Category Archives: Radiation

Even Nobel Laureates can make a mistake needing correction

Edward J. Calabrese. Muller’s Nobel Prize data: Getting the dose wrong and its significanceEnvironmental Research 176 (2019) 108528

This paper evaluates the significant historical paper of Muller and Mott-Smith (1930), which successfully disputed the proposal of Olson and Lewis (1928) that background ionizing radiation is the driving mechanism of evolution. While the present analysis supports the general conclusion that background radiation is not a quantifiable factor affecting evolution, the paper reveals methodological errors and questionable conclusions in the Muller and Mott-Smith (1930) paper, which may have impacted the acceptance of the linear non-threshold (LNT) model. Most importantly, this paper reveals that in Muller’s (1927) Nobel Prize research he used a treatment exposure (total dose) that was 95 million-fold greater than the average background exposure, a value far greater than the 200,000 fold reported by Muller and Mott-Smith (1930). Such a large exposure rate dis- crepancy may be historically important as it may have led to the over-reliance on Muller’s research in support of the derivation and use of the LNT single-hit model.

When politics override the best available science when deciding a regulatory policy…

“… overpowering influence of low dose biostatistical modeling perspectives that swayed the quantitatively overwhelmed chemical toxicologists. This resulted in the LNT policy going forward, becoming broadly institutionalized across many governmental agencies and in multiple countries. The rest is history.”

Edward J. Calabresea, Robert J. Golden. Why toxicologists resisted and radiation geneticists supported EPA’S Tadoption of LNT for cancer risk assessment Chemico-Biological Interactions Volume 310, 1 September 2019, 108736

The linear non-threshold (LNT) dose response model for cancer risk assessment has been a controversial concept since its initial proposal during the 1930s. It was long advocated by the radiation genetics community in the 1950s, some two decades prior to being generally adopted within the chemical toxicology community. This paper explores possible reasons for such major differences in the acceptance of LNT for cancer risk assessment by these two key groups of scientists.

Assessment of Water Treatment for Radium Removal and NORM Formation, Estonia

Hill L, Suursoo S, Kiisk M, Jantsikene A, Nilb N, Munter R, Realo E, Koch R, Putk K, Leier M, Vaasma T, Isakar K. Long-term monitoring of water treatment technology designed for radium removal-removal efficiencies and NORM formation. J Radiol Prot. 2017 Dec 6;38(1):1-24. doi: 10.1088/1361-6498/aa97f2.

A drinking water treatment plant in Viimsi, Estonia, was monitored over three years for iron, manganese, radium-226, radium-228, as well as their daughter nuclides, in order to determine the efficiency of the treatment process, gain an insight into the removal mechanisms and interactions between radium, iron, and manganese, and assess the overall longevity and performance of the technology along with the possible build-up of NORM in the treatment process. During the study, samples were collected from raw water, first and second stage filtrate, consumer water, backwash water and filter materials. The results show consistent removal efficiency for iron and manganese, as well as an average of over 85% removal for radium with a slight decline over time. The backwash process has been optimised for maximum radium removal from the filters, while keeping concentrations in the backwash water below exemption levels. However, the accumulation of radium and thorium occurs in the filter material, exceeding exemption levels in the top layer of the filter columns in less than a year. By the end of the observation period, activity concentrations in the top layer of the columns were above 30 000 Bq kg-1 for Ra-226 and Ra-228, and around 15 000 Bq kg-1 for Th-228. Radionuclides are not homogenously distributed in the filter columns. In order to estimate the average activity concentrations in the filter media, the height distribution of radionuclides has to be accounted for. Two years and two months after commissioning the treatment plant, the average activity concentrations of Ra isotopes in the filter columns were in the range 10 000 Bq kg-1, while Th-228 activity concentration was roughly 3500 Bq kg-1.

Radon in Groundwater, 12 Cities, China

Wu Y, Cui H, Liu J, Shang B, Su X. Radon Concentrations in Underground Drinking Water in Parts of Cities, China. Radiation protection dosimetry. 2017 Aug 31:1-5. doi: 10.1093/rpd/ncx121.

222Rn concentrations in underground drinking water samples in 12 cities from seven provinces (municipalities), China were determined by using a continuous radon monitor with air-water exchanger. A total of 73 underground water samples were collected. The observed radon levels were in a range of 1.0-63.8 Bq l-1, with a mean of 11.8 Bq l-1. The annual effective dose from inhalation of water-borne radon for average radon content in underground water was 72.6 μSv and for maximal observed radon concentration in underground water the corresponding dose was 393.8 μSv. The dose contribution of inhalation dose from water-borne radon should be paid attention in some granitic area.

Radon in Water Samples Within Health Guidelines, Jammu District, Jammu and Kashmir, India

Kumar A, Kaur M, Mehra R, Sharma DK, Mishra R. Comparative Study of Radon Concentration With Two Techniques and Elemental Analysis in Drinking Water Samples of the Jammu District, Jammu and Kashmir, India. Health physics. 2017 Aug 7. doi: 10.1097/HP.0000000000000644.

The level of radon concentration has been assessed using the Advanced SMART RnDuo technique in 30 drinking water samples from Jammu district, Jammu and Kashmir, India. The water samples were collected from wells, hand pumps, submersible pumps, and stored waters. The randomly obtained 14 values of radon concentration in water sources using the SMART RnDuo technique have been compared and cross checked by a RAD7 device. A good positive correlation (R = 0.88) has been observed between the two techniques. The overall value of radon concentration in various water sources has ranged from 2.45 to 18.43 Bq L, with a mean value of 8.24 ± 4.04 Bq L, and it agreed well with the recommended limit suggested by the European Commission and UNSCEAR. However, the higher activity of mean radon concentration was found in groundwater drawn from well, hand and submersible pumps as compared to stored water. The total annual effective dose due to radon inhalation and ingestion ranged from 6.69 to 50.31 μSv y with a mean value of 22.48 ± 11.03 μSv y. The total annual effective dose was found to lie within the safe limit (100 μSv y) suggested by WHO. Heavy metal analysis was also carried out in various water sources by using an atomic absorption spectrophotometer (AAS), and the highest value of heavy metals was found mostly in groundwater samples. The obtained results were compared with Indian and International organizations like WHO and the EU Council. Among all the samples, the elemental analysis is not on the exceeding side of the permissible limit.

Protective Action and Planning Guidance for Radiological Incidents

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Linear No-Threshold Extrapolation for Ionizing Radiation: Let the Sacred Cow Die

Two very important papers detailing the history behind the default assumption of linear no-threshold for extrapolation of ionizing radiation cancer risk assessment were published in 2013 by Ed Calabrese. His work on hormesis is well-established.

Edward J. Calabrese. How the US National Academy of Sciences misled the world community on cancer risk assessment: new findings challenge historical foundations of the linear dose response. Archives of Toxicology, 2013; DOI: 10.1007/s00204-013-1105-6

This paper extends several recent publications indicating that Hermann J. Muller: (1) Made deceptive statements during his Noble Prize Lecture on December 12, 1946, that were intended to promote the acceptance of the linear dose-response model for risk assessment for ionizing radiation and (2) that such actions of Muller were masked by a series of decisions by Muller’s long-time colleague and esteemed radiation geneticist Curt Stern, affecting key publications in the mutation literature. Such actions further enhanced acceptance of the linearity dose-response model while preventing Muller’s deceptions from being discovered. This paper provides documentation that Muller reinforced such practices within the scientific literature in the early 1950s, by supporting scientifically questionable actions of Stern. Detailed documentation is provided that demonstrates how these actions affected national and international risk assessment policy for ionizing radiation and chemical carcinogens via the recommendations of the National Academy of Sciences Biological Effects of Atomic Radiation committee in 1956, to adopt the linear dose-response model.

Edward J. Calabrese. Origin of the linearity no threshold (LNT) dose–response concept. Archives of Toxicology, 2013; DOI: 10.1007/s00204-013-1104-7

This paper identifies the origin of the linearity at low-dose concept [i.e., linear no threshold (LNT)] for ionizing radiation-induced mutation. After the discovery of X-ray-induced mutations, Olson and Lewis (Nature 121(3052):673–674, 1928) proposed that cosmic/terrestrial radiation-induced mutations provide the principal mechanism for the induction of heritable traits, providing the driving force for evolution. For this concept to be general, a LNT dose relationship was assumed, with genetic damage proportional to the energy absorbed. Subsequent studies suggested a linear dose response for ionizing radiation-induced mutations (Hanson and Heys in Am Nat 63(686):201–213, 1929; Oliver in Science 71:44–46, 1930), supporting the evolutionary hypothesis. Based on an evaluation of spontaneous and ionizing radiation-induced mutation with Drosophila, Muller argued that background radiation had a negligible impact on spontaneous mutation, discrediting the ionizing radiation-based evolutionary hypothesis. Nonetheless, an expanded set of mutation dose–response observations provided a basis for collaboration between theoretical physicists (Max Delbruck and Gunter Zimmer) and the radiation geneticist Nicolai Timoféeff-Ressovsky. They developed interrelated physical science-based genetics perspectives including a biophysical model of the gene, a radiation-induced gene mutation target theory and the single-hit hypothesis of radiation-induced mutation, which, when integrated, provided the theoretical mechanism and mathematical basis for the LNT model. The LNT concept became accepted by radiation geneticists and recommended by national/international advisory committees for risk assessment of ionizing radiation-induced mutational damage/cancer from the mid-1950s to the present. The LNT concept was later generalized to chemical carcinogen risk assessment and used by public health and regulatory agencies worldwide.