当某一金属的吸入量超过其排泄量时,就会在体内发生蓄积,通常以生物学半减期表示。不过只有当排泄量接近一简单的一级指数函数时,生物学半减期的概念才有意义。对实验动物和志愿者的研究表明甲基汞的排泄接近一级指数函数。当一种金属(如甲基汞)的排泄情况符合简单一级指数函数时,则可用下面这个等式表示某个器官在任何时间上的浓度。 When a metal inhales more than its amount of excretion, it accumulates in the body, usually expressed as a biological half-life. However, the concept of biological half-life makes sense only when the excretion approaches a simple first-order exponential function. Studies of experimental animals and volunteers showed that excretion of methylmercury approached the first-order exponential function. When the excretion of a metal such as methylmercury complies with a simple first-order exponential function, the following equation can be used to indicate the concentration of an organ at any time.