ICRP Publication 103: Recommendations of the ICRP

Annals of the ICRP Volume 37/2-3
Elsevier, Price: £ 116.00

Abstract- These revised Recommendations for a System of Radiological Protection formally replace the Commission’s previous, 1990, Recommendations, and update, consolidate, and develop the additional guidance on the control of exposure from radiation sources issued since 1990.

The present Recommendations update the radiation and tissue weighting factors in the quantities equivalent and effective dose and update the radiation detriment, based on the latest available scientific information of the biology and physics of radiation exposure. They maintain the Commission’s three fundamental principles of radiological protection, namely justification, optimisation and the application of dose limits, clarifying how they apply to radiation sources delivering exposure and to individuals receiving exposure. The Recommendations evolve from the previous process-based protection approach using practices and interventions by moving to an approach based on the exposure situation. They recognise planned, emergency, and existing exposure situations, and apply the fundamental principles of justification and optimisation of protection to all of these situations. They maintain the Commission’s current individual dose limits for effective dose and equivalent dose from all regulated sources in planned exposure situations. They re-inforce the principle of optimisation of protection, which should be applicable in a similar way to all exposure situations, subject to restrictions on individual doses and risks: dose and risk constraints for planned exposure situations, and reference levels for emergency and existing exposure situations. The Recommendations also include an approach for developing a framework to demonstrate radiological protection of the environment.

(For details: www.icrp.org)

The Latest ICRP Recommendations -2007 are now available

NEWS ITEM

User’s Edition

This lower-cost version includes the full text of the actual Recommendations
(pp. 1 – 135) but not the scientific Annexes with background data (pp. 137 – 332); it can be ordered at: http://intl.elsevierhealth.com/catalogue/

Bulk orders and/or sponsored copies

Significant discounts are available if you wish to purchase a number of copies, e.g., for your employees, or regulators may wish to distribute copies to licensees. It is also possible if desired to discuss overprinting the cover with your logo on a print run (however, ICRP reserves the right to edit or reject specific proposals). For more information about these options, please contact Sarah Cahill at our publisher’s, at: s.cahill@elsevier.com

Special discount options and translations
Developing countries

In about 100 countries, the reports of ICRP (and many other scientific publications) are available at little or no cost through the ‘HINARI’ programme. In order to investigate whether you qualify for this programme, and to register, please visit: http://www.who.int/hinari/en/

IRPA Associated Societies

If your IRPA Associated Society has made the appropriate deal with our publishers and ICRP, there is a discount for members. For more information, please see: http://www.icrp.org/freepubl.asp

Microwaves for Cancer treatment

It is reported in Cancer Therapy Journal that large tumors in the breast, treated with a combination of chemotherapy and microwave heat treatment, have shown 50% higher size reduction than the tumors treated with chemotherapy alone. The combination of different cancer treatment techniques has been consistently showing better results than using a single technique such as chemotherapy or surgery.

It is worth mentioning here that radiation, either ionizing radiation such as X-rays and gamma rays or non-ionizing radiation such as microwaves can cause cancers under some conditions, and can also cure (destroy) cancers when the dose and dose rates are sufficiently high to kill the cancer tissues.

Two important precautions, however to be taken from the considerations of radiation protection are i) to ensure that the radiation dosage given should be optimized (not less, not more) and ii) the healthier tissues around the tumor are protected while giving the radiation dose.

International Nuclear Event Scale (INES) is being revised

A staff reporter of the IAEA reported that the INES scale, originally developed for nuclear power plants in the 1990s, is being revised to make it more versatile and informative tool. Its aim is to consistently communicate the severity of nuclear and radiological incidents and accidents in nuclear industry in the scale 1-3 (incidents) and 4 to 7 (accidents). The scale will now cover all events associated with radiation and radioactive material, including transport related events and human exposure to sources of radiation. The underlying methodology of assessment originally planned for the events rating has not changed. However, the previous procedures were not detailed enough to consistently rate events related to all radiation sources and transportation of the radioactive materials. Over the years, the procedures employed for rating the events have been considerably improved /modified.

The revised scale considers the impact on people and the environment of localized events of exposure of a few people close to the location of the event, or widespread impact, as with the release of radioactive material from an installation. The impact on facilities covers unplanned increased radiation fields due to breach in shielding and spillage of significant quantities of radioactive material resulting from failure of barriers. Degradation in defense-in-depth covers those events without direct impact on people or facilities but for which the measures put in place to prevent accidents did not function as intended.

The revision process has engaged IAEA experts, the INES Advisory Committee and consultants in nuclear safety and radiological protection. The target date for officially issuing the new and improved scale is the end of 2008.

HEALTH CONCERNS OF MOBILE PHONES

It is true that mobile phones have brought in revolution is telecommunications industry. These devices keep people from anywhere is the world connected. The expected mobile phone usage is projected to be 500 million within a short period of time. As per the recent reports, of the service providers have projected erection of over 90,000 base stations all over India to meet the ever increasing demand from rural areas.

Communication between a mobile phone and the nearest base station is achieved by the microwave emissions from the transmitters connected to the antennas mounted at the base stations, located on top of buildings or specially built towers. The beams from the antennas spread out with distance and tend to reach ground level at distances in the range 50-300 meters from the antennas. With larger capacity base stations having multiple transmitters, the output power can vary over time and with the number of calls being handled. The total radiated power from an antenna could be up to around 100 W with multiple transmitters present.

In view of this exponentially increasing and prolonged usage of the mobile phones, there is much apprehension worldwide about the long term health effects. Some of the health effects of exposure to the microwave radiation can be thermal effects such as heating of the exposed tissues. The exposure is reported to increase the risk of malignant tumors on the side of the head. Many other non-thermal health effects such as cellular genotoxicity are also reported in the literature. Most of the results could not be confirmed due to limited exposure period of 10 to 15 years available. Indirect effect can be just increase in the road accidents due to mobile usage during driving.

Keeping in mind of the above uncertainty, scanty nature of the studies and the gaps in our knowledge about the health effects, it is advised to keep the exposure much below the international guidelines. There is a need for strict regulation with respect to the manufacturers maintaining the limits on the radiation emission levels of the mobiles much lower than the standards. The required numbers of the base stations should be minimized and optimized by way of sharing of the base stations by the different service providers. Regulators should periodically monitor the ambient levels near base stations for compliance of the limits by the service providers.

AN IRRADIATION EVENT

There was an irradiation incident on June 15, 2007 involving, a radiation therapist at the radiation therapy centre Georges François Leclerc at Dijon, France. This event occurred during the treatment of a patient in radiation therapy. The irradiation of the patient was started as a radiation therapist was still present in the treatment room. The irradiation was interrupted in emergency after around ten seconds. The radiation therapist (occupational worker) who was staying near the accelerator has been exposed to a part of the radiation beam delivered to the patient. An assessment of the dose received by the radiation therapist could confirm that the dose received was in excess of the annual regulatory dose limit allowed for a worker of 20 mSv, the effective dose received was about 30 mSv. No health effects are expected for this person from this exposure. Investigation of the incident is being performed to determine the chronology and causes of the incident and to assess the corrective actions taken by the centre. It has been found that the incident resulted from human errors and a lack of proper procedure.

It is reported that the centre has taken immediate corrective administrative measures and committed itself to perform an in-depth risk identification analysis. Due to the overrun of one of the regulatory exposure limits (effective dose in excess of the yearly limit of 20 mSv), the Nuclear Safety Authority of France (ASN) ASN rates this incident at level 2 on the International Nuclear Event Scale. – Source IAEA News

EARTHQUAKE IN JAPAN TIPPED OVER 100 NUCLEAR WASTE BARRELS

It was reported that a powerful earthquake of 6.8 magnitude on July 16, 2007 at the Kashiwazaki-Kariwa facility run by Tokyo Electric, Japan caused tipping over of about 100 barrels of low-level nuclear waste at waste storage building of a nuclear power plant. Some of the barrels were found with the lids open. The earthquake also caused some contaminated water from the Tokyo Electric's plant to escape into the sea.

Water which is thought to be from the spent fuel storage pool spread on the operation floors 3 and 3M of the reactor building (non-controlled zone) of unit #6. It was recognized that some leaked water was discharged into sea through draining route. Discharged water activity (after dilution) is reported to be fully less than legislative criteria (0.2Bq/cm^3). It is claimed the discharging had already stopped.
Radionuclides such as I-131, I-133, I-135, Cr-51 and Co-60 were detected on July 17, 2007 in the main ventilation duct (Unit # 7). The ventilation ducts were found bent at the connections to the main stack. The total amount of radioactivity (release?) was estimated to be 3x10^8 Bq. The main stack radiation monitors (units # 1to 6) and monitoring posts in the power station has shown no significant indication of radiation.

Just after the earthquake on July 16th, fire broke out in the unit #3 house transformer that supplies electricity to the reactor facility. It was extinguished at 11:58 AM. The regulator requested licensee to review its fire protection and preparedness system.

The four operating reactors at Kashiwazaki-Kariwa were shut automatically after the earthquake, and the other three had already been halted for routine maintenance, Tokyo Electric said on its Web site. The plant is 9 kilometers (5.6 miles) from the epicenter of the quake. The trade ministry and Kashiwazaki town authorities ordered Tokyo Electric to keep the seven nuclear reactors idle pending safety checks. The government criticized the company for being slow to disclose the radioactive leaks.

The Kashiwazaki-Kariwa plant was not designed to withstand an earthquake as powerful as the magnitude 6.8 tremor. The Trade ministry last year updated regulations to make the nation's nuclear power stations more earthquake resistant. Japan has 55 reactors that generate about one-third of the country's power, making the nation the third-largest nuclear producer in the world. Tokyo Electric operates 17 reactors.

On July 19, Shares of Tokyo Electric Power Co. dropped to a nine-month low on concern that the company's nuclear facility in central Japan, the world's biggest, may be shut for a year after the earthquake caused radioactive leaks.

ICRP PUBLICATION NO. 95

The International Commission on Radiological Protection (ICRP) has brought out recently a CD containing the ICRP publication no. 95. The publication is a complementary report to other earlier publications which provided age-specific bio-kinetic models and dose coefficients (dose per unit intake of radioactive substance) for members of the public (Publications 56, 67, 69, 71, and 72).

The ICRP-95 provides information on radiation doses to the infant due to intakes of radionuclides in maternal milk. Intakes by female members of the public and female workers are addressed, and dose coefficients per unit intake by the mother (Sv per Bq) are given for radioisotopes of 35 elements including sodium, magnesium, phosphorus, and potassium. The CD provides all the dose coefficients in Publication 95 in a handy electronic format, and includes a considerable amount of additional information. Thus, committed equivalent doses to the various organs and tissues of the offspring are provided. Dose coefficients are also given for inhalation for ten aerosol sizes (0.001, 0.003, 0.01, 0.03, 0.1, 0.3, 1, 3, 5, and 10 µm AMAD) as well as for ingestion. Effective doses and equivalent doses for all important tissues for a range of post-natal integration times (1, 5, 10, and 20 years) are given, together with the dose coefficients to age 70 years. All intake scenarios are considered.

WHAT IS ACCEPTABLE LEVEL OF RISK ?

The health risk considered here is the fatal cancer, the ultimate end effect of exposure to carcinogens, which is also used as the basis for establishing the radiation dose limits for workers and the public. It is often said that “Nothing is poison but the dose makes it so”. Many substances (such as chemicals) which are toxic at high doses are beneficial to health in small doses, as medicines, to cure diseases. There is no credible scientific evidence that low-dose radiation is harmful. It is also widely reported that low-dose ionizing radiation is harmless and often beneficial to health.

Life is evolved, over millions of years in an environment of ionizing radiation. Even today, there are many radioactive elements existing in the nature. The variation in the background radiation exposures due to these radioactive isotopes is in the range of about 2 to 6 milli-Sievert and more per year in various countries and areas. No adverse health effects are found amongst people living in High Background Radiation Areas (HBRAs).

Public perception of acceptability of risk is based on the benefits that can be derived by taking or accepting the risk. For example, the risk of radiation exposure to much higher levels is accepted by the people in diagnostic and therapeutic radiological procedures. Whereas, the general exposure levels of occupational radiation workers fall in the same range of variation of natural background radiation doses.

For the purpose of regulation of public exposures, a numerical value for the acceptable risk is arrived at in accordance with the principle of protection optimization. In line with the US-Nuclear Regulatory Commission, one can accept a risk of fatality from cancer of one in a million per year, corresponding to the annual public exposure of 0.01 mSv (exposure which can be considered as of below regulatory concern) may be adopted. In case of annual exposures of 1 mSv (dose limit to the public) of small population (like critical group), one can accept a conservative lifetime (75 years) risks to individuals as high as five cancer fatalities in a thousand exposed.

Radiation exposures of the individual members of the public which result in risks below these limits are considered to be safe and acceptable.

USE OF CHEAPER BRICKS - HEALTH CONCERNS

Construction cost of buildings is increasing by the day. Everybody is familiar with the “red bricks”, which are seen stacked up in any construction site. It is estimated that the cost of construction of a brick wall has gone up from about 500 rupees a square meter in 2003 to over a thousand rupees in 2007!

Cheaper alternatives suggested are: 1) bricks made up of “fly ash”, a waste product from coal-based thermal power plants and 2) gypsum load-bearing panels. The fly ash contains the natural radionuclides which are present in the coal and get concentrated in the fly-ash while burning. Gypsum salt (Phospho-gypsum), obtained as a waste product of the phosphoric acid production process, generally contains significant amount of naturally occurring radioactivity, mainly uranium and its decay products. The radionuclides of concern are: Uranium-238, Radium-226, Thorium-232 and naturally occurring K-40. A few hundreds of Becquerel (unit to express the quantity of radioactivity) of the activity per kg of the materials are likely to be present.

The storage areas of such materials or the houses made by using bricks made out of such materials are potential sites of radioactive radon (Rn-222) gas (decay product of Ra-226) inhalation hazard. From radiation protection considerations, it is suggested that before such materials are used for commercial exploitation, an assessment of the materials is made for their radioactive content. If necessary, the material should be processed to remove the radioactivity content as much as possible. Clearance from the appropriate authorities may be required before large scale use of the “waste” materials.

ICRP APPROVES NEW FUNDAMENTAL RECOMMENDATIONS ON RADIATION PROTECTION

International Commission on Radiological Protection (ICRP, a non-governmental, independent organization, founded in 1928), in its meeting held at Essen, Germany during 19-21 March, 2007 approved a set of new fundamental recommendations on the protection of man and the environment against ionizing radiation. These recommendations will replace the existing 1990 Recommendations of the ICRP, published in 1991 (ICRP-60, 1991). The new recommendations take into account of new biological and physical information and trends in the setting of radiation standards. For the first time, recommendations were made giving more emphasis to protection of the environment and developing a framework for protection of non-human species.

In brief (as per the final draft): Individual related protection principles remain the same. There are changes in Radiation weighting factors, particularly for protons and neutrons and Tissue weighting factors (reduced for some organs/tissues). There is considerable reduction in the nominal risk coefficient for hereditary effects. However, there is no change in the numerical values in individual-related dose limits applicable for all planned exposure situations.

The recommendations will be published in the Commission’s journal, the Annals of the ICRP, 2007.

SYMBOLS TO WARN OF THE PRESENCE OF RADIOACTIVE MATERIALS

This new symbol (ISO 21482), a triangular shape with three icons - the trefoil emitting radiation, a skull and a man running away - is meant to warn of the presence of dangerous levels of ionizing radiation on large sealed radioactive sources. The symbol conveys: Danger - Run Away – Do Not Touch. The new symbol does not replace the old one but is in addition to it. IAEA recommends that the symbol may be used on IAEA Category 1, 2 and 3 sealed radiation sources.




The trefoil symbol, the magenta image (Berkeley Lab, US) on a yellow background is being used for decades to denote / warn the presence of radioactive material. The history of the symbol is not very clear, though as it looks today, it originated from Oak Ridge National Lab in late forties. The symbol, however, has little recognition beyond the nuclear community.

RADIATION ACCIDENTS – REDUCE RADIATION EXPOSURE

With all the terrorist activities on the rise and with availability of nuclear materials not so difficult, it is essential that adequate emergency preparedness is developed and kept in readiness. Assuming that the mass destruction is not in the mind of the terrorists, it is the use Radiological Dispersal Device (RDD), is the likely terrorist act. The RDD is mixing of any radioactive material with conventional explosives and use the same in public domain. The result is large scale contamination of the areas, which is likely to cause panic among the public and disruption of the public utilities such as transport system, food supplies, etc. One should remember that potential health effects may not be alarming in such situations.

There are some simple precautions which the members of the public should take under such situations to reduce the exposures and the health effects. Do not panic. Simply follow the instructions on the protection measures issued by the well identified government agencies responding to such a situation. Some of the simple protective actions can be:

1. Keep away from the affected area. Radiation exposure reduces with distance.
2. Hold a handkerchief, preferably wet, over the nose and mouth. Respiratory protection devices of the type used by medical staff in operation theaters are available in medical stores. This prevents inhalation of the radioactive dust which is likely to get airborne.
3. If you are indoors, remain indoors. Close windows and doors. You may have to close the common ventilation system if the incoming air is not filtered.
4. If one is coming from outside, have change of clothing including shoes, take a shower, clear your nose, wash your mouth and be indoors for further instructions, via Television/Radio from the authorities.

RADIATION HAZARDS OF AIR TRAVEL

Modern commercial aircrafts operate at altitudes varying from 8 to 16 km from the surface of the earth. Cosmic radiation coming from space is a mixture of many different types of radiation, such as protons, alpha particles, electrons and other high energy particles. The radiation is affected by the earth’s magnetic field and while entering the atmosphere, its intensity reduces due to interaction with the environment. At ground level, the cosmic radiation is mainly consists of muons, neutrons, electrons, positrons and photons. Thus, as the altitude decreases, the cosmic radiation dose also reduces. For example, the dose rate at sea level, at the top of Himalayas, and at 15 km height can be 0.03 micro Sv/h, 1 microSv/h and 10 micro Sv/h. European Commission working group ((EURADOS WG-5) reported typical per flight exposures of 67 microSv and 47.8 microSv to the aircraft crew flying from London to Tokyo and Montreal to London respectively.

This brings into focus the radiation protection aspects of airline crew and of frequently flying airline passengers. The International Commission on Radiological Protection (ICRP) recommends that the airline crew should be treated as radiation workers and for normal flying hours put up by the crew, the expected average annual dose is reported to be of the order of about 2.5 milliSv. This can be compared with the 20 milliSv, the annual average occupational dose limit recommended by the ICRP for all radiation workers. Annual dose limit recommeneded for the members of the public from man-made radiation sources is 1 milliSv.

The number of passengers flying is growing fast, rather exponentially in some countries and if all the doses of the passengers and the crew are added up (collective dose), the statistically estimated health consequences due to the radiation exposure of the group of population is of concern from radiation protection point of view. Now, compares this risk of the health consequences with the risk of potential airline accidents, the radiation exposure risk will work out to be higher!

Any comments?

RADON AT HOME

Radon-222, a radioactive noble gas isotope, the daughter product of Radium-226 in the naturally occurring Uranium-238 Series has become a centre of attention in radiation protection. Similarly, another isotope of radon, i.e., Radon-220 (called thoron) is the daughter product of Radium-224 in Thorium-232 series. The radon isotopes, Rn-222 and Rn-220 are alpha emitters with half lives of 3.82 days and 55.6 seconds respectively. The decay products of the two isotopes are also short-lived, but they are particulate radionuclides of elements polonium, lead, bismuth and thallium. Official regulatory requirements in some countries call for the measurement of radon indoors before clearance of dwellings for human occupation.

Becquerel (Bq) is the unit used to express the quantity of radioactive material disintegrating at a rate of 1disintegration per second). The radon daughter concentration can also be expressed in terms of working level (WL) units. One WL corresponds to an equilibrium concentration of 3700 Bq / cubic meter of air. Sievert (Sv) is the unit used to express the dose (energy absorbed per kg - effective dose) received due to the exposure to radiation.

Being gaseous, the radon isotopes generated in the underground rocks (about 4 ppm-parts per million), in soil and from the building materials diffuses out and gets mixed up with the air in the environment. The radon gas also comes out from the cracks in the rocks and in hot spring water. Healing property of spring waters is attributed to the presence of radon. Once out in the open, the outside air provides enough dilution. Typical average concentration of radon outdoors is 10 Bq per cubic meter. It varies from place to place. Seasonal variations are seen. In the uranium mines, the concentration can be much higher and it is a potential occupational hazard for the mine workers. However, the radon concentration is much higher indoors due to limited dilution provided for the radon diffusing inside the dwellings from the building materials and the underlying soil (particularly in basement areas). The radon concentration varies with the building material used, the type of the house, quality of construction and ventilation provided. Thus, depending upon the time spent indoors, the exposure of the population can be significant, particularly in cold countries where the ventilation rate provided is low.

On inhalation of the contaminated air, the particulate activity gets deposited in the lung and gives dose to the lung tissues. As compared to the radiation dose resulting from inhalation of unit concentration of the particulate radon daughters, the dose from inhalation of unit concentration of the inert gas is about 50 times lower. Lung cancer is the radon induced malignancy known amongst the mine workers.

Major contribution (70 to 80%) to the average dose of 2.4 milliSv per year to the public from natural sources comes from these radon isotopes and their short-lived daughter products. In some of the high background areas (HBRA), the radon concentration in dwellings may be much higher, which may call for intervention measures, such as relocation to reduce the human exposure.

The International Commission on Radiological Protection (ICRP) recommends Action Levels for regulatory intervention of 200-600 Bq per cubic meter of air with an indoor occupancy of 7000 hours in a year and an equilibrium factor of 0.4 (concentration of radon daughters divided by the concentration of radon gas). This concentration corresponds to an effective dose of 3-10 mSv.

There are various radon measurement techniques / portable monitors are available commercially for the measurement of radon accurately for the estimation of radiation dose and for regulatory compliance. Portable Alpha spectrometry based detection systems, electrets, direct scintillation based radon gas counting systems are employed for the measurement of radon in water, air and for radon exhalation measurements from soil and construction surfaces. Calibration of the systems is one of the important requirements for validation of the system operation and reliability of the data.

FEAR OF RADIATION – UNNECESSARY

The word RADIATION reminds of dropping of atomic bombs over Japan during the Second World War and the mass destruction of everything in the vicinity of the explosion sites. The effects of the exposures were short term like radiation syndrome and long term, like cancer. That is how the world today came to know about radiation. Since then, there have numerous beneficial effects and peaceful uses of radiation, which has been benefiting the society to a very great extent. Examples are: nuclear power and medical uses of radiation and radioisotopes for diagnosis and therapy. Safety records of such applications are very good as compared to other industries. In fact, other industries should emulate the safety considerations and provisions made in the nuclear industry.

Unlike in other industries, because of the fear of radiation, the effects of radiation exposure on humans are extensively studied and documented. The radioactivity measurement techniques are very well developed and at present a very small amount of radioactive material, in less than nano-gram (one-billionth of a gram) levels can be measured with required accuracy using specially designed electronic instruments. The very data on the health effects of the survivors of the bomb explosion served as the primary database for determination of the radiation exposure risk to the workers and the members of the public. We also have enough data on the health effects of low level radiation exposures of the people living in high radiation background areas (HBRA) in countries like India and China.

The truth is we are all living in this world where there exists natural background radiation, such as cosmic radiation and radiation from the earth consisting of small amounts of radioactive materials like uranium and thorium. This exposure is unavoidable. Public is unawareness of this fact. Nobody really told them or explained to them to be convinced.

However, public reacts to radiation with fear and anxiety. It is the fear of unknown. These indications need to be counterbalanced. How?
1. Two-way open communication between all the stakeholders to be enhanced to break the mutual distrust.
2. Natural background radiation levels can be displayed in public places. Follow one unit to express exposure to radiation. Too many units confuse the public.
3. Use of the term dose limit can be discontinued. It has lost its significance.
4. Improve public familiarity with respect to the effects of radiation and compare the effects with other more familiar environmental pollutants. Use the language which is easily followed by the public, in their language.
5. Educate the public what to do by themselves in case of any release of radioactivity into the environment and high radiation levels.
6. There is no point in highlighting health effects of human exposure to high radiation levels (radiation syndrome) which is likely to occur only during incidents or accidents.
7. Beneficial effects of radiation for health care (medicine) should be projected in schools and collages rather than the biological effects of radiation.
8. In general, public accepts whatever is beneficial or useful to them. Good examples are electricity and use cooking gas. Controllable risk is generally acceptable.

What is radiation hormesis

It is the hypothesis to explain the lower cancer incidences observed at higher radiation background areas, and inverse correlation observed between lung cancer mortality and indoor radon (a radioactive inert gas – decay product of a naturally occurring uranium -238 radionuclide) levels measured in some US counties. Adaptive response / enhanced immunity of the human biological system at low radiation dose levels are being invoked to explain this effect. This means radiation exposure is beneficial for health, at low doses!

If accepted, the radiation hormesis concept challenges the very basic approach of linear non-threshold model traditionally used by the International Commission for Radiological Protection (ICRP) for the dose-response relationship. The dose limits prescribed are likely to be enhanced from the existing limits of 30 mSv/year and 1 mSv/y for occupational workers and the members of the public respectively. The ICRP recommendations on dose limits are accepted by majority of the nations.

MOBILES DON'T CAUSE CANCER?

In view of the exponentially increasing usage of mobile phones, there has been much apprehension worldwide about the health concerns of its prolonged use. It is reported in the media that researchers at Danish Institute of Cancer Epidemiology in Copenhagen concluded that “Mobiles don’t cause cancer”. The conclusion was based on their recent study on 420,095 people who had a phone at some point between 1982 and 1995, examined through until 2002. That is occasional radio-frequency (RF) exposures for a period of 13 years.

I strongly recommend that the conclusion should be taken in the proper perspective keeping in mind the following:

1. Cancer is a late-effect. The latent period (since its initiation) for a solid cancer to appear is 30-40 years.
2. The current level of mobile usage is not occasional, but can be quite high, as high as a few hours in day.

Keeping in mind the above uncertainty and the gaps in our knowledge about the health effects, it is not possible to completely rule out adverse health effects even at levels of RF exposures below the international guidelines. Hence, it advisable to have a precautionary approach, such as i) using the phones only occasionally, ii) find out its RF emission levels / SAR Value of the mobiles before it’s purchase, iii) using hand-free types to minimize the exposure to head and neck region and iv) avoid exposure of the mobile to small children.

NUCLEAR ISSUES – NEW YEAR WISHES

1. No more incidents of detection of Polonium-210 contamination in London or elsewhere. From hazard considerations, it is very mobile and easily dispersed due to its nuclear property. It is one of the daughter products of naturally occurring U-238 series. It has a half life of 138 days and the alpha particle, of energy 5.3 MeV, emission from its nucleus makes it very hazardous if taken internally.

2. Final US Legislation on the Nuclear – deal addresses the concerns of Senior Indian scientists who have been holding Indian Flag high during the harder times of SANCTIONS imposed on India from the west.

3. Full participation of US firms in civilian nuclear power plants, including thorium based reactors in India in the future. The participation shall ensure adequate liability in case of accidents in the reactors.

4. Solve the issue of safe management of spent nuclear fuel from these collaborated reactors. High-value plutonium in the spent fuel should be recovered to exclusively fuel the future Indian fast breeder reactors.

5. Early recovery of the Ash Analizer (if it recovered, it is not well known) belonging to the Central Coal Fields Limited at Hazanbagh, India. The analyzer might have been used to analyze the natural radionuclides in the coal ash. To the best of my knowledge, the natural radioactivity (uranium, thorium) in coal ash in PPM (parts per million) level. As reported in the Press, the instrument can not become radioactive just because it is used to analyze the samples. It only gets contaminated by the use and can be decontaminated easily. I feel, it is over-reaction by the media. However, it needs clarification from the concerned authorities without much delay.