|Year : 2015 | Volume
| Issue : 3 | Page : 57-58
Associate Editor, RPE, Head, Internal Dosimetry Section, Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra, India
|Date of Web Publication||10-Nov-2015|
D D Rao
Associate Editor, RPE, Head, Internal Dosimetry Section, Radiation Safety Systems Division, Bhabha Atomic Research Centre, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Rao D D. Editorial
. Radiat Prot Environ 2015;38:57-8
This is the third issue of the year 2015 being published in the month of November, 2015 and the Editorial Board wishes to be in line with time for the fourth issue and also future issues. This issue contains four review articles by eminent scientists in their respective fields covering naturally occurring radionuclides materials (NORM), marine environmental radioactivity, radiation exposure in emergency situations, and a thought provoking article on re-look of linear no-threshold (LNT) hypothesis. The issue also contains six research papers covering diverse subjects such as radiobiology, radiotherapy, and occupational radiation protection.
There is a review article by Dr. M. R. Iyer and Dr. Pushparaja, on the most debated (also being debated) topic of LNT concept, rightly so due to its far reaching implications on radiation protection philosophy. The article discusses the work carried out by researchers in the initial stages and how over a period of two decades, the National Academy of Sciences, the United States Environmental Protection Agency, and International Commission on Radiological Protection (ICRP) have gradually accepted the LNT hypothesis, primarily on the basis of absence of evidence on the effect of low-level radiation exposure and also as a precautionary measure. The article discusses the challenges faced by the ICRP in accepting the LNT hypothesis and the implications of LNT on radiological protection standards. It also quotes that the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has hinted, and now admits that LNT hypothesis cannot be used for predicting cancers from low doses of radiation exposure. The article gives important observations of various agencies involved in framing radiological protection guidelines "verbatim," making the article to be tagged with a "must read" for radiation protection professionals and also for those debating in favor of LNT hypothesis. The authors also gave a hint, quoting Health Physics Society that there should not be any estimates of health risks below an individual dose of 50 mSv in 1 year.
This is all the more important, as in the present day scenario where enthusiastic scientists come up with estimates of risk of cancer even for trivial environmental radiation exposures, which are extremely low, at nano-Sievert (10−9 Sv) dose levels from dietary intakes of radioactivity. These estimates certainly seem to be adventurous, particularly when there are numerous documents categorically specifying that there are absolutely no health effects for radiation exposure of <100 mSv (0.1 Sv) and the inherent defense mechanism of the body effectively corrects cell damages, if any.
There is an article by Dr. P. P. Haridasan et al., which reviewed the radiological protection standards for exposure to NORMs. The author has been with International Atomic Energy Agency (IAEA) in the past and, therefore, contains criteria type of information for developing regulatory guidelines for NORM. It gives summary of radioactivity levels and the corresponding occupational doses at different nuclear facilities and also non nuclear facilities such as in Oil and Gas Industry and Fertilizer Industry. For instance, the article gives that the 226 Ra concentration in water contained in oil and gas formations can be as high as 1000 Bq/g. The paper reviews the current situation on radiological protection applicable to NORMs.
A review article on Marine environmental radioactivity by Dr. S. K. Jha et al., gives the outline of monitoring program that is being practiced in India to generate knowledge base on fall-out levels of radioactivity due to man-made and natural radionuclides. The paper gives details of in situ radio-analytical procedure developed for processing large volume of seawater (~1000 L) for the estimation of 137 Cs content using copper ferrocyanide cartridges. The studies conducted in India revealed that ocean waters of India has 137 Cs concentration in the range of 0.65-0.95 mBq/L with an average of 0.8 mBq/L. This average concentration definitely acts as a reference value for comparison to delineate the nuclear power plant releases of 137 Cs through their liquid effluents, if any. The concentrations of 137 Cs in ocean waters, world over, range from 0.25 mBq/L to 29.6 mBq/L.
The paper of Dr. Pushparaja gives updated information on emergency exposure situations. Author has compiled the updated guidance levels based on IAEA basic safety standards (BSS-2014) for radiation protection professionals, operators of nuclear facilities, and regulators.
Among the six research papers, there are three papers on radiotherapy/radiation biology. Dr. Majunatha has computed changes in the effective atomic number for a cancerous kidney and noncancerous kidney tissue. The author has observed, through his computational study, that the values of Z eff for cancerous kidney are higher than normal kidney. The article by Sirazi et al., gives the results of their studies on protective effects of melatonin and captopril on early effects of radiation on the heart tissue of rats. Forty-eight adult male Wistar rats weighing about 200 g each were used in the study. The rats were exposed to 8 Gy whole body dose from 60 Co source.
In an article, Dr. M. R. Iyer has put forth the use of stable isotope ratios to understand and establish with some certainty, the origin of Thorium deposits. He advocated the utilization of all the lead isotopes of uranium and thorium series. The author has observed that the ratio of 206 Pb/ 207 Pb from the two uranium series is of interest and found the ratio to be varying up to 100 times, whereas the natural isotopic ratio is around unity. Dr. Sinha et al., have emphasized the need of acceptance tests and quality assurance aspects in setting up and using of a radiotherapy treatment unit. Dr. Subramanian et al., have compared the attenuation properties of ferro boron slabs with other high density materials such as Ferrow tungsten and mild steel. These experiments were conducted in the South beam-end of Kalpakkam Mini reactor. Dr. Sawant et al. have emphasized the importance of using site-specific aerosol characteristics and breathing patterns of individual occupational workers. The authors have compared the variations in Nasal swab reference levels in terms of annual limits on intake for plutonium with changes in the particle size and breathing patterns as against the default parameters.
In the end, the editors are of the opinion that the review articles in this issue and also some research papers will ignite the minds of quite a few young scientists to venture into further investigations and build a structured scientific basis for any not fully understood or any unanswered issues in radiation science.