[15]A picocurie is one trillionth of a curie; a curie is the basic unit of intensity of radioactivity, approximately equal to that in 1 gram of radium.

[16]For more about these studies, see Fallout from Nuclear Weapons Tests, a companion booklet in this series.

[17]Information on this research is found in Radioactive Wastes, a companion booklet in this series.

[18]The lake, drained in 1955, makes an interesting natural basin in which residual radionuclides are used in studies of mineral cycling.

[19]A roentgen is a unit of exposure to radiation, measuring the alteration of the atoms (ionization) of the radiated tissues. The rat dosages compare with recommended limits of exposure to man-made radiation for average individuals in human populations of an amount that approximates 0.5 roentgen per year.

[20]The area where highest readings were obtained in the survey. These studies are described in more detail in Whole Body Counters, a companion booklet in this series.

Transcriber’s Notes