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Politics : Depleted Uranium -- Ignore unavailable to you. Want to Upgrade?

To: maceng2 who wrote (11)	9/28/2003 3:48:25 PM
From: maceng2	Respond to of 55

How Much Depleted Uranium Can Someone Be Exposed to Before the Limits Are Reached? ---------------------------------------------------------- NRPB > FAQ > Depleted Uranium > nrpb.org ---------------------------------------------------------- This depends on the route of intake into the body, and on various assumptions about the size of the aerosol and solubility in the lungs and gut. For insoluble compounds, the material will tend to remain in the lungs for longer, and so the principal damage would be irradiation of the lungs. For more soluble material, the DU would be absorbed more quickly from the lungs into the blood stream where about 10% of it would initially concentrate in the kidneys. The following table shows how much would have to be inhaled or ingested to lead to a dose of 1 mSv (radiation dose limit) or alternatively to lead to a kidney concentration of 3 µg per gram of kidney (chemical toxicity limit). These values have been calculated with the biokinetic models currently recommended by the ICRP. Route of intake Intake [(mass) leading to a kidney concentration of 3 µg per gram][Intake (mass) leading to a dose of 1 mSv] inhalation of reference 'moderately soluble' aerosol [230 mg][ 32 mg] inhalation of a reference 'insoluble' aerosol [7,400 mg] [11 mg] ingestion of a reference 'moderately soluble' DU compound [400 mg][1,500 mg] ingestion of a reference 'insoluble' DU compound [4,000 mg][8,800 mg] In order to express these amounts in becquerels, it should be noted that 1 mg of DU corresponds to about 15 Bq. It should also be borne in mind that the amounts required to give a kidney concentration of 3 µg per gram would be larger if the intake was given over a longer period of time since it would give the kidneys more time to excrete the DU. It can be deduced from the table that, for ingestion of DU, the chemical toxicity limit of 3 µg per gram of kidney tissue needs a smaller intake than the radiological limit (for a member of the public) of 1 mSv. For inhalation of a DU aerosol, the reverse is the case.