During the worst week of the Japanese nuclear crisis, the EPA's radiation monitor in Dutch Harbor recorded the highest levels of radioactive iodine fallout in the United States among reporting stations, the agency said.
Despite the relatively high levels in the Aleutian Island community on March 19 and 20, state and federal health officials continued to say Tuesday that the amounts of radioactive byproducts were way too small to pose a health risk.
"It may be high relative to the other readings, but it is inconsequential," said Bernd Jilly, director of the state's health lab in Anchorage.
The EPA report, issued Monday, is based upon laboratory analyses of filters and charcoal canisters on the monitors, and only a handful of stations were reported among more than 100 in its network.
Among the missing results were from stations in Anchorage and Fairbanks. An EPA spokeswoman said the missing information may be attributed to a backlog at the agency's lab in Alabama.
The report is the first broad, if limited, set of results of the radioactive material captured by the filters and canisters around the Pacific from Nome to Guam, and as far inland as Montgomery, Ala. Of all those stations, Guam is the closest to Fukushima, about 1,700 miles south and outside the prevailing winds. At its highest reading, on March 22, Guam reported only a fifth as much radioactivity from iodine-131 as Dutch Harbor.
Dutch Harbor is more in line with normal air and ocean currents from Fukushima, about 2,700 miles away. Nome is 2,850 miles away, and its highest reading, on March 23, was only a third as high as Dutch Harbor's.
Anchorage, at 3,320 miles, is the closest large U.S. city to Fukushima. Juneau is 3,890 miles away, Honolulu about 3,810 miles, Seattle about 4,650 miles and Anaheim, Calif., about 5,400 miles. Aside from Anchorage, all reported some fallout, with Anaheim coming closest to Dutch Harbor in reported levels of radioactive iodine -- 1.9 picocuries of radioactivity in each cubic meter of air in Anaheim to Dutch Harbor's 2.8.
Dutch Harbor also reported the highest levels of cesium-137, more than three times any other reporting station in the United States and twice the level of the next highest station, in Guam. Dutch Harbor's reading on quickly decaying but dangerous tellurium-132, though tiny, was more than 100 times higher than any place else that reported.
As one of Alaska's most important fishing ports, state officials have sought to quell fears in Europe that Dutch Harbor fish were contaminated from Fukushima radiation. Even though the raw numbers in the EPA report showed levels of radiation that are probably right around background -- the monitor there is new and actual background radiation is unknown, state health lab chief Jilly said -- the news was enough for the state to issue a new set of assurances.
The headline of the state's news release announcing the EPA report was, "Harmless amounts of Japanese radiation detected in Alaska," and among the assurances was this: "These types of findings are to be expected in the coming days and are still hundreds of thousands of times below levels of public health concerns."
Each of the 100-plus monitors in the EPA's RadNet system automatically reports real-time levels of beta and gamma radiation from all sources. The signals are sent by satellite to the EPA's Alabama lab, where dangerous levels would set off alarms. The Anchorage beta and gamma results are available on-line and show only modest increases in activity on March 17 and March 21.
Jilly said he has not yet seen the analyses from the filters on the Anchorage or Fairbanks monitors. Naturally occurring radioactive substances produce background radiation, while the lab looks for the common markers of nuclear fission from a reactor or atomic bomb -- iodine-131, cesium-137 and tellurium-132, among others.
Monitors in Anchorage, Fairbanks and Juneau have long been part of the EPA system. But after Japanese technicians lost control of the Fukushima reactors and fuel storage facilities following the March 11 earthquake and tsunamis, the EPA deployed portable monitors to Dutch Harbor, Nome and to a second site in Juneau. They also shipped new monitors to Oahu and Guam. The Dutch Harbor device went into service March 19 and immediately recorded the relatively high levels of radiation, the report showed.
The canisters and filters on the devices capture air blown by a fan, Jilly said. The canister is about the size of a large thermos, and the filter is about the size of a coffee filter.
Reach Richard Mauer at firstname.lastname@example.org or 257-4345.