The Japnese authorities have started releasing treated nuclear wastewater at Fukushima nuclear power plant that has stirred controversies.
The release has led to concerns among fisherfolk in the area and other seafaring communities about the possible impact on marine environmental and animals.
China has also banned the import of seafood from Japan over safety concerns after the Japanese authorities started the release of treated wastewater. The Chinese ban are bound to have economic and political undertones as China and Japan have disputes and rivalries and Japanses seafood exports to China and Hong Kong are a billion dollar industry.
The release of treated wastewater at the Fukushima nuclear power plant is the first step in the process to safely decommission the plant that can take three decades. The plant was ransacked in the 2011 Japan tsunami-earthquake and went into meltdown. As cooling systems failed, water was pumped into the plant and it is this water that is now being released after treatment.
Here we explain the Fukushima nuclear disaster of 2011, the subsequent containment of the fallout, the release of wastewater and why it is controversial.
The 2011 Fukushima nuclear disaster
Japan was struck a 9-magnitude earthquake on March 11, 2011 that also triggered a tsunami.
Besides the widespread deaths and devastation across Japan, the Fukushima Daiichi nuclear power plant was also struck and went into meltdown.
A meltdown refers to the situation wherein chain reactions in a nuclear reactor go out of control and nuclear cores overheat. As a result, a very large amount of radiation is released that's bound to be disastrous. The overheating occures as cooling systems fail. This happened in Fukushima nuclear plant after the earthquake and the tsunami.
The water from the tsunami filled the Fukushima nuclear power plant and damaged the generators that would have provided the Fukushima plant back-up power to run the cooling systems. The back-up power was required as main supply was cut from the earthquake and tsunami's impact. As the cooling systems failed, the plant went into meltdown.
The Britannica Encyclopaedia states, "With power gone, the cooling systems failed in three reactors within the first few days of the disaster, and their cores subsequently overheated, leading to partial meltdowns of the fuel rods...Explosions resulting from the buildup of pressurized hydrogen gas in the outer containment buildings enclosing reactors 1, 2, and 3, along with a fire touched off by rising temperatures in spent fuel rods stored in reactor 4, led to the release of significant levels of radiation from the facility in the days and weeks following the earthquake."
While the meltdown is attributed in general to the tsunami-induced failure of back-up power (which in turn led to failure of coolant system), some Fukushima plant workers attributed at least one partial meltdown to coolant-pipe bursts caused by the earthquake’s ground vibrations, according to Britannica.
To contain the situation, seawater and boric acid were pumped continuously into the plant to cool the systems. The seawater pumped inevitably got contaminated with nuclear products and, over the years, so much of such water got accumulated that it could fill 500 Olympics-size swimming pools, according to BBC News.
The Japanese authorities treated this contaminated water over the years and now, after getting the nod from the United Nations (UN) nuclear watchdog International Atomic Energy Agency (IAEA), the authorities have started releasing the treated wastewater.
How is Japan releasing Fukushima wastewater?
The release of wastewater at Fukushima nuclear plant is the first step to decomission the plant safely. The full process would take 30 years.
Prior to the release, which began last week, the wastewater was stored in around 1,000 tanks.
"Japan says it needs the land occupied by the tanks to build new facilities to safely decommission the plant. It has also raised concerns about the consequences if the tanks were to collapse in a natural disaster," reports BBC.
The release would be completed in four tranches, the final one of which is expected to be completed by March 2024.
Japan is releasing the wastewafter after treating it, which means that it has been separated from any radioactive contamination.
Why is Fukushima wastewater release controversial?
There are two main reasons for the Fukushima wastewater release being controversial. One, while most of the compounds have been cleared of the water, one called radioactive element called tritium is believed to be still there in the water. Two, the impact of the potential release has not been assessed adequately, as per critics
As per Japanese authorities and UN watchdog, the tritium levels are within permissible limits, but concerns about the possible impact on environment remain nonetheless. BBC reports, "The IAEA, which has a permanent office at Fukushima, said an 'independent, on-site analysis' had shown that the tritium concentration in the water discharged was 'far below the operational limit of 1,500 becquerels per litre (Bq/L)'. That limit is six times less than the World Health Organization's limit for drinking water, which is at 10,000 Bq/L, a measure of radioactivity."
Tritium is the only radioactive isotope of hydrogen that reacts with oxygen to form “tritiated water” (HTO). Tritium is produced mostly in nuclear reactors and nuclear weapons production, but it is also found naturally. Even though there are concerns about wastewater with tritium being released, people frequently ingest tritium on a regular basis as it is found aplenty in the world.
"People are exposed to small amounts of tritium every day, since it is widely dispersed in the environment and in the food chain. Tritium primarily enters the body when people swallow tritiated water, inhale tritium as a gas in the air, or absorb it through their skin," notes US Environmental Protection Agency (EPA).
Moreover, tritium cannot penetrate the human skin and is only dangerous if very high quantities are consumed.
"In human tissue, tritium’s beta particle cannot penetrate the typical thickness of the dead layer of skin that exists on the outside of the human body. For this reason, the beta particle emitted by tritium is generally only considered to be hazardous if a large quantity of tritium is, or has the potential to be, taken into the body by inhalation, skin absorption, and ingestion of tritiated water. Tritium mostly behaves just like ordinary water in the body, distributing equally throughout the body’s water and excreted in the same ways as water, such as in the forms of urine and sweat," says a fact sheet published by Health Physics Society (HPS).
However, some experts are still convinced with the safety of releasing Fukushima wastewater into the ocean. Some have said that the wastewater could affect fertility and cell structure of marine animals upon ingestion.
Prof. Emily Hammond of George Washington University told BBC, "The challenge with radionuclides (such as tritium) is that they present a question that science cannot fully answer; that is, at very low levels of exposure, what can be counted as 'safe'? One can have a lot of faith in the IAEA's work while still recognising that compliance with standards does not mean that there are 'zero' environmental or human consequences attributed to the decision."
Marine biologist Robert Richmond of University of Hawaii is also not convined.
Richmond told BBC, "We've seen an inadequate radiological, ecological impact assessment that makes us very concerned that Japan would not only be unable to detect what's getting into the water, sediment and organisms, but if it does, there is no recourse to remove it... there's no way to get the genie back in the bottle.
