Study type: Medical/biological study (experimental study)

Metamorphosis delay in Xenopus laevis (Daudin) tadpoles exposed to a 50 Hz weak magnetic field med./bio.

Published in: Int J Radiat Biol 2010; 86 (1): 37-46

Aim of study (acc. to author)

The study was performed to prove that exposure to a relatively weak extremely low frequency magnetic field retards tadpoles development.

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).



Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for 60 days

Exposure 1

Main characteristics
Frequency 50 Hz
Exposure duration continuous for 60 days
Exposure setup
Exposure source
Setup 1.6 m long solenoid with an internal diameter of 0.4 m, equipped with a wooden board along its axis without direct contact to the walls to support the glass aquariums; aquariums positioned symetrically to the solenoid's center
Measurand Value Type Method Mass Remarks
magnetic flux density 63.9 µT effective value measured - minimum value
magnetic flux density 76.4 µT effective value measured - maximum value

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 long-term exposure (about 60 days) of cohort tadpoles to an extremely low frequency magnetic field of 50 Hz caused a significant reduction of tadpoles mean developmental rate of 0.05 stages/day during the whole larval stage, that brought about an increase of 2.5 days in mean maturation time of exposed tadpoles compared to controls. Maturation rates of exposed and control tadpoles changed during the course of the maturation period. Mortality, malformations or teratogenic effects were not observed in exposed matured tadpoles.
The authors conclude that a long-term exposure of Xenopus laevis tadpoles to a relatively weak 50 Hz magnetic field causes a sublethal effect that slows down their larval developmental rate and delays their metamorphosis.

Study character:

Study funded by

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