Our bodies are subject to all sorts of chemical and physical insults from the food we eat to thermal changes that occur. These insults’ to our body, as they are called, cause breaks in the strands of our DNA at very high rates: 8,000 per body cell per hour. Any one of these can result in cancer. The lifetime damage is immense: 5 x 1019 breaks in 75 years so it would seem that it’s almost certain we will have cancer.
Fortunately, most of this damage is bypassed by cell reproduction (the damaged ones reproduce less often) or they are repaired. We have a wonderful body.
But anti-nuclear activists teach us that any radiation can cause cancer. How might that happen?
If we add radiation to our normal cancerous background about 100 more breaks are added to the 8,000 per cell per radiation unit (10 mGy.) This is true if we are irradiated instantaneously and receive all the radiation in one dose. However, if we get that radiation unit spread out over a year as an increased background dose we add about one break per cell. That compares to 200,000 breaks from oxidative and thermal insults from food and our environment. Such a low increase in harm (1 in 200,000) is negligible in adding to the risk of cancer.
However, there are important benefits because this low level radiation enhances the repair mechanism for the other potential cancers and it makes our risk of cancer lower.
The effects have been well demonstrated in epidemiological studies (studies of effects) of large populations. Low-level radiation effects are difficult to study because, by definition, the effects are small and take a long time to develop. So, we study them through studies of large populations that experience the same radiation conditions for a long time. We also have to remove confounding effects such a smoking, poverty, bad diet and so on.
Long-term studies have been performed with stable populations up to 80,000 people, in places where the people can be tracked. Chinese peasants, for example, do not move around like Americans so it’s easy to track large populations for decades. A large population that lives in a high background radiation area is compared to a similarly sized population in a low background radiation area.
These studies have been done in China, in India, in Brazil, and in the USA, among groups subjected to weapons testing, in populations whose work is with nuclear materials, in patients of low-dose radiation therapies, and in survivors at Nagasaki and Hiroshima. It is universally true that no adverse effects have been found and in most cases the rates of different cancers have been lower where the radiation is higher.
A stable Chinese population of 74,000 in an area of high radiation (about 4 times at sea-level) was compared to a 77,000-person control group. There were no adverse effects and cancer rates were lower.
In Kerala where the exposure is also 4 times higher, a 13,000-person group was compared over years against a 6,000-person control group. There were no adverse effects but a slightly higher rate of Down’s syndrome although still lower than the overall Indian rate.
Similarly in Guarapari, Brazil, at six times background there were no adverse effects.
Nearly 47,000 nuclear weapon test participants had no increase in the normal rate of cancers or leukemia.
There was no increase in the cancer rate among 36,000 Swedish patients who received doses of radiation for hyperthyroid. This was true also for British radiologists and workers at the major nuclear site.
At Hiroshima and Nagasaki there were no significant harmful effects below 10 rem a comparatively large dose of about 50 times sea-level background. Moreover, there were fewer cancers for all those exposed to 20 rem or less.
Some US examples:
Bernard Cohen of the University of Pittsburgh studied 1,729 US counties for the effects of radon in the homes on lung cancers. He found a decrease in lung cancer with increasing radon in homes. This was not true for smokers so if you are worried about getting cancer from the radon in your basement, the solution is to stop smoking.
108,000 Virginia shipyard workers who had additional radiation doses from working on nuclear submarines were found to have 24% less cancers than the totality of 700,000 workers most of whom worked on non-nuclear ships.
The population of the seven Colorado plateau states with two to three times sea level background exposure to radiation was compared to the Gulf States. We have 15% less cancers at our altitude.
Much work is also being done in the laboratory on cellular effects to confirm the larger studies.
In France, experiments were performed in which protozoa (elementary organisms) were shielded from radiation. Some were shielded by 5 cm of lead and others by 10 cm. They discovered that the more the protozoa were protected, the more abnormal was their growth. Indeed, they needed radiation to grow normally. This also appears to be true for humans: after all we have grown up in a sea of radiation.
Unfortunately at one time we only knew that very high doses of radiation can kill so for safety we theorized that any dose would harm you. That is the same as saying if 100 aspirins can kill then any aspirin is harmful (despite our knowledge that aspirin in small doses is very beneficial.)
High doses have severe results, including death, but low doses have positive health effects and the crossover point is called the threshold’ to harm above which a dose becomes harmful. This is at about ten times background at sea level.
OUR PRESENT RADIATION REGULATION IS KILLING PEOPLE
Some people still hold to the “any radiation is harmful” straight-line respons and so our regulations are draconian. When you compare harmful levels of radiation against the regulations it is approximately the same as saying:
If there were a cliff over which we might fall to our death and we lived 1,578 miles away, our regulators require that we take great care and correct ourselves if we move 0.06 thousandths of inch towards the cliff.
A million women have a certain chance of dying of cancer eventually. If those million women where given a diagnostic exposure of 15 cGy for breast cancer international regulations predict that 900 more of the women would die than if they didn’t have that exposure. However, actual low-dose Canadian data shows, with better than 99% confidence, that 10,000 deaths fewer of those million women would die of cancer.
Thus, our Government regulations are actually killing people by discouraging radiation treatments.
In summary our cancerous background is caused by many oxidative and thermal insults but we are very well protected by a natural repair mechanism and that repair mechanism can be enhanced, improved, by small amounts of radiation.
A large amount of radiation taken instantly is dangerous, but a small amount of radiation is beneficial: it reduces the number of cancers.
I’m very glad I live in a high background radiation area in Colorado.
