Linear Non-Threshold (LNT) - sounds like some thing I encountered in soil physics many years ago.
Nope - my new BFF, Joe Cotruvo, is once again educating me about dose, response, LNTs, and similar things. It's another paper!
Joe included this message:
Here is another recent 2-pager from Ed Calabrese [see his earlier papers I posted] on the history of the Linear Non Threshold vs Threshold cancer risk methodology in radiation carcinogenesis. He feels that the traditional threshold approach was buried via some bias by committee selection by the senior leadership in the NAS and The Rockefeller Foundation in NAS reports in the 50's,60's and 70's.. He feels that the committees mistakenly based their revised LNT conclusions on a megamouse study by Russell et al, that Russell later reexamined and determined that there were thresholds. The committees assumed cumulative dose, rather than dose rate, which eliminated consideration of repair processes at lower dose rates.
The LNT was then applied to chemicals.
I don't know if your readers are into this esoteric stuff, but it is important. But for the LNT risk assessment approach, there would be very little to talk about with regard to potential risks from trace ppb, ppt ...environmental contaminants in food and water.This is an easy read.
Highlights
- •The NCRPM became the first organization to recommend LNT for cancer risk assessment in 1958.
- •Two NAS BEAR (genetic and medicine) panels in 1960 concluded cancer risk assessment was too unreliable to perform.
- •These recommendations were ignored by BEIR (1972) and EPA in 1975 that adopted LNT.
This paper provides an historical assessment of how the linear non-threshold (LNT) model became adopted as policy by the United States Environmental Protection Agency (US EPA) in 1975 [1] and how prior United States National Academy of Sciences (US NAS) radiation advisory panels may have affected
this EPA decision. The paper highlights a generally unrecognized set of recommendations of the 1960 Biological Effect of Atomic Radiation [2] Genetics and Medical/Pathology Panels that did not support LNT for cancer risk assessment due to their judgements of its scientific limitations and unacceptable uncertainties. These convergent, independent and high profile recommendations were not promoted by the sponsors (i.e., Rockefeller Foundation and the NAS), and were ignored by the media, Congress and thescientific community in contrast to the vast attention directed to the linearity recommendation for germ cell mutation by the BEAR Genetics Panel in 1956 [3,4]. The subsequent Biological Effects of Ionizing Radiation (BEIR) I Committee (1972) [5] report ignored these BEAR Panel (1960) [2] recommendations, only commenting on the BEAR 1956 linearity supporting recommendation [3,4]. These actions are documented and assessed for how they influenced why and how EPA adopted linearity for cancer risk assessment based on the BEIR I report.
Enjoy!
“Done is better than perfect.” – Sheryl Sandberg
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