The first woman to earn a chemistry PhD in Japan traced the global reach of nuclear fallout

Katsuko Saruhashi discovered how the effects of fallout extended far and wide.
Katsuko Saruhashi discovered how the effects of fallout extended far and wide.
Image: Hiroshima Peace Memorial Museum/U.S. Army via AP
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Katsuko Saruhashi, a Japanese geochemist, became one of the leading voices in nuclear disarmament and female empowerment through her work in the late 20th century. She’s being memorialized today (March 22) with a Google Doodle on what would have been her 98th birthday.

Katsuko Saruhashi's Google doodle.
Katsuko Saruhashi’s Google doodle.
Image: Google

Saruhashi, born in Tokyo in 1920, lived through World War II as a young adult. Global events undoubtedly shaped her field of research.

Katsuko Saruhashi’s pioneering work

After graduating from Toho University (formerly the Imperial Women’s College of Science) in 1943, she went on to study carbon dioxide in ocean water at the Meteorological Research Institute. In 1957, she became the first woman in Japan to earn her PhD in chemistry from the University of Tokyo.

Few researchers were interested in studying carbon-dioxide levels in water when Saruhashi embarked on her work, which ended up being instrumental for decades. She penned the formula that would allow scientists to determine the amount of carbonic acid in oceans—now one of the hallmark measures of climate change—by hand. Now, researchers use computers for that task.

Saruhashi also studied the amount of radioactive isotopes of elements in seawater following nuclear- bomb test detonations. Working at the Central Meteorological Observatory, she found that tiny radioactive particles floating in the ocean waters along the coast of Japan resulting from the 67 nuclear explosions the US detonated in the Marshall Islands. “There was a controversy over her argument that the radioactive fallout in seawater was more than what they used to think,”  Toshihiro Higuchi, a historian at Georgetown University, told the Verge.

Scientists at the US Atomic Energy Commission quickly became interested in her work, and invited Saruhashi to work at the Scripps Institution of Oceanography at UC San Diego to compare US methods of measuring these radioactive isotopes to those used by the Japanese. It wasn’t entirely a friendly working environment: One of her American male colleagues, Theodore Folsom, told her that there was no need for her to come into the office daily, and that instead she should work out of an isolated wooden hut (pdf, p. 4).

Nevertheless, Saruhashi persisted. Her analyses of radioactive isotopes were essentially identical to Folsom’s, despite her inferior working conditions.

Saruhashi became a beacon for women in science

Saruhashi became an advocate for her fellow female scientists and for world peace. In 1958, she co-founded Society of Japanese Women Scientists, and in 1981 established a prize in her name awarded annually to young Japanese female scientists for their excellence in research and mentorship. In 1980, she became the first woman elected to the Science Council of Japan, and went on to receive the Miyake Prize for geochemistry and the Tanaka Prize from the Society of Sea Water Sciences.

She died in September 2007, and her legacy as a scientist, pacifist, and feminist lives on. “I wanted to highlight the capabilities of women scientists,” she said. “Until now, those capabilities have been secret, under the surface.”