The state Health Department confirmed that strontium-89 from Japan’s nuclear release was detected in Big Island dairy milk after a nationwide high level of cesium also was found in the same April 4 testing.
The U.S. Environmental Protection Agency posted the finding Tuesday on its website, saying 1.4 picocuries per liter of strontium were detected in Hilo.
However, Lynn Nakasone, administrator of the Health Department’s Environmental Health Services Division, said the strontium is not a danger.
"It’s of no health consequence," Nakasone said. "I realize it is a different reading and new data, but I guess from our point of view, it’s not a health risk."
Trace amounts of cesium-134 and 137 and iodine-131 were previously reported in Hilo milk. The U.S. Food and Drug Administration’s "action level" for strontium-89 and 90 is 4,400 picocuries per liter, Nakasone said.
Although still far below health risk concerns, Hilo dairy milk had the highest nationwide levels of cesium when testing was conducted on April 4, she said. That may have triggered additional testing for strontium, an isotope not part of the EPA’s "RadNet" publicly available radiation readings. The EPA posted the Hilo finding as a separate update.
"Usually, if you see cesium, you will see strontium, so I guess what EPA did was they ran the tests for strontium (based on Hilo’s cesium detection), and that determined there was a small amount of (strontium) in the milk," Nakasone said.
Forbes blogger Jeff McMahon reported the Hilo detection was the first for strontium in the country.
"We have completed our first strontium milk sample analysis and found trace amounts of strontium-89 in a milk sample from Hilo. The level was about 27,000 times below the Derived Intervention Level set by the U.S. Food and Drug Administration," McMahon reported the EPA as saying in a statement.
The EPA in Honolulu could not confirm the information, or explain why strontium is not part of regular RadNet reporting on its website.
"We tried to call EPA, but I think the lab is just totally booked up and they are not returning all their phone calls," Nakasone said. Testing for strontium is done on different equipment than that used for cesium and iodine, she said.
A second Hilo milk sample was taken by the EPA on April 13 — the most recent testing — and cesium and iodine levels dropped significantly, officials said. Iodine-131, in fact, was no longer detected.
Because the trace cesium levels have dropped even further in Hilo, Nakasone speculated that the EPA won’t test for strontium from the April 13 sampling.
Strontium-90 is chemically similar to calcium, and is referred to as a "bone seeker" because it tends to deposit in bone and bone marrow, the EPA said on its website.
About 70 to 80 percent of ingested strontium-90 passes through the body and virtually all of the remainder is absorbed and deposited in bone.