International and national regulations and guidelines pertinent to human exposure to radium are summarized in Table 7-1. Recommendations for radiation protection for people in the general population as a result of exposure to radiation in the environment are found in the Federal Radiation Guidance (FRC 1960) and ICRP No. 26 (ICRP 1977). National guidelines for occupational radiation protection are found in the “Federal Radiation Protection Guidance for Occupational Exposure” (EPA 1987). This guidance for occupational exposure supercedes recommendations of the Federal Radiation Council for occupational exposure (FRC 1960). The new guidance presents general principles for the radiation protection of workers and specifies the numerical primary guides for limiting occupational exposure. These recommendations are consistent with the ICRP (ICRP 1977).

The basic philosophy of radiation protection is the concept of AURA (As Low As Reasonably Achievable). As a rule, all exposure should be kept as low as reasonably achievable, and the regulations and guidelines are meant to give an upper limit to exposure. Based on the primary guides (EPA 1987a), guides for Annual Limits on Intake (ALIs) and Derived Air Concentrations (DACS) have been calculated (EPA 1988). The AL1 is defined as “that activity of a radionuclide which, if inhaled or ingested by Reference Man (ICRP 1975), will result in a dose equal to the most limiting primary guide for committed dose” (EPA 1988; ICRP 1979) (see Appendix B). The DAC is defined as “the concentration of radionuclide in air which, if breathed by Reference Man (ICRP 1975) for a work-year, would result in the intake of one AL1 (EPA 1988). The ALIs and DACs refer to occupational situations but may be converted to apply to exposure of persons in the general population by application of conversion factors (Table 7-1).

TABLE 7-1

Regulations and Guidelines Applicable to Radium.