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Marie Curie's tale is one of sacrifice and suffering for science and of unparalleled dedication to unlocking nature’s secrets.

Marie Curie: The Price of Knowledge

Marie Curie is rightly regarded as not just one of the greatest women who ever lived, but also, one of the most accomplished scientists in history. Her tale is one of sacrifice and suffering for science and of unparalleled dedication to unlocking nature’s secrets. 

The life and work of Marie Curie will, for better or worse, forever be tied to one substance  — radium. It was Curie, with her husband at her side, that would first isolate this extremely dangerous radioactive element in 1902. The duo synthesized one single gram of radium, which they would use in their work on radioactivity in the following years. The discovery would lead to Curie’s second Nobel Prize, this time in chemistry, in 1911. 

Marie and Pierre at work in their lab (Wellcome Library, London. Wellcome Images/ CCbySa 4.0)

In 1921, whilst touring the states, she would be awarded another solitary gram of the element in recognition of her service to science by the women of America. Poignantly, and cruelly ironically, radium would eventually lead Curie to her death in 1934 as a result of pernicious anemia caused by chronic radiation poisoning. 

But, Curie’s ties to radium would be so monumental that the relationship would continue after her death. Her daughter, Irène, herself a groundbreaking scientist, and her husband Frédéric Joliot, would use the gram of radium Marie had travelled across the Atlantic to obtain as the bedrock that would earn them their own Nobel in 1935. Irène would also follow in her mother’s footsteps in another, far less enviable way, as radiation poisoning would majorly contribute to her death also.

Beyond Curie herself, those two grams of radium have a storied tale surrounding them, if only elements could speak. The first had to be protected against the ravages of the First World War. Whilst the second would not only be saved from the clutches of the Nazis but was so coveted and valuable that before Frédéric married Irène, Marie made her daughter’s suiter sign a prenuptial agreement forfeiting all rights to the radium should they separate. 

The Early Days of Radioactivity

I was taught that the way of progress was neither swift nor easy.”

Marie Curie. 

‘Radioactive’ is a word we take for granted today. It’s well known outside journals and the halls of academia, capturing the attention of the general public from the 1950s onwards thanks to lurid sci-fi tales, and radioactive spider-bites granting teenagers amazing powers.

Yet unlike many other words in common parlance, the first published use of ‘radioactive’ has not been lost to time, it is preserved and still relevant today. That first usage was in the title of Marie and Pierre’s July 1898 paper: ‘On a New Radioactive Substance, Contained in Pitchblende.’

Curie in 1898, the year she and her husband published their paper featuring the first recorded use of the word ‘radioactive’ (Public Domain)

The story of Curie’s exposure to radium and radiation doesn’t begin with her, but with another great scientist, Henri Becquerel. In 1895, whilst intending to study the fluorescent properties of substances such as uranium salts, the French physicist had noticed that uranium blackened photographic plates wrapped in black paper and sealed in a drawer before they had been exposed to sunlight. What Becquerel had discovered was the spontaneous radioactivity of uranium. 

In the same year that Becquerel was making his finding, Marie married her first husband Pierre, who would come to share in many of her accolades. Marie, born Maria Salomee Sklodowska on November 7th, 1867 in Warsaw, Poland, had first met Pierre Curie after moving to France, studying at the Sorbonne and acquiring a position studying magnetism. In order to conduct this research, she would need a lab.

Pierre Curie was a teacher and the head of the laboratory in which Marie found herself, he was also already fairly well-known for his work with magnets. As Marie studied towards a mathematics degree, simultaneously conducting experiments with steel in the lab, Pierre attempted to woo her, at one point attempting to win her affections with an autographed copy of one of his studies. 

After a brief sojourn back to her country of origin, Marie agreed to marry Pierre in July of 1895. She attended the ceremony in a dark blue suit so that she could return to the lab and resume work after the wedding.

Marie, Pierre and daughter Irene, sit on an outdoor bench posing for a picture in 1902. (CORBIS/ Public Domain)

A year later, the couple celebrated the birth of their first child Irène. It was in this same year, 1896, that Marie would become fascinated with the work of Becquerel. Many researchers and scientists had pretty much ignored Becquerel’s uranium finding, but Marie saw further than they did. She decided that his ‘uranium rays’ would make an excellent subject of study for her doctorate. 

The First Gram: Polonium and Radium are isolated

“All my life through, the new sights of nature made me rejoice like a child.”

Marie Curie.

Pitchblende, or ‘bad luck rock’ from the German origin of the name, was the substance that Martin Klaproth, a pharmacist from Berlin, first used to extract and isolate a new element in 1789. This element, uranium, would soon also be joined by polonium — named by Marie for her home country — when the Curies isolated it from pitchblende in 1898.

Pitchblende, a ore that the Curies will become very familiar with. (Jędrzej Pełka/ CCbySA 3.0)

The Curies had examined pitchblende detecting extra radiation that could not be accounted for by considering uranium alone. Marie herself was determined to discover the source of this extra radiation.

The identification of polonium, described in the paper mentioned above, was something of a first in science, marking the first time that an element had been discovered solely as a result of the rays it emitted. It was also the first material to be officially described as radioactive. 

By the point that she discovered that pitchblende contained another element that could be isolated, Curie had checked the periodic table as it existed at the time, finding that thorium also produced rays in a similar way to uranium. 

By December in the same year, Marie was certain she and her husband had isolated another element in pitchblende, one even more radioactive than polonium. She had discovered radium. But if the Curies were to sway the scientific community about the existence of these two new elements, they would have to isolate a pure enough sample of both to establish that both had unique atomic numbers  —  the number of protons in an atom — a count that is unique to every element. 

After obtaining large amounts of pitchblende from a mine in Austria, the Curies set about isolating pure enough radium to identify its atomic number. The process took years and required strenuous physical labour, with Marie having to melt pitchblende and stir it with a metal rod that she described as being larger than she was. During this period, Marie also produced several papers, worked to complete her doctoral degree, taught at a teacher’s college in Sevres, and raised her daughter, Irène.

To give a hint at just how difficult and excruciating the work of isolating the first gram of radium was, consider that the second gram Marie would work with took a team of scientists 500 tonnes of ore, the same amount of acid, over a 1,000 tonnes of coal and 10,000 tonnes of water to extract. Marie and Pierre did themselves. By hand.

Finally, in July of 1902, Marie’s dedication and hard work would pay dividends. She was finally able to determine the atomic weight of radium, identifying it as possessing 88 protons, marking it out from any other elements. 

Words can’t really do justice the sheer physical strain that extracting radium from tonnes of pitchblende put on Marie and Pierre. Nor can it do justice, the damage to their health. (Wellcome Collection gallery/ CCby SA 4.0)

If anyone was in doubt of Marie’s dedication and love for the field of science and the pure pursuit of knowledge, then the action she took upon the identification of radium should be the deciding factor. Had Marie and Pierre claimed the rights to the process of purifying radium, they would have become very rich indeed.

Instead, the Curies rebuffed ideas of personal wealth and shared their process with the wider scientific community. But still, accolades and recognition awaited the pair. 

Unfortunately, so did tragedy and hardship. 

Accolades and Tragedy

“Be less curious about people and more curious about ideas.”

Marie Curie

By 1903 Marie had become the first woman in Europe to receive a doctorate, and she and her husband’s reputations and fame had begun to grow exponentially. But, this increase in notoriety was inversely proportional to their mutual decrease in health.

From the symptoms displayed by the couple at the time, it would now be easy to diagnose severe radiation exposure. Marie, in particular, was suffering from the effects of her work. In addition to the constant state of exhaustion and burnt fingers and hands, shared by Pierre, Marie had suffered a miscarriage and was rapidly losing weight.

Ironically, at the time, radium was being widely touted for its health benefits, it even found its way into cosmetics. It had also already been selected as a cancer treatment showing great potential in curtailing the growth of cancer cells. 

Radium was so touted for its health benefits in the early 20th Century it even found its way into cosmetics. (New York Tribune Magazine, page 12/ Public Domain)

Marie’s ill health prevented her from travelling to Sweden in 1905 to speak on her 1903 Nobel Prize in physics, which she and Pierre shared with Becquerel. 

Yet, despite deteriorating health the three year period between 1903 and 1906 was a happy one, both professionally and personally for the Curies. Pierre would be awarded the Humprey Davy Medal in chemistry in 1903 in addition to his joint Nobel. The substantial monetary award associated with the Nobel prize allowed the Curies to not only continue their research but also, to upgrade their laboratory and equipment.

Thus, the Curies were established as leaders in the field of chemistry, and in radioactivity, of course.

In 1904, the same year as Pierre was made a professor at the Sorbonne and Marie his paid assistant, reflective of the poor treatment of women in science at the time, she gave birth to their second daughter Eve. 

Two years later, tragedy would rear its ugly head in the lives of the Curies, taking with it Pierre. As he crossed the streets of a rain-soaked Paris, a tired and ill Pierre slipped and fell under the wheels of a horse-drawn carriage. The scientist was killed instantly.

A devasted Marie continued her work without her husband, accepting his position at the Sorbonne. She began her first lecture shortly after his death in a crowded lecture hall, stood within steps of where her husband had very recently delivered his last.

 Pure Radium

A scientist in his laboratory is not a mere technician: he is also a child confronting natural phenomena that impress him as though they were fairy tales.

Marie Curie

In 1909, Marie achieved something that Pierre, her late husband, had dreamed of, when plans were drafted to establish the Radium Institute in Paris. Here Marie would oversee her own lab, the Curie Pavillion, a fact that was no doubt bittersweet for the scientist, as her husband had never lived to see it. 

Marie stand resolute in her own lab in 1912, a sight her husband did not live to see. (Public Domain)

The Radium Institute would be completed in 1914, whilst Marie helping considerably in the war effort supplying x-ray equipment for locating shrapnel and bullets in the broken bodies of troops returning from the front. Marie also showed incredible bravery during the First World War, opting to stay in Paris to protect the gram of radium that she and her husband had extracted from tonnes of pitchblende. 

Over this period, Marie continued to synthesise purer and purer radium and polonium, driven on in no small part by the scepticism of some of her fellow scientists, such as Lord Kelvin, who still believed these were not elements in their own right. By 1910 she had produced a bright white metal with a melting point of 700⁰C — pure radium. 

Her professional achievements continued with the publication of work ‘Treatise on Radiation’ published in 1910, and the award of her second Nobel Prize, this time in chemistry awarded in 1911. The same year she was rejected for membership to the French Academy of Sciences. This rebuttal very likely came because of the fact she was a woman, as no one could doubt the pedigree of her work.

Also in 1911, the need for a unit of measurement to describe radiation was determined by an international group of scientists. The Radiology Congress honoured the Curies by naming this unit the ‘Curie,’ but Marie would not simply accept the honour passively. She herself would set about the difficult task of calculating the value of the ‘curie unit (Ci).’

The unit was equivalent to the radiative activity of one gram of radium per second. Unfortunately, as experiments into radioactivity progressed the value of the curie, 3.7 × 10¹⁰ radioactive decays per second., was too large for precise work. It was eventually replaced by the Becquerel (Bq) as the standard unit for radioactivity. 

Marie in a mobile x-ray vehicle used to search soldiers bodies for bullets and shrapnel. (Public Domain)

By the 1920s the dangers of contact with radioactive materials were finally being realised by the scientific community at large. Researchers were using increasingly stringent safety precautions. But it was too late for Marie. 

The damage to Curie’s health had been done. Yet her dedication to her studies, institute and science en masse would take her across the Atlantic on a strenuous speaking tour of the US. For Marie though, the reward wasn’t fame or recognition.

The reward was another gram of radium. 

The Second Gram: Curie’s Sacrifice for Science

“Life is not easy for any of us. But, what of that? We must have perseverance and above all confidence in ourselves.”

Marie Curie.

Marie Curie must have created quite an impression on American journalist Marie Maloney when they met in 1920. By this point, her hands were permanently bandaged. She was near deaf and her vision was afflicted by severe cataracts for which she would need a series of operations to keep at bay.

Curie’s perception in the public’s eye was similarly afflicted. Scandal had surrounded her friendship with physicist Paul Langevin after he left his wife. The newspapers had dogged Marie and the negative attention had had a further detrimental effect on her health. 

1921 visit to the United States: Marie Mattingly Meloney, Irène, Marie and Eve Curie. (Public Domain)

Maloney was determined to restore Curie’s public image, and despite the scientist’s mistrust of journalists in general, the two quickly struck up a friendship. This relationship got off to a notably spikey start. Moloney had already been nervous to interview Curie, and it was only shortly after the process began that the scientist became interrogator questioning the journalist on her knowledge of radium. 

The article Maloney produced for the Delineator hailed Marie Curie as the ‘greatest woman in the world’ and a brilliant scientist. But it was a piece of information that Curie had given Maloney during the interview that reshaped the two women’s lives. 

Maloney was already shocked by the virtually impoverished conditions of Curie’s lab compared to the setups of other scientists the journalist had interviewed such as Edison and Bell, when the scientist informed her about the prohibitive cost of radium. At the time a single gram of the element cost an incredible $100,000 or more. Adjusted for inflation, that’s about $1.3 million dollars today.

Maloney was outraged, and rightfully so. It wasn’t right that this great scientist was denied the resources she desperately needed to conduct her work, whilst her male counterparts seemed well provided for. 

The journalist began a drive across the United States, which had just given women the right to vote, to raise funds to enable Curie to continue her work less constricted by petty financial concerns. 

The Radium Drive, as it would become to be known, was even more of a success than Maloney expected, raising a staggering $156,413 — $2 million today. Not only was Maloney able to acquire the radium for Curie, but she could use the rest of the money to set Marie and her daughters up with a trust fund. 

In return for the generosity, Maloney requested that Curie tour the States and speak to American women. Despite ill-health and being a naturally retiring person, in 1921, Curie agreed. The draw of radium was just too tempting. 

It was only a short time after her arrival in the US with daughters Irène and Ève that the press and public began to notice the strain on Curie. The scientist hated to be seen as vulnerable, to conceal what she saw as a weakness she had kept her many cataract operations secret, but her ill health could not be denied. 

It was at the White House that President Warren Harding presented Marie with the one gram of radium in a 130-pound lead-lined case that opened with a suitably auspicious gold key. Or that was what the press was lead to believe. The radium was actually stored securely at a local government scientific facility.

On July 2nd, Curie returned to Paris. Her arrival home could not have been more in contrast to her arrival in the US via New York. In Paris, there were no brass bands, crowds of well-wishers, girl scout troops to greet her here.

For Marie, there was something much more important here than pomp and circumstance, however. This was where her work was.

After Marie

“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.”

Marie Curie.

The gram of radium that Curie collected, which had been extracted for her by scientists at the Standard Chemical Company, near Pittsburgh, would form the bedrock of Curie’s work until 1934 and her death as a result of complications arising from severe radiation exposure. 

Curie in 1925. (American Museum of Natural History/ No Restrictions)

Just the year after her death the same gram of radium would lead Irène and Frédéric to a Nobel Prize in Chemistry in 1935 for their discovery that stable atoms could be encouraged to become radioactive. An important step in nuclear chain reactions.

Irène would follow her mother’s footsteps in another way, displaying remarkable bravery to protect the radium when Nazi troops invaded Paris in 1940. She and her husband, who Marie had forced to sign a prenuptial agreement to waive rights to the element should his marriage to her daughter falter, fled west with the radium to Bordeaux. 

And the trust fund that Maloney had provided for Curie and her girls would be a life-saving asset to Irène and her own daughters in 1944 when Marie’s eldest used it to flee to Switzerland. Sadly, Marie Maloney would never get the satisfaction of knowing that her devotion to Marie Curie had saved her daughter and granddaughter from war-torn Franca, as the firebrand journalist had passed away from pneumonia just the year previous to their daring escape. 

Marie Curie’s life was one of great irony, she risked it many times over for the substance that eventually ended it. But, Curie’s sacrifice, the hardship she worked through, her struggle with grief, physical pain, illness and war, wasn’t really for radium. Nothing so mundane.

It was for knowledge itself and for the betterment of humankind.

I am one of those who think like Nobel, that humanity will draw more good than evil from new discoveries.

Marie Curie.

A radioactive couple: the glowing legacy of the Curies

A motif present in virtually all Balkan countries’ folklore is that of the creator sacrificing part of himself for his work. In Romanian folklore, this theme surfaces in the story “Meşterul Manole“, who immured his wife in the walls of the monastery he was tasked with building. I couldn’t help but remember that story as I was reading about the Curies, who laid the groundwork on which our understanding of radioactivity is based.

Marie and Pierre Curie.
Image via Wikimedia, author unknown.

Marie Curie, born Maria Sklodowska in Warsaw on November 7, 1867, was the daughter of a secondary-school teacher. She received a general education in local schools with some scientific training from her father. In 1891, she went to Paris to continue her studies at the Sorbonne University where she obtained Licentiateship in Physics and Mathematical Sciences. There, she met Professor of Physics Pierre Curie and in 1895 they got married.

But that’s just context — this story starts in 1895, when German physicist Wilhelm Roentgen discovered X-Rays but couldn’t uncover the mechanisms by which they formed. One year later, in 1896, French Nobel Laureate Henri Becquerel discovered that uranium salts spontaneously emit radiation very similar to X-Rays and proved that they originate from the uranium atoms.

Uranite (or pitchblende) crystals from Topsham, Maine.
Image via wikipedia, credits to Rob Lavinsky.

Intrigued by these findings, Marie started her own research on pitchblende, today sought-after as an uranium ore. Using a version of the electrometer that her husband had developed fifteen years earlier, she discovered that the “uranium rays” caused the air around the samples to simply conduct electricity. Using this method, she observed that the pitchblende with higher uranium content would give off stronger radiation. She also recorded this behavior in minerals containing thorium.

Then one day, as she was performing radioactivity measurements on a samples of pitchblende, she recorded a much higher radioactivity than its uranium content would allow for — and there’s no thorium in pitchblende. The only explanation was the presence of another, unknown radioactive element. This is when Pierre, excited by the idea of discovering a new element, put his own research aside and started working with Marie.

The two would go on to discover Polonium, named for Marie’s home country, and Radium, from the Latin word for ray, in 1898. They also coined the term “radioactivity” to describe the effects seen by Becquerel. Either together or separately, they published more than 32 papers, including the first paper to describe how tumors can be destroyed by exposure to radium. Their work attacked the previously held beliefs that atoms are indivisible.

Their work wasn’t even sponsored by the University, the couple drawing on private, corporate and government funds. Unaware of the dangers they were exposing themselves to, they worked either in their home laboratory or out in a converted, leaky shed next to the School of Physics and Chemistry. They wore no protective gear, just woefully inadequate lab coats.

Their achievements and vision helped shape the world as we know it. But as Uncle Ben used to say, “with great scientific results comes great genetic damage by processes you don’t yet fully understand,” or something close to that.

The Curies’ work literally bathed them in radiation, day in and day out for decades. They handled samples without any care or protective gear. They took the pieces of radium they were able to refine — and today we know this is the most radioactive element in the periodic table — in their bare hands to examine. Even when she wasn’t in the lab, Marie carried her passion with her: she would have test tubes of radioisotopes in her pocket or stashed in her desk drawer.

Radium clock-hands from 1940-1950’s watches.
Image credits Mauswiesel.

The Curies knew about radioactivity but had no idea of the damage it was wreaking on them. Their research attempted to find out which substances were radioactive and why, so many dangerous elements–thorium, uranium, plutonium–were just sitting there in their home laboratory.

“One of our joys was to go into our workroom at night; we then perceived on all sides the feebly luminous silhouettes of the bottles or capsules containing our products. It was a really lovely sight and one always new to us,” she wrote in her autobiography.

“The glowing tubes looked like faint, fairy lights.”

Pierre died 19 April 1906, aged 46, run over by horse-drawn carriage on a rainy day in Paris. Marie continued their research and had several breakthroughs. She died at age 66 in 1934 from aplastic anemia, believed to be an effect of her prolonged exposure to radioactive materials.

Now, researching any famous historical figure is a daunting task, and there are mountains of obstacles to overcome if you want to get your hands on any of their papers or objects. But in the Curies’ case, it’s actually dangerous to do so. Because of how they worked, their papers, clothes, pretty much every worldly possession is still dangerously radioactive — and will be for at least 1,500 years to come. If you want to look at her manuscripts at France’s Bibliotheque Nationale, you first have to sign a liability waiver. Only then can you access the papers, which are stored in a lead-lined box.

Marie Curie’s manuscript. A book to die for. Literally.
Image credits The Wellcome Trust.

Their house remained in use up to 1978 by the Institute of Nuclear Physics of the Paris Faculty of Science and the Curie Foundation. Authorities finally became aware of how insanely dangerous it was when people in their neighborhood, suffering from very high rates of cancer, blamed the Curies’ home. The building and laboratory were decontaminated in 1991.

Marie Curie was an incredibly gifted person, and her achievements speak for themselves. From a humble birth, she was to become the first woman to ever hold the position of Professor at the University of Paris, the first woman to win a Nobel prize, the first and only woman to win it twice, the only person to have ever received the award in different fields of research and the first woman to be entombed for her merits at the Panthéon in Paris. Pierre was a pioneer in the fields of crystallography, magnetism and piezoelectricity, in addition to his work with Marie, for which he jointly received the Nobel Award.

Together, these two brilliant people forever changed how we understand the world we live in. They did so at a huge cost, with incredible levels of radiation exposure, that would in the end claim Marie’s life. But by tackling some of the deadliest forces known to man with their bare hands, they earned life unending in the scientific community.


Ken Buesseler, oceanographer, answers questions about Fukushima’s impact on the oceans

Ken Buesseler studies marine radioactivity. He uses radioactive elements such as thorium that are naturally occurring in the ocean as a technique to study the ocean’s carbon cycle, as well as fallout from atmospheric nuclear weapons testing and recently, the sources of radionuclides from Fukushima Dai-ichi in 2011. Following the 2011 earthquake in Japan and the subsequent tsunami, the Fukushima Dai-ichi nuclear power plant was severely affected, with massive quantities of radioactive material spilling into the oceans.

Buesseler took the time to answer some questions on Reddit as part of an AMA (Ask Me Anything). Here are some of his most interesting insights, you can read all of it here.

What is the estimated scale of radiation released into the ocean, from Fukushima, in terminology, or comparison, a layman might understand?

Total levels and scales vary depending upon the mix of contaminants, but if we pick just one, cesium-137, there was about 10 times more cesium-137 released during nuclear testing globally, than Chernobyl. And for cesium-137, Chernobyl was 2-5 times greater than Fukushima, but then again most of the Chernobyl fallout fell on land, not in the ocean.

Can you give any insight on how long it took for the ocean to return to normal after the atomic tests, and perhaps compare it to the Fukushima leak?

In the 1960, immediately after the end of testing on the Pacific atolls, the concentration of radioactive cesium in the Pacific off the coast of Japan was about 50 Becquerels per cubic meter (Bq/m3) and 10 Bq/m3 off California. By 2011 immediately before the earthquake and tsunami, that had fallen throughout the Pacific to about 2 Bq/m3 as a result of radioactive decay. Today, the highest we have seen off the coast of North America is 6 Bq/m3. Off the coast of Japan after the accident, (aside from the extremely high levels detected at the source of release from the reactors) we recorded a high of 4,500 Bq/m3. You can see more about pre-Fukushima levels worldwide here:

Living in San Francisco during and the the years after Fukushima, I heard about people taking iodine tablets as a precautionary measure against radiation poisoning. Was I right in ignoring this as an overreaction since Japan is half a world away?

The California Coastal Commission had a report in 2014, that if you were in California in 2011 and drank tap water at the highest levels found and breathed in the air at its peak level- both for an entire year- your dose or net health impact would be about 5 micro Sieverts or about the same exposure as a single dental X ray. This is not zero, but a very low dose indeed. And no need to be taking iodine tablets, though remember at that time it was less certain what was going on and if it was going to get worse

I live in Osaka, Japan. How safe would you say is the seafood caught off the coast of western Honshu?

Off Japan today, except for those in the vicinity of the reactors, seafood and other products taken from the Pacific are currently below strict limits set by the Japanese for human consumption. Tens of thousands of fish have been and are being tested off Japan. If fish are found above the limits, commercial fishing remains closed. In 2011 about half the fish caught near Fukushima were above Japan’s limit (100 Bq/kg). In 2014 that had dropped to 1%. BTW, none of the fish caught on “our side” of the Pacific have been found to be above any of the limits set by Japan or higher limits in US/Canada.

What was the most unexpected things about your findings?

Sampling off Japan in 2011, we were more worried about hitting debris and harming our research vessel, than the levels of radioactivity which we were measuring with hand held devices as we sampled.
Another thing, maybe not unexpected but disappointing is the fact that no US Federal agency takes responsibility for ocean radioactivity studies

I teach middle school science. What is one major misconception about oceanic radioactivity that I (and the Internet) should clear up immediately?

The danger is in the dose, so while we should be concerned about any level of exposure to radioactivity, there is a huge difference in the levels, in this case in cesium from Fukushima, which ranged from 2 to 50 million in the units we use. That is like the difference in the temperature on earth and the temperature on the center of the sun. There’s already radioactive forms of cesium in the ocean. So it is a good question how much more radioactive cesium did Fukushima add, but we need to be aware that since the testing of atomic weapons there are many radionuclides we can measure in the ocean and on land.

(1) To what extent do radionuclides generally bioaccumulate (increase in concentration in an individual organism/population)?
(2) To what extent do radionuclides generally biomagnify (increase in concentration with trophic level)?
(3) Do the specific radionuclides released from Fukushima Dai-ichi differ in terms of their potential for bioaccumulation/biomagnification from other naturally occurring radionuclides in the ocean, e.g., Cesium?

Different radionuclides do not behave the same in all marine organisms, just as for other non-radioactive contaminants. For example cesium, which behaves like a salt, will accumulate in fish by a factor of 50 to 100 times the levels in water, but as a salt, it will also flush out of organisms quickly, about half in 2 months, through normal bodily functions and therefore does not bioaccumulate at higher levels. Strontium however behaves more similarly to calcium in humans and animals and is taken up and concentrated in bones where it remains with a biological half life of a couple years.
Think of it this way. If a cesium-137 contaminated fish were to be canned, it would take 30 years (the radiological half-life) for 50% of the cesium-137 to disappear. In contrast, if that same fish were to swim to cleaner waters, it would lose 50% of its radioactive cesium burden in just two months.