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  • Section 9 Sources of Radiation to the Human Population Answers and Feedback

  • Section 9 Sources of Radiation to the Human Population (NCRP 160) Answers and Feedback 

    1. ANSWER:  A
    FEEDBACK: At the time of the Three Mile Island accident, it was estimated that the number of cancer deaths due to the release of radioactive materials was about 0.5. The closest and correct option is A. 

    2. ANSWER: A
    FEEDBACK: The excess cancer risk estimated by the UNSCEAR and BEIR V committees was 8%/Sv, based on the data from the Japanese survivors. However, the Japanese survivors experienced an acute exposure. The ICRP uses a dose and dose-rate reduction factor (DDREF) of 2, so that the estimate of cancer risk at low doses and low dose rate, applicable to the radiation protection of a working population, is 4%/Sv. The correct option is A. 

    3. ANSWER: A-TRUE, B-TRUE, C-TRUE, D-TRUE
    FEEDBACK: The total number of excess malignancies attributable to radiation at Hiroshima and Nagasaki is about 600. Option A is true. There was an increase in leukemia and many solid tumors, including those of the breast. Option B is true. Exposure in utero led to an increased incidence of reduced head diameter and mental retardation. Option C is true. While there is a trend, there was no statistically significant increase in hereditary (genetic) effects in the first-generation children of persons exposed. Option D is true.

    4. ANSWER: 1-D, 2-C, 3-A, 4-B
    FEEDBACK: The effective dose from average background radiation, including radon, for the United States is about 3 mSv per year. D matches with 1. Once a pregnancy is declared, the NCRP dose limit to the conceptus is 0.5 mSv per month. Until a pregnancy is declared, there are no special dose limits other than those applicable to any radiation worker. C matches with 2. The effective dose received in flying across the North Atlantic in a commercial jetliner is about 0.05 mSv. This is due to the cosmic radiation at the altitude of about 35 ,000 feet. A matches with 3. The genetically significant dose (GSD) is the dose that if given to everyone in the U.S. population would result in the same number of mutations as would the actual variable dose received by part of the population during medical irradiation. The GSD is about 0.25 mSv. B matches with 4. 

    5. ANSWER: A-TRUE, B-TRUE, C-TRUE, D-FALSE, E-TRUE
    FEEDBACK: Radon tends to accumulate in the basement of a house as it seeps in from rocks and soil. This is particularly true in winter when the house is heated and the pressure inside is a little less than that outside. This draws radon into the house. In the outside air, radon dissipates. Option A is true. The BEIR VI best estimate of lung cancer deaths from radon was 15,400 to 21,800 per year, depending on which model is adopted. This is about 10% of the lung cancer deaths per year, which were about 157,990 in 2003 in the United States. Option B is true. Two of the progeny of radon emit energetic alpha particles, which are thought to be the cause of lung cancer. Option C is true. When radon decays into solid progeny, it does so with a half-life of about 3 days. Option D is false. The parent is indeed radium. Option E is true. 

    6. ANSWER: A-TRUE, B-TRUE, C-TRUE, D-FALSE, E-FALSE
    FEEDBACK: Radon is a naturally occurring radioactive gas that seeps out of the ground into mines and the basements of homes. Option A is true. Radon constitutes about 55 % of the effective dose to the U.S. population, which is about double that from medical x rays. Option B is true. In the United States, the action level for radon (the maximum concentration in the lived-in area of a house above which modifications to the building are recommended) is 4 pCi/L. This is lower than the action levels in Canada and Europe. Option C is true. The half-life of radon is about 3 days; it is radium that has a half-life of about 1,600 years. Option D is false. Two of the progeny of radon emit energetic alpha particles, which are thought to cause lung cancer. Option E is false.  

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Discounted Dues: Eligible North American Countries 
Belize
Costa Rica
Dominican Republic
El Salvador
Grenada
Guatamala
Haiti
Honduras
Jamaica
Netherlands Antilles
Nicaragua
Panama
St.Lucia
St. Vincent & Grenadines
Country    Country    Country 
Afghanistan   Grenada   Pakistan
Albania   Guatemala   Papua New Guinea
Algeria   Guinea   Paraguay
Angola   Guinea-Bissau   Peru
Armenia   Guyana   Phillippines
Azerbaijan   Haiti   Rwanda
Bangladesh   Honduras   Samoa
Belarus   India   Sao Tome & Principe
Belize   Indonesia   Senegal
Benin   Iran   Serbia
Bhutan   Iraq   Sierra Leone
Bolivia   Jordan   Solomon Islands
Bosnia & Herzegovina   Jamaica   Somalia
Botswana   Kenya   South Africa
Bulgaria   Kiribati   South Sudan
Burkina Faso   Korea, Dem Rep (North)   Sri Lanka
Burundi   Kosovo   St Lucia
Cambodia   Kyrgyzstan   St Vincent & Grenadines
Cameroon   Laos\Lao PDR   Sudan
Cape Verde   Lesotho   Swaziland
Central African Republic   Liberia   Syria
Chad   Macedonia   Tajikistan
China   Madagascar   Tanzania
Colombia   Malawi   Thailand
Comoros   Maldives   Timor-Leste
Congo, Dem. Rep.   Mali   Togo
Congo, Republic of   Marshall Islands   Tonga
Cote d'Ivoire   Mauritania   Tunisia
Djibouti   Micronesia, Fed. Sts.   Turkmenistan
Dominica   Moldova   Tuvalu
Domicican Republic   Mongolia   Uganda
Ecuador   Montenegro   Ukraine
Egypt   Morocco   Uzbekistan
El Salvador   Mozambique   Vanuatu
Eritrea   Myanmar   Vietnam
Ethiopia   Namibia   West Bank & Gaza
Fiji   Nepal   Yemen
Gambia, The   Nicaragua   Zambia
Georgia   Niger   Zimbabwe
Ghana   Nigeria    

Legacy Collection 2
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Tier 1

  • Bed count: 1-400
  • Associate College: Community, Technical, Further Education (UK), Tribal College
  • Community Public Library (small scale): general reference public library, museum, non-profit administration office

Tier 2

  • Bed count: 401-750
  • Baccalaureate College or University: Bachelor's is the highest degree offered
  • Master's College or University: Master's is the highest degree offered
  • Special Focus Institution: theological seminaries, Bible colleges, engineering, technological, business, management, art, music, design, law

Tier 3

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  • Research University: high or very high research activity without affiliated medical school
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Tier 4

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  • Medical School: research universities with medical school, including medical centers

Tier 5

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  • Research Institute: government and non-government health research
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