Study type: Medical/biological study (experimental study)

DNA strand breaks are not induced in human cells exposed to 2.1425 GHz band CW and W-CDMA modulated radiofrequency fields allocated to mobile radio base stations med./bio.

By: Sakuma N, Komatsubara Y, Takeda H, Hirose H, Sekijima M, Nojima T, Miyakoshi J
Published in: Bioelectromagnetics 2006; 27 (1): 51-57
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Aim of study (acc. to author)

To conduct a large-scale in vitro study focused on the effects of low level radiofrequency fields from mobile radio base stations employing the International Mobile Telecommunications-2000 (IMT-2000) cellular system in order to test the hypothesis that modulated radiofrequency fields may act as a DNA damaging agent.

Background/further details

First, the responses of human cells to microwave exposure at a specific absorption rate (SAR) of 80 mW/kg, which corresponds to the limit of the average whole body SAR for general public exposure defined as a basic restriction in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines were evaluated.
Second, it was investigated whether continuous wave and Wideband Code Division Multiple Access (W-CDMA) modulated signal radiofrequency fields at 2.1425 GHz induced different levels of DNA damage.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.1425 GHz
Modulation type: pulsed
Exposure duration: continuous for 2 or 24 hours
Exposure 2: 2.1425 GHz
Modulation type: CW
Exposure duration: continuous for 2 or 24 hours

Exposure 1

Main characteristics
Frequency 2.1425 GHz
Type
Exposure duration continuous for 2 or 24 hours
Modulation
Modulation type cf. additional info, pulsed
Additional info

W-CDMA (IMT-2000) cellular system. The chip rate of the spread code of this system is 3.84 Mcps.
Exposure setup
Exposure source
Chamber A beam-formed RF exposure incubator employing a horn antenna, a dielectric lens, and a culture case in an anechoic chamber was developed. For details, see the reference article. Briefly, two identical RF field exposure incubators, one for RF field exposure and the other for sham exposure, were established in separate anechoic chambers, and a mechanical switch in a dummy box allows the selection of RF field exposure or sham exposure.
Setup This system allows simultaneous exposure of 49 (7 x 7 array) 35 mm culture dishes with a uniform SAR distribution in the medium of all 49 culture dishes. Five dishes in the inner dish positions were used in this study. They were subjected to RF field or sham exposure for 2 or 24 h, respectively.
Parameters
Measurand Value Type Method Mass Remarks
SAR 80 mW/kg mean - - -
SAR 250 mW/kg mean - - -
SAR 800 mW/kg mean - - -
Measurement and calculation details

For the culture fluid at the bottom of the inner 25 culture dishes (5 x 5 array) used in the in vitro experiments the standard deviation of the SAR distribution was 47%.

Exposure 2

Main characteristics
Frequency 2.1425 GHz
Type
Exposure duration continuous for 2 or 24 hours
Modulation
Modulation type CW
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 80 mW/kg mean - - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Under the same radiofrequency field exposure conditions, no significant differences in the DNA strand breaks were found between the test groups exposed to W-CDMA or continuous wave irradiation and the sham exposed negative controls. The data confirm that low level exposures do not act as a genotoxicant up to a SAR of 800 mW/kg.

Study character:

Study funded by

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