The Black Swan Lands in Japan – Part 5 – Cancer in the water

There is a continuing debate as to whether Hawaiians and other Americans are being exposed to harmful levels of radiation from the Fukushima nuclear power plants. Although there has been a lot of discussion about radioactive isotopes in Hawaiian milk, the highest concentrations of I-131 in the US has been found in rain water. However, no rainwater has been tested in Hawaii (although samples from precipitation have been collected in 19 other states, from Alaska to New Hampshire). This is odd because many Hawaiians get their drinking water from rain.

From: Guidelines on Rainwater Catchment Systems for Hawai‘i by Patricia S. H. Macomber, 2010

An estimated 30,000 to 60,000 people in the state of Hawai‘i are dependent on a rainwater catchment system for their water needs.

The concentration of I-131 in the air in Oahu, HI on March 21, 2011 was 1.4 picocuries per cubic meter. This is the fifth highest concentration, from 229 samples, reported in the US, thus far. Since rain carries fallout from the air to the ground, it seems reasonable to propose that there is a relationship between the amount of fallout in the air and the amount in rainwater. This suggests a possible method for estimating the amount of fallout in Hawaiian rainwater.

I’ve extracted the following information from EPA sampling data:

Air (picocuries per cubic meter)
Boise, ID – March 27, 2011 – 0.22

Rain (picocuries per liter)
Boise, ID – March 27, 2011 – 390

Thus, on March 27, 2011 in Boise, Idaho, every 0.1 picocurie of I-131 per cubic meter of air appears to have resulted in 177 picocuries per liter of rainwater. If a similar relationship between air and rainwater held on in Hawaii on March 21, 2011, then we would have expected that the rain would contain approximately 2,481 picocuries per liter.

In an outstanding blog, Jeff McMahon at Forbes reveals that the EPA’s Maximum Contaminant Level for drinking water for 1 year is 700 picocuries per liter. Since most people drink at least 2 liters of water per day, the 30,000 to 60,00o Hawaiians who get their drinking water from the rain could have gotten more than the EPA maximum yearly exposure in a single day! What’s the FDA’s warning threshold? 4,700 picocuries (Big Island Video News, April 14, 2011).

Jeff McMahon’s blog also discloses that the EPA levels are based on 1 cancer death per million people exposed while the FDA’s levels are based on 1 cancer death per 10,000 exposed people. Given that tens of thousands of Hawaiians may have been exposed to about 5,000 picocuries of I-131 per day for weeks, it is certainly possible that some of them may get thyroid cancer as a result.

My estimate of possible rainwater contamination in Hawaii is admittedly based on very little data and could easily be off by quite a bit. But it should raise some hard questions about the actions of public health officials in Hawaii. They did not test rainwater for radioactive isotopes even though they knew that tens of thousands of Hawaiians use this as their primary drinking water. They have indicated that they may start testing next week (Big Island Video News, April 14, 2011), but this is too late. I-131 has a half life of 8 days. Thus, levels will be greatly reduced by the time testing is done. We may never know how much radiation Hawaiians who use cachments were exposed to.

In my opinion, public health officials have botched the response to the disaster in Japan in a way that puts Hawaiians at risk. It is possible that there will be another large release of radioactivity from the reactors at Fukushima, perhaps much larger than the ones in the past. If this occurs, Hawaiians (and all Americans) need to know that their potential exposures are being monitored in a timely way. Further, they need specific information on how to purify their water to prevent exposure to radioactive fallout. Public health officials could start by publicising this paper:

Preparing an Emergency Food Supply – Storing Water Supplies
by Drs. Andress and Harrison at the University of Georgia, Department of Food and Nutrition


Distillation will remove microbes, heavy metals, salts, most other chemicals, and radioactive dust and dirt, called radioactive fallout. Filtering will also remove radioactive fallout. (Water itself cannot become radioactive, but it can be contaminated by radioactive fallout. It is unsafe to drink water that contains radioactive fallout.)


[edited April 17, 2011 to correct quote from Jeff McMahon to read “700 picocuries per liter” instead of “4,700 picocuries per liter”. Thanks to Commentator hemlock for this correction.]


11 thoughts on “The Black Swan Lands in Japan – Part 5 – Cancer in the water

  1. Thanks for that information. I see that that bit of data was published on April 15, after my blog was written.

    The date the sample was collected, April 7, is well past the time period of maximum exposure. Note, the Idaho results were from March 27. I’m sure that when the rain cachments are measured next week the levels for I-131 will be low. The question is, what would have been found March 14-21 when exposure levels were at their highest?

  2. Another thought occurs to me about the information Flina has provided. The date the sample was collected was April 7 but the date the information was made public was April 15. From a public health standpoint, what good is information 1 week later? If dangerous levels of radiation are present in rainwater, don’t people need to know that right away, not a week later? Under the current system, people could be making formula for infants with water with high levels of radioactive isotopes for a week before they are informed of this fact.

  3. You blog article states that the Forbes article stated that the EPA’s MCL for drinking water per year is 4,700 picoCuries per liter.
    I believe what you state is incorrect and what he stated in his article is also incorrect or a typo.
    The Forbes writer states the EPA’s MCL is 700 picocuries per liter per year while the FDA states the MCL for Milk is 4700 picoCuries per liter. It doesn’t compute.
    If it was 700 picoCurries per liter and one drank 2 liters a day of H2O one would get a dose of 1400 picocurries per day. you see where I am going.

    I think the truth is closer to the EPA’s MCL is about 700 picoCuries per year.
    Since the EPA’s MCL for drinking water is 3 picocuries per liter per day that would make more sense wouldn’t it.

    Also where didn you get that data for Boise? I ma trying to find it on the EPA site but I can’t see to find via your link.

    Thanks. If I am wrong let me know too.

  4. hemlock, you’re right that Mr. McMahon has 700 picocuries as the EPA’s MCL for yearly I-131 instead of 4,700. Thanks for pointing this out. I’ve corrected this in my blog.

  5. hemlock, the document Mr. McMahon gets his information from is apparently:

    Prepared by
    Clement International Corporation
    1201 Gaines Street
    Ruston, Louisiana 71270
    Wade Miller Associates
    1911 North Myer Drive
    Arlington, Virginia 22209
    July 1991

    Prepared for

    Drinking Water Standards Division
    Office of Ground Water and Drinking Water and Office of Radiation Programs
    U.S. Environmental Protection Agency
    Washington, DC 20460

    Here are some excerpts:
    “In drinking water, average concentrations of the beta emitting radionuclides of concern are as follows: <0.2 pCi/L (strontium-90), 100 to 300 pCi/L (tritium), and <0.1 pCi/L (iodine-131).”

    “Although not having a 4 mrem per year equivalent level specified in the current drinking water regulations as do tritium and strontium-90, the compliance monitoring scheme indicates that an iodine-131 level of 3 pCi/L is the MCL compliance level (presumably derived from the NBS Handbook); the ANPRM indicates that 700 pCi/L is the 4 mrem/year equivalent. As shown in Table II-l, the annual composite measurements for iodine-131 are far below these levels, with a range of -2.5 to 0.4 pCi/L, and typical average values falling below 0.1 pCi/L (including many that are negative values)”

    “In animals receiving 525 or 875 pCi, fibrosis occurred in the peripheral portions of the parathyroid glands and slight glomerular congestion and slight cloudy swelling was observed in the kidneys up to one week after exposure (Goldberg et al. 1950).”

  6. hemlock, you may be right about Mr. McMahon misinterpreting the FDA limits, which are referred to as “protective action guides” (PAGs), “Derived Intervention Levels” (DILs) and “Levels of Concern” (LOCs) . The calculations for these are complicated.

    The relevant FDA document appears to be:
    Supporting Document for Guidance Levels for Radionuclides in Domestic and Imported Foods

    There are 8 tables. The column headers refer to ages for which the standards apply. It is possible that he confused the header for a 1 year old for 1 year of exposure. However, table 5 estimates the amount of food consumed by each age group for 1 year.

    From the FDA publication:

    “By definition, a DIL corresponds to the radionuclide activity concentration in food present throughout the relevant period of time that, in the absence of any intervention, could lead to an individual receiving a radiation dose equal to the PAG. The equation given below is the formula that the agency used for calculating recommended DILs.

    DILs (Bq/kg) = [PAG (mSv)] / [f x FI (kg) x DC (mSv/Bq)]


    DC = Dose Coefficient; the radiation dose received per unit of radionuclide activity ingested (mSv/Bq)

    f = Fraction of the food intake assumed to be contaminated

    FI = Food Intake; the quantity of food consumed in an appropriate period of time (kg)”

    So, what is “an appropriate period of time”?

    Also, in the FDA document:

    “Following the Chernobyl nuclear accident in 1986, FDA that same year issued CPG Sec. 560.750 Radionuclides in Imported Foods — Levels of Concern (CPG 7119.14) which established guidance levels referred to as Levels of Concern (LOCs) for radionuclide activity concentration in food offered for import.

    The LOCs in CPG 7119.14 were derived from the Preventative PAGs established in the 1982 FDA guidance document and were based on the following assumptions: 1) the entire intake of food would be contaminated, 2) Iodine-131 would be a major source of radiation dose for only 60 days following the accident, and 3) Cesium-134 + Cesium-137 could be a major source of radiation dose for up to one year. ”

    So, I think that FDA levels in this document assume exposure to I-131 will only be for 60 days, but I’m not 100% sure of this. However, if this interpretation is correct, then using the FDA limits for the current crisis is inappropriate. These limits were established for a Chernobyl-like accident which led to a single pulse of contamination. Fukushima is releasing radiation over an extended period of time. When it will stop, no-one knows.

  7. hemlock:

    Also where didn you get that data for Boise? I ma trying to find it on the EPA site but I can’t see to find via your link.

    I checked my link, and it appears to work fine. Try this URL:

    The information is in a Socrata table which may not display properly in the browser you are using. It works fine in Safari. You will need to use the scroll bar to get down to Idaho.

  8. Hmm, does the fact that hawaii has 10x the rainfall of boise mean that the estimate for the amount of radiation in the water should be decreased by a factor of 10?

  9. I see what you’re saying, but if I understand what is going on, I think the answer to your question is no.

    Very fine particles from Japan are wafting on the wind. When it rains or snows, they precipitate out of the air in, well, precipitation. So, the question is, will it all be gone after the first rain? I think the answer to that question is clearly no. It must have rained many times before the particles reached Idaho, yet, they clearly received a very significant dose of radiation in their rainwater. There must be a *lot* of fine particles with radioactive isotopes along for the ride in the air. How many rains will it take before they are all gone? No-one knows, but there is no evidence that we have reached this point yet.

    So, I would take your observation, that Hawaii has 10X the rainfall of Boise and turn it around. Hawaii is likely receiving 10X the total amount of radiation in their environment as Idaho, imo.

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