"Low Level
Radiation Health Effects: Compiling  the Data"

Revision 1
March 19, 1998

 
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.3
Animal & Plant Biology

1.3.2
Lower-Order Animals

References

Professor Emeritus Dr. H. Planel reports (1987) on research (at the Laboratoire de Biologie Medicale in France), on paramecia, that:  In cultures placed in two identical chambers, the shielded chamber surrounded by a Pb wall, 5 or 10 cm thick, the cell growth rate of shielded cultures is lower than that of controls: the thicker the Pb shielding device, the more obvious the effect... Yearly dose rates... were 1.75 mGy in the control chamber and 0.3 mGy in the 10-cm Pb shielded chamber. This stimulatory effect of background radiation is confirmed by several complementary experiments.

Planel reports further that similar results are obtained on cyanobacteria, showing that: "Shielding results in a lower cell growth rate (Fig. 8); this growth inhibition disappears when shielded cultures are simultaneously irradiated. Dose rates per year were 1.49 mGy in the control chambers, 0.27 in the shielded chamber, and 1.59 in the shielded chamber including a thorium nitrate source. Cell proliferation is stimulated when cultures are irradiated at a dose rate of 20.90 mGy/y."

In the abstract, Drs. J.P. Soleilhavoup, H. Planel and colleagues report (1975) that: "Paramecia cultures placed at 3800 meter altitude, show a proliferating activity acceleration if we compared them to control cultures placed at low altitude under the same environment conditions. These results confirm the cosmic irradiation influence upon the activating effect produced by the natural ionizing radiations on living organisms."

Dr. Hugh F. Henry, of the Oak Ridge National Laboratory, discusses (1961) gamma-ray effects on flour beetles: "Data obtained by gamma-ray exposure of the flour beetle also indicate the effects of large and small radiation doses. (Cork 1957) A single dose of about 3,000 r produced an increased life span; a single dose of 20,000 r was the LD-100 dose. Similarly, chronic daily doses of about 100 r produced life-lengthening, although a few of the control animals were the last survivors. Even at the higher doses of about 11,000 to 15,000 r, there were initial casualties, but the survivors showed a lower casualty rate"