Return of the Radium Hound

Mayo Clinic, September 3, 1942. Sometime between 8:30 and 9:30 PM, three 50 mCi radium needles were accidentally flushed down a toilet. On the plus side, there were no NRC regulations at that time requiring that radioactive materials going into a sewer be soluble or readily dispersible. Unfortunately, the hospital authorities didn't know what had happened to their lost sources and an extensive search was mounted. Alas, the search was fruitless. It was clearly time to bring in the heavy hitters, and our old friend Prof J.W Buchta of the Physics Department of the University of Minnesota was contacted. In a possible attempt to repeat his earlier triumph in Sioux Falls (see In the Groove), Buchta searched the city hog farm to which the hospital garbage had been hauled. Finding nothing there, he correctly concluded that the sources must be somewhere in the sewer lines leaving the hospital. There was a problem though. The lines were 10 to 12 feet below street level. Too low for the sources to be detected from above ground.

With considerable effort, a custom-built scraper was dragged though the sewer lines and two of the tubes were recovered. Two down. One to go.

It seemed certain that the third tube was also in the sewer, but stuck. Before it could be dislodged it would be necessary to pinpoint its exact location. The first thought was to drag a GM through the sewer line but this was wartime and the necessary length of cable was unavailable. Another thought was to deploy a line of waterproofed dental film packets strung in a line, but the sewer was 2 miles long making this approach somewhat impractical. The next idea was to run 8 mm movie film along the sewer and develop this. Before this was attempted they decided to pull a Lauritsen electroscope through section of sewer and read it. The electroscope was waterproofed with what was described as a "rubber stocking" wrapped in felt and housed in a capped iron pipe about 1 foot long. By pulling or pushing the detector a short distance and checking the position of the fiber, they quickly traced the source to a section of sewer line approximately half a block from the point where the line left the building. The scraper was put back to work, and source recovered some 54 days after its loss.

[This is the earliest situation that I am aware of in which a radiation detector was actually pulled through a sewer line.]

Monroe, NC, winter 1935. The hospital safe was empty—the two 12.5 mCi radium needles that should have been inside weren’t. Time to call for the services of a radium hunter Robert Taft in Charleston. He quickly built a few extra hounds (electroscopes) performed a quick calibration and he and his assistant Ben Heyward, "sallied forth to Monroe".

It was soon determined that the sources had probably made their way to the city dump. Gadzooks! North Carolina frowns on the disposal of radioactive materials at an undesignated site. So, bright and early the next morning, Taft, his assistant and their pack of radium hounds found themselves at the dump. With help from the city manager H.L Burdette, the probable location was narrowed down to a 40 by 200 foot area. Taft used little yellow flags into blocks 8 ft by 6 ft. The five electroscopes were charged, and placed at grid marks at one end of the gridded area five minute counts measurements were performed. The electroscopes were recharged and advanced to the next line of markers. The intrepid surveyors went up and down embankment, parts of which were afire and other parts covered with frozen puddles of water. Around fire, over ice, through brambles and scrap iron. At times the instruments had to be covered with tin cans to protect them from the ashes and dew. At one time a Chevrolet crankcase was scavenged to float the electroscope on the ice. Another time a high heel shoe was used to prop up the hound on a steep incline Then, quoting the Associated Press account, "At 11:30, one detector responded. Radium was near. All the detectors were brought into play. The ‘pack was in full cry.’ Then the searchers started to dig. Each scoopful was tested and finally one was ‘hot.’ It was sifted and at noon the first fragment of the precious substance was recovered." Amazing. All of this accomplished without the use of non-parametric, or any other kind of, statistics!

The Associated Press account went on to comment that the first thing Taft did after finding the radium was to take a bath. Most of us who have done similar surveys know that this was unlikely. As Taft later admitted, the first thing he did was take a drink.

[To my knowledge, the preceding is the earliest application of a grid system in a radiological survey.]

References

• Taft, R.B. Radium—lost and found. Second ed. Walker, Evans & Cogswell Co.; 1946.
• Williams, M.M.D. Recovery of radium tubes from sewer. Radiology 42: 478-482; 1943.