From what I can tell, you would be interested in studies in India (Kerala) [1] and China (Yangjiang) [2] on (what are more or less indigenous) populations with large background radiation (>70mSv/year) that have been done, with no effects seen on cancer or mortality, but they did detect some chromosomal aberration. Also, 1 million people undergo radiation therapy each year, without a statistical increase in secondary (caused by the radiation as opposed to the one they were trying to cure) cancers. And it has been shown that low dose radiation increase protective functions [3]. However, you might want to look for studies on the Navajo Uranium miners.[4] Lots of lung caners, but this was really due to inadequate precautions taken for airborne alpha radiation, which is well known to cause lung cancer, and is actually likely the main reason smokers develop lung cancer from the Polonium in tobacco [5], which of course also disproportionately effects native populations, who are known to smoke more.

I am convinced that the Linear No-Threshold low-dose has been pretty well debunked for cancer and early mortality (see review below)[6], and in fact several studies have shown benefits (hormetic) to low-dose exposure (10 mGy), with no ill effects below 100 mGy. Hiroshima bomb survivors also saw no effects below 150 mSv and other studies have shown no increase in cancer or mortality below 200 mSv. Chernobyl data showed an increase in thyroid cancer, but not below 200 mSv as well, however, children are much more susceptible, and you can get an increase in leukemia from iodine doses that would not affect adults. Airplane crews get a substantial increase in dose and see no ill effects for their dose levels (greater than 50 mSv/year).

Good luck, hope this helps!

[1] Population study in the high natural background radiation area in Kerala, India. Nair MK, Nambi KS, Amma NS, Gangadharan P, Jayalekshmi P, Jayadevan S, Cherian V, Reghuram KN, Radiat Res. 1999 Dec; 152(6 Suppl):S145-8

[2] Cancer mortality in the high background radiation areas of Yangjiang, China during the period between 1979 and 1995. Tao Z, Zha Y, Akiba S, Sun Q, Zou J, Li J, Liu Y, Kato H, Sugahara T, Wei L J Radiat Res. 2000 Oct; 41 Suppl():31-41

Effect of high-level natural radiation on chromosomes of residents in southern China. Hayata I, Wang C, Zhang W, Chen D, Minamihisamatsu M, Morishima H, Wei L, Sugahara T Cytogenet Genome Res. 2004; 104(1-4):237-9

[3] (linked below) Doss, Mohan. “Low Dose Radiation Adaptive Protection to Control Neurodegenerative Diseases.” Dose-Response 12.2 (2014): 277–287. PMC. Web. 2 Mar. 2016. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4036399/

[4] Brugge, Doug, and Rob Goble. “The History of Uranium Mining and the Navajo People.” American Journal of Public Health 92.9 (2002): 1410–1419. Print.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222290/

[5] Cigarette Smoke Radioactivity and Lung Cancer Risk

Hrayr S. Karagueuzian, Celia White, James Sayre,and Amos Norman, Nicotine Tob Res (2012) 14 (1): 79-90. doi: 10.1093/ntr/ntr145  http://ntr.oxfordjournals.org/content/14/1/79.abstract

[6] (linked below) Tubiana, Maurice et al. “The Linear No-Threshold Relationship Is Inconsistent with Radiation Biologic and Experimental Data.” Radiology 251.1 (2009): 13–22. PMC. Web. 2 Mar. 2016. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663584/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663584/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4036399/

Also, don't forget about the Bikini Islanders, native peoples the US basically forcibly moved to irradiate their homeland.  A sad bit of Cold War history.

https://www.bikiniatoll.com/

Kirk Flippo has done excellent job in answering this question. I may add, however, that Indian study referred to by Kirk:

is not nuclear generated but due to presence of Thorium in Kerala beach sands.

C.L. Sanders. 2010. Radiation Hormesis and the Linear-No- Threshold Assumption. Springer, Berlin.

FYI a brand new piece on the Navajo impact of uranium mining.

http://www.npr.org/sections/health-shots/2016/04/10/473547227/for-the-navajo-nation-uranium-minings-deadly-legacy-lingers?utm_source=facebook.com&utm_medium=social&utm_campaign=npr&utm_term=nprnews&utm_content=20160417

Uranium mining effects on population in the area have been carried out in Germany and other countries. Looking up for references?

Thank you to Kirk, Hardev, and Charles for your helpful replies to my question about low level radiation exposure and indigenous peoples. My research team and I have scouring sources to find studies of high level and low level exposure to radiation and toxic chemicals among indigenous peoples at about 22 nuclear detonation and radiactive waste dumps around the world (see our article regarding this topic here: https://intercontinentalcry.org/fourth-world-nuclear-cloud/

Your suggestions have been helpful and now I would broaden my question to encompass a wider array of  locations. We are in touch with the Marshall Islands government, Yakama Indian Nation government and the Maralinga peoples in Australia.

Look also for the studies concerning the Ransar area in Iran. Also not consistent with the LNT: http://www.ncbi.nlm.nih.gov/pubmed?term=ramsar%20background%20radiation&itool=QuerySuggestion

Thank you Radu for that url.

FYI. Environmental Action has a campaign to help the Navajo Nation clean up the Uranium mining contaminated water.

https://environmental-action.webaction.org/p/salsa/donation/common/public/?donate_page_KEY=15993&utm_campaign=Navajo_Water&utm_medium=email&utm_source=email_22312&track=email_22312

Kirk, Your note is well taken.  We have incorporated the Navajo experience in our study. Thank you for this reminder.

Hi. The Norwegian Radiation Protection Agency have done some studies on the sami people regarding cesium pollution. Not sure if there are any material in English.

I guess maybe you are familiar with this monitoring.

"NRPA´s measurements of radioactive caesium in reindeer herders and other people from Kautokeino in northern Norway were finalised in December 2010. This report summarises the monitoring program which was started in 1965" (NRPA, 2012)

The sami people in South of Norway have also been monitored after the Tsjernobyl accident. There are still "high" levels of Cesium in the inviroment where reindeers are eating. Any healtheffects is difficult to find because of the small population, but the sami people in the South of Norway are the most radioactive population in the world. Earlier studies in Norway on this population shows lower cancer risks than the rest of the Norwegian population, despite beeing exposed to higher levels of Cesium. This can be explained by their healthy lifestyle, eating natural food and getting a lot of exercise working with the herds in the wild.

Chronic low dose rate exposure in natural high back ground area may increase cataract risk but not cancer risk.

Article Ionizing radiation sensitivity of the ocular lens and its do...