This dissertation examines ecological imaginaries of citizen radiation detection labs in Japan in the aftermath of the Fukushima nuclear disaster. Ecological imaginaries that are represented and performed in radiation detection data allow citizens to question and challenge the nuclear world in which they live and die. Irradiated bodies and ecology have been normalized or rationalized as “natural,” despite the fact that neither the environment nor human and more-than-human bodies are inherently radioactive in nature. Ecological imaginaries through radiation detection activities have broadened my interlocutors' worldviews, allowing them to understand and engage with various aspects and actants of ecology in new ways. In this process, radiation detection data have evolved into a politico-techno-ecological thing for citizen labs to contest the naturalization of environmental injustice.

Through long-term, in-depth ethnographic research at twenty citizen radiation detection labs in Japan, I explore political subjectivities and posthuman perspectives of these labs, approaching the Fukushima disaster and the nuclear world from multiple angles – politics, machines, radionuclides, soil, and bodies. Through their experience of the disaster and involvement in radiation detection activities, my interlocutors have developed political subjectivities, empowering them to speak out and take action against the neoliberal environmental governance of the Japanese state. In addressing the “politics of not detected,” I shed light on how citizen radiation detection labs have become spaces where individuals confront technological limitations, question the reliability of scientific knowledge, and engage in political and ethical resistance against the Japanese state and the nuclear industry. Ecological imaginaries related to radionuclides have become a vehicle not only to broaden people’s understanding of the environment beyond anthropocentric perspectives but also to reshape their worldviews in the “nuclearocene,” or the era of nuclear. Citizens also expand their scope of ecological care from food to soil, embracing previously excluded ecological actants – non-food plants, lakes, and residents in the mountains – while exploring the radioactive relationality among them. Ultimately, bodies – both human and more-than-human – become the intersection where ideologies, materialities, and practices of care converge in the nuclear world. By conducting radiation detection tests on teeth, bones, urine, and breastmilk and monitoring thyroid cancer, citizen labs offer alternative care for irradiated bodies that the Japanese state has normalized and failed to medicalize and institutionalize.