Information AboutToxic |
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Toxicity (from Greek '''τοξικότητα''' - ''poisonousness'') is a measure to the degree to which something is toxic or Poison ous. The study of poisons is known as Toxicology . Toxicity can refer to the effect on a whole Organism , such as a human or a Bacterium or a Plant , or to a substructure, such as the Liver . By extension, the word may be Metaphor ically used to describe '''toxic''' effects on larger and more complex groups, such as the Family unit or "society at large". In the science of toxicology, the subject of such study is the effect of an external substance or condition and its deleterious effects on living things:organisms, organ systems, individual organs, tissues, cells, subcellular units. A central concept of toxicology is that effects are Dose -dependent; even Water is toxic to a human in large enough doses, whereas for even a very toxic substance such as Snake Venom there is a dose for which there is no toxic effect detectable. There are generally three types of toxic entities; chemical, biological, and physical.
Toxicity can be measured by the effects on the target (organism, organ, or tissue). Because individuals typically have different levels of response to the same dose of a toxin, a population-level measure of toxicity is often used which relates the probability of an outcome for a given individual in a population. One such measure is the LD50 , "LD" standing for "lethal dose", which is a concentration measure for a toxin at which fifty-percent of the members of an exposed population dies from exposure. When such data does not exist, estimates are made by comparison to known similar toxic things, or to similar exposures in similar organisms. Then " Safety Factor s" must be built in to protect against the uncertainties of such comparisons, in order to improve protection against these unknowns. Factors influencing toxicity Toxicity of a substance can be affected by many different factors, such as the pathway of administration (is the toxin applied to the skin, inhaled, injected), the time of exposure (a brief encounter or long term), the number of exposures (a single dose or multiple doses over time), the physical form of the toxin (solid, liquid, gas), the genetic makeup of an individual, an individual's overall health, and many others. Several of the terms used to describe these factors have been included here. ;acute exposure: a single exposure to a toxic substance which may result in severe biological harm or death; acute exposures are usually characterized as lasting no longer than a day. ;chronic exposure: continuous exposure to a toxin over an extended period of time, often measured in months or years See also
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