Radioactivity measurements in water see also Chapter

Standard values for tolerable radioactivity levels in water have been agreed upon between the various international organizations and also established by way of legislation in the various countries. Thus, for example, the tolerable level for the total a-activity is 0.1 Bq/1 corresponding to 2.7 pCi/1. 

These standard values are extremely low and are designed to totally preclude any risk to human beings and animals caused by radionuclides in water. If these total values are exceeded, this does not however mean that the water would be unsuitable for use by humans and for animals, but rather that it is then necessary to determine the radionuclides responsible for the radioactivity in the water. Radium 226 has become an established tracer for a -activity and strontium 90 (under certain circumstances also iodine 129) for -activity. 

General mention should be made of the a-emitters radium 226, polonium 210, radon (radioactive inert gas) 220 and 222, uranium isotopes and thorium isotopes. 

B -emitters radium 228, lead 210, strontium 89, strontium 90, iodine 129, carbon 14 and tritium. 

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