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Medical/biological study (experimental study)

Reduced growth of soybean seedlings after exposure to weak microwave radiation from GSM 900 mobile phone and base station.

Published in: Bioelectromagnetics 2015; 36 (2): 87-95

Aim of study (acc. to author)

To investigate the possible effects of exposure to radiofrequency electromagnetic fields (GSM or continuous wave (CW)) on soybean seedlings.
Background/further details: Seven experiments with different exposure protocols were performed: 1.) 2 h sham exposure + 2 h GSM exposure (electric field strength 41 V/m) 2.) 2 h sham exposure + 2 h GSM exposure (5.7 V/m), 3.) 2 h sham exposure + 2 h GSM exposure (41 V/m) + 2 h sham exposure, 4.) 2 h sham exposure + 2 h GSM exposure (5.7 V/m) + 2 h sham exposure, 5.) 5 days sham exposure + 5 days GSM exposure (0.56 V/m), 6.) 2 h sham exposure + 2 h CW exposure (41 V/m) and 7.) 2 h sham exposure + 2 h CW exposure (5.7 V/m) + 2 h sham exposure. Additional seedlings were sham exposed. The experiments 1, 3, 5, 6, and 7 were conducted twice. The fifth experiment was performed to simulate base station-like conditions, i.e. long lasting but low electric field strength.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 2 hours
experiment 1 and 3
Exposure 2: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 2 hours
experiment 2 and 4
Exposure 3: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 5 days
experiment 5
Exposure 4: 900 MHz
Modulation type: CW
Exposure duration: continuous for 2 hours
experiment 6
Exposure 5: 900 MHz
Modulation type: CW
Exposure duration: continuous for 2 hours
experiment 7
General information
EF values were measured with and without the petri dishes present and were found to be identical
Exposure 1
Main characteristics
Frequency 900 MHz
Type
Waveform
Exposure duration continuous for 2 hours
Additional info experiment 1 and 3
Modulation
Modulation type pulsed
Pulse width 0.576 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Chamber 10 seedlings were placed in a Petri dish (nearly 2.4 cm apart) in total darkness
Setup petri dish with seedlings was placed in the middle of the testing area (400 x 400 mm) in the GTEM cell; temperature in the GTEM cell (23°C) was measured at the beginning, during, and at the end of the exposure and did not vary more than ± 0.1°C; humidity level was 70%
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 41 V/m - measured - -
power density 560 mW/m² average over time - - -
power density 4,400 mW/m² peak value - - -
SAR 2.6 mW/kg - calculated - -
Exposure 2
Main characteristics
Frequency 900 MHz
Type
Waveform
Exposure duration continuous for 2 hours
Additional info experiment 2 and 4
Modulation
Modulation type pulsed
Pulse width 0.576 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 5.7 V/m - measured - -
power density 11 mW/m² average over time - - -
power density 86 mW/m² peak value - - -
SAR 0.049 mW/kg - calculated - -
Exposure 3
Main characteristics
Frequency 900 MHz
Type
Waveform
Exposure duration continuous for 5 days
Additional info experiment 5
Modulation
Modulation type pulsed
Pulse width 0.576 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 0.56 V/m - measured - -
power density 0.1 mW/m² average over time - - -
power density 0.8 mW/m² peak value - - -
SAR 0.48 µW/kg - calculated - -
Exposure 4
Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 2 hours
Additional info experiment 6
Modulation
Modulation type CW
Exposure setup
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 41 V/m - measured - -
power density 4,400 mW/m² average over time - - -
power density 4,400 mW/m² peak value - - -
SAR 20 mW/kg - calculated - -
Exposure 5
Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 2 hours
Additional info experiment 7
Modulation
Modulation type CW
Exposure setup
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 5.7 V/m - measured - -
power density 86 mW/m² average over time - - -
power density 86 mW/m² peak value - - -
SAR 0.39 mW/kg - calculated - -
Reference articles
  • Tkalec M et al. (2009): Effects of radiofrequency electromagnetic fields on seed germination and root meristematic cells of Allium cepa L.
  • Durney CH et al. (1979): An empirical formula for broad band SAR calculations of prolate spheriodal models of humans and animals.
  • Lin JC et al. (1973): Power Deposition in a Spherical Model of Man Exposed to I-20-MHz Electromagnetic Fields.
Exposed system:

Methods Endpoint/measurement parameters/methodology

  • growth of seedlings one week (or in experiment 5 two days) after exposure: length of epicotyl (i.e. between leaves and cotyledon), length of hypocotyl (i.e. between cotyledon and start of roots), length of roots
Investigated material:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Seedlings exposed to GSM signals with an electric field strength of 41 V/m (experiments 1 and 3) showed significantly shorter epicotyls compared to sham exposed ones. No significant differences were observed between exposure to electric field strength of 5.7 V/m (experiments 2 and 4) and the sham exposure.
However, exposure of seedlings to a weak electric field strength for five days (experiment 5) resulted in significantly shorter epicotyls and hypocotyls as well as in significantly elongated roots compared to the sham exposed seedlings.
The roots of seedlings that were exposed to CW with an electric field strength of 41 V/m (experiment 6) were significantly shorter than those of the corresponding sham exposure, while in the group exposed to CW with an electric field strength of 5.7 V/m (experiment 7), the hypocotyls were significantly shortened.
The authors conclude that effects of radiofrequency electromagnetic fields on soybean seedlings depend on electric field strengths and modulation characteristics.
Study character:

Study funded by

  • not stated/no funding

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  • Tkalec M et al. (2009): Effects of radiofrequency electromagnetic fields on seed germination and root meristematic cells of Allium cepa L.
  • Tafforeau M et al. (2002): SIMS Study of the Calciumdeprivation step related to epidermal meristem production induced in flax by cold shock or radiation from a GSM telephone.
  • Bigu-del-Blanco J et al. (1977): Effects of low-level microwave radiation on germination and growth rate in corn seeds.