Lung Cancer Risk from Radon and Progeny and Statement on Radon. ICRP Publication 115, Ann. ICRP 40(1), ICRP Publication 115, Ann. ICRP 40(1), 2010.
The document reviews recent epidemiological studies of the association between lung cancer and exposure to radon and its decay products. Particular emphasis is given to pooled case-control studies of residential exposures and to cohorts of underground miners exposed to relatively low levels of radon. The residential and miner epidemiological studies provide consistent estimates of lung cancer risk with statistically significant associations observed at average annual concentrations of about 200 Bq m-3 and cumulative occupational levels of about 50 WLM, respectively.
Based on recent results from combined analyses of epidemiological studies of miners, a lifetime excess absolute risk of 5 × 10-4 per WLM (14 × 10-5 per mJ h m-3) should now be used as the nominal probability coefficient for radon and radon progeny induced lung cancer, replacing the previous ICRP Publication 65 value of 2.8 × 10-4 per WLM (8 × 10-5 per mJ h m-3).
Unlike the recommendations of ICRP Publication 65, it is now concluded that radon and its progeny should be treated in the same way as other radionuclides within the ICRP system of protection; that is, doses from radon and radon progeny should be calculated using ICRP biokinetic and dosimetric models.
ICRP will provide dose coefficients per unit exposure to radon and radon progeny for different reference conditions of domestic and occupational exposure, with specified equilibrium factors and aerosol characteristics (source:www.ICRP.org).
Wednesday, February 15, 2012
Thursday, December 1, 2011
Current regulations are too much stringent?
Like any other pollutant, radioactive materials and radiation are also present in our environment since the formation of earth.
The fear of radiation in everyone’s mind is due to the destruction caused by the effects of explosions of atomic bombs over Japan in 1945. The possible innumerable benefits of radiation in medicine and industry are simply not considered or exploited enough or publicized by the policy makers due to fear of negative reaction by the public. The ghost memories of the bombings and the Chernobyl disaster always remained fresh in the public mind! This is typical “Culture of fear” being promoted by various groups of people (so-called anti-nuclear lobby) with vested interests.
The organizations dealing with radiation protection also promote this culture by accepting the Linear Non-Threshold (LNT) approach for radiation protection and safety. Regulators have not much choice but to formulate regulations to address the acceptable dose limits which are based on the calculated risks assuming much debated LNT approach.
As such, the background radiation levels around us vary quite a bit from place to place and in some places it is of the order of the current dose limits. People are living in those places of high background radiation for ages. No abnormal health issues are observed.
At the Chernobyl accident site, the emergency workers (about 30 workers) who received doses above 4000 mSv have died within a few weeks due to Acute Radiation Syndrome (ARS). There were 140 workers who received less than 2000 mSv dose (which is 100 times more than the annual dose limit for radiation workers) and none died. In Fukushima (Japan), 30 workers received doses in the range of 100 and 250 mSv range in a few days and none is expected to die of the radiation exposure. In medical therapy, for the treatment of cancer, thousands of mSv doses are given to kill the cancer tissues.
There was no increased risk of cancer observed amongst the survivors of Hiroshima and Nagasaki whose exposures were below 100 mSv. Animal experiments could not prove the non-threshold theory to induction of cancer by radiation exposure assumed by the radiation protection fraternity.
Once we accept this fact, there is no need to have such stringent regulations for the applications of radiation and radioisotopes. One can save un-justified expenditure of resources, hardship and suffering to the population (based on the lecture given by Prof. Wade Allison, University of Oxford, August 2011).
Let us NOT say NO to the benefits of applications of radiation such as food irradiation, medical / industrial applications, pest control and electricity generation.
The fear of radiation in everyone’s mind is due to the destruction caused by the effects of explosions of atomic bombs over Japan in 1945. The possible innumerable benefits of radiation in medicine and industry are simply not considered or exploited enough or publicized by the policy makers due to fear of negative reaction by the public. The ghost memories of the bombings and the Chernobyl disaster always remained fresh in the public mind! This is typical “Culture of fear” being promoted by various groups of people (so-called anti-nuclear lobby) with vested interests.
The organizations dealing with radiation protection also promote this culture by accepting the Linear Non-Threshold (LNT) approach for radiation protection and safety. Regulators have not much choice but to formulate regulations to address the acceptable dose limits which are based on the calculated risks assuming much debated LNT approach.
As such, the background radiation levels around us vary quite a bit from place to place and in some places it is of the order of the current dose limits. People are living in those places of high background radiation for ages. No abnormal health issues are observed.
At the Chernobyl accident site, the emergency workers (about 30 workers) who received doses above 4000 mSv have died within a few weeks due to Acute Radiation Syndrome (ARS). There were 140 workers who received less than 2000 mSv dose (which is 100 times more than the annual dose limit for radiation workers) and none died. In Fukushima (Japan), 30 workers received doses in the range of 100 and 250 mSv range in a few days and none is expected to die of the radiation exposure. In medical therapy, for the treatment of cancer, thousands of mSv doses are given to kill the cancer tissues.
There was no increased risk of cancer observed amongst the survivors of Hiroshima and Nagasaki whose exposures were below 100 mSv. Animal experiments could not prove the non-threshold theory to induction of cancer by radiation exposure assumed by the radiation protection fraternity.
Once we accept this fact, there is no need to have such stringent regulations for the applications of radiation and radioisotopes. One can save un-justified expenditure of resources, hardship and suffering to the population (based on the lecture given by Prof. Wade Allison, University of Oxford, August 2011).
Let us NOT say NO to the benefits of applications of radiation such as food irradiation, medical / industrial applications, pest control and electricity generation.
Tuesday, September 13, 2011
Radiation emission from towers
Since last three years, “I care for you” has been pursuing the issue of potential health hazard from exposure to radiation from mobile phones and towers through the blog: http://radsafe.blogspot.com. The potential hazards to the public from exposure to radiation from the towers are being highlighted. Periodically, articles are appearing in Mumbai Mirror, Times of India and DNA. But, there is no persistence in the reporting.
However, it is understood now that some actions are being taken in this direction by the Indian Government authorities to control this avoidable public health concern. DNA Navi Mumbai reported on September 4, 2011 that the radiation levels measured in certain areas of Navi Mumbai are 100 times higher than what is considered safe!
Is this not a matter of grave concern for every one of us?
However, it is understood now that some actions are being taken in this direction by the Indian Government authorities to control this avoidable public health concern. DNA Navi Mumbai reported on September 4, 2011 that the radiation levels measured in certain areas of Navi Mumbai are 100 times higher than what is considered safe!
Is this not a matter of grave concern for every one of us?
Saturday, September 10, 2011
NORM MANAGEMENT
The acronym NORM means all Naturally Occurring Radioactive Materials. Humans are continuously exposed to these materials such as potassium-40, uranium, thorium and their daughter products present in our environment. Some times, human activities such as uranium mining, phosphate mining, oil exploration, etc enhance the NORM concentration, which increases the potential of exposures of population groups to the radiation. Two important decay products of concern are Ra-226 and a radioactive gas - Radon-222. NORM received a global attention during last 4 decades.
Hence, it is important that the concentration of NORM is measured in suspected industrial activities and take appropriate measures to protect the workers and the environment. The industrial activities which generate NORM waste should be regulated to prevent environmental hazard from the disposal of the waste. Many countries have already aware of the issue and initiated remedial measures to control occupational exposures and to ensure environmental safety. NORM is discovered in the sludge being generated in deep oil well exploration /production activities. GM detectors or scintillation detectors are used for the NORM survey.
Radiation levels due to NORM are measured at the work sites. Personnel monitoring and personal protective equipments, if required are used to measure radiation exposures of the workers and its control. Thermoluminescence dosimeters (TLDs) are used to measure personal exposures and respirators (dust/gas), gloves, overalls, goggles are some of the personal protective equipments (PPEs) used. Above all, the workers should be made aware of the possible NORM exposures so that they follow proper and safe work procedures for the NORM management and environmental safety.
Hence, it is important that the concentration of NORM is measured in suspected industrial activities and take appropriate measures to protect the workers and the environment. The industrial activities which generate NORM waste should be regulated to prevent environmental hazard from the disposal of the waste. Many countries have already aware of the issue and initiated remedial measures to control occupational exposures and to ensure environmental safety. NORM is discovered in the sludge being generated in deep oil well exploration /production activities. GM detectors or scintillation detectors are used for the NORM survey.
Radiation levels due to NORM are measured at the work sites. Personnel monitoring and personal protective equipments, if required are used to measure radiation exposures of the workers and its control. Thermoluminescence dosimeters (TLDs) are used to measure personal exposures and respirators (dust/gas), gloves, overalls, goggles are some of the personal protective equipments (PPEs) used. Above all, the workers should be made aware of the possible NORM exposures so that they follow proper and safe work procedures for the NORM management and environmental safety.
Friday, June 24, 2011
Revision of the Basic Safety Standards (BSS)
The IAEA International Basic Safety Standards for Protection Against Ionizing Radiation and for the Safety of Radiation Sources is in the final stage of revision.
A review of the Basic Safety Standards (the BSS) was carried out in 2006 in cooperation with the cosponsors (FAO, ILO, NEA, PAHO and WHO) and potential cosponsors UNEP and EC. The review concluded that, while there was no major issue requiring urgent revision, there was a case to be made for the revision of the BSS in order to take account of the many improvements that have been suggested. The International Atomic Energy Agency (IAEA), in cooperation with the co-sponsoring and potential co-sponsoring organizations, initiated the revision of the BSS in 2007.
The revised International Basic Safety Standards was endorsed by the Commission on Safety Standards (CSS) at its meeting from 25-27 May 2011. The CSS has asked that Member States be consulted about the change (Draft 5.0) to the dose limit for the lens of the eye. Member States are invited to on this change by 7 July 2011. This is a major milestone in the development process of the revision. The revised BSS will now be submitted to the Board of Governors for approval at its meeting to be held from 12-16 September 2011 (IAEA News).
A review of the Basic Safety Standards (the BSS) was carried out in 2006 in cooperation with the cosponsors (FAO, ILO, NEA, PAHO and WHO) and potential cosponsors UNEP and EC. The review concluded that, while there was no major issue requiring urgent revision, there was a case to be made for the revision of the BSS in order to take account of the many improvements that have been suggested. The International Atomic Energy Agency (IAEA), in cooperation with the co-sponsoring and potential co-sponsoring organizations, initiated the revision of the BSS in 2007.
The revised International Basic Safety Standards was endorsed by the Commission on Safety Standards (CSS) at its meeting from 25-27 May 2011. The CSS has asked that Member States be consulted about the change (Draft 5.0) to the dose limit for the lens of the eye. Member States are invited to on this change by 7 July 2011. This is a major milestone in the development process of the revision. The revised BSS will now be submitted to the Board of Governors for approval at its meeting to be held from 12-16 September 2011 (IAEA News).
Wednesday, May 18, 2011
Risk of radiation exposure – ICRP Recommendations
The International Commission of Radiological Protection (ICRP) provides recommendations on radiation protection standards. Since the ICRP-60, there has been significant progress in understanding the genetic risk associated with the induction of mutations in germ cells. The clearer understanding is that the genetic risk is much lower than the earlier estimates. In ICRP-103 (2007), the risk estimates considered only two generations rather than the all generations (theoretical equilibrium) considered in ICRP-60. The overall contribution to the detriment (total harm) from genetic effects works out to be 3-4% as compared to 18% considered in ICRP-60. Hence, the tissue weighting factor was reduced from 0.2 (ICRP-60) to 0.08 (ICRP-103).
The radiation detriment (overall harm to stochastic effects) was assessed (ICRP-60) taking in to account the cancer incidence, mortality, length of life lost if cancer occurs and the morbidity and quality of life lost due to suffering in incidences of non-fatal cancers. The ICRP-103 considered the detriment based on lethality and life impairment weighted on cancer incidence data.
The detriment values were assessed for both genders and also for working (18 to 64 years) the whole population (0 to 85years). The detriment adjusted nominal risk coefficients for cancer and hereditary effects combined have been estimated to be 5.7 and 4.2% per Sv for the whole population and working population respectively.
Based on the new risk assessments, the Tissue Weighting Factors (WT) for specific organ/tissue are the fractional harm associated with the stochastic effect (gender averaged relative detriment) were also reviewed by the ICRP in ICRP-103. The important changes in ICRP-103 are the upgrading the value of risk for breast from 0.05 (ICRP-60) to 0.12 and for gonads, the WT was reduced from 0.12 (ICRP-60) to 0.08.
Conclusion
In-spite of the some changes in the nominal risk coefficients and in WT values, the total detriment remains close to 5% per Sv. In view of this, the dose limits for occupational and public exposures remain same at an average of 20mSv/y and 1mSv/y respectively as in ICRP-60 (1991).
The radiation detriment (overall harm to stochastic effects) was assessed (ICRP-60) taking in to account the cancer incidence, mortality, length of life lost if cancer occurs and the morbidity and quality of life lost due to suffering in incidences of non-fatal cancers. The ICRP-103 considered the detriment based on lethality and life impairment weighted on cancer incidence data.
The detriment values were assessed for both genders and also for working (18 to 64 years) the whole population (0 to 85years). The detriment adjusted nominal risk coefficients for cancer and hereditary effects combined have been estimated to be 5.7 and 4.2% per Sv for the whole population and working population respectively.
Based on the new risk assessments, the Tissue Weighting Factors (WT) for specific organ/tissue are the fractional harm associated with the stochastic effect (gender averaged relative detriment) were also reviewed by the ICRP in ICRP-103. The important changes in ICRP-103 are the upgrading the value of risk for breast from 0.05 (ICRP-60) to 0.12 and for gonads, the WT was reduced from 0.12 (ICRP-60) to 0.08.
Conclusion
In-spite of the some changes in the nominal risk coefficients and in WT values, the total detriment remains close to 5% per Sv. In view of this, the dose limits for occupational and public exposures remain same at an average of 20mSv/y and 1mSv/y respectively as in ICRP-60 (1991).
Sunday, May 1, 2011
ICRP - Statement on Tissue Reactions
As per the ICRP communication, it has approved “Statement on Tissue Reactions” in April 21, 2011. The effects of radiation which was called as deterministic effects previously are now referred as Tissue Reactions. Based on the data various aspects of the effects with very late manifestation such as cataract of the eyes, the threshold in absorbed dose is now considered as 0.5Gy.
Similarly, for occupational exposure in planned exposure situations the Commission now recommends an equivalent dose limit for the lens of the eye of 20mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50mSv.
The Commission continues to recommend that optimization of protection be applied in all exposure situations and for all categories of exposure, including patient’s exposure during some complex interventional procedures, With the recent evidence, the Commission further emphasizes that protection should be optimized not only for whole body exposures, but also for exposures to specific tissues, particularly the lens of the eye, and to the heart and the cerebrovascular system.
Similarly, for occupational exposure in planned exposure situations the Commission now recommends an equivalent dose limit for the lens of the eye of 20mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50mSv.
The Commission continues to recommend that optimization of protection be applied in all exposure situations and for all categories of exposure, including patient’s exposure during some complex interventional procedures, With the recent evidence, the Commission further emphasizes that protection should be optimized not only for whole body exposures, but also for exposures to specific tissues, particularly the lens of the eye, and to the heart and the cerebrovascular system.
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