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What is the definition of 'Toxic'?
What is the definition of 'Toxic'?
Age may be important in determining the response to toxicants. Some chemicals are more toxic to __________ or the elderly than to young adults.
Age may be important in determining the response to toxicants. Some chemicals are more toxic to __________ or the elderly than to young adults.
infants
Inhaled toxicants immediately enter the general blood circulation.
Inhaled toxicants immediately enter the general blood circulation.
True
Match the following metals with their essential/nonessential classification:
Match the following metals with their essential/nonessential classification:
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What is the purpose of determining the median effective concentration or time at which 50% of the test populations show a defined response?
What is the purpose of determining the median effective concentration or time at which 50% of the test populations show a defined response?
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What factor can greatly impact the toxicity of metallic elements?
What factor can greatly impact the toxicity of metallic elements?
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What happens to ingested chemicals when they are absorbed from the intestine?
What happens to ingested chemicals when they are absorbed from the intestine?
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What is selective toxicity?
What is selective toxicity?
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What is the effect of hydrogen cyanide on cells?
What is the effect of hydrogen cyanide on cells?
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Study Notes
Toxicology and Insecticides
- Toxicology is the study of the adverse effects that chemicals or physical agents may produce in living organisms under specific conditions of exposure.
Basic Definitions
- 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.
Types of Toxicity
- 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.
The Basic Components of Toxicity Test
- The selection of a test organism
- The selection of a response to measure
- An exposure period
- The test duration (observation period)
- A sequence of doses to test
Factors Affecting Toxicity
- Form and innate chemical activity
- Dosage
- Exposure route
- Age
- Sex
- Presence of other chemicals
Metal Toxicity
- 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.
Essential Metals
- Have important biological roles and are essential for good health.
- Examples: cobalt, copper, iron, magnesium, manganese, and molybdenum.
Nonessential Metals
- Have no known beneficial role to play in biological function.
- Examples: beryllium, cadmium, lead, mercury, thallium, titanium, and uranium.
Toxicology of Selected Metals
Arsenic
- 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.
Mercury
- 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 and Insecticides
- Toxicology is the study of the adverse effects of chemicals or physical agents on living organisms under specific conditions of exposure.
Basic Definitions
- 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 and Chronic Exposure
- 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).
Toxicity Types
- 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 and Safety
- 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.
Types of Toxicants
- Chemical toxicants: include inorganic substances and organic compounds.
- Biological toxicants: include bacteria and viruses that can induce disease in living organisms.
The Basic Components of Toxicity Test
- The selection of a test organism
- The selection of a response to measure
- An exposure period
- The test duration (observation period)
- A sequence of doses to test
Lethal and Sub-Lethal Toxicity
- 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).
Factors Affecting Toxicity
- Form and innate chemical activity
- Exposure route
- Dosage
- Age
- Sex
- Presence of other chemicals
- Selective toxicity
Insecticides and Resistance
- Not mentioned in the provided text.
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Description
This quiz covers the basics of toxicology, including the definition of toxicity, factors affecting it, and metal toxicity, as well as pollution.
