Study type: Medical/biological study (experimental study)

Temperature changes in chicken embryos exposed to a continuous-wave 1.25 GHz radiofrequency electromagnetic field med./bio.

By: Thalau HP, Raczek J, Marx B, Hombach V, Cooper J
Published in: Radiat Res 2003; 159 (5): 685-692
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Aim of study (acc. to author)

To investigate the relationship between exposure and temperature changes in exposed tissues, without considering biological and medical effects. The extent of the thermic effects of a 1.25 GHz field on chicken embryos at several stages of embryonic development was evaluated.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 1.25 GHz
Modulation type: CW
Exposure duration: 1 to 2 h per day for 21 days
  • power density: 25 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively)
  • power density: 7.5 W/m² minimum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively)
  • power density: 90 W/m² maximum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 10.26 W/kg and 5.67 W/kg respectively)
  • power density: 53 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively)
  • power density: 70 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 7.98 W/kg and 4.41 W/kg respectively)
  • power density: 12.5 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively)
Exposure 2: 1.25 GHz
Modulation type: CW
Exposure duration: continuous for 21 days
  • power density: 53 W/m² maximum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively)
  • power density: 12.5 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively)
  • power density: 25 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively)
  • power density: 7.5 W/m² minimum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively)

Exposure 1

Main characteristics
Frequency 1.25 GHz
Type
Exposure duration 1 to 2 h per day for 21 days
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber BBS breeding/hatching incubator/ 80 cm high x 60 cm long x 56 cm wide
Setup Eggs were placed on a movable plastic rack 10 cm under the aperture of the horn antenna
Additional info Eggs turned automatically around their longitudinal axis once per hour Electric polarization was along the longest egg axis
Parameters
Measurand Value Type Method Mass Remarks
power density 25 W/m² unspecified measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively
power density 7.5 W/m² minimum measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively
power density 90 W/m² maximum measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 10.26 W/kg and 5.67 W/kg respectively
power density 53 W/m² unspecified measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively
power density 70 W/m² unspecified measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 7.98 W/kg and 4.41 W/kg respectively
power density 12.5 W/m² unspecified measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively

Exposure 2

Main characteristics
Frequency 1.25 GHz
Type
Exposure duration continuous for 21 days
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber BBS breeding/hatching incubator/ 80 cm high x 60 cm long x 56 cm wide
Setup Eggs were placed on a movable plastic rack 10 cm under the apreture of the horn antenna
Additional info Eggs turned automatically around their longitudinal axis once per hour
Parameters
Measurand Value Type Method Mass Remarks
power density 53 W/m² maximum measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively
power density 12.5 W/m² unspecified measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively
power density 25 W/m² unspecified measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively
power density 7.5 W/m² minimum measured - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

Throughout the entire 21 days of embryonic development, the mean temperature increases in the eggs during the exposure were found to be up to 0.25°C for a power flux density of 1.25 mW/cm² and increased to 2.3°C for 9 mW/cm². The field-induced temperature increase was greatest in the first week of incubation and was less pronounced in the last week before hatching. In both the short- and long-term exposures, the temperature of the exposed tissue and the amniotic fluid reached its maximum approximately 40-50 min after the radiofrequency field was switched on.

Study character:

Study funded by

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