UNIT 5: INTRODUCTION TO TOXICOLOGY Flashcards
The branch of pharmacology that concerns the study, regulation, and treatment of adverse effects in humans resulting from exposure to chemicals encountered at work or in the general environment.
Toxicology
How do we get exposed to such chemicals?
- Environment (air, water, soil, food)
- Occupational
- Most common chemicals (used in households, personal care, consumer products)
What variables affect the extent of the effect of the toxic chemicals?
- Dose
- Duration of exposure
- Vulnerability of individuals
What are the most commonly affected system/organs of these chemicals?
- Central nervous system
- Liver (hepatotoxicity), kidneys (nephrotoxicity)
- Reproductive system (teratogenic effects)
Deals with the effects of chemicals in the workplace.
Occupational Toxicology
The amount of exposure to a given agent that is deemed safe for a stated time period.
Threshold limit value
Deals with the deleterious impact of chemical pollutants in the environment, on living organisms, or to the ecosystem itself.
Ecotoxicology
Deals with the effects of agents found in the environment.
Environmental toxicology
The ability of a chemical agent to cause injury/disease in a given situation or setting.
Hazard
Expected frequency of the occurrence of an undesirable effect; the likelihood of harm taking place.
Risk
Hazard + exposure equates to?
Risk
What is the route of exposure in industrial settings?
Inhalational > Transdermal > Oral
What is the route of exposure for water & soil pollutants?
Inhalational > Ingestion > Transdermal
Exposure to a toxic substance that is absorbed by the target human or animal.
Dose
Single/multiple exposure over a brief period of time.
Acute exposure
Single/multiple exposure over a longer period of time
Chronic exposure
What is the Hierarchy of Controls?
In order: (Most to least effective)
Elimination
Substitution
Engineering Controls
Administrative Controls
PPEs
The increasing concentration of a substance in the environment that leads to accumulation in biologic tissues.
Bioaccumulation
The concentration of the contaminant is magnified hundreds or thousands of times as the contaminant passes up the food chain.
Biomagnification
An odorless, colorless, non-irritating gas which is a byproduct of incomplete combustion
Air Pollutants
Carbon monoxide
What is the mechanism of action of CO?
Air Pollutants
Combining tightly but reversibly on oxygen-binding sites of hemoglobin, forming carboxyhemoglobin.
True or False:
Oxygen has a higher affinity to hemoglobin than CO
Air Pollutants
False; CO has a higher affinity (220x higher affinity)
What is the primary clinical effect of carbon monoxide poisoning?
Air Pollutants
Tissue hypoxia
What clinical effect/s occurs when approximately 40% of hemoglobin has been converted to carboxyhemoglobin?
Air Pollutants
Collapse & syncope
Prolonged hypoxia due to carbon monoxide poisoning causes what?
Air Pollutants
Irreversible damage to the brain and myocardium?
**True or False: **
Carbon monoxide have potential teratogenic effects
Air Pollutants
True
Exposure at critical fetal developmental periods: fetal death/serious and irreversible but survivable birth defects
What is/are the recommended treatment options for carbon monoxide poisoning?
Air Pollutants
Supportive treatment and oxygenation
Supportive treatment - removal from source
__________ __________ accelerates the clearance of carbon monoxide
Air Pollutants
Hyperbaric oxygen
A colorless, irritant gas formed from the combustion of fossil fuels
Air Pollutants
Sulfur dioxide
What is the mechanism of action of sulfur dioxide?
Air Pollutants
Forms sulfurous acid on contact with moist mucous membranes
What is/are the primary sign of exposure for sulfur dioxide?
Air Pollutants
Conjunctival & bronchial irritation
What are the primary clinical effects of sulfur dioxide exposure?
Air Pollutants
- eyes, nose, throat irritation
- reflex bronchroconstriction
- increased bronchial secretions
What are the primary treatment options for sulfur dioxide exposure?
Air Pollutants
Supportive, non-specific
Non-specfic treatment includes: oxygenation, bronchodilation, use of mucolytics
A brownish, irritant gas associated with fires and silage on farms
Air Pollutants
Nitrogen oxides
What is the mechanism of action for nitrogen oxide exposure?
Air Pollutants
- acts as a deep lung irritant, affecting the alveoli,
- damaging the lung infrastructure producing the surfactant
- dissolving the surfactant itself
What is/are the primary clinical effect/s for nitrogen oxide exposure?
Air Pollutants
Deep lung irritiation and pulmonary edema
Other names for nitrogen oxide exposure
Air Pollutants
- Silo-Filler’s Disease
- Non-allergic Asthma
- Twitchy-airway Disease
What is the chronic effect for nitrogen oxide exposure?
Air Pollutants
Emphysematous changes
What is the treatment for nitrogen oxide exposure?
Air Pollutants
Supportive, non-specifc
Measures to reduce inflammation and pulmonary edema are important
A bluish, irritant gas, found in air & water purification devices, eletrical fields and in the Earth’s atmosphere.
Air Pollutants
Ozone
What is the mechanism of action for ozone exposure?
Air Pollutants
- Acts as an irritant of mucous memranes
- Formation of reactive free radicals
What are the primary clinical effects of ozone exposure?
Air Pollutants
- Irritation and dryness of mucous membranes
- Decrease in pulmonary compliance
What are the acute clinical effects of ozone exposure?
Air Pollutants
- Substernal pain
- Acure respiratory distress (ARDS)
What are the treatment options for ozone exposure?
Air Pollutants
Supportive, non-specific
Measures to reduce inflammation and pulmonary edema are important
What are the two types of solvents encountered that may cause toxicity?
Solvents
- Halogenated Aliphatic Hydrocarbons
- Aromatic Hydrocarbons
True or False:
Do solvents contribute to air pollution?
Solvents
True
Other name for halogenated aliphatic hydrocarbons
Solvents
Halohydrocarbons
What are examples of halohydrocarbons?
Solvents
- Carbon tetrachloride
- Trichloroethylene
- Tetrachloroethylene
- 1,1,1-trichloroethane
- Chloroform
True or False:
Most halohydrocarbons are classified as known or probable human carcinogens
Solvents
True
What is the primary clinical effect for halohydrocarbon poisoning?
Solvents
CNS depression
What are the chronic clinical effects to halohydrocarbon poisoning?
Solvents
hepatic toxicity, nephrotoxicity
What is the effect of long-term exposure to tetrachloroethylene/trichloroethane?
Solvents
Peripheral neuropathy
What is the primary treatment options for halohydrocarbon poisoning?
Solvents
Supportive, non-specific
What is the treatment option for peripheral neuropathy?
Solvents
Vitamin B12 intake
What are examples of aromatic hydrocarbons?
Solvents
- Benzene
- Toluene
- Xylene
What is the primary acute effect for exposure to any of the aromatic hydrocarbons?
Solvents
CNS depression
True or False:
Toluene and Xylene are carcinogenic and myelotoxic
Solvents
False
Only benzene is carcinogenic/myelotoxic
True or False:
Benzene is not a clastogen
Solvents
False
A colorless, sweet-smelling agent
Solvents
Xylene
What are the classifications of pesticides?
Pesticides
- Organophosphates, Carbamates (Acetylcholinesterase Inhibitors)
- Chlorinated Hydrocarbons (Organochlorates, DDT)
- Botanical Agents (Nicotine, Rotenone, Pyrethrum Alkaloids)
Chemicals in the environment that have estrogen-like/antiandrogenic activity or disrupt thyroid function.
Endocrine Disruptors
These agents are persistent, poorly metabolized, lipophilic chemcicals that exhibit significant bioaccumulation.
Pesticides
Chlorinated Hydrocarbons
Aryl, carbocylcic or herterocyclic compounds with chlorine substituents
Pesticides
Organochlorine Pesticides
What is the mechanism of action for organochlorate exposure?
Pesticides
Interfere with inactivation of the sodium channels, causing rapid repetitive firing in most neurons
What is the primary clinical effect for organochlorate exposure?
Pesticides
Tremors
Examples of organochlorates
Pesticides
- Paraquat dichloride
- DDT (dichlorodiphenyltrichloroethane)
- Rotenone
- Pyrethrine I
What is the treatment option for organochlorate exposure?
Pesticides
No specific treatment available
These are effective pesticides with short environmental half-lives, inexpensive, and are heavily used in agriculture.
Pesticides
Cholinesterase inhibitors
What is the mechanism of action for cholinesterase inhibitors?
Pesticides
- increase nicotine & muscarinic cholinergic activity
- inhibition of acetylcholinesterase activity through phosphorylation of the esteratic state
What is/are the primary clinical effect/s for organophosphate exposure?
Pesticides
M.U.D.D.L.E.S
miosis, urination, diarrhea, diaphoresis, lacrimation, excitation of the CNS, salivation
What is the most common cause of death from exposure to cholinesterase inhibitors?
Pesticides
Respiratory failure
What is the treatment option for organophosphate exposure?
Pesticides
Specific treatment: Pralidoxime & physostigmine
What drug is used to control muscarinic excess?
Pesticides
Atropine
in large doses
What does pralidoxime do?
Pesticides
Regenerate cholinesterase
Enumerate
Botanical Pesticides (3)
Nicotine
Rotenone
Pyrethrum
What is the mechanism of action for nicotine?
Pesticides
excitation, followed by paralysis of ganglionic, CNS and neuromuscular transmission.
A plant alkaloid pesticide
Pesticides
Rotenone
What are the clinical effects of rotenone?
Pesticides
Ingested: gastrointestinal distress
Direct contact: conjunctivitis and dermatitis
A mixture of plant alkaloids that causes contact dermatitis as its common toxic effect.
Pesticides
Pyrethrum
What are the most important members of chlorophenoxy acids?
Pesticides
- 2,4-dichlorophenoxyacetic acid
- 2,4,5-trichlorophenoxyacetic acid
What are the clinical effects after long term exposure to chlorophenoxy acids?
Pesticides
muscle hypotonia and coma
What is the principal ingredient of weed killers?
Pesticides
Glyphosate
What is the target of glyphosate in plants?
Pesticides
5-enolpyruvylshikimate-3-phosphate synthase
What is/are the primary clinical effects of glyphosate exposure?
Pesticides
Significant eye and skin irritation
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A bipyridyl herbicide
Pesticides
Paraquat
What is/are the primary clinical effects of paraquat contact?
Pesticides
None
Paraquat is only toxic when ingested
What is/are the primary clinical effects of paraquat ingestion?
Pesticides
- Gastrointestinal irritation with hematemesis and bloody stools
- Pulmonary impairment to pulmonary fibrosis, leading to death
Hematemesis - vomiting blood
Chemical compounds that contribute to environmental pollution.
Environmental Pollutants
Highly halogenated biphenyl compounds that are poorly metabolized, lipophilic, and is highly persistent in the environment.
Environmental Pollutants
- Polychlorinated Biphenyls
- Polybrominated Biphenyls
What is the primary source of PCB/PBB for humans?
Environmental Pollutants
Food
What is the primary clinical effect of PCB/PBB toxicity?
Environmental Pollutants
Dermatoxicity
What are the other clinical effects of PCB/PBB?
Environmental Pollutants
- Potent endocrine disruptors
- Severe reproductive and teratogenic effects
These chemicals are used as:
- coolant material
- used as heat-, stain-, and stick-resistant coating
Environmental Pollutants
Perfluorinated Compounds
A group of naturally occurring long, flexible mineral fibers most commonly contaning silicon; widely used in manufacturing and building
Environmental Pollutants
Asbestos
True or False:
Asbestos is poorly metabolized, lipophilic, and highly persistent in the environment.
Environmental Pollutants
True
What is/are the primary clinical effects of asbestos inhalation?
Environmental Pollutants
- asbestosis
- mesothelioma
- lung cancer
True or False:
Asbestos has no synergistic effect with cigarette smoking & exposure to radon daughters.
Environmental Pollutants
False
What are examples of toxic metals used in the industry?
Metals
Beryllium and Cadmium
A light alkaline metal that enters through inhalation
Metals
Beryllium
A transitional metal that is either inhaled or ingested
Metals
Cadmium
What is/are the primary clinical effect/s of beryllium poisoning?
Metals
- Progressive pulmonary fibrosis
- Acute & Chronic Beryllium Disease
What is/are the primary clinical effect/s of cadmium poisoning?
Metals
- Progressive pulmonary fibrosis
- Renal failure
- Cadmium Fume Fever
What is the Carcinogen Classification of Cadmium & Beryllium
Metals
Class 1 (Known carcinogen to humans)
Any material, natural or manufactured, bearing the size of at least 1 - 100 nm in size
Metals
Nanomaterials
What is the route of exposure for nanomaterials?
Metals
- Inhalation
- Oral
- Dermal
- Parenteral
True or False:
Nanomaterials cannot cross cellular membranes, penetrate nuclear material and genetic information
Metals
False
Due to their small size, it is possible for nanomaterials to cross cellular membranes and dependent on the nanomaterial, can affect genetic material.
Identify
Aldicarb
Aminocarb
Carbaryl
Carbofuran
Dimetan
Dimetilan
Isolan
Methomyl
Pyramat
Pyrolan
Zectran
Carbamate Pesticides
Enumerate
Herbicides (5)
Chlorophenoxy Acids
2,4-Dichlorophenoxyacetic Acid
2,4,5-Trichlorophenoxyacetic Acid
Glyphosate
Biphyridyl Pesticides (Paraquat)
Enumerate
DDT and analogs
Organochlorine Pesticides
Dichlorodiphenyltrichloroethane (DDT)
Methoxychlor
Tetrachlorodiphenylethane (TDE)
Enumerate
Benzene hexachlorides
Organochlorine Pesticides
Benzene hexachloride (BHC)
Lindane
Enumerate
Cyclodienes
Organochlorine Pesticides
Aldrin
Chlordane
Dieldrin
Heptachlor
Enumerate
Toxaphenes
Organochlorine Pesticides
Toxaphene (camphechlor)
lol
Identify
Azinphos-methyl
Chlorfenvinphos
Diazinon
Dichlorvos
Fenitrothion
Malathion
Parathion
Parathion-methyl
Trichlorfon
Organophosphorous Pesticides