Radiation from Japanese Reactors Found in SJC Rainwater

By Stan Matthews
County Communications Program Manager

San Juan County Health Officer, Frank James, M.D., reports that measurable amounts of radiation from Japan have been found in rainwater in San Juan County, but in amounts that do not raise health concerns.

In statewide tests, the measurable amount of radioactive iodine in the air peaked in tests conducted in Olympia on March 20 and in rainwater about a week later.

Results of tests on samples taken from a rainwater catchment system in San Juan County on April 1 found a level of iodine 131 at only 10% of the level which would normally trigger re-testing, and a fraction of a percentage point of the level at which it would be a public health concern for “a single point in time exposure.”

Dr. James notes that the level is slightly above the drinking water standard; however he said, “That standard considers that the risk of drinking 2 liters of contaminated water daily for 70 years would increase the risk of cancer by one person in one million.”

Dr. James said that because the half-life of radioactive iodine is only 8 days, the amount of radiation in the water should drop below detectable levels in approximately 80 days. A second test may be performed here next week to confirm that radiation levels here are falling, as expected

The vast majority of San Juan County residents get their drinking water from wells, community or municipal water systems, which have not been affected by the release of radiation in Japan.

The radioactive iodine contamination is related to a single ‘venting’ of the pressurized containment vessels that occurred on March 12, 2011 at a Japanese electrical plant. No other releases are believed to have occurred that would lead to additional contamination reaching the US.

For further information see the Washington Department of  Health “Frequently Asked Questions” at www.doh.wa.gov/Topics/japan2011