Section 9 Sources of Radiation to the Human Population

2. The International Commission on Radiological Protection (ICRP) estimates of the total number of cases of cancer of all types produced by a total body exposure of a working population to 1 Sv of low-LET radiation at a low-dose rate is closest to __________.
A. 4 in 100
B. 4 in 1,000
C. 4 in 10,000
D. 4 in 100,000

3. Which of the following statements characterize findings in the study of the atomic bomb survivors in Hiroshima and Nagasaki? (Select all that apply.)
A. Less than 2,000 excess radiation-induced malignancies were found.
B. There was an increased risk of radiation-induced breast cancer.
C. There was an increased incidence of mental retardation in children exposed in utero.
D. No statistically significant excess heritable effects in children of those exposed were found.

4. For each of the following quantities (1–4), match the dose (in millisieverts) (A–D).

1. Average background radiation in the United States, including radon
2. Dose limit per month (NCRP) to an occupationally exposed worker who has declared her pregnancy
3. Dose received in flying across the Atlantic in a commercial jetliner
4. Genetically significant dose from medical radiation in the United States
A. 0.05
B. 0.25
C. 0.50
D. 3 3.0

5. Which of the following statements correctly describe radon? (Select all that apply.)
A. Concentrations are higher in the basement of a house than outside.
B. The BEIR VI committee estimates that radon is the cause of 10% of lung cancer cases in the United States.
C. Decay of radon involves emission of alpha particles.
D. The half-life of radon is 1,600 years.
E. The parent element of radon is radium.

6. Which of the following statements characterize radon? (Select all that apply.)
A. Radon is a naturally occurring radioactive gas.
B. Radon contributes a larger average effective dose to the U.S. population than do medical x–rays.
C. The action level of radon recommended by the EPA is 4 pCi/L.
D. The half-life of radon is 1,600 years.
E. The effective radiation emitted by radon daughters is in the form of gamma rays.

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