Radiation from Japan’s nuclear crisis has reached Hawaii’s food stream in milk from a Big Island dairy, but the trace amounts are nowhere near levels of concern, a state health official said.

"There’s no question the milk is safe," said Lynn Naka­sone, administrator of the Health Department’s Environmental Health Services Division.

Recent testing showed that milk collected on April 4 in Hilo had 43 picocuries per liter for cesium-134 and 137 combined, and 18 picocuries for iodine-131.

Nakasone said the U.S. Food and Drug Administration’s "derived intervention level" — the point at which steps would be taken to safeguard the public — is 33,000 picocuries for the combined cesium isotopes and 4,700 picocuries for iodine-131.

At that level the sale of affected milk could be stopped, she said.

The Health Department might request another dairy milk sample within the next month or so, as well as sample surface water catchments. Officials also are looking into the possibility of testing leafy green vegetables.

But Nakasone also said the minute levels of radiation detected in Hawaii should decrease as long as there are no additional significant releases from the Fuku­shima reactor complex.

"(With) the air sampling, we’re seeing sort of a decreasing trend," she said. "Most of this stuff that we’re seeing is from the initial three massive explosions that occurred."

The U.S. Environmental Protection Agency and FDA said in a joint statement on March 30 that in response to the ongoing nuclear crisis in Japan, the EPA had taken steps to increase nationwide monitoring of milk, precipitation, drinking water and other potential radiation exposure routes.

Results from a screening sample taken March 25 from Spokane, Wash., detected 0.8 picocuries per liter of iodine-131 in milk — more than 5,000 times lower than the derived intervention level set by the FDA, the government agencies said.

Iodine-131 has a half-life of about eight days, and the level detected in milk and milk products is expected to drop "relatively quickly," according to the agencies.

"These types of findings are to be expected in the coming days and are far below levels of public concern, including for infants and children," the agencies said.

Cesium-137, by contrast, has a half-life of about 30 years. Iodine and cesium are the two radionuclides detected to date in Hawaii, Naka­sone said. She characterized the amount as "trace" levels.

"Our instruments are so good now that we can detect down to these levels," she said. "Just because we can detect it doesn’t necessarily mean it’s a hazard."

There has been no radiation detected in drinking water in Hawaii, but officials said it takes eight years for surface water to reach aquifers.

Milk was sampled at one unidentified Big Island dairy. Officials said the same results would be expected at other dairies in Hawaii.

"Milk is just one of those indicators," Naka­sone said. "It’s like taking air samples or rainwater samples or drinking water samples. It’s another indicator."

Nakasone also took some issue with postings by Forbes blogger Jeff McMahon — which have circulated on the Internet — in which McMahon referenced a separate radiation measurement for milk that Hawaii officials said was extrapolated from EPA water radiation limits.

McMahon states, and EPA officials confirmed, that the EPA’s "maximum contaminant level" for iodine-131 is 3 picocuries per liter. McMahon noted that a Little Rock, Ark., milk sample was three time higher at 8.9 picocuries and that the Hilo sample was higher yet at 18 picocuries.

What McMahon reported is "technically correct," Naka­sone said.

"The limits for water as derived by the EPA are totally different from how it’s derived through the FDA," Naka­sone said. "The EPA is saying (their limit) is over a 70-year period, whereas FDA is more of a short-term duration."

Using McMahon’s premise, "it’s like drinking two liters of water for 70 years to get their (the EPA’s) limit. So if you extrapolated to milk, you’d have to drink two liters of milk for 70 years to get that limit."

Siobhan DeLancey, an FDA spokes­woman, confirmed there are differences in the EPA and FDA radiation measurements in any given food.