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Dates to remember from 75 years ago: July 16, 1945 - the Trinity Blast, the world's first atomic bomb tested in New Mexico; August 6, 1945 - the bombing of Hiroshima; and August 9, 1945 - the bombing of Nagasaki. These long-ago dates changed the world forever. Discussion continues as to the rationale for the Hiroshima and Nagasaki bombings, but the horror of the bombings is certain. On a recent revisit to the Peace Museum in Hiroshima, I saw again the pictures of destruction and of victims (135,000 in Hiroshima and 64,000 in Nagasaki), some dying immediately and others suffering gruesome deaths from burns, and reread their stories. There are also the stories of those killed years later by a wave of childhood leukemia in the 1950s and by excess radiation-caused cancer that persists among survivors. The photos and stories haunt - the picture and school uniform of a child killed by acute leukemia. There are stories of resiliency as well, as the citizens of the bombed cities regrouped and rebuilt.
One legacy of the bombings is the profound gift made by the survivors, called "hibakusha" in Japan: their participation in epidemiological research launched after the bombings and now carried out by the Radiation Effects Research Foundation, or RERF. In fact, the studies of the atomic-bomb survivors are the longest-running epidemiological studies to date. Following the end of World War II, the Atomic Bomb Casualty Commission (ABCC) was established in 1947 by the United States to study "the medical and biological effects of radiation." The ABCC was charged with investigating scientific questions about the short- and long-term consequences of radiation exposure for the survivors of the atomic bombings and for their children. In 1975, the ABCC was replaced by the binational RERF with support from the Japanese and United States governments.
I have served on the Board overseeing RERF twice, in the 1990s and now for almost a decade. The research of RERF is based on follow-up of large groups, or cohorts, of the survivors and their children. For the survivors, exposure to radiation at the time of the blasts and the resulting radiation doses to the body and its organs have been rigorously calculated. The scientific questions that led to the creation of the ABCC and its continuation as RERF have been investigated through these cohorts. Those questions include: are there transgenerational effects of radiation exposure; and what are the long-term consequences of ionizing radiation for risk for cancer and other diseases? The early research on the first question found no effects on the survivors' children but continues, while research on the second has linked radiation exposure from the bombs to cancer, cataract, cardiovascular disease, and lifespan reduction.
The information gleaned from the survivors has been the foundation for radiation protection worldwide. The epidemiological studies have described the course of the excess cancer caused by radiation and quantified how risk varies with exposure. Risk models based on the cohorts of atomic bomb survivors are used by all agencies concerned with radiation standards, such as the International Commission for Radiological Protection (ICRP), the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the National Council of Radiological Protection (NCRP) and more. Given their long course, the studies have provided data that were used for pioneering longitudinal data analyses.
Yet another research direction has emerged as the methods of "21st century science" (e.g., genomics and epigenomics) can now be informatively applied to the many biosamples stored over decades of research. RERF is working through complex ethical issues related to using these specimens with the survivors and their children. These specimens are another gift from the survivors to humanity.
My appreciation of that legacy continues to deepen. When in Hiroshima, I often start the day with a walk through Hiroshima's Peace Park, sited at the hypocenter of the blast. The A-Bomb Dome is the remains of a partially standing building at the hypocenter. There is the Peace Cenotaph, an empty grave holding the names of the victims of the bombings, and the Peace Flame, burning since 1964. As the Japanese walk by the arch of the Cenotaph, they stop and bow. Now, I do the same.
Some Readings and More:
- John Hersey, Hiroshima, New Yorker, 1946. A master reporter's description of the aftermath of the Hiroshima bombing.
Until next week,
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