Experts from Woods Hole Oceanographic Institution (WHOI) reported on Thursday, Dec. 3, that higher levels of radiation were detected off the west coast of North America. The recent discovery was made years after the 2011 Japan nuclear accident.
The new report shows the rise of sampling areas where indications of contamination are present. Furthermore, the researchers were able to identify the highest level of radiation ever recorded from a sample obtained in an area 1,600 miles west of San Francisco.
Although the amount of radioactive cesium isotopes (approximately 264 gallons) is 50 percent larger than any other sample obtained along the West Coast, the number is still 500 times smaller than the safety limits for drinking water set by the government of the United States. The levels are also significantly lower than the limits that warrant concern for radiation exposure during water activities such as swimming and boating, among others.
Monitoring radiation levels in the Pacific began about three months following the accident in March 2011. Experts utilized advanced sensors to search for minute levels of radioactive substances in the ocean from Fukushima. They also got support from citizen scientists who helped obtain samples. In 2015, over 110 new samples from the Pacific were added by scientists.
One of the first researchers who took part in the monitoring mission was Ken Buesseler from WHOI.
"These new data are important for two reasons," said Buesseler. Although the radiation levels are below hazardous limits, the fluctuation of numbers signifies that there is a need to strictly monitor levels across the Pacific. Buesseler also mentioned that these long-staying isotopes will aid scientists who focus on ocean currents and combine offshore and coastal waters.
Among Buesseler's works is the continuous monitoring of leaks from Fukushima Dai-ichi through samples obtained from nearby areas such as one-half mile from nuclear power plants. In October 2015, the samples obtained by his team exuded sustained elevation of about 10 to 100 times higher than the U.S. West Coast levels. At present, the team is working to find out how they can identify the amount of radioactive material that is still being emitted to the ocean each day.
Buesseler reiterated that present values of radiation are notably lower compared to 2011 levels. With this, discovering elevated levels away from Fukushima establishes the continuous discharge of radioactive materials from the plant.