Radionuclides in water

Depending on the origin of the water, the following radionuclides may be important  

Carbon 14, phosphorus 32, sulphur 35, cobalt 60, strontium 89 or strontium 90, yttrium 90, ruthenium 106, silver 110, iodine 131, caesium 137, barium 137, barium 140, cerium 144, 

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Li Y-H, Santschi PH, Kaufman A, Beraiinger LK, Feely HW (1981) Natural radionuclides in waters of the New-York Bight. Earth Planet Sci Lett 55 217-228... 

Clulow, F.V., M.A. Mirka, N.K. Dave, and T.P. Lim. 1991. 226Ra and other radionuclides in water, vegetation, and tissues of beavers (Castor canadensis) from a watershed containing U tailings near Elliot Lake, Canada. Environ. Pollut. 69 277-310. 

HEW and the Federal Radiation Council have been assisted by the technical recommendations of the National Council on Radiation Protection and Measurements. The NCRP has been particularly involved in developing the concept and the values of the maximum permissible concentrations (MPC) of radionuclides in water, which values could be applied to foods (16). [The National Council on Radiation Protection and Measurements was created on July 14,1964, by Public Law 88-376. The council is the successor to the unincorporated association which was known as the National Committee on Radiation Protection and Measurements and which for 35 years served as the focal point for developing radiation protection philosophy and standards in the United States. The current address of the NCRP is 4201 Connecticut Ave., N.W., Suite 402, Washington, D. C.]... 

Second, generic and site-specific assessments of near-surface disposal facilities for radioactive waste have shown that allowable doses to hypothetical inadvertent intruders usually are more restrictive in determining acceptable disposals than allowable doses to individuals beyond the boundary of the disposal site. This conclusion is based on predictions that concentrations of radionuclides in the environment (e.g., ground-water) at locations beyond the site boundary usually should be far less than the concentrations at the disposal site to which an inadvertent intruder could be exposed, owing to such factors as the limited solubility of some radionuclides, the partitioning of radionuclides between liquid and solid phases, and the dilution in transport of radionuclides in water or air beyond the site boundary. More people are likely to be exposed beyond the site boundary than on the disposal site, but acceptable disposals of radioactive waste in near-surface facilities have been based on assessments of dose to individuals, rather than populations. 

Some types of collection provide a concentrated or reduced-volume sample directly. Examples include filtration to collect airborne or waterborne particles, and sorption of airborne gases on charcoal and of aqueous ions on ion exchange resins. Water samples are reduced in volume by evaporation, and organic solids, by ashing. Certain radionuclides in water are concentrated by precipitation. 

Using the Methodic Guides [5] trough an assigned value a, for volumetric activity of / radionuclide in water and a specified human exposure time tj via path j the radiation dose Dij through this path due to water contamination by the indicated nuclide can be calculated via the following formulae ... 

In radioecology, the transfer of radionuclides from water, soil or food to animals, man or plants is described in various ways. In aquatic ecosystems, concentration factors CF are detennined, given by the concentration c, (2) of a certain radionuclide i in microorganisms or animals in relation to the concentration c, (1) of that radionuclide in water at the same time CF = Ci(2)/cj(l). Some typical concentration factors for Cs and °Sr measured in freshwater and marine ecosystems are listed in Table 21.2. The influence of the competition of K and Na with Cs, and of Ca with °Sr, in marine ecosystems is obvious. 

Radioactive waste is any waste material—gas, liquid, or solid—whose radioactivity exceeds certain limits. These limits have been established by governments or by local authorities, guided by the recommendations of the International Commission on Radiation Protection (ICRP). The ICRP recommendations define the maximum permissible concentration (MPC) for each individual radionuclide and for mixtures of radionuclides in water or air. The U.S. regulation defines such limiting concentration as the radioactivity concentration limit (C), which is the terminology used in this text, Values of C for selected actinides and long-lived fission products in water or air are given in App. D. 

In drinking water indirect indicators are allowed from the viewpoint of radiology, such as total volume activity alpha and total volume activity beta, which help to assess the occurrence of alpha or beta active radionuclides in waters without the necessity to identify actual radionuclides whose... 

Practical experience suggests that water is the easiest matrix to process. Problems with water samples include the distinction between dissolved and suspended radionuclides and the preservation of dissolved radionuclides in the sample in their original form. The sampling location and process can modify the sample for example, radionuclides in water may deposit on pipe and valve surfaces and later may dissolve again. 

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. 

Other radionuclides in water (General analytical information)... 

Seymour, R.S. and Cox, J.E. (1991). HPGe gamma spectroscopy measurement of natural radionuclides in water with a focus on current hardware and software technologies, in Monitoring Water in the 1990s Meeting New Challenges, ASTM STP 1102, J.R. Hall and G.D. Alyson (Eds), American... 

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