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Chương này IS dự kiến để cho các nonspecialist một sự hiểu biết hữu ích về cách cư xử hạt nhân phóng xạ trong môi trường nước và đất. Một mục đích IS để lắp ráp các thông tin sử dụng cho các phép đo đánh giá môi trường hạt nhân phóng xạ vào một mẫu đó là hữu ích cho một môi trường chuyên nghiệp nonnuclear. Ví dụ, nước uống MCL cho tổng lượng khí thải là 4 mrem b = y, kết quả phòng thí nghiệm khách quan là về chung Với pCi = L. Bảng và các. | 9 Behavior of Radionuclides in the Water and Soil Environment 9.1 INTRODUCTION This chapter is intended to give the nonspecialist a helpful understanding of how radionuclides behave in water and soil environments. Another purpose is to assemble information used for evaluating environmental radionuclide measurements into a form that is useful for a nonnuclear environmental professional. For example the drinking water MCL for gross b emissions is 4 mrem y but laboratory results are generally given in terms of pCi L. Tables and rules of thumb for many required conversions are found in this chapter. A third purpose less important perhaps than the first two is to offer a concise introduction to the basics of radioactivity and the properties of radiation. The nuclear processes of fission and fusion are not covered. Section 9.2 which comprises the introduction to nuclear structure is not essential to using the rest of the chapter but might help to remove some of the mystery that often surrounds a layman s perception of radionuclides and radioactivity. 9.2 RADIONUCLIDES A radionuclide is an atom that has a radioactive nucleus. A radioactive nucleus is an atomic nucleus that emits radiation in the form of particles or photons thereby losing mass and energy and changing its internal structure to become a different kind of nucleus perhaps radioactive perhaps a different element perhaps neither. All radionuclides have finite lifetimes ranging between billions of years to less than nanoseconds each time a particle is emitted the original radionuclide is transformed into a different species. The emitted particles can possess enough energy to penetrate into solid matter altering and damaging the molecules with which they collide. Radionuclides cannot be neutralized by any chemical or physical treatment they can only be confined and shielded until their activity dies to a negligible level. Radionuclides are unique in being the only pollutants that can act at a distance harming .
