Derived air concentrations

During refueling, the respective concentrations were 1.64, 1.33, 0.78, 0.19, and 6.34 mBq/m3 (44.3, 35.9, 21,5.1, and 171 fCi/m3). The derived air concentration recommended by the ICRP for occupational exposure is 80.0 mBq/m3 (2,200 fCi/m3). In 1997, the French radiation protection office conducted monitoring (24-hour urine analysis/whole body activity measurements) of workers in the non-nuclear energy field (i.e., nuclear medicine, research laboratories, and non-nuclear industries) to ascertain the occupational intake of radionuclides (De Vathaire et al. 1998). 241Am was not detected in samples from any of the 37 workers who worked with the isotope. 

ALI = Annual Limit of Intake DAC = Derived Air Concentration EPA = Environmental Protection Agency FRC = Federal Radiation Council... 

Gevao, B., Al-Omair, A., Sweetman, A., Al-Bahloul, M., Al-Ali, L., Helaleh, M., et al. Passive-sampler derived air concentrations for polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons in Kuwait. Environmental Toxicology and Chemistry, 25(6) 1496-1502 (2006). 

Hamer, T., Shoeib, M., et al. (2006) Passive sampler derived air concentrations of PBDEs along an urban-mral transect spatial and temporal trends. Chemosphere, 64(2) 262-267. 

For the control of internal doses, annual limits of intake (ALI) and derived air concentrations (DAC) have been determined. ALIs and DACs in EPA guidance and the USNRC and DOE regulations are based on the recommendations of the ICRP (ICRP 1979). Values of the ALIs and DACs for uranium isotopes are presented in Table 7-1. These values are for soluble. Class D (Days) material, which has a half-time for clearance from the pulmonary region of the lung of less than 10 days. Values of ALIs and DACs for Class W (Weeks) and Class Y (Years) uranium are available in Appendix B to 10 CFR 20 (USNRC 1993f). 

DOE. 1996c. Annual limits on intake (ALIs) and derived air concentrations (DACs) of radionuclides for occupational exposure effluent concentrations concentrations for release to sewerage. 10CFR20 Appendix B. U. S. Department of Energy, Washington, D.C. 

Most of the properties mentioned in the previous paragraph are taken into account in the ALI and DAC concept (ALI = Annual Limits of Intake DAC = Derived Air Concentration, based on the ALI value). 1 ALI corresponds to an annual committed equivalent dose of 50 mSv. 

The activity concentration of radon daughters is much higher than the Derived Air Concentration value of artificial radionuclides. For example, the Pu public DAC (2.4 10" Bq m ) is lower than four orders of magnitude of a mean radon daughters concentration (30 Bq m ). 

Radioactive Strontium. The Department of Energy (DOE) has established derived air concentrations (DAC) for workplace exposure to radiation at DOE facilities. The DAC ranges from 0.000000002 pCi/mL (2xl0"9 pCi/mL of air) for 100-day retention in the lung to 0.000000008 p Ci/mL (8xl0 9 p Ci/mL of air) for retention less than 10 days. The Nuclear Regulatory Commission established an annual intake limit of 20 pCi for on-the-job exposure to 90Sr in air. 

ACGIH = American Conference of Governmental Industrial Hygienists ADEC = Alaska Department of Environmental Conservation ALI = annual limits on intake BNA = Bureau of National Affairs CFR = Code of Federal Regulations DAC = derived air concentration DEP = Department of Environmental Protection DOE = Department of Energy DOT = Department of Transportation EPA = Environmental Protection Agency ... 

Derived air concentration (DAC) the concentration for a given radioisotope is that concentration in air that, if breathed by an adult for a working year of 2000 hours under conditions of light activity (inhalation rate l.DE mL/min), would result in total intake of 1 ALI. Values of ALI and DAC for several radioisotopes are given in App. B of 10CFR20. ... 

A substance which represents a hazard within the body due to its radioactivity is referred to as radiotoxic. The radiotoxicity depends on the properties of the radiation and on a number of physical, chemical, and biological conditions such as mode of intake (via air, in water or food, through wounds, etc.), the size of the ingested or inhaled particles, their chemical properties (e.g. solubility), metabolic affinity, and ecological conditions. Most of these conditions are considered in the ALI concept. ALI Annual Limits of Intake) and D AC Derived Air Concentrations, from the ALI value) and other relevant data are presented in Table 18.12. An annual intake of 1 ALI corresponds to an annual committed dose equivalent of 50 mSv. 

DAC Derived air concentration of a radionuclide that is related to an intake limit. 

Derived air concentration (DAC) means the concentration of a given radionuclide in air which, if breathed by the reference man for a working year of 2,000 hours under conditions of light activity (corresponding to an inhalation rate of 1.2 m air per hour), results in an inhalation of 1 ALI. These are comparable to the MFCs in the older Part 20. 

It is expected that under normal operational conditions, the airborne concentration level In the Zone 2A canyon would be well below the derived air concentration (DAC) limits (2E-8 ci/m3 for 1-131 from 10 CFR 835). This assessment is based on normal handling and containerization of process materials and the fact that the Zone 2A canyon volume is continually circulated by the ventilation system. However, contamination above these levels may exist in the canyon on a transient basis. An accident condition, such as simultaneous process spill and SCB failure, could hypothetically release a target s volatile contents, or 100% of the iodine inventory directly to the canyon. These theoretical contamination levels can also serve as a basis for evaluation of the potential consequences of ventilation failure. 

Airborne Radioactivity Area An area where the measured concentration of airborne radioactivity, above natural background concentrations, exceeds either (1) 10% of the derived air concentration (DAC) averaged over 8 hours or (2) a peak concentration of 1 DAC. DAC values are contained in the SNL RPPM. 

US NRC, 10 CFR Part 20, Appendix B, April 28, 1995, Aimual Limits on Intake and Derived Air Concentrations of Radionuclides for Occupational Exposure Effluent Concentrations Concentrations for Release to Sewerage. 

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