Dose-response is a fundamental concept in determining the effects of hazardous materials and is used to create the standards for employee exposures. Industrial hygienists and safety professionals use these limits along with their knowledge of chemical processes and other information to best protect workers.
Dose-response is a basic too toxicology. It measures the amount of a biological effect as the amount of a stimulus increases or decreases. Just because a substance is hazardous does not mean it harmful to humans, animals, or other living things. Even Clostridium botulinum, one of the deadliest substances, used in small amounts, can be beneficial such as with Botox. Medicines can be beneficial but if not used with the proper dosage can have ill-effects.
In order to determine the effects of a chemical, toxicologists look at the amount of chemical needed to get a response. Increasing the amount of the dose will increase the amount of response. The toxicologist may use alternative test methods such as in vitro testing or the traditional, or less desired, lab animal experimentation. The experiment design must best reflect possible exposure effects in humans. From these experiments, a LD50 (lethal dose to 50% of the animal population) or LC50 (lethal concentration to 50% of the animal population) is determined. When applying the results to humans, these and other factors are used to develop a proposed exposure limit. It may include a protection factor of 10X, 100X, or greater, based upon the relative toxicity of the chemical.
Industrial hygienists and safety professionalsuse the findings of toxicologists to ensure that workers are exposed to hazardous chemicals at only a healthful level. They use these results in the form of occupational exposure limits (OEL). These are created by OSHA and NIOSH, both governmental organizations, and scientific organizations such as the American Conference of Governmental Industrial Hygienists (ACGIH) and the American Industrial Hygiene Association (AIHA). Panels of industrial hygienists and scientists create the final OEL.
In the manufacturing of pharmaceuticals new compounds and mixtures are created. There are often no available standards for the new compound. In such cases where toxicological information is not available, company standards may be developed using control banding. Control banding takes the experimental limits of similar or a band of chemicals to infer a new exposure limit. Similarly, industrial hygienists can use control banding to set OELs where there are none available.
Studying dose-response and using those results is central to determining hazardous and beneficial levels and dosages for drugs, pollutants, foods, and other substances which humans and other organisms are exposed. It is most important in ensuring worker health.
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