This diary is part of an ongoing series that represents an effort to communicate peer-reviewed scientific studies of the impact of the Fukushima nuclear disaster on the North Pacific Ocean and residents of the west coast of North America. A frequently asked question of those involved in monitoring the health of the North Pacific is why more measurements of the long lived, alpha-emitting isotopes of plutonium (239-Pu half-life 24,100 years; 240-Pu 6,570 years) are not being made given the potential for these isotopes to pose radiological health risks. Measurements of air, soil and water indicate that Pu was released and broadcast into the environment as a result of the triple reactor meltdowns with estimates of the source on the order of 2.3x10^9 Bq of 239,240-Pu or 580 milligrams of the isotopes. Measurements of isotope composition and activity of Pu in seawater and sediments off the coast of Japan indicate that there was no detectable change resulting from the nuclear disaster (behind pay wall). Given that the Fukushima signal is not detectable in the ocean off Japan relative to legacy sources from atmospheric weapons testing in the 20th century there is likely little information in making the same measurements in the eastern Pacific off of North America.
The purpose of this diary is to bring to the attention of interested readers a recent peer-reviewed, open-access study published in the Journal or Radiological Protection. The investigators describe the design and manufacture of a whole body sensor whose purpose is the detection of 137-Cs (half-life ~30 years) in children who were proximate to radionuclide releases after the triple meltdowns at the Fukushima-Daiichi nuclear power plant which began in March 2011. The detector in question (called BABYSCAN) is demonstrated to have a detection limit of better than 50 Bq/body and has been installed in a hospital in Fukushima. Because children are most vulnerable to the impacts of ionizing radiation, 100 Fukushima children were scanned for the presence of 137-Cs and none were found to have detectable levels of the isotope in their bodies. Larger scale measurements of the population will be reported as the long term impacts of low levels of ionizing radiation present owing to the Fukushima disaster warrant further study.
The purpose of this diary is to bring to the attention of those interested the most recent results of Kelp Watch 2014 a program dedicated to monitoring for the presence of Fukushima sourced radionuclides off our Pacific Coast. This diary is the latest contribution to a series that aims to provide information about the impacts of the Fukushima Dai-ichi disaster on the North Pacific Ocean ecosystem and on North American public health. New results from the first sampling period (February to March 2014) of Kelp Watch 2014 were just released and can be found here. As with previously reported results no radioactive isotopes from Fukushima were detected in kelp growing at sampling sites spread across the eastern Pacific. However, significant quantities of the short lived radioisotope 131-Iodine (half life ~8 days) were detected in samples collected in southern California. Rather than being transported across the Pacific these isotopes were likely released locally in waste water that carries significant 131-I because of its application in nuclear medicine to treat thyroid maladies.
This diary is part of an ongoing series that endeavors to report measurements of Fukushima derived radionuclides in the environment to help determine the likely impact on ecosystem and public health in western North America. The purpose of this diary is to summarize results of a recent peer reviewed study by Kaeriyama and colleagues published in Environmental Science & Technology who measured radioactive isotopes of cesium (137-Cs half life ~30 yr and 134-Cs half life ~ 2 yr) in the western North Pacific Ocean to help track the location and movement of the Fukushima contaminated seawater plume. They measured the depth distribution of 134-Cs and 137-Cs from August 2011 until March 2013. Measurements indicate Fukushima isotopes had spread as far to the south as 18°N along 135°E longitude at 300 meters depth by September 2012. They estimate that 9.0% of the Cs from the Fukushima disaster is being transported to the south into the subtropical western Pacific Ocean. This result supports and is consistent with a previous study which suggested significant amounts of Fukushima derived radionuclides are being transported south towards the tropics at depths centered around 300 meters. Measurements are thus indicating that previous models have likely overestimated the eastward transport of Fukushima radioactive elements and thus the maximum activity concentrations that will impact the west coast of North America and highlight the utility of trace concentrations of Cs as a tool to build a better understanding of ocean circulation.
This post updates an original diary to address concerns that radionuclides from Fukushima released to the North Pacific were negatively impacting the growth of photosynthetic algae at the base of the marine food chain. The new satellite data product that estimates phytoplankton biomass for April 2014 from NASA's MODIS satellite was recently made available through their GIOVANNI data portal. A new plot showing increased peak algae in Spring 2014 is included where chlorophyll a concentrations are significantly increased relative to 2013 and similar to record high biomass levels in the satellite record.
The purpose of this diary is to address what impact the Fukushima Dai-ichi disaster has had and is having on the growth of photosynthetic algae or phytoplankton in the North Pacific Ocean ecosystem. There is some concern among the public that the radioactivity released from Fukushima represents a potentially acute and chronic risk to algae or phytoplankton that represent the base of the marine food web. A simple internet search will raise stories which speculatively describe the North Pacific Ocean as a "dead-zone" suggesting that activities of radionuclides from Fukushima are killing phytoplankton and leading to biological desert-like conditions in this important ecosystem. Microbes, algae included, are some of the most radiation resistant organisms on the planet that can survive acute and chronic doses of radiation that would kill multi-cellular organisms like ourselves. Satellite measurements of ocean temperature and the abundance of marine algae going back to 1997 suggest that Fukushima has had little if any impact on phytoplankton in the coastal waters of Japan and offshore waters of the North Pacific to this point.
The purpose of this short diary is to bring to your attention a report recently released by the California Coastal Commission on the Fukushima Dai-ichi Nuclear Disaster and Radioactivity along the California Coast. The report refers to many published peer reviewed, scientific studies previously summarized here as part of an ongoing series dedicated to providing the best available science on the impacts of Fukushima on the health of the Pacific and residents of the west coast of North America. While the language in the Coastal Comissions Report is specific to CA it is very applicable to other residents of the Pacific coast. For those interested the document is a very useful primer and compendium of current scientific inquiry into the impact of Fukushima on ecosystem and public health. The report summary concludes:
The levels of Fukushima-derived radionuclides detected in air, drinking water, food, seawater and marine life in California are extremely low relative to the preexisting background from naturally occurring radionuclides and the persistent residues of 20th century nuclear weapons testing. The additional dose of radiation attributable to the Fukushima disaster is commensurately small, and the available evidence supports the idea that it will pose little additional risk to humans or marine life. However, it should be noted that the long-term effects of low-level radiation in the environment remain incompletely understood, and that this understanding would benefit from increased governmental support for the monitoring of radioactivity in seawater and marine biota and the study of health outcomes linked to radiation exposure.
The purpose of this diary is to summarize results from various studies that monitored the timing of arrival and activity of radioactive iodine falling from the atmosphere in western North America following the Fukushima disaster in 2011. The diary is part of an ongoing series dedicated to reporting on the results of scientific studies aimed at understanding the impact of this nuclear disaster on the health of the North Pacific ecosystem and the potential health risks for residents of the Pacific coast. Determining the activity of 131-I (half life ~8 day) in rain and seaweed, which serves as a biological monitor, is important because of the isotopes short half life and its propensity to concentrate in the human body, specifically the thyroid gland. This combination of rapid energy release and biological tissue targeting can represent a potential radiological health risk. Measurements of 131-I in rain collected in the San Francisco Bay area and southern British Columbia, Canada indicate that the atmospheric transport brought contaminated air from Fukushima to North America by March 18 roughly 1 week after the earthquake and tsunami. Depending on location, activities of 131-I in rain peaked between March 20-24 and were observed to decrease to background levels in the first week of April. Peak activities in seaweed occurred later on March 28 and were observed to return to background levels in mid-May. Maximum 131-I activities in rain resulting from Fukushima were a factor of 10 lower for rainwater and a factor of 40-80 lower for seaweed compared to similar measurements made following the Chernobyl disaster in 1986. Observed 131-I activities suggest that the upper limit of radiation dose to the public resulting from Fukushima was similarly an order of magnitude lower than that from Chernobyl suggesting that the short and long-term impact on human health in western North America is expected to be minor.
This diary serves as an update to a previously published diary summarizing efforts to determine how much plutonium (Pu) was released to the environment as a result of the Fukushima Dai-Ichi nuclear disaster. Plutonium is an alpha radiation emitting isotope that, if internalized, can represent a significant radiological health risk. Previous measurements of Pu in air, soil, plants and seawater following the 2011 disaster suggest that Fukushima released about 100,000 times less Pu to the environment than the Chernobyl disaster did in 1986. New measurements of "black substances" found along roadsides in high radiation areas in Fukushima Prefecture support previous work showing that Pu was released from the Fukushima plant. Based on the relative activity of Pu to radioactive cesium (137-Cs) the study determined that 2.3x10^9 Bq of 239,240-Pu (580 mg) was released or about 0.00004% of the Pu core inventories. This release from Fukushima is roughly 40,000 times lower than Chernobyl and 5,000,000 times lower than 239,240-Pu released during atmospheric weapons testing in the 20th century.
The purpose of this diary is to report new measurements of radioactivity in fish caught off the west coast of Canada. A collaborative effort between Health Canada, Department of Fisheries and Oceans Canada, and the University of Victoria is now published in the peer-reviewed, open-access scientific journal Radiation Protection Dosimetry (link). The authors examined the activities of cesium radioisotopes (134-Cs half-life ~2 years and 137-Cs half-life ~30 years) that were released in large quantities from the Fukushima Dai-ichi Nuclear Power Plant disaster in 2011 as well as a naturally occurring polonium isotope (210-Po) that can pose radiological health concerns for human consumers of marine fish. Samples of chum and coho salmon, halibut, sablefish and spiny dogfish were analyzed and none were found to contain detectable levels of Fukushima derived radionuclides. Radiation doses to human consumers were determined by assuming a conservative worst case scenario where Cs isotopes were present at detection limits of the measurement and found to be 18 times lower than doses attributable to the naturally occurring, alpha-emitter 210-Po. The authors conclude that the radiation dose from Fukushima derived isotopes present in fish caught in Canadian waters represent a very small fraction of the annual dose from exposure to natural background radiation. Based on these measurements, at present, Fukushima derived radionuclides in fish do not represent a significant radiological health risk to Canadians.
This diary is the latest in a series that aim to understand what the likely impact of Fukushima sourced radionuclides will be on ecosystem and human health on the North American west coast. Herein, I report on a newly published, open-access study by Smith et al. (2014) in the Journal of Environmental Protection who studied the levels of Fukushima radionuclides in air, rainwater and food resulting from atmospheric fallout in the San Francisco Bay area. Monitoring of the fallout isotopes 90-Sr (in rainwater) 131-I, 132-I, 132-Te, 134-Cs, 136-Cs and 137-Cs began shortly after the disaster on March 11, 2011 and continued through the end of 2012. The results of the study are compared to similar measurements made in the aftermath of the Chernobyl disaster in 1986. Peak fallout activities of radionuclides from Chernobyl in 1986 in the Bay area were 10 times greater than the levels measured from Fukushima in 2011.
A stunning new report indicates the U.S. Navy knew that sailors from the nuclear-powered USS Ronald Reagan took major radiation hits from the Fukushima atomic power plant after its meltdowns and explosions nearly three years ago. Many of the sailors are already suffering devastating health impacts, but are being stonewalled by Tepco and the Navy.Still radioactive?
The $4.3 billion carrier is now docked in San Diego. Critics question whether it belongs there at all. Attempts to decontaminate U.S. ships irradiated during the Pacific nuclear bombs tests from 1946-1963 proved fruitless.
The purpose of this diary is to compare the concentrations of Sr-90 and Cs-137 in the North Pacific Ocean over the last 50 years to the concentrations predicted to arrive on the west coast associated with waters affected by release of radionculides from the Fukushima-Daiichi Nuclear Power Plant. Given present levels that are being measured in the eastern Pacific and barring release rates that significantly exceed past rates in March-April 2011 the impact on marine organisms and the marine environment is going to be very minimal. What follows below the fold is a comparison of the concentrations measured and predicted over much of the Pacific owing to Fukushima to the concentrations that were present in the mid-1960s from the fallout of atmospheric weapons testing that is free from any discussion of safe doses or models of radiation exposure to organisms.