Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.2.6
Natural Radiation and Radioactivity

1.2.6.2
Natural Background: Populations

Dr. Yalow also states (1994b) that: "In China, of 150,000 Han peasants living near each other to six generations, about half receive about three times the radiation of the other half from radioactivity in the soil. Investigations since 1972 for doses and health effects find no discernible differences in the health of these populations (Wei 1990). Similar negative results are found in higher background areas in Brazil and India."

Professor and Chairman Emeritus Dr. Don Luckey, Dept. of Biochemistry of the U. Missouri-Columbia School of Medicine reports (1991) on human cancer epidemiology in the U.S.: that showed inverse correlations of cosmic radiation vs. leukemia and lymphomas. Brues (1959), Henry (1961), and Oakley (1972) concluded that the inverse correlation between background radiation and cancer mortality was general. Frigerio at ANL (1973) assumed that all radiation is carcinogenic and persons in high background radiation should have higher cancer mortality. The data for the contiguous U.S. produced exactly the opposite result for 56 cancers, especially leukemias, p<0.001, and confirmed in counties, states, and regions. Other studies of the Western states, found considerably lower cancer mortality vs. the average of the other U.S. states. With total cancer mortality 84.5% of that for the average of the U.S., and lung cancer mortality only 71% of the U.S. average. Both low-dose coastal areas were found to have higher cancer mortality rates than the average. Sauer et al. (1980) exhausted all possibilities for any correlation between the death rates of white males in the eastern coastal areas and about 30 possible factors, including air and water composition, factories, economic status, ethnic background, and social status. However, background radiation produced statistically significant, p <0.01, inverse correlations with total death rates, cancer death rates and cardiovascular death rates (Sauer 1982).

Professor Luckey reports further on the effect of radiation on reproduction (1991) that: fertility is more than the flip side of sterility; it includes embryo viability and quantitative as well as qualitative factors. The poorly fed coastal population in Kerala receives 4-8 times more background radiation than the average for other areas. The people of Kerala have a higher fertility rate with the fewest neonatal deaths than any other state of India. The high terrestrial radiation, 9 mGy/year, in Espirito Santo, Brazil, did not affect the fertility or fecundity of 8000 couples. (Freire-Maya 1978) When Chinese women over 35 years old were chronically exposed to three times more background radiation than the control group, they had more children than the control women, p<0.05. (Wei et al. 1986) There was no difference in fertility of younger women between the two groups.

Professor Luckey also finds (1995) that: in 77,000 Chinese peasants living at a world-average background radiation level, vs. 73,000 peasants living with background radiation doses three times higher, with a total of 2,500,000 person-years, the non-leukemia cancer mortality rate of the 40-70 years age group is statistically lower in peasants living in the high background radiation group. Cancer mortality rate, lung cancer mortality, and leukemia mortality were lower in the high-background population, p=0.05. In the high-background population, infertility was lower, p<0.05 neonatal mortality was only 76 percent that of the controls, p=NS, and life expectancy of people over 40 years old was longer, p<0.05.

Professor Emeritus, and Member of the UN Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), of the Central Laboratory for Radiological Protection, Dr. Zbigniew Jaworowski states (1995a) that: "The question arises: why governments of various countries do not relocate populations living in areas where lifetime dose of natural radiation is higher than 350 mSv. For example, why are people not evacuated from Norway where all country average lifetime dose is 365 mSv (Henriksen 1988), or from high background regions in India with a lifetime dose of >2000 mSv (Sunta 1990) and in Iran with lifetime dose of >3000 mSv (Sohrabi 1990)? Perhaps in Iran, for example, the government considered not to follow the ICRP guidelines when it considered the fact that in a house in the city of Ramsar several generations were receiving average individual lifetime doses of natural radiation of 17,000 mSv (240 times more than the current ICRP limit for exposure of members of the public to natural sources of radiation). Yet these individuals show no increased incidence of any disease, and some of them lived to 110 years of age (Sohrabi 1990)."

Professor Jaworowski also states (1995b) that: "The best radioepidemiological study at low doses to date has been carried out in China. Between 1970 and 1986, 74,000 people in Yangjiang county, which has a high level of natural background radiation (5.5 mSv per year), were compared to 77,000 people in two adjacent low-background counties (Enping and Taishan, 2.1 mSv per year). In the high-background county, the inhabitants receive a 70-year lifetime dose of 385 mSv, which is higher than the intervention level for evacuation adopted for Chernobyl, and 5.5 times higher than the dose limit proposed in the EPA. Should the Chinese government evacuate Yangjiang county? The epidemiological data show that.... in an age group of 10-79 years the general (non-leukemia) cancer mortality was 14.6% lower in the high-background county than in the low-background counties. The leukemia mortality among men was 15% lower and among women 60% lower in Yangjiang (Wei et al. 1990)."

From the abstract, Black and colleagues, of the UK National Health Service in Scotland report (1994) that: "Cancer incidence in the Dalgety Bay area of Fife, Scotland, was examined following the detection of radium-226 particles. In the period 1975-90, 211 residents were registered as having cancer compared with 214.21 expected from Scottish national rates. Of specific cancers possibly associated with radiation, the incidence of stomach, liver, lung, bone, prostate, bladder and kidney cancer and lymphoma were lower than expected while colon, rectum, pancreas, skin, breast and thyroid cancer and multiple myeloma and leukaemia were higher. There were three cases of childhood leukaemia compared with 1.22 expected. The only statistically significant differences observed were for pancreas (11 cases, O/E 2.28), lung (25 cases, O/E 0.65) and non-melanoma skin (36 cases, O/E 1.50). Stomach cancer was of borderline statistical significance (four cases, O/E 0.40). ..The anatomical distribution of the 36 cases was similar to that found elsewhere in Scotland."

Dr. Norman Frigerio, Dr. Keith Eckerman, and Ralph Stowe reported (1973) that: Argonne was contracted to aid AEC for environmental statements for nuclear facilities being licensed, and that "the hypothesis has been advanced that a significant fraction of human cancer mortality may be due to the human radiation background", i.e., at 170 millirem/yr, U. S. cancer mortality excesses are about 3,000 to 100,000 per year (about 1% to 30% of current experience). Since so important an etiologic factor would be of major significance in cancer epidemiology, we examined these hypotheses from current vital statistics and known radiation background. At about 33,600 cancer deaths/yr, i.e., about 10% of experience, spread over 56 Mn types, about 54 radiogenic deaths per million population per Mn type for the 18-year period of observation is expected.

Populations at rates below 0.3 and 0.03, by sex, race, Mn type, and state of residence, were applied to bracket a rate at which the linear additive model would be easily tenable. Cancer epidemiology does not usually consider expectations <5 or so, much less as decimals, but this is the practice in radiation carcinogenesis studies. Thus, we have allowed this practice at rates of 0.3 or 0.03. At 0.003 a plus sign (+) indicates that the value is mathematically real but less than 1. With so many Mn sites "violating the requirements of the model", even as judged simply by the ‘t’-test, we had to admit that it was extraordinarily improbable, at least at these levels. So, we dropped our search value until, at 0.006, all of the observations went to zero except for the three stalwarts, ICD 151, 153 and 171. Since we might have something, we did our estimations on 0.003, the mid-value of the interval, rather than 0.006, its upper bound. In this range level, the normal ‘t’-test becomes awkward, so we resorted to the more powerful Monte Carlo method. The U.S. population was subjected to a random "rain" of radio-carcinogenic deaths at 0.003 for 100 18-year periods. Ergo, not only is the null hypothesis, at 0.003, improbable, but Monte Carlo results suggest that a level of roughly 0.003/20 would be needed to reach even a 63% confidence level. This corresponds to about 16 deaths/yr per 200,000,000 population, about 0.005% of current U. S. mortality. In any case the model certainly seemed untenable at any level much greater than 0.003/20 = 1.5x10^-4, at least as its authors originally presented it. extended summary:

Dr. Luxin Wei of the High Background Radiation Research Group of the Laboratory of Industrial Hygiene in the Ministry of Health, Beijing China, reports on a Chinese HBRA study (1997) that: if we consider the High Background Radiation Area (HBRA) as a whole (with three groups of ‘high’, ‘medial’ and ‘low’), the ratio of external dose rates between HBRA and Control Area (CA) is 3.5 for indoors, and 3.7 for outdoors. Adjusted RRs (90% CI) of site-specific cancers for the four dose groups show no statistical difference. Cancer mortality does not increase with the increased radiation dose rate. The prevalence of 31 kinds of hereditary diseases and congenital defects in children (<12 years old ) were almost identical, except the rate of Down Syndrome was higher in the HBRA. However, Down Syndrome was in the normal range of spontaneous rate compared with other places in the same Province and other places in China. The "no-threshold, linear" hypothesis estimates the risk for low dose exposure as ‘no matter how small the dose, there will be increment of cancer induction.’ But the HBRA results have not demonstrated any increment of cancer mortality.

Increased chromosome aberrations were observed in the HBRA, and effects induced by ionizing radiation can not be excluded. Nevertheless, to the contrary, cell-mediated immunity examination revealed that there is a tendency of strengthening of immune functions among the HBRA inhabitants. If the former is disadvantageous, thus the latter is beneficial. So, there is a competition between these two kinds of effects. We have found no increase of mutation-based diseases. Possibly, the beneficial effects are superior to the detrimental effects in case of low level radiation of HBRA.

Dr. ZuFan Tao of the High Background Radiation Research Group of the Laboratory of Industrial Hygiene in the Ministry of Health, Beijing China , and colleages from China and Japan, reports on the Chinese HBRA study (1997) that: early cancer mortality data (1970-1978) were collected by a retrospective survey and the data from 1979 on were by a prospective survey through a death registry system. To the end of 1986, there were 467 cancer deaths among 1,008,769 person-years (PYr) at risk in HBRA, vs. 533 cancer deaths and 995,070 Pyr in the CA. Cancer mortality in HBRA was lower than that in CA, though the difference was not statistically significant. The crude mortality rate of overall cancers (per 100,000 PYr) is 51.41 in HBRA and 64.31 in CA.

Dr. P.C. Kesevan of the Bhabha Atomic Research Centre in Bombay, India states (1997a) that: during its first phase of epidemiological studies in the 1970s BARC could not find any significant difference between the groups exposed to different radiation levels. The indicators of genetic change employed by BARC were: sex ratio among offspring; fertility index; infant mortality; pregnancy terminations; multiple births; gross abnormalities. Per capita daily intake of gross alpha, gross beta, 85 keV gamma, radium-228 and potassium-40, activity are estimated to be 215, 3648, 96, 162 and 3551 pCi, respectively, and urinary excretion of thorium and Ra-228 in male adults residing at Chinnavilai village are at least an order of magnitude higher than those collected from subjects residing at normal background radiation level areas. A substantially increased frequency of chromosomal aberrations exist in the HBRA populations vs. the normal (control) populations. The mean daily intake of Ra-228 by the population living in the monazite area of Kerala is about 40 to 50 times the normal daily intake of this radionuclide. The HBRA studies so far carried out, within the scope of their resolving power, have not revealed any adverse biological effects.

Dr. M. Sohrabi of the National Background Radiation Protection Department, Atomic Energy Organization of Iran, ports (1997)on the three HBRA's that: On the SW coast of India, in an area with 140,000 inhabitants, a sizeable proportion of the population receives exposures exceeding 10 mGy y^-1 with the highest personal dose rate of 32.6 mGy y^-1 to a resident of a house that registered 38.4 mGy y^-1. The average radiation level was estimated to be 15.7 mGy y^-1, vs. an overall mean of 2.08 mGy y^-1 in the nearby control area. The results of the demographic survey for dose-genetical effect correlation, and epidemiological studies as well as studies on chromosomal anomalies of human blood cells and plants, have shown no statistically significant biological effects on the population of HBRAs in India vs. control groups.
In Yangjiang, China, which has been studied since 1972, the average effective dose is 5.4 mSv y^-1, about three times higher than its mean background of 2 mSv y^-1. The results of epidemiological studies over a population of 80,000 have led to a firm conclusion; i.e. no difference was found in mortality rates from all types of cancer or due to leukemia in the HBRAs of Yangjiang vs. the control group.
In Japan, in areas with exposure rates 1) below 7.6 m Gy h^-1, 2) between 7.6 to 10.5 m G h^-1 and 3) above 10.5 m Gy h^-1, with populations of 1) 2,230,300; 2) 2,885,787; and 3) 2,790,818, from 39 areas, including 28 cities and 11 towns and villages, cancer mortality rates of the public exposed to these variations in natural radiation levels in different geological zones show no detectable increase in cancer mortality.