人对膳食中重金属的耐受量不易简单地测定。作为人的直接或间接的食品的植物和动物对镉、汞和铅的吸收、运送和生物转换以及这些金属对人的作用,取决于许多因素。本文讨论了影响重金属镉、汞和铅的毒性的若干因素,这些因素是: (一) 生物体的防御机制在生物进化过程中,所有生物包括人在内,都在同重金属的接触中,形成了一些处理机制,如选择性地吸收和排泄,使能安全地处理这些物质,例如动物可以生 People’s tolerance to heavy metals in the diet is not easy to measure. Absorption, transport and bioconversion of cadmium, mercury and lead to plants and animals as a direct or indirect food for humans, as well as the human effects of these metals, depend on many factors. This article discusses a number of factors that affect the toxicity of heavy metals such as cadmium, mercury and lead. These factors are: (i) Organisms’ defensive mechanisms During biological evolution, all organisms, including humans, are exposed to the same heavy metals Some processing mechanisms, such as selective absorption and excretion, enable the safe handling of these substances, such as animals