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CHARACTERIZATION OF RADON DAUGHTERS AND CARCINOGENESIS

Objective


A simple method for estimating the particle sizes of radon-222 daughters has been developed. The technique has been experimentally tested and produces satisfactory results (ie aerosol concentration, level of activity). This experimentation has confirmed that the routine use of the technique by biologists is satisfactory for measuring the inhaled doses in experimental animals.
FOR MANY YEARS, OUR LABORATORY HAS BEEN PROVIDING SCIENTIFIC AND TECHNICAL SUPPORT FOR THE HEALTH PROTECTION DEPARTMENT (DPS). THE LATTER HAS BUILT A DEVICE FOR EXPOSING RATS TO RADON AND ITS DAUGHTERS, THE PURPOSE OF SUCH ANIMAL EXPERIMENTS BEING TO TEST HYPOTHESES CONCERNING CARCINOGENESIS AND ENDEAVOUR TO SIMULATE THE PROCESSES THAT TAKE PLACE IN MAN.
IN ORDER TO EVALUATE MORE PRECISELY THE RISKS ASSOCIATED WITH RADON DAUGHTERS, IN PARTICULAR IN THE SUB-MICRON RANGE, IT IS NECESSARY TO ASCERTAIN THEIR GRAIN SIZE AND ELECTRICAL CHARGE. SUCH PARAMETERS ARE CLOSELY RELATED TO THE CHARACTERISTICS OF THE CARRIER GAS (RELATIVE HUMIDITY AND TEMPERATURE), THE NUMBER OF RATS PRESENT IN THE ENCLOSURE AND OTHER FACTORS; THEIR VARIATIONS HAVE NOT SO FAR BEEN SUFFICIENTLY MASTERED.
THESE EXTREMELY DELICATE MEASUREMENTS REQUIRE SOPHISTICATED TECHNICAL RESOURCES AND GREAT FAMILIARITY WITH THE METROLOGY OF SUB-MICRON RADIOACTIVE AEROSOLS.
OUR LABORATORY HAS SEPCIALIZED FOR OVER 15 YEARS IN THE PHYSICAL CHEMISTRY OF AEROSOLS. ITSEQUIPMENT MAKES IT POSSIBLE TO ASCERTAIN THE CONCENTRATION OF GRAIN-SIZE DISTRIBUTION OF AEROSOLS WITH THE AID OF THE FOLLOWING APPARATUS:
0.03 UM - 0.2 UM : DIFFUSION BATTERIES COUPLED WITH A CONDENSATION NUCLEI COUNTER (METHOD DEVELOPED AND MARKETED BY THE LABORATORY);
0.01 UM - 1 UM : ELECTRICAL ANALYSERS;
0.03 UM - 10 UM : DIFFUSION BATTERIES COUPLED WITH CASCADE IMPACTORS.
THE ELECTRICAL CHARGE OF THE AEROSOLS MAY BE DETERMINED WITH THE AID OR ELECTRICAL MOBILITY ANALYSERS.

IN THIS STUDY WE INTEND TO CHARACTERIZE THE GRAIN-SIZE DISTRIBUTION OF RADON DAUGHTERS WITH THE AID OF THE ABOVE-MENTIONED APPARATUS, FOR DIFFERENT EXPERIMENTAL CONDITIONS (RELATIVE HUMIDITY, RADON CONCENTRATION, NUMBER OF RATS PRESENT IN THE ENCLOSURE, DUST DEPOSITION RATE, ETC.).

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Commissariat à l'Energie Atomique (CEA)
Address
Centre D'études De Fontenay-aux-roses
92265 Fontenay-aux-roses
France