某一元素中质量较大的同位素，相对于质量较小的同位素而言，称为重同位素。在周期表后半部的同位素，质量数较大，相对于前半部质量数较小的同位素而言，也称为重同位素。
目前情况下值得忧虑的是电离辐射，它由重同位素——如碘131和铯137——自发衰变而生成。
Of concern in the current situation is ionizing radiation, which is produced by spontaneously decaying heavy isotopes, such as iodine 131 and cesium 137.
因此，更多的重氧同位素留在了海洋里，并被海洋有机物吸收。
Thus, more of the heavy isotope is left behind in the ocean and absorbed by marine organisms.
它们晶体里重轻同位素的比例并不像是从地底挖出来的东西那样。
The ratio between the heavy and light isotopes of the element in their crystals is not quite right for stuff that has come out of the ground.
应用推荐