Sức khoẻ con người ảnh hưởng 12,1 Bối cảnh đánh giá rủi ro Đối với hầu hết lịch sử nhân loại, mối quan tâm về những ảnh hưởng độc hại của hoá chất đã tập trung vào các chất độc hành động nhanh chóng và dẫn đến tử vong. Một ví dụ nổi tiếng là cây độc cần, Socrates ăn để tự tử. Cho đến gần đây, tiếp xúc với các hóa chất này không phổ biến và những rủi ro đã được biết đến, vì vậy có rất ít công chúng quan tâm về các chất độc. Tuy nhiên, trong thế. | chapter twelve Human health effects Risk assessment Background For most of human history concern about the toxic effects of chemicals has focused on poisons that act quickly and result in death. A well-known example is hemlock which Socrates ingested to commit suicide. Until recently exposure to these chemicals was not common and the risks were well known so there was little public concern about these poisons. In this century however people have become increasingly concerned with poisons including those that cause adverse effects only after long periods of exposure. There are two main reasons for this change. One is that the average human lifespan has increased tremendously due to cures and treatments for infectious diseases. This longer lifespan has made chronic noninfectious illness more common. The second is that the Industrial Revolution has led to new and increased uses of known chemicals and the synthesis and widespread use of newly developed chemical compounds. This tremendous increase in both the quantity and variety of chemical uses has led to greater awareness of possible adverse health effects from industrial products. Risk assessment One result of this attention was the establishment of the Environmental Protection Agency EPA in 1970 and the enactment of new legislation during the 1970s to regulate chemicals in the environment. With the passage of these laws an important problem was how to evaluate the severity of the threat that each chemical posed under the conditions of use. This evaluation is known as risk assessment and is based on the capacity of a chemical to cause harm its toxicity and the potential for humans to be exposed to that chemical in a particular situation . workplace or home. Risk assessment did not begin in the 1970s. The safety of our food supply has been investigated since early in the 20th century. In addition scientists in industrial toxicology laboratories had been evaluating the toxic properties of potential products as
