Scientists have identified trace amounts in Southern California of radioactive iodine, cesium, and tellurium from the earthquake-and-tsunami damaged Fukushima Daiichi Nuclear Power Station in Japan.

The radioactive elements picked up by air monitor filters in Riverside and Anaheim are "consistent with the Japanese nuclear incident," the U.S. Environmental Protection Agency said in a statement.

The detected quantities of iodine isotopes and other radioactive particles are minuscule and pose no health concern at the detected levels, according to the EPA.

"The levels we're measuring are extremely low," Mike Bandrowski, manager of EPA radiation programs in San Francisco, said in an interview Wednesday. "They're a fraction of natural background radiation. People should not be concerned."

The EPA conducted detailed analysis of samples captured by air monitor filters in Riverside, Anaheim, San Francisco, and Seattle on March 18, analyzed results over the weekend and Monday, and published them Tuesday.

"The radiation levels detected on the filters from California and Washington monitors are hundreds of thousands to millions of times below levels of concern," the agency said.

According to the EPA, filters in Riverside measured:

Cesium-137: 0.00024 picocuries - minute radioactive particles - per cubic meter.

Tellurium-132: 0.0014 picocuries per cubic meter.

Iodine-132: 0.0015 picocuries per cubic meter.

Iodine-131: 0.011 picocuries per cubic meter.

To underscore how harmless these levels are considered, the EPA stated:

"In a typical day, Americans receive doses of radiation from natural sources like rocks, bricks and the sun that are about 100,000 times higher than what we have detected coming from Japan."

The radiation levels coming from Japan are also 100,000 times lower than what a traveler would be exposed to after taking a roundtrip international flight, according to the EPA.

The EPA described its RadNet system as "designed to protect the public by notifying scientists, in near real time, of elevated levels of radiation so they can determine whether protective action is required."

As part of the federal government's effort to make EPA activities and science transparent, the agency will keep RadNet data at: http://www.epa.gov/japan2011/

The Fukushima Daiichi plant was severely damaged by the 9.0-magnitude earthquake and tsunami on March 11.

In Tokyo on Wednesday, authorities warned that radiation from the plant had affected the capital's water supply, and that tap water was unfit for babies to drink.

Radioactive iodine levels in some areas of Japan were twice the recommended safe level, according to Japanese and international media reports.

The death toll in Japan from the earthquake and tsunami has climbed to more than 9,000, with more than 15,000 people considered missing.