Một độc, hoặc độc tố, là một chất có hại cho sinh vật sống bởi vì các tác động có hại của nó trên các mô, các cơ quan, hoặc quá trình sinh học. Chất độc là khoa học về chất độc. Một nghiên cứu chất độc giao dịch với các chất độc hại, ảnh hưởng của họ, và xác suất của những hiệu ứng này. Các định nghĩa này có thể một số trình độ. Một chất độc hại hay không phụ thuộc vào loại sinh vật tiếp xúc, số lượng của chất, và tuyến đường tiếp xúc. Trong. | Chapter 6 Toxicology introduction Poisons and Toxicology A poison or toxicant is a substance that is harmful to living organisms because of its detrimental effects on tissues organs or biological processes. Toxicology is the science of poisons. A toxicologist deals with toxic substances their effects and the probabilities of these effects. These definitions are subject to a number of qualifications. Whether a substance is poisonous depends on the type of organism exposed the amount of the substance and the route of exposure. In the case of human exposure the degree of harm done by a poison can depend strongly on whether the exposure is to the skin by inhalation or through ingestion. For example a few parts per million of copper in drinking water can be tolerated by humans. However at that level it is deadly to algae in their aquatic environment whereas at a concentration of a few parts per billion copper is a required nutrient for the growth of algae. Subtle differences like this occur with a number of different kinds of substances. History of Toxicology The origins of modern toxicology can be traced to . Orfila l787 1853 a Spaniard born on the island of Minorca. In 1815 Orfila published a classic book 1 the first ever devoted to the harmful effects of chemicals on organisms. This work discussed many aspects of toxicology recognized as valid today. Included are the relationships between the demonstrated presence of a chemical in the body and observed symptoms of poisoning mechanisms by which chemicals are eliminated from the body and treatment of poisoning with antidotes. Since Orfila s time the science of toxicology has developed at an increasing pace with advances in the basic biological chemical and biochemical sciences. Prominent among these advances are modern instruments and techniques for chemical analysis that provide the means for measuring chemical poisons and their metabolites at very low levels and with remarkable sensitivity .
