Saruhashi graduated from the Imperial Women’s College of Science in 1943 and in 1957 she became the first woman in Japan to earn a doctorate in chemistry from the University of Japan.
She was the first to accurately measure the concentration of carbonic acid in water based on temperature, pH Level and chlorinity, which is known as Saruhashi Table today.
Saruhashi worked at the Central Meteorological Observatory in Tokyo to develop a technique to trace the travel of radioactive fallout in seawater and in rainfall.
In 1954 the US started testing nuclear weapons at Bikini Atoll and Saruhashi’s work established it took a year and a half for the radioactivity to reach Japan in the seawater from Marshal Islands – the site of US atomic tests.
The radioactivity dispersed through the entire Pacific Ocean within 15 years.
These results helped to restrict the nuclear experimentation in the ocean and encouraged the US, UK and Soviet Union to sign the Limited Nuclear Test Ban Treaty in 1963.
The treaty prohibited underwater nuclear tests along with tests in space or in the atmosphere.
In 1980 Saruhashi became the first woman elected to the Science Council of Japan and the first woman honoured with the Miyake Prize (named after Professor Miyake) for geochemistry in 1985.
Saruhashi has previously said: “There are many women who have the ability to become great scientists. I would like to see the day when women can contribute to science & technology on an equal footing with men.”
She also started the Saruhashi Prize which recognised the female scientists for eminent research in the field of natural sciences.
Toshihiro Higuchi, a historian at Georgetown University, said: “She was very conscious of the social responsibility of scientists in general.
“She was a trailblazer.”
By 1979, Saruhashi had become the executive director of the Geochemical Laboratory where she had carried out the groundbreaking work on radioactive fallout.
“Today on her 98th birthday, we pay tribute to Dr Katsuko Saruhashi for her incredible contributions to science, and for inspiring young scientists everywhere to succeed,” Google wrote on its blog.