By J. E. Hinners, MD MPH
March 11, 2011 (JAPAN)–The 9.0 magnitude Tōhoku earthquake set off a tsunami which struck the Fukushima I Nuclear Power Plant, resulting in the the largest radioactive material leak since the 1986 Chernobyl nuclear disaster.
Fukushima Nuclear Disaster
Over 15,000 people died from earthquake and tsunami destruction, and roughly 300,000 people evacuated the Fukushima region. No short-term fatalities were reported due to radiation exposure; some longer-term health effects (including signs and symptoms of leukemia) appear to be manifesting among children and workers who had been located near the Fukushima vicinity.
Why Did the Plant Melt Down?
The company that owns the plant (Tokyo Electric Power Company) claimed that the power plant ultimately melted down due to the tsunami and not the earthquake. Onsite workers, however, had seen cooling pipes burst shortly after the quake; nuclear engineers had later assessed that the plant’s cooling system appeared to have failed as a result of the earthquake, suggesting that the plant had not been properly designed to withstand earthquakes.
What Radioactive Materials Are Being Released By This Disaster?
Two of the most concerning radioactive materials released from this disaster are iodine-131 and caesium-137. If inhaled or eaten, iodine-131 can attach to thyroid tissue and cause thyroid cancer; caesium-137 has a 30-year half-life and can cause DNA damage, leading to delayed onset of cancer. Other radioactive materials released included plutonium, strontium, and tritium.
How Is the Cleanup Process Going?
The job of cleaning and controlling the radioactive leakage is still decades from full completion. The extent of the power plant meltdown appears to be greater than was originally reported, as it appears that nearly all fuel rods have melted as a result of the tsunami. Contaminated water spills at the plant and into the sea pose ongoing health threats and remain high cleanup priorities.
Is My Health At Risk By Stepping Foot In Japan?
Well, let’s first of all take a look at the regularly updated radiation dose measurements for the Fukushima region as well as other Japanese and non-Japanese cities around the world for a little perspective:
These dose levels indicate that even in the most concentrated radiation zone within the Fukushima region, radiation dose rates only exceed those of Seoul’s everyday radiation levels by 3.6%. Cities outside of Fukushima contain even lower levels than those of other international cities. Tokyo, for example, is 230 kilometers (142 miles) away from Fukushima and has a dose rate of 0.033 nGyh–which is lower than the dose rates in New York, Paris, Berlin, London, Singapore, Hong Kong, Beijing, Taipei, and Seoul.
What About the Safety of Consuming Japanese Food and Drinks?
Concerns about food, water, and other drinks in Japan are valid concerns, as these products are not strictly limited to the immediate Fukushima region.
On the One Hand…
There should be some reassurance that Japan’s Ministry of Health, Labor, and Welfare does have strict regulations and monitoring of radionucleotide levels in food, tap water, and other beverages. In fact, Japan’s allowable levels of radioactive cesium are even stricter than other international country limits:
Food and beverage products
Food and beverage products with radionucleotide levels exceeding the allowable limit are presumably taken off the market. Levels of radioactive contaminants and food are updated daily and publicly shared. There is even a searchable database where the public may look up individual foods for updated information.
Tap water contaminant levels are also daily updated, and there are currently no restrictions for the general public or for infants, specifically, on drinking tap water in Japan.
While many local Fukushima farmers have evacuated, some have refused to evacuate in efforts to salvage animals and crops, insisting that radiation levels are below the allowable limit–particularly for caesium levels among cattle products, as cows appear to not absorb radioactive caesium as readily as humans do.
On the Other Hand…
Fisheries and seafood products
Fisheries and seafood products from the Fukushima region are particularly vulnerable to contamination, as radiation leakage into the ocean has not yet been completely stopped or cleaned. Main fisheries that have been closed have been mostly local fisheries based near Fukushima. Japan’s Fisheries Agency, however, has still consistently found radioactive caesium in 60-80% of fishing catches in Japan on a monthly basis since the Fukushima nuclear incident.
The Environmental and Science Technology journal has discussed in more detail some of the marine life effects of the continued radiation leaks and has illustrated the direction of radiation flow in the neighboring waters:
These food contaminations affect not only those located in Japan but also those who consume fish exports.
While Japan is traditionally one of the few countries that systematically monitors for radiation in fish products, the Canadian Food Inspection Agency (CFIA) conducted its own investigation and acknowledged that 60% of these fish imported into Canada had been shown to contain radionucleotides; caesium was identified in:
- 100% of shark, seaweed, carp, and monkfish tested
- 94% of anchovies and cod
- 93% of eel and tuna
- 92% of sardines
- 91% of halibut
- 73% of mackerel
More specific reports from the CFIA indicated that only one out of the 169 tested products specifically from the Fukushima region were found to contain radiation.
Researchers from Oregon State found Pacific waters albacore tuna to contain three times the amount of radionucleotide levels as had been identified prior to the Fukushima nuclear disaster; albacore tuna findings are said to indicate ongoing radiation leakage and also represent possible radiation findings in other fish species.
Is This Seafood Contamination Harmful?
- The CFIA dismisses these high pacific seafood radionucleotide percentages in seafood products, saying they do not pose significant risk due to the small amounts of caesium that are detected.
- The Oregon State scientists of the albacore tuna study emphasized that such levels are harmless and are at acceptable amounts that are comparable to radiation experienced from many other everyday exposures.
- Dr. Dewer, Canadian physician and director of Physicians For Global Survival, is not fully convinced of the harmlessness of even small radiation levels and suspects “we’re going to see more cancers, decreased fetal viability, decreased fertility, increased metabolic defects – and we expect them to be generational.”
In short, while many sources seem to say that these small radionucleotide levels in Pacific seafood are harmless, there are still differing opinions, and each individual will need to assess the information and make health decisions for him or herself.
I, myself, tend to be on the conservative side and will generally avoid eating large amounts of seafood from the Pacific. However, I won’t feel obligated for health reasons to keep myself from an occasional, delicious meal of fresh fish when I find myself on the Pacific coast…just too hard to resist sometimes!
Resources For Further Reading:
- Japan Travel Advisory
- The U.S. Embassy in Japan
- The New Scientist Fukushima Report
- World Health Organization’s 2013 health risk assessment after the 2011 East Japan earthquake and nuclear disaster
- U.S. Nuclear Regulatory Commission’s FAQs about radiation