Auteurs

Cammaerts MC, Debeir O,  Cammaerts R. 2011. Changes in Paramecium caudatum (Protozoa) near a switched-on GSM telephone. Electromagn Biol Med 30: 57-66.

Background
Many studies have been conducted on the possible negative impact of electromagnetic waves on living animals and these waves are increasingly recognized as severely perturbing their orientation, communication, and physiological functions. However, not much is known about how animals avoid these effects.

Objective
The objective of this study was to determine the effects of exposure to a 900 MHz GSM telephone on the cytological structures of the protozoa Paramecium caudatum and how negative effects can be avoided.

Methods
Approximately 3 ml of P. caudatum culture (containing a few hundred individuals) were placed in a small glass Petri dish and were exposed to a phone emitting electromagnetic waves at a frequency of 900 MHz. The phone emitted a power intensity of approximately 2 watts in 30 s cycles and the protozoa were placed at a distance of 100 m from the antenna. P. caudatum were either exposed for 2 min at least four times (the authors noted that if protozoa were exposed for more than 2 min they would either die or encyst) or were subjected to a sham exposure and both quantitative and qualitative observations were taken. For quantitative observations, the trajectories of the animals were observed and measured under a stereomicroscope and the movements of the animals were recorded under a light-transmission microscope provided with a webcam linked to a computer. For qualitative observations, the morphological and physiological characteristics of 20 protozoans maintained under each of the two experimental conditions were recorded.

Results
Individuals exposed to electromagnetic waves moved more slowly and more sinuously than individuals exposed to the sham treatment. When positioned next to the phone, P. caudatum often changed their direction of movement. They also seemed to have difficulties swimming and their trajectories were more helicoid than under normal conditions. Their physiology was also affected. During exposure they became broader, their cytopharynx appeared broader, their pulse vesicles had difficulty in expelling their content outside the cell, their cilia moved less efficiently, and trichocysts became more visible. These effects disappeared however, within 5 min of being removed from exposure.

Interpretation and Limitations
The movement and physiology of P. Caudatum were both affected by short-term exposure to 900 MHz electromagnetic waves. The authors hypothesize that the protozoans’ difficulties in moving may result from a less efficient beating of the cilia and that the different appearance of the cells including that of the cytopharynx, may be a consequence of the slower functioning of the pulse vesicles. The GSM effects may be due to damages in the cellular membrane and the authors note that their results are consistent with the effects seen in other studies on rats and ants. The main limitations of this study are that the sample size was at times small (e.g. 20 animals for the qualitative experiment), and that because this study was conducted in single-cell organisms the results are difficult to extrapolate to more complex organisms and humans.

Conclusions
This study suggests that exposure to electromagnetic waves is associated with changes in patterns of movement and physiology in P. Caudatum  and may be due to malfunctioning or damage to the cellular membrane.

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