what is the definition of toxicity?

Answer 1

(m)

Toxicity is a measure to the degree to which something is toxic or poisonous. 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 metaphorically 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.

Chemicals include both inorganic substances such as lead, hydrofluoric acid, and chlorine gas, as well as organic compounds such as ethyl alcohol, most medications, and poisons from living things.
Biological toxicity can be more complicated to measure, as the "threshold dose" may be a single organism, as theoretically this one virus, bacterium or worm can reproduce to cause a serious infection. 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. A similar situation is also present with other types of toxic agents. In particular, toxicity of cancer-causing agents is problematic, since for many such substances it is not certain if there is a minimal effective dose or whether the risk is just too small to see; here too the possibility exists that a single cell transformed into a cancer cell is all it takes to develop the full effect. Mixtures of chemicals are more difficult to assess in terms of toxicity, such as gasoline, cigarette smoke, or industrial waste. 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.
Physically toxic entities include things not usually thought of as such by the lay person: direct blows, concussion, sound and vibration, heat and cold, non-ionizing electromagnetic radiation such as infrared and visible light, ionizing non-particulate radiation such as X-rays and gamma rays, and particulate radiation such as alpha rays, beta rays, and cosmic rays.
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 factors" must be built in to protect against the uncertainties of such comparisons, in order to improve protection against these unknowns.

Answer 2

Toxicity -- The degree to which a substance or mixture of substances can harm humans or animals. Acute toxicity involves harmful effects in an organism through a single or short-term exposure. Chronic toxicity is the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed organism. Subchronic toxicity is the ability of the substance to cause effects for more than one year but less than the lifetime of the exposed organism.

Answer 3

I used dictionary.com to find this:

Toxicity is the quality or condition of being toxic, or
the degree to which a substance is toxic. Before you really understand toxicity you must understand toxic which I have also defined here:

Toxic means capable of causing injury or death, especially by chemical means, or poisonous.

Answer 4

Toxicity is the degree to which a substance can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity).

-SYMBIOSIS ONLINE TESTING

Answer 5

the level at which something can become either deadly or make someone extremely ill with death soon to follow...Something does not always have to be become toxic, but basically that is what it means...

Answer 6

The level of deadly poison in a liquid, gas, or material.

Answer 7

1. degree of poisonousness: the degree to which something is poisonous
2. capability to poison somebody: the state of being poisonous to somebody or something