What the document says
This is a joint report from the Los Alamos Scientific Laboratory of the University of California and the Atomic Energy Project of the University of Rochester School of Medicine and Dentistry. The work began under the supervision of the Manhattan Engineer District and was finished under contract for the Atomic Energy Commission. The first tracer study, meaning a study using a small measured amount of radioactive material, was initiated April 10, 1945. The report gives final results for twelve plutonium tracer cases. Data from Berkeley and Chicago groups brings the total to sixteen cases, with added observations on three Los Alamos personnel who absorbed plutonium at work.
The report states that this information could be obtained only by giving small tracer amounts of plutonium to people with a relatively short life expectancy. As a rule the subjects chosen were past forty-five and had chronic disorders that made survival for ten years highly improbable, so late radiation effects would be avoided and tissue could be obtained within a few months or a few years. Ten of the twelve were past forty-five. One was eighteen. Ten of the twelve were cared for in the metabolic ward of Strong Memorial Hospital, where urine, feces and blood were collected on a set schedule.
Single doses of 5 to 100 micrograms produced no acute subjective or objective clinical effects. Blood levels fell fast, from 35.7 per cent of the dose four hours after injection to 0.3 per cent at thirty days. Using vertebra, sternum and whole rib as average bone, the report estimates 65.7 per cent of the dose in the skeleton of a 70 kg man. Liver deposition averaged 23.1 per cent of the dose in a 1700 gram liver, higher than animal work predicted. Skeleton and liver together account for 90 per cent or more of the plutonium in the body.
Key points
- 01Twelve subjects were injected. Their data was combined with cases from other investigators for sixteen total, plus three Los Alamos workers who absorbed plutonium on the job.
- 02Subjects were picked for short life expectancy: as a rule past forty-five and chronically ill, so that survival for ten years was highly improbable.
- 03By the time of the report, about five years after the first study, five of the twelve subjects had died of their diagnosed illness. Autopsy and tissue samples came from only three of the five.
- 04Blood plutonium dropped quickly after injection: 35.7 per cent of the dose at four hours, 15.7 per cent at one day, 1.2 per cent at ten days.
- 05Plutonium held in the liver appeared to last far longer in man than in animals, with a retention half-time of one year or greater against 40 to 60 days for rats.
- 06The National Bureau of Standards subcommittee had set a tentative maximum permissible body content of 0.5 micrograms, adopted by the AEC Division of Biology and Medicine.
From the original
Thirty days after injection the blood concentration of plutonium read from the curve in Fig. 3 was only 0.3 per cent of the injected dose in the total blood volume.
Source: U.S. Department of Energy, OpenNet declassified document archive, OSTI ID 16290872. The summary is written from the document’s own text. Old scans can be hard to read, so check the original for anything you plan to cite.