ESTIMATION OF EXPOSURE LEVELS OF TERRESTRIAL BIOTA AND RADIATION EXPOSURE AROUND IPEN´S FACILITIES

Resumen

Humans are exposed to natural radiation; soil is a major source of external and internal exposure of radiation. The aim of this study is to evaluate the exposure levels of terrestrial biota and to estimate the radiation exposure around Instituto of Pesquisas Energéticas e Nucleares (IPEN) facilities. The ERICA Tool was used to calculate the exposure levels of terrestrial biota; the estimation of radiation exposure for humans was determined using a model proposed by UNSCEAR and Excess Lifetime Cancer Risk. Six soil points were collected and their activity concentrations were measured by gamma spectrometry. Two soil points showed a risk coefficient greater than 1, suggesting that the screening dose ratio of 10μGy h^-1 might be exceeding for the most exposed species, namely lichen and bryophytes, even though the activity concentration values of the analyzed radionuclides showed no evidence of soil contamination due to the atmospheric discharges of the IPEN facilities. Thus, the radioactive discharges in the soil from all facilities are negligible. Hence, the authors concluded that the ERICA Tool can be useful in assisting environmental radiological monitoring program for decision-making, especially regarding: points collected, sample types and sampling frequency.