SUBLETHAL EFFECT OF A 50Hz MAGNETIC FIELD ON THE ...

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16 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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SUBLETHAL EFFECT OF A
S
INUSOIDAL

MAGNETIC FIELD ON
THE
XENOPUS LAEVIS

(DAUDIN) TADPOLES
COHORTS
DEVELOPMENT


Massimo Loy
1
,
Roberta Alilla
2
, Emanuele Giacomozzi
1
,
Claudia Giliberti
3
,

Angelico Bedini
3
,
Raffaele
Palomba
3
, Livio Giuliani
3
,
Maurizio

Bonori
1
,
Ag
ostina Congiu Castellano
1


and Maurizio Severini
1


1

Dipartimento di Fisica, Università degli Studi di Roma “La Sapienza”


2

Dipartimento di Scienze Ambientali, Università degli Studi della Tuscia di Viterbo


3

Istituto
Superiore per la

Prevenzione e
la
S
icurezza
de
l Lavoro (ISPESL)

4

Istituto di Scienze dell’Atmosfera e del Clima (ISAC
-
CNR), sezione di Roma


T
he results
of a recent work

show that a long
-
term exposure of
X
enopus

laevis

tadpoles to the

saw
-
tooth

shaped

magnetic
f
ield of a television set

(a
mplitude <

25 μT
)

causes a measurable increase of
t
he
animals’ maturation times

(1)
.
This increase is not accompanied by mortality or malformations of the
exposed individuals, and can be classified among the sublethal effects of magnetic fields.
According to
Adey
(2
)
,

biological matter seems to be particularly sensitive to

pulsing electromagnetic fields. One
possible explanation

of this phenomenon could be the so
-
called window effect

(
3), i.e. particular
co
mbinations of

frequencies and small amplitudes of EM waves pr
oduce

significant biological effects.

Although

a
television set is probably the most readily available source of pulsing electromagnetic
fields
,

a living being exposed to a magnetic field

emitted

from a TV set
,

receives
its whole spectrum
whose main

harmon
ic components

fall into the ELF and VLF wave band
.

So
it is not possible to
establish which

harmonic component of the two perpendicular magnetic

fields emitted from the TV set
caused the
sublethal effect showed.

In order to

find

one or more windows in the
range of amplitude 0
-
100

μT

and frequency 50

Hz,
an

experimental system based on a solenoid as magnetic source was build
up.

It permits to choose
the

amplitude
-
frequency

combination
of the magnetic
field
,

between the
possible ones
,

that causes
the sublethal
effect

showed in (1).
H
ere we present a detailed description of
method
ology

used

and the results of

a first

series of
three
experiments
in which

tadpoles are expsosed
to a
67

μT

magnetic field
. The results showed

an
increase of
t
he animals’ maturation times

in exposing
cohort
s

like in (1),

but less
evident. This confirms that a
magnetic
f
ield

cause
s

development delay,

still
it
suggests that the
window effect

could
involve an
amplitude

small
er than that used.



REFERENCES


1
-

Severini M., Dattilo A.M., De Gaetano A., (2003)
S
ublethal effect of a weak intermittent magnetic

f
ield on the development of
Xenopus laevis

(Daudin) tadpoles. Int. J. Biometeorol. 48
:

91
-
97.

2
-

Adey W
.
R
.

(1979) Long
-
range electromagnetic field interactions at brain cell surfaces. In: Tenforde

T.
S
.

(
ed) Magnetic field effects on biological systems. Plenum, New York, 57

80
.

3
-

Ubeda A., Leal J., Trillo M., Chacon L., Jimenez M.A., Delgado J.M.R.(1983)
Pulse shape of MF

i
nfluences chick embryogenesis. J
.
Anat
.

137:

513

536
.