is on land, it goes through a similar process. is taken uv by plants and grass, Strontiun 90, for example, The grass is then eaten by cows, 'thich manufacture milk containing strontium, Human heinas then drink the mil and consequently some of this contamination will reside in the bones of their bodies, 3 This state of affairs would be extremely dangerous to man if it were not for one factor, which Dr. Neuman also mentioned: "No counterfeit is perfect, however, and there are sliqht differences in properties between strontium and calcium which permit our regulating systems to select calcium preferentially, or to discriminate against (p. 710) the less desirable strontium." The same is true for olants, animals, and fish. For example, if we started out with $109 worth of strontium fallout on the ground in a small area around a rlant, the plant might absorb $60 worth. ‘The milk from the cow that ate the plant would only contain $20 worth of the strontium. The man who drinks the milk would, perhaps, retain at the end only $5 worth of the While the proportions are not real and only Original $100 worth of strontium, used as an examole, they illustrate what is called the "discrimination factor"--a factor which means that part of the counterreit chemical is rejected all along the route of the food chain. Despite this rejection factor, however, worldwide stratospheric fallout and local fallout still present considerable threats to the health of the average person and future generations. sr?9 gives off beta particles. speed in nature, Although these particles are high- they are also relatively small in mass, or size and weight; cannot travel far through matter; and can be stopped easily by a layer of clothing or the upper layers of the skin. However, when they enter the body and reside in the bone close to the marrow, they can, in sufficient quantities, do great damage, 29 é = ¢ ~