Submitted by Anonymous (not verified) on Mon, 2011-04-18 12:17.
Above post is a must read included in report by EPA is low level exposure risks..
Radionuclide slope factors are calculated for each radionuclide individually, based on its unique chemical, metabolic and radioactive properties. The calculation methodology is documented in Federal Guidance Report No. 13 (10). The risk coefficients derived in Federal Guidance Report No. 13, and used to calculate the slope factors presented in the Radionuclide Table, are based on state-of-the-art methods and models that take into account the age- and gender-dependence of radionuclide intake, metabolism, dosimetry, radiogenic risk, and competing causes of death in estimating the cancer risk from low-level exposures to radionuclides in the environment. The risk coefficients in Federal Guidance Report No. 13 are estimates of the probability of radiogenic cancer mortality (fatal cancers) or morbidity (fatal plus nonfatal cancers) per unit activity of a given radionuclide inhaled or ingested, for internal exposure, or per unit time-integrated activity concentration in air or soil, for external exposure. These risk coefficients may be interpreted either as the average risk per unit exposure for persons exposed throughout their lifetime to a constant activity concentration of a radionuclide in an environmental medium (air or soil), or as the average risk per unit exposure for persons exposed for a brief period to the radionuclide in an environmental medium. These risk coefficients are based on the age and gender distributions and the mortality characteristics of the 1989-91 U.S. decennial life tables.
Submitted by Anonymous (not verified) on Mon, 2011-04-18 12:23.
Federal Guidance Report No.13 tabulates risk coefficient values for both cancer mortality and cancer morbidity for six exposure pathways: inhalation, ingestion of tap water, ingestion of foodstuffs, external radiation from submersion in contaminated air, external radiation from radionuclides deposited on the ground surface, and external exposure from radionuclides uniformly distributed through soil. Additional risk coefficients are also provided for ingestion of milk for radioisotopes of iodine only. Inhalation risk coefficients are tabulated separately for each of the three lung absorption types considered in the lung model currently recommended by the International Commission on Radiological Protection (ICRP), and, where appropriate, for inhalation of radionuclides in vapor or gaseous forms. In order to maintain consistency with risk assessment algorithms presented in the RAGS documents referenced above, only four of these exposure pathways are tabulated in the Radionuclide Table: inhalation, water ingestion, food ingestion, and external exposure from radionuclides distributed in soil. One additional exposure pathway which is not directly considered in Federal Guidance Report No. 13, incidental ingestion of soil, is also included in the Radionuclide Table.(11) In addition, the values in the Radionuclide Table have been converted from the International System (SI) units used in Federal Guidance Report No. 13 to the conventional units of activity, again for greater consistency with the risk assessment algorithms in current guidance (e.g., RAGS
Above post is a must read
Above post is a must read included in report by EPA is low level exposure risks..
Radionuclide slope factors are calculated for each radionuclide individually, based on its unique chemical, metabolic and radioactive properties. The calculation methodology is documented in Federal Guidance Report No. 13 (10). The risk coefficients derived in Federal Guidance Report No. 13, and used to calculate the slope factors presented in the Radionuclide Table, are based on state-of-the-art methods and models that take into account the age- and gender-dependence of radionuclide intake, metabolism, dosimetry, radiogenic risk, and competing causes of death in estimating the cancer risk from low-level exposures to radionuclides in the environment. The risk coefficients in Federal Guidance Report No. 13 are estimates of the probability of radiogenic cancer mortality (fatal cancers) or morbidity (fatal plus nonfatal cancers) per unit activity of a given radionuclide inhaled or ingested, for internal exposure, or per unit time-integrated activity concentration in air or soil, for external exposure. These risk coefficients may be interpreted either as the average risk per unit exposure for persons exposed throughout their lifetime to a constant activity concentration of a radionuclide in an environmental medium (air or soil), or as the average risk per unit exposure for persons exposed for a brief period to the radionuclide in an environmental medium. These risk coefficients are based on the age and gender distributions and the mortality characteristics of the 1989-91 U.S. decennial life tables.
Report detail
Federal Guidance Report No.13 tabulates risk coefficient values for both cancer mortality and cancer morbidity for six exposure pathways: inhalation, ingestion of tap water, ingestion of foodstuffs, external radiation from submersion in contaminated air, external radiation from radionuclides deposited on the ground surface, and external exposure from radionuclides uniformly distributed through soil. Additional risk coefficients are also provided for ingestion of milk for radioisotopes of iodine only. Inhalation risk coefficients are tabulated separately for each of the three lung absorption types considered in the lung model currently recommended by the International Commission on Radiological Protection (ICRP), and, where appropriate, for inhalation of radionuclides in vapor or gaseous forms. In order to maintain consistency with risk assessment algorithms presented in the RAGS documents referenced above, only four of these exposure pathways are tabulated in the Radionuclide Table: inhalation, water ingestion, food ingestion, and external exposure from radionuclides distributed in soil. One additional exposure pathway which is not directly considered in Federal Guidance Report No. 13, incidental ingestion of soil, is also included in the Radionuclide Table.(11) In addition, the values in the Radionuclide Table have been converted from the International System (SI) units used in Federal Guidance Report No. 13 to the conventional units of activity, again for greater consistency with the risk assessment algorithms in current guidance (e.g., RAGS