Study type: Medical/biological study (experimental study)

Delayed maturation of Xenopus laevis (Daudin) tadpoles exposed to a weak ELF-MF: sensitivity to small variations of magnetic flux density. med./bio.

Published in: Non-thermal effects and mechanisms of interaction between electromagnetic fields and living matter Mattioli 1885, 2010: 247-260, ISBN 9788862611664

Aim of study (acc. to author)

The data of a previous experiment (Severini et al. 2010) are re-processed to evaluate the sensitivity of tadpole developmental rate to small variations of weak extremely low frequency magnetic flux densities (in two different aquariums E1 and E2).

Background/further details

Two cohorts of 35 tadpoles were exposed during their immature period (whole larval stage) at two different magnetic flux densities and two comparable cohorts served as controls. The experiment was replicated three times (with litters from three different frog pairs).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 22 days

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Exposure duration continuous for 22 days
Exposure setup
Exposure source
Setup 1.6 m long solenoid with a diameter of 0.4 m; aquariums E1 and E2 placed on a wooden board in the center of the solenoid
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 70.1 µT mean calculated - +/- 0.3 µT in the center of E1
magnetic flux density 72.4 µT mean calculated - +/- 0.4 µT in the center of E2
magnetic flux density 63.9 µT minimum measured - E1
magnetic flux density 76.4 µT maximum measured - E1
magnetic flux density 68.4 µT minimum measured - E2
magnetic flux density 76.4 µT maximum measured - E2

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

The data showed that tadpoles of aquarium E2 under the stronger field matured with a significant delay of 2.5 days with respect to tadpoles of aquarium E1 under the weaker field. This delay was clearly caused by exposures to two slightly different ranges of magnetic flux densities. The results suggest the existence of a field threshold around 70 µT in controlling the animal's developmental rate.

Study character:

Study funded by

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