抄録
Environmental radioactivity could arrive from various sources and can incur higher health risks to those receiving the exposure. One of the most atypical and non-conventional exposure from man-made radioactive sources to a general public occurred in Taiwan in early 1980s, which were developed through recycled steels and more than 20,00 tons of radio-contaminated steel parts and rebar, made their ways to civilian constructions like apartments and school classrooms in a few years since their production. More than 10,000 occupants and students were noted to have stayed in these buildings since then until their discoveries by governmental and civilian societies and individuals from 1992. These individuals received untold protracted low dose-rate gamma-irradiation periodically and daily for up to 10 years, and cumulatively with several to more than 1,000 folds of extra ionizing radiation exposure above the background. Researches since then have identified significantly higher risks of specific malignancies, reduced reproductive fecundity, higher frequencies of lens opacities, increased incidences of benigh thyroid enlargement, and much higher frequencies of cytogenetic damages in peripheral the peripheral lymphocytes, shown as chromosomal abnormalities and micronuclei frequencies. Several of these studies evidenced a none- or lower- thresholds of ionizing radiation exposure on human subjects. Discussion will be provided to elaborate their implications for radiation safety and environmental health for the public.
