Isotopes

The Navy lists 33 isotopes in the "radionuclides of concern" portion of the historical radiological assessment. Four appear most frequently at impacted sites.

The report lists each isotope's half-life, which is the amount of time it takes for its potency to degrade to half its original amount. The measurement provides a starting point for understanding what contaminants could still be present at the shipyard.

Radionuclides of Concern

| Nuclide: half-life |

Ac-227 (Actinium): 21.8 Years | Am-241 (Americium): 432.7 Years | Am-243: 7,370 Years | Ba-133 (Barium): 10.5 Years | Bi-207 (Bismuth): 32 Years | C-14 (Carbon): 5,715 Years | Cl-36 (Chlorine): 3.01 x 10₅ | Cm-244 (Curium): 18.1 Years | Co-60 (Cobalt): 5.27 Years | Cs-137 (Cesium): 30.1 Years | Eu-152 (Europium): 13.5 Years | Eu-154: 8.6 Years | Gd-152 (Gadolinium): 1.1 x 10₁₄ Years | H-3 (Tritium): 12.3 Years | In-115 (Indium): 4.4 x 10₁₄ Years | K-40 (Potassium): 1.27 x 10₉ Years | Nb-94 (Niobium): 2 x 10₄ Years | Ni-63 (Nickel): 100 Years | Np-237 (Neptunium): 2.14 x 10₆ Years | Pb-210 (Lead): 22.6 Years | Pu-238 (Plutonium): 87.7 Years | PU-239: 2.41 x 10₄ Years | Ra-226 (Radium): 1,599 Years | Sr-90 (Strontium): 28.78 Years | Tc-97 (Technetium): 2.6 x 10₆ Years | Tc-99: 2.1 x 10₅ Years | Th-232 (Thorium): 1.4 x 10₁₀ Years | Ti-44 (Titanium): 67 Years | Tl-204 (Thallium): 3.78 Years | U-233 (Uranium): 1.59 x 10₅ Years | U-235: 7.04 x 10₈ Years | U-236: 2.34 x 10₇ Years | U-238: 4.478 x 10₉ Years