毒理学中阈值的概念在危险评定的剂量-反应研究中有重要的意义。近年来提出了非癌终点和癌终点统一的剂量-反应关系的概念模型,有助于健康危险评定的发展。1生物学阈值指某一剂量或暴露浓度,低于此剂量或暴露浓度时所指定的生物学效应不发生。阈值是不引起生物效应的最高剂量和引起生物效应的最低剂量之间的过渡点。对某种效应,易感性不同的个体可有不同的阈值。同一个体对某种效应的阈值也可随时间而改变。有害 The concept of thresholds in toxicology is of great importance in the dose-response study of risk assessment. In recent years, a unified dose-response relationship model of non-cancer end point and cancer end point has been proposed, which contributes to the development of health risk assessment. Biological thresholds refer to the biological effects specified at a dose or exposure concentration below which the dose or exposure does not occur. The threshold is the transition point between the highest dose that does not cause a biological effect and the lowest dose that causes a biological effect. There may be different thresholds for individuals with different effects and sensitivities. Thresholds of the same individual for some effect may also change over time. harmful