Tag 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.

Downward longwave radiation is not independent of surface temperature

Vargas Zeppetello, L. R., Donohoe, A., & Battisti, D. S. (2019). Does surface temperature respond to or determine downwelling longwave radiation? Geophysical Research Letters, 46, 2781–2789. https://doi.org/10.1029/2019GL082220

Downward longwave radiation (DLR) is often assumed to be an independent forcing
on the surface energy budget in analyses of Arctic warming and land-atmosphere interaction. We use radiative kernels to show that the DLR response to forcing is largely determined by surface temperature perturbations. We develop a method by which vertically integrated versions of the radiative kernels are combined with surface temperature and specific humidity to estimate the surface DLR response to greenhouse forcing. Through a decomposition of the DLR response, we estimate that changes in surface temperature produce at least 63% of the clear-sky DLR response in greenhouse forcing, while the changes associated with clouds account for only 11% of the full-sky DLR response. Our results suggest that surface DLR is tightly coupled to surface temperature; therefore, it cannot be considered an independent component of the surface energy budget.

 

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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Uranium in Drinking Water of Certain Populations

Corlin L, Rock T, Cordova J, Woodin M, Durant JL, Gute DM, Ingram J, Brugge D. Health Effects and Environmental Justice Concerns of Exposure to Uranium in Drinking Water. Current environmental health reports. 2016 Nov 4.

We discuss the recent epidemiologic literature regarding health effects of uranium exposure in drinking water focusing on the chemical characteristics of uranium. While there is strong toxicologic evidence for renal and reproductive effects as well as DNA damage, the epidemiologic evidence for these effects in people exposed to uranium in drinking water is limited. Further, epidemiologic evidence is lacking for cardiovascular and oncogenic effects. One challenge in characterizing health effects of uranium in drinking water is the paucity of long-term cohort studies with individual level exposure assessment. Nevertheless, there are environmental justice concerns due to the substantial exposures for certain populations. For example, we present original data suggesting that individuals living in the Navajo Nation are exposed to high levels of uranium in unregulated well water used for drinking. In 10 out of 185 samples (5.4 %), concentrations of uranium exceeded standards under the Safe Drinking Water Act. Therefore, efforts to mitigate exposure to toxic elements in drinking water are warranted and should be prioritized.

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.

 

Lessons from Fukushima; Nuclear Power Safer than Thought

A different point of view than that of the popular press. But a point of view well justified indeed.

“So what were the lessons learned from Fukushima? Quite simply they are that nuclear power has been proven to be much safer than anyone previously imagined.

The nuclear fraternity worldwide should have celebrated after the Fukushima drama. The world watched the entire saga, second by second…and what was the outcome?

Answer: total people killed by radiation, zero. Total injured, zero. Total private property damaged by radiation, zero. Expected long term effects on people; zero.” – Dr. Kelvin Kemm (click here)