Toxicity

This article is about the scientific term. For other uses, see Toxicity (disambiguation).

"Intoxicated" redirects here. For alcohol intoxication, see Drunkenness. Drunkenness or inebriation is the state of being intoxicated by consumption of Alcoholic beverages to a degree that mental and physical faculties are noticeably

"Toxic" redirects here. For other uses, see Toxic (disambiguation).

1 Types of toxicity
2 Factors influencing toxicity
3 Etymology
4 See also
5 External links

Toxicity is the degree to which something is able to produce illness or damage to an exposed organism. 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 a cell (cytotoxicity) or an organ (organotoxicity such as the liver (hepatotoxicity). The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The liver is a vital organ in the human body and is present in Vertebrates and some other animals By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or "society at large". Metaphor (from the Greek: μεταφορά - metaphora, meaning "transfer" is language that directly compares seemingly unrelated subjects

In the science of toxicology, toxicity is the degree of impact of an external substance or condition and its deleterious effects on living things: organisms, organ systems, individual organs, tissues, cells, subcellular units is the subject of study. A central concept of toxicology is that effects are dose-dependent; even water – generally not considered to be toxic – can lead to water intoxication when taken in large enough doses, whereas for even a very toxic substance such as snake venom there is a dose below which there is no detectable toxic effect. Water intoxication (also known as hyperhydration or water poisoning) is a potentially fatal disturbance in Brain functions that results when the A snake is an elongate Reptile of the suborder Serpentes Like all reptiles snakes are covered in scales. This article is about the class of Biotoxins For other uses see Venom (disambiguation and Venomous (disambiguation.

The skull and crossbones is a common symbol for toxicity. A skull and crossbones is a Symbol consisting of a human Skull and two bones crossed together under the skull

Toxicity is the ability of a chemical or physical agent to induce detrimental temporary or permanent tissue change or to detrimentally interfere with normal biochemical processing.

Types of toxicity

There are generally three types of toxic entities; chemical, biological, and physical.

Chemicals include inorganic substances such as lead, hydrofluoric acid, and chlorine gas, organic compounds such as methyl alcohol, most medications, and poisons from living things. A chemical substance is a Material with a definite chemical composition. Traditionally inorganic compounds are considered to be of mineral not biological origin Characteristics Lead has a dull luster and is a dense, Ductile, very soft highly Hydrofluoric acid is a Solution of Hydrogen fluoride in Water. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and An organic compound is any member of a large class of Chemical compounds whose Molecules contain Carbon. Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a Chemical compound
Biological toxic entities include those bacteria and viruses that are able to induce disease in living organisms. Biological toxicity can be complicated to measure because the "threshold dose" may be a single organism. Theoretically one virus, bacterium or worm can reproduce to cause a serious infection. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable A worm is a common name given to a diverse group of invertebrate animals that have a long soft body and no legs An infection is the detrimental Colonization of a host Organism by a foreign Species. However, in a host with an intact immune system the inherent toxicity of the organism is balanced by the host's ability to fight back; the effective toxicity is then a combination of both parts of the relationship. An immune system is a collection of mechanisms within an Organism that protects against Disease by identifying and killing Pathogens and Tumor A similar situation is also present with other types of toxic agents. A biological agent is an Infectious disease or Toxin that can be used in Bioterrorism or Biological warfare.
Physically toxic entities include things not usually thought of under the heading of "toxic" by many people: direct blows, concussion, sound and vibration, heat and cold, non-ionizing electromagnetic radiation such as infrared and visible light, and ionizing radiation such as X-rays and alpha, beta, and gamma radiation. Oscillation is the repetitive variation typically in Time, of some measure about a central value (often a point of Equilibrium) or between two or more different states Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. Image talkNew_radiation_symbol_ISO_21482svg for details --> Ionizing radiation X-radiation (composed of X-rays) is a form of Electromagnetic radiation. Alpha particles (named after and denoted by the first letter in the Greek alphabet, α consist of two Protons and two Neutrons bound together into a Beta particles are high-energy high-speed Electrons or Positrons emitted by certain types of Radioactive nuclei such as Potassium -40 Gamma rays (denoted as &gamma) are a form of Electromagnetic radiation or light emission of frequencies produced by sub-atomic particle interactions

Toxicity can be measured by the effects on the target (organism, organ, tissue or cell). 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. In Toxicology, the median lethal dose, LD50 (abbreviation for “Lethal Dose 50%” or LCt50 (Lethal Concentration & Time of a 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 factors" are added to account for uncertainties in data and evaluation processes. Factor of safety ( FoS) can mean either the fraction of structural capability over that required or a Multiplier applied to the maximum expected load ( Force For example, if a dose of toxin is safe for a laboratory rat, one might assume that one tenth that dose would be safe for a human, allowing a safety factor of 10 to allow for interspecies differences between two mammals; if the data are from fish, one might use a factor of 100 to account for the greater difference between two chordate classes (fish and mammals). Similarly, an extra protection factor may be used for individuals believed to be more susceptible to toxic effects such as in pregnancy or with certain diseases. Or, a newly synthesized and previously unstudied chemical that is believed to be very similar in effect to another compound could be assigned an additional protection factor of 10 to account for possible differences in effects that are probably much smaller. Obviously, this approach is very approximate; but such protection factors are deliberately very conservative and the method has been found to be useful in a wide variety of applications.

Assessing all aspects of the toxicity of cancer-causing agents involves additional issues, since it is not certain if there is a minimal effective dose for carcinogens, or whether the risk is just too small to see. In addition, it is possible that a single cell transformed into a cancer cell is all it takes to develop the full effect (the "one hit" theory).

It is more difficult to assess the toxicity of chemical mixtures than of single, pure chemicals because each component display its own toxicity and components may interact to produce enhanced or diminished effects. Common mixtures include gasoline, cigarette smoke, and industrial waste. Tobacco Smoking is the inhalation of smoke from burned dried or cured leaves of the Tobacco plant most often in the form of a Cigarette. Industrial waste is a type of waste produced by industrial activity, such as that of factories, mills and mines. Even more complex are situations with more than one type of toxic entity, such as the discharge from a malfunctioning sewage treatment plant, with both chemical and biological agents.

Factors influencing toxicity

Toxicity of a substance can be affected by many different factors, such as the pathway of administration (whether the toxin is applied to the skin, ingested, 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 can cause irreversible side effects.

Etymology

"Toxic" and similar words came from Greek τοξον = "bow (weapon)" via "poisoned arrow," which came to be used for "poison" in scientific language, as the usual Classical Greek word ('ιον) for "poison" would transcribe as "io-", which is not distinctive enough. Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly A bow is a Weapon that projects arrows powered by the elasticity of the bow Arrow poisons are used to poison arrow heads or darts for the purposes of hunting In the context of Biology, poisons are substances that can cause damage, Illness, or Death to Organisms usually by In some biological names, "toxo-" still means "bow", as in Toxodon = "bow-toothed" from the shape. Toxodon ("Archer's bow teeth" is a large Genus of extinct South American ungulate, ecologically similar to the Hippopotamus

External links

In the context of Biology, poisons are substances that can cause damage, Illness, or Death to Organisms usually by Registry of Toxic Effects of Chemical Substances ( RTECS) is a Database of Toxicity information compiled from the open scientific literature without reference Soil contamination is caused by the presence of man-made chemicals or other alteration in the natural soil environment Teratology stems from the Greek ( Genitive) meaning monster, or marvel and, meaning word, speech. A toxin ( Greek:, toxikon, lit (poison for use on arrows is a Poisonous substance produced by living cells or organisms that is active at very low A toxic tort is a special type of Personal injury lawsuit in which the Plaintiff claims that exposure to a chemical caused the plaintiff's injury or disease A toxicophore is a feature or group within a Chemical structure that is thought to be responsible for the toxic properties either directly or via Metabolic In the Law of the European Union, indicative limit values, more exactly indicative occupational exposure limit values (IOELVs are Human Exposure

Dictionary

-noun

(toxicology) Degree to which a toxic substance may harm a cell or organism.
(toxicology) The quality of being toxic.

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