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.]