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Radiochemistry. Concepts and Applications in Environmental Chemistry. Isotopes. Too heavy, too light, rarely just right. Table of Isotopes. 1998 Version, 3000+ isotopes. Properties of , ,  and . Properties of , ,  and . ALPHA BETA X-, & GAMMA

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Concepts and Applications in Environmental Chemistry


Too heavy, too light, rarely just right.

Table of Isotopes

  • 1998 Version, 3000+ isotopes

Properties of , ,  and 

Properties of , ,  and 


  • Symbol, 42He 2+, 0-1, 0-1e  and 

  • Charge +2 -10

  • Mass (kg)6.642x10-27 9.116x10-31 0

  • Velocity 0.05cup to 0.995cc


  • Relative

    Ionization 1x104 1x1021


  • Relative

    Penetrating 1 1x1021x104


Penetration Potential

Ionization of Gas

Ionization of Liquids

 Scintillation Detection

Solid-State Semiconductor Detectors

HPGe Detector StructureCANBERRA Analytical Nuclear Instruments

Ionization of Solids

 Spectroscopy with HPGe

“Ultra-Low” Background Considerations

Cosmogenic - from the cosmos


Naturally Occurring Radioactive Materials (“NORM”)

  • Cosmogenic:

    3H 7,10Be 14C 18F 22,24Na 26Al 31,32Si 32,33P35,38S 36,38,39Cl 37,39Ar 53Mn 59Ni 80Kr

  • Primordial:

    40K 50V 87Rb 113Cd 115In 123Te 138La144Nd 147Sm 148Sm 152Gd 174Hf 176Lu187Re 190,192Pt 209Bi

    232Th+daughters 235U+daughters 238U+daughters


Localized “Hot Spots”

LocationAnnual Dose(mSv/y)

  • United Arab Emirates 14

  • Radon Springs, France 16

  • Kerala Region of India 30

  • Guangdong Province, China 33

  • Morro De Faro, Brazil 70 - 140

  • Guarapari, Brazil175

  • Ramasari, Iran480

    USNRC Occupational Dose Limit50

    USNRC Limit for Members of Public20

Oklo Quarry, Gabon

Fossil Fission Reactor

  • Oklo Quarry, Gabon

    In 1972 ore deposits were found to contain significantly different isotopic compositions of certain elements than from the mean found in nature.

    142Nd normally 27% in nature, at Oklo it was <6%.

    99Ru normally ~28% in nature, at Oklo it was 13%.

    235U normally 0.72%, at Oklo it was 0.48%.

    From 87Rb/87Sr dating, Oklo deposits are 1.7E9 years old, at that time U enrichment was ~3% 235U!

Fossil Fission Reactor

  • Operated on and off at ~100kW output for 1E6 years.

  • Once the natural reactors burned themselves out, the highly radioactive waste they generated was held in place deep under Oklo by the granite, sandstone, and clays surrounding the reactors’ areas

  • Significance today with Yucca Mountain proposed national repository.

Radioactive Material is Everywhere

  • Cosmic Radiation

  • Indoor Air & Structural Materials

  • Rock & Soil Radiation

  • Water & Aquatic Food Ingestion

  • Food, milk digestion

  • Crop digestion

  • Inhalation Skin Absorption

“Reference Man” with a 70Kg. Body Mass

Sources of Radiation Exposure -UpdateRelease of NRCP No. 160 (03/03/09)

Energy Liberated can be Absorbed

  • Absorption in body tissue may result in physiological injury

  • Absorption is the principle by which detection is based.

  • The degree of absorption or type of interaction is a primary factor in determining shielding requirements.

Health Effects of Ionizing Radiation

  • Direct Effect on Cells:

    damage to DNA from ionization.

    If the cell is exposed to radiation, the probability of the radiation interacting with the DNA is very small since these critical components take up less than 0.5% of the cell volume.

    USDOE: Human Genome Project

Indirect Effect on Cells:

decomposition of water.

If the cell is exposed to radiation, the probability of interaction with cellular water is greater since water is 99.5% of the cell volume.

Radiolysis of water produces the following types of sequences:

H2O +  ray  HOH+ + e- H2O + e- HOH-

HOH+ H+ + OH*HOH- H* + -OH

OH* + OH* H2O2 (hydrogen peroxide)

Net Effect: Free radical formation

Health Effects of Ionizing Radiation

Risk Models


  • The basic tenants of ALARA are the use of time, distance, and shielding to minimize radiation exposures.

Radon Target Organ - Lungs

  • Radon (Rn) and Daughter Products (RDPs) inhaled or ingested.

  • Most of the Rn from respiration is exhaled.

  • Ingested Rn out-gasses through the lungs.

  • RDPs remain stuck to lung tissue. Po218 & Po214 emit alpha particles within the 1st hour.

Alpha Particle in the Lung

  • Alpha particles strike lung cells causing possible physical and/or chemical damage.

  • 3 fates for cell

    • Damaged & Repaired

    • Damaged, not Repaired

    • Killed

    48 hour time lapsed microscopic photograph of alpha tracks emitted from a radioactive particle of Pu-238 lodged in the lung tissue of an ape.

Iowa Radon Lung Cancer Study

  • Found excess risk of 50% for exposures that are equivalent to 15-years spent at an average radon exposure of 4 pCi/L. Overall, the risk estimates obtained in the study suggest that cumulative Radon exposure in the residential environment is significantly associated with lung cancer risk.

    Field, R.W., Lynch, C.F., Brus, C.P., Woolson, R.F., Fisher, E.F., Platz, C.E., Robinson, R.A., Steck, D.J., Neuberger, J.S. Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study, American Journal of Epidemiology, 151(11);1091-1102, 2000.

Radon Geology

  • Source

    Rn is constantly being generated by the uranium in rocks, soil, water, and construction materials derived from rocks and soil.

    Uranium is found in small concentrations throughout the earth’s crust. On average, 1 acre down to a 5 ft. depth would contain 50 lbs. of Uranium.

Radon Potential  Uranium Potential

Actual Radon Zones

Radon Migration

  • Typical Indoor Air Rn range - 1 to 1000 pCi/L.

  • Typical Soil Air Rn range - 200 to 100,000 pCi/L.

  • Dissolved Rn in Groundwater range - 100 to 3,000,000 pCi/L.

High Variability in Radon Concentration

Nuclear Generating Plants



Fuel is inexpensive

Easy to recover (in U.S. and China)


Requires expensive air pollution controls (e.g. mercury, sulfur dioxide)

Significant contributor to acid rain and global warming

Requires extensive transportation system

“Clean Coal” does not yet exist



Fuel is inexpensive

Energy generation is the most concentrated source

Waste is more compact than any source

Extensive scientific basis for the cycle

Easy to transport as new fuel

No greenhouse or acid rain effects


Requires larger capital cost because of emergency, containment, radioactive waste and storage systems

Requires resolution of the long-term high level waste storage issue in most countries

Potential nuclear proliferation issue

Every form of energy generation has advantages and disadvantages.

New NGP designs - ABWR

New NGP designs - PBMR

  • Westchester County Dept. of Labs & Research is a FRMAC partner

  • Laboratory and Personnel Assets are registered in the event of an emergency

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