation type CW
Exposure setup
Exposure source
  • not specified
Parameters
Measurand Value Type Method Mass Remarks
power density 10 mW/cm² - - - -
SAR 4.8 W/kg - - - 2.6-4.8 W/kg

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Pathological neurological findings were not more common in the exposed group than among the control referents. In addition, the psychometric tests and the psychiatric rating scales did not reveal any statistically significant adverse effects of microwave irradiation. Routine cytological and chemical analysis of the cerebrospinal fluid did not reveal any differences between the exposed subjects and the control referents. Isoelectric focusing of the cerebrospinal fluid after absorption chromatography of serum protein is a very sensitive method for detecting small amounts of protein. The frequency of the occurence of an increased protein band with an isoelectric point of 4.5 in the cerebrospinal fluid was higher among subjects exposed to microwaves than among the referents. The nature and clinical significance of this/these proteins are unclear.

Study character:

Study funded by