Document 3qx5REjo3EeBeDG1wGr1NVbD

40CHAPTER ELEMENTS OF INDUSTRIAL TOXICOLOGY Toxicity vs hoxord -- ............. - ------- -- -------- ---------40-1 Toxicity yofoet: threshold limit values . . . maximal acceptable concentrations . . application of the values--------------------------------------------------40-1 Catalog of toxic substances: acetalaldehyde through zirconium------------------------------- 40-13 Glossary of taxicologicol terms----- ----------------------------------------------------------------------- 40-59 Industrial toxicology is primarily con cerned with the physiological effects pro duced m individuals who have been exposed to harmful materials encountered during the course of their employment These effects usually result from inhala tion of the toxic agent Local slon injury can be caused by direct contact with some solids and liquids and some materials can also be ingested or absorbed through the skin. In these cases, however, there would usually be considerable inhalation of the toxic agent In the majority of situations, therefore, the toxic agent absorbed by the body is suspended in the air m the worker's breathing zone Toxicity vs Hazard The toxicity of a material is not synony mous with its health hazard Toxicity is the capacity of a material to produce injury or harm. Hazard is the possibility that a ma terial will cause injury when a specific quantity is used under specific conditions The key elements to be considered in evalu ating a health hazard are. (1) how much of the material is needed to produce injury, and (2) the probability of the material be ing absorbed by the body to produce it Since toxicity is not a definite physical constant, but rather the degree to which a substance will affect living cells under cer tain conditions, it can be measured only after recognizable changes have occurred following absorption. Some changes--un paired judgment, delayed reaction tunemay be produced at levels too low to cause actual cell damage Then too, toxicity is dependent on the dose, rate, method, and site of absorption, and many other factors, including general state of health, individual differences, tolerance, diet, and temperature. Toxicity Values The first attempts at estimating the tox icity of a substance are usually made on the baas of animal experiments Data from these experiments are expressed as lethal doses (LD) in milligrams of substance per kilogram of body weight of the test animal. Thu chapter was revised by Julian Ollshifskt, PJS, based upon reviews by selected members of the National Safety CounaL 40-1