Toxicology: Study of Poisons and Insecticides

Study Notes

Toxicology is the study of the adverse effects that chemicals or physical agents may produce in living organisms under specific conditions of exposure.

Toxic: having the characteristic of producing an adverse health effect.
Toxicity: any toxic (adverse) effect that a chemical or physical agent might produce within a living organism.
Toxicant: any substance that causes a harmful (or adverse) effect when in contact with a living organism at a sufficiently high concentration.
Dose: the total amount of a toxicant administered to an organism at specific time intervals.
Target organ dose: the amount of toxicant reaching the organ (known as the target organ) that is adversely affected by the toxicant.
Exposure: to cause an adverse effect, a toxicant must first come in contact with an organism.

Acute toxicity: an adverse or undesirable effect that is manifested within a relatively short time interval ranging from almost immediately to within several days following exposure (or dosing).
Chronic toxicity: a permanent or lasting adverse effect that is manifested after exposure to a toxicant.
Local toxicity: an adverse or undesirable effect that is manifested at the toxicant’s site of contact with the organism.

Metals are extensively used in commercial and industrial applications and, as a result, exposure can occur from direct and indirect pathways.
Classification of metals: essential and nonessential metals.

A gray-colored metal found in the environment in both organic and inorganic compounds.
Human exposure may involve inhalation of arsenic dusts; ingestion of arsenic in water, food, or soil; or dermal contact with dust, soil or water.
Symptoms of toxicity: nausea or vomiting, abdominal pain, diarrhea, garlic odor on breath, headache, vertigo, fatigue, paresthesia, paralysis, kidney failure.

Found in the environment in a metallic or elemental form, as an inorganic compound, or as organic mercury compounds.
Symptoms of toxicity: metallic taste in the mouth, excess salivation, gingivitis, tremors, stomach and kidney troubles, shyness, irritability, apathy and depression, psychosis, mental deterioration, and anorexia.

Toxicology is the study of the adverse effects of chemicals or physical agents on living organisms under specific conditions of exposure.

Toxic: having the characteristic of producing an adverse health effect.
Toxicity: any toxic (adverse) effect that a chemical or physical agent might produce within a living organism.
Toxicant: any substance that causes a harmful (or adverse) effect when in contact with a living organism at a sufficiently high concentration.
Dose: the total amount of a toxicant administered to an organism at specific time intervals.
Target organ dose: the amount of toxicant reaching the organ (known as the target organ) that is adversely affected by the toxicant.
Exposure: the means by which an organism comes in contact with the substance.

Acute exposure: exposure over a brief period of time (generally less than 24 hours).
Chronic exposure: exposures over a long period of time (greater than 3 months).

Acute toxicity: an adverse or undesirable effect that is manifested within a relatively short time interval following exposure.
Chronic toxicity: a permanent or lasting adverse effect that is manifested after exposure to a toxicant.
Local toxicity: an adverse or undesirable effect that is manifested at the toxicant's site of contact with the organism.

Hazard: the qualitative nature of the adverse or undesirable effect resulting from exposure to a particular toxicant or physical agent.
Safety: dose will not produce a toxic effect.

Chemical toxicants: include inorganic substances and organic compounds.
Biological toxicants: include bacteria and viruses that can induce disease in living organisms.

Lethal toxicity: the median lethal concentration or time at which 50% of the test population die (LC50 or LT50).
Sub-lethal toxicity: the median effective concentration or time at which 50% of the test populations show a defined response (EC50 or ET50).