Study type: Medical/biological study (experimental study)

Genotoxicity of radiofrequency signals. I. Investigation of DNA damage and micronuclei induction in cultured human blood cells med./bio.

By: Tice RR, Hook GG, Donner M, McRee DI, Guy AW
Published in: Bioelectromagnetics 2002; 23 (2): 113-126
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Aim of study (acc. to author)

To assess the ability of radiofrequency signals emitted by various cellular telephones (analog, CDMA, TDMA, or PCS signals) to induce DNA and chromosomal damage in cultured human leukocytes and lymphocytes.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 837 MHz
Modulation type: FM
Exposure duration: continuous for 3 or 24 h
  • SAR: 1 W/kg average over mass (1 g)
  • SAR: 2.5 W/kg average over mass (1 g) (3 h only)
  • SAR: 5 W/kg average over mass (1 g)
  • SAR: 10 W/kg average over mass (1 g)
Exposure 2: 837 MHz
Modulation type: pulsed
Exposure duration: continuous for 3 or 24 h
  • SAR: 1 W/kg average over mass (1 g)
  • SAR: 2.5 W/kg average over mass (1 g) (3 h only)
  • SAR: 5 W/kg average over mass (1 g)
  • SAR: 10 W/kg average over mass (1 g)
Exposure 3: 837 MHz
Modulation type: pulsed
Exposure duration: continuous for 3 or 24 h
  • SAR: 1 W/kg average over mass (1 g)
  • SAR: 2.5 W/kg average over mass (1 g) (3 h only)
  • SAR: 5 W/kg average over mass (1 g)
  • SAR: 10 W/kg average over mass (1 g)
Exposure 4: 1,909.8 MHz
Modulation type: pulsed
Exposure duration: continuous for 3 or 24 h
  • SAR: 1 W/kg average over mass (1 g) (24 h)
  • SAR: 1.6 W/kg average over mass (1 g) (3 h)
  • SAR: 2.9 W/kg average over mass (1 g) (3 h)
  • SAR: 5 W/kg average over mass (1 g) (3 h)
  • SAR: 10 W/kg average over mass (1 g) (3 h + 24 h)

Exposure 1

Main characteristics
Frequency 837 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 3 or 24 h
Modulation
Modulation type FM
Modulation frequency 12.5 kHz
Additional info

voice modulated
Exposure setup
Exposure source
Chamber The exposure system employing two TEM cells operated in series in a vertical position has been described in the reference article.
Setup A plastic rack held six 14 ml tubes (half of the tubes on each side of the septum) so that they were exposed from the bottom with the long axis parallel to the direction of wave propagation. Input power levels for the first TEM cell were set for a given average SAR in the bottom 1 ml of the sample. A length of coaxial cable was used to attenuate the input power for the second TEM cell. A terminating load absorbed any power not absorbed by the samples. Power level fluctuation was below 10%.
Additional info Negative (sham-exposed) and positive (with EMS) controls included in each experiment were obtained by the second TEM cell being disconnected from the input power.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg average over mass measured and calculated 1 g -
SAR 2.5 W/kg average over mass measured and calculated 1 g 3 h only
SAR 5 W/kg average over mass measured and calculated 1 g -
SAR 10 W/kg average over mass measured and calculated 1 g -
Measurement and calculation details

The culture temperature in each TEM cell was monitored using fiberoptic thermometers, two of which were inserted into a test tube containing blood in complete media. The procedures used to measure and calculate SARs have been described in the reference article. Using an FDTD analysis, average SARs for the entire 10 ml and the bottom 1 ml were calculated for both frequencies. Calculated average SARs over the entire 10 ml volume were based on time-temperature profiles produced using the fiberoptic probes.

Exposure 2

Main characteristics
Frequency 837 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 3 or 24 h
Modulation
Modulation type pulsed
Additional info

TDMA, voice modulated
Exposure setup
Exposure source
Setup A plastic rack held six 14 ml tubes.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg average over mass measured and calculated 1 g -
SAR 2.5 W/kg average over mass measured and calculated 1 g 3 h only
SAR 5 W/kg average over mass measured and calculated 1 g -
SAR 10 W/kg average over mass measured and calculated 1 g -

Exposure 3

Main characteristics
Frequency 837 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 3 or 24 h
Modulation
Modulation type pulsed
Additional info

CDMA
Exposure setup
Exposure source
Setup A plastic rack held six 14 ml tubes.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg average over mass measured and calculated 1 g -
SAR 2.5 W/kg average over mass measured and calculated 1 g 3 h only
SAR 5 W/kg average over mass measured and calculated 1 g -
SAR 10 W/kg average over mass measured and calculated 1 g -

Exposure 4

Main characteristics
Frequency 1,909.8 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 3 or 24 h
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Additional info

GSM (PCS), voice modulated
Exposure setup
Exposure source
Setup A plastic rack held four 14 ml tubes.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg average over mass measured and calculated 1 g 24 h
SAR 1.6 W/kg average over mass measured and calculated 1 g 3 h
SAR 2.9 W/kg average over mass measured and calculated 1 g 3 h
SAR 5 W/kg average over mass measured and calculated 1 g 3 h
SAR 10 W/kg average over mass measured and calculated 1 g 3 h + 24 h

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Exposure for either 3 or 24 h did not induce a significant increase in DNA damage in leukocytes, nor did radiation for 3 h induce a significant increase in micronucleated cells among lymphocytes. However, radiation to each of the four radiofrequency signals for 24h (at an average SAR of 5 or 10 W/kg) resulted in a significant and reproducible increase in the frequency of micronucleated lymphocytes. The results demonstrate that radiofrequency signals (at an average SAR of at least 5 W/kg) are capable of inducing chromosomal damage in human lymphocytes.

Study character:

Study funded by

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