Saturday, December 15, 2007

Morning thoughts, Leukemia and German Reactors

Lee Progress

On Thursday, Duke Energy submitted a licensing application for the Lee Nuclear Station in Cherokee County, North Carolina. This must have been a moment of great satisfaction to Ruth of We Support Lee, Nuclear Australia has already extended its congratulations and I join them in the sentiment.

Leukemia and reactors

There is a considerable gap between the the known causes of leukemia and the causes of cancer clusters in a given population. A recent German report found that between 1980 and 2003, 37 children living in the vicinity of 16 reactors contracted leukemia. The report states that for the subject population, 17 cases would have been expected. More information would have been helpful. For example, news releases do not mention patterns associated with individual reactors. It is very unlikely that the cases were distributed between all reactors evenly, or that they were distributed evenly through time. I say this because it is known that a leukemia cluster occurred in the North German community of Elbmarsch between 1990 and 1996. All nine of the children involved lived within 4500 meters of the Kruemmel reactor. Five of the nine cases were reported within 18 months of each other in 1990-1991.

The other 4 were reported in 1995-1996. The first six cases could be further localized to about 20% of a 5 Km ratdius from the plant. Five more cases were reported in the same area between 1999 and 2005. The same report stated that there were several other leukemia clusters associated with reactors in Europe. However, a comparative study of the area around the Savannah River Reactor operation, and the Kruemmel revealed that childhood leukemia case levels were not elevated in the Savannah River area. Since several releases of radioactive tritium were known to have occurred from the Savannah River site, and those releases exceed those from the Kruemmel site by several orders of magnitude, it is unlikely that releases of tritium played a role in the Kruemmel cluster.

Radiation monitoring in at the Kruemmel reactor and in the surrounding area have not detected releases of radioactive material from the reactor. However, reports (for example, here) indicate the presence of 238Pu, 239,240Pu, 241Am, and 244Cm in homes in the Elbmarsch community.

There have been reported leaks of coolant water from the Kruemmel facility, but this could hardly explain the presence of transuranium elements in Elbmarsch homes. No transport vector between the Kruemmel reactor has been found, or as far as I can tell, even suggested. The transuranium element could have come from fall out from nuclear tests, or Chernobyl fallout. But this is deemed unlikely. The Elbmarsch leukemia cluster has been the subject of extensive and ongoing study. The Kruemmel facility has also been the subject of intensive study and on going monitoring. To date no source of environmental transport of reactor byproducts inside the reactor or from within the facility has been found.

Studies of an association between childhood leukemia and the proximity of reactors have been inconclusive. One 1991 study of 107 counties near 62 nuclear facilities by the American National Cancer Institute found that the childhood leukemia rate for the reported areas dropped slightly after the reactors started operating. Another report of the same study indicated that one childhood Leukemia cluster was associated with the Millstone Power Plant located in New London, Connecticut. Three of the studied facilities had significantly fewer leukemia cases than were expected. Windham County, Vermont, where the Vermont Yankee reactor is located was reported to have only 9% of expected childhood leukemia cases.

Repeated studies failed to uncover an association between The Three Mile Island accident and childhood leukemia (see here , and here. Even more remarkable, studies have failed to uncover a relationship between exposure to radiation from Chernobyl and childhood leukemia (see here, and here). In the latter study, "Childhood leukaemia in Belarus, Russia, and Ukraine following the Chernobyl power station accident: results from an international collaborative population-based case–control study," S.Davis, RW Day, KJ Kopecky, MC Mahoney, PL McCarthy, AM Michalek, KB Moysich, LE Onstad, VF Stepanenko, PG Voillequé and others, "conclude that this study provides no convincing evidence of an increased risk of childhood leukaemia as a result of exposure to Chernobyl radiation, . ." They report some evidence that suggest effects of exposure to very low levels of radiation, as a causivetive factor in leukemia, but acknowledge that "prolonged exposure to very low radiation doses may increase leukaemia risk as much as or even more than acute exposure, but are inconsistent with published literature regarding the risk of leukaemia in relation to protracted radiation doses of the very low magnitude observed in this study."

It is clear then that radiation and isotope dangers from large scale and well known incidents like Three Mile Island and Chernobyl are not correlated with increased incidents of leukemia among exposed children. To date, leukemia clusters are far more likely to be associated with the operation of European than American reactors. They do not appear to be associated with large scale radiation releases. If they are caused by low level radiation increases in the environment, it should be expected that leukemia clusters should be associated with locations know to be at higher risk for radiation exposures. One such risk would be found in mountains, but altitude seems to play less a role in mountain related cancer clusters than the presence of tungsten.

It is clear then that there have been leukemia clusters associated with a few nuclear reactors. Some have been explained and others have not. Most reactors appear to be safe. Despite extensive German investigations the Elbmarsch cluster is still unexplained. If a defect in the design or operation of the Kruemmel reactor was responsible for the leukemia cluster, it would be very useful to know. Thus the Elbmarsch leukemia cluster has not been explained and leaves us with a mystery.


Randal Leavitt said...

OK - I have a theory. Leukemia is caused by cleanliness. When children are raised in very clean surroundings their immune systems do not develop sufficiently. This leads to leukemia. That is why it is a rich person disease. Around nuclear plants there are a lot of well-off people due to the well paid local economy caused by the plant. This means that a lot of children are raised in very clean facilities, and in isolation without much contact with other children. This is the perfect breeding ground for leukemia.

Charles Barton said...

In fact on of the theories of the Elbmarsch cluster is that the children had immature immune systems. Immature, because the immune systems had not been sufficiently activated by challenges. The problem with this theory is that nothing unusual has been identified about child rearing in Elbmarsch. As far as we know, the Elbmarsch kids are not cleaner than other German kids. I don't know if it is still true, but when I was young, it was notorious that Europeans did not bath as often as Americans.

Stephen said...

I've seen some reports which claim association with leukemia around nuclear plants, but they're always very very very vague like this one. If there were such an association you'd expect there to be a larger number than this relatively small increase. The sample size ends up being tiny.

Even still, you'd expect this to show up around certain reactors, assuming that not all would be equally "leaky."

I've actually looked at the numbers myself in some very large studies and statistical analysis. There's really no evidence. People can point to a supposed cluster here or there but they're all very small and not able to be directly associated with the power plant.

Alison Cox said...

There are only 439 reactors currently operating across the globe- this is an insufficient number to truly classify the impacts on childhood leukaemia. At the moment the main focus is on proving the pattern- there has been very little information on the mechanistic toxicological effects, i.e. HOW does the proximity of a nuclear plant cause it?

Unfortunately, due to the traumatic nature of childhood leukaemia, ethics behind these kind of studies are complex and a lot of phrases such as "for the greater good" etc get banded about.

But this is what the Precautionary Principle is for: a world-reknowned environmental notion that states that in the absence of certainty, err on the side of caution. Don't take the risk with something that impacts on lives.

Charles Barton said...

Alison, You have first significantly under counted the number of reactors in the world. You have ignored hundreds of reactors that are not used in civilian power generation. You have also ignored hundreds of naval reactors, used to power surface and subsurface vessels. Many thousand men and women on board reactor powered ships. They live in close proximity to operating reactors. There is never been empirical evidence of radiation caused sickness among navy crew members.

I submit that the history of civilian and military reactor operation has been extensive enough to determine their safety, and the dangers, if any, which they pose to workers and neighboring populations. The evidence from numerous nuclear facilities in the United States and France, is that nuclear workers have a longer life expectancy than other workers in our society, and that neighboring populations do not suffer adverse health consequences. The empirical evidence is that reactors are highly safe, and even in cases involving major reactor accidents , the long term danger to the civilian population proved to be minimal.

You do not accept the evidence. Would any evidence, no matter how powerful convince you? Or is it simply a matter of a closed mind?


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