Radioactive ocean water from the Fukushima Dai-ichi nuclear plant in Japan will reach the U.S. by April should a Fukushima plume prediction hold true.

"The plume of radiation from the Fukushima Dai-ichi nuclear power plant is forecasted to be detectable at the Pacific coast in April 2014, according to a scientific model developed by Vincent Rossi, a post-doctoral research associate at the Institute for Cross-Disciplinary Physics and Complex Systems in Spain," reports Woods Hole Oceanographic Institute (WHOI).

Marine chemist Ken Buesseler, the man behind crowdsourcing campaign 'How Radioactive Is Our Ocean', says that radiation levels will most likely be not that high but remarked that the ocean's radiation levels need ample monitoring as it is "an evolving situation."

Contrary to other reports that radioactive ocean water has already arrived at the California coast, Buesseler and his team says that radiation from the Fukushima nuclear disaster has not yet reached ocean waters along the Pacific coast, reports the San Francisco Chronicle.

The San Francisco Chronicle explains that according to Buesseler, four coastal monitoring sites in California and Washington have detected no traces of radiation from the Fukushima Dai-ichi nuclear plant destruction, at least "not yet," notes the report.

"We have results from eight locations, and they all have cesium-137, but no cesium-134 yet," Live Science quotes Buesseler. The marine chemist adds that cesium-137 levels from the gathered ocean water sample were 1.3 to 1.7 Becquerels per cubic meter.

The U.S. safety limit for cesium levels in drinking water is about 28 Becquerels, the number of radioactive decay events per second, per gallon (or 7,400 Becquerels per cubic meter), adds Live Science.

The tell-tale element for the Fukushima Dai-ichi meltdown is reportedly cesium-134, says Live Science. The radioactive isotope has been released from the Japanese nuclear plant in 2011 after the Tohoku earthquake, along with cesium-137 and iodine-131.

According to John Smith, a research scientist at Canada's Bedford Institute of Oceanography, cesium-137 is present in the North Pacific partly due to nuclear weapon tests and nuclear power plant discharge but says that the only cesium-134 in the North Pacific is there from Fukushima, reports Live Science.

Unlike the U.S., ocean water samples collected by Smith and his team from west of Vancouver, Canada in June 2013 showed cesium-134 concentration reaching 0.9 Becquerels per cubic meter, says Live Science. Smith's team is still awaiting results for the February 2014 sample.