RSH Data & Documents

"Low Level
Radiation Health
Effects: Compiling
the Data"

Revision 2
March 30, 1999
by Radiation, Science, and
Health, Inc.,
Edited by J. Muckerheide

1.3
Plant and Animal Biology

References

"Lorenz and co-workers (Lorenz et al 1954) found an increased after-survival of mice that had been exposed throughout adult life to 0.11 r of gamma rays daily. The increase was small and hardly significant, but they confirmed it in a subsequent test. Carlson and co-workers (Carlson et al 1957; Carlson and Jackson 1959) found significantly increased after-survival in two independent experiments on rats exposed to about 1 r daily throughout adult life. It was observed by Sacher and Grahn (1961) that in three different strains of mice there was no reduction in mean after-survival at daily doses of 5 r/day. Since 5 r/day results in an accumulated dose of about 2500 r, which is expected to produce in excess of 20% life shortening, these instances of survival significantly in excess of expectation must be considered to be cognate to the previous instances of increased mean after-survival. However, several other mouse strains studied by Grahn and Sacher showed about the expected amount of decrease of mean after-survival at 5 r/day, and other investigators working under similar conditions have failed to find evidence of excess survival."

"Increased life expectation has also been found in insects exposed to x or gamma rays daily throughout adult life. The exposure levels required for this effect in insects are on the order of hundreds or thousands of roentgens per day. Figures 2 and 3 show the nature of this effect in fruit flies (Sacher unpublished work). Each group consists of 200 to 1000 flies, and increased mean after survival was produced by exposures ranging from 1.5 to 3 kr/day throughout adult life.…Similar results have been obtained with flour beetles given some hundreds of roentgens per day of X or gamma rays (Davey 1919 and Cork 1957)."

Figure 2             Figure 3