Mangano and Rancho Seco

[Holloway3@aol.com]

I have just read the Mangano paper about the claimed health effects due to 
the operation and subsequent closing of the Rancho Seco reactor.  I have not 
had time to thoroughly examine his paper but I want to point out one instance 
of what is a less than complete examination of the situation by Mangano.  He 
makes the following statement on the first page of his paper:

"The opening of Rancho Seco corresponds with an increase of local "in vivo" 
radioactivity.  Estimates of dietary intake of Strontium-90 in urban west 
(mostly San Francisco) adults were made from 1961 to 1982, based on 
post-mortem measurements of human bone.  In the early 1970s, Sr-90 
concentrations were falling, but from 1974 to 1980, the rate remained at or 
above 3.0 pCi of Sr-90 per gram of calcium in bone (figure 1)." 

Mangano then goes on to suggest that the Sr-90 levels in San Franciso were 
affected by emissions from Rancho Seco.  Figure 1 of his paper does indeed 
show a minor spike of Sr-90 during 1974 - 1975.  But Mangano fails to 
mention, perhaps because he does not know, of an alternative explanation for 
increased 
Sr-90 in the environment during the period 1973 to 1975.  The Chinese 
exploded two atmospheric nuclear tests during that period.  The first was on 
March 18, 1972 and the second was on June 27, 1973.  This radioactive debris 
was detected in the United States within a week or so after each explosion.  
I measured some of it in Arkansas in 1973 and 1974.  However, the 1973 test  
injected most of the radioactivity into the stratosphere so that much of it 
did not return to earth until the first half of 1974, when it was easily 
measured in the United States.   This debris from the 1973 explosion could 
easily account for the slight peak of Sr-90 in bone mentioned by Mangano.  
The fact that he does not mention this important source of radioactivity 
during the time period does not inspire confidence in his conclusions. 

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