Agent Name

Neptunium

CAS Number

7439-99-8

Formula

Np

Major Category

Physical/Radiation

Category

Radionuclides

Description

A man-made, radioactive metal with a melting point of 577 degrees C; [Merck Index # 6471]

Sources/Uses

Neptunium is usually produced in nuclear reactors as a byproduct of plutonium production. There are no commercial uses, but Np-237 has been used in instruments to detect neutrons. Of the 17 known isotopes, Np-237 is the most prevalent at DOE sites such as Hanford. [Argonne]

Comments

Neptunium is toxic after ingestion or inhalation. Some of the isotopes also have a small risk of generating significant external radiation (Np-236 and Np-237). [Argonne] Most Important Radionuclide: Np-237 Half-Life: 2.1 million years Effective Half-Life: 200 years Specific Activity: 0.00071 Ci/g Decay Mode: Alpha GI Absorption: 0.05% Lung Clearance Half-Time: Weeks (10-100 days) for all compounds; Critical Organ: Bone Internal Toxicity: Very High Annual Limit on Intake: 0.000004 mCi Average Radiation Energy (MeV): Alpha 4.8; Beta 0.070; Gamma 0.035 [Argonne] [See Glossary for references.] See "Radiation, ionizing."

Exposure Assessment
Half Life

Biological half-life: 20 years (liver) and 50 years (bone); [ANL Radiological Fact Sheets]

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

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Chemical Information

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Related Information in HazMap
Other Information

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