CHAPT 56: ENVIRONMENTAL & OCCUPATIONAL TOXICOLOGY Flashcards
Pure Baby Katzung Content
branch of pharmacology that encompasses
the deleterious effects of chemicals on biologic systems
Toxicology
air pollutants
CO
SO2
NO2
O3
is an odorless, colorless gas that competes avidly with oxygen for hemoglobin
Carbon Monoxide
The affinity of CO for hemo-
globin is more than ____-fold greater than that of oxygen.
200
The threshold limit value of CO for an 8-h workday is ___ parts per million (ppm);
25
Effect of CO
tissue hypoxia
Collapse and syncope occur when approximately ___% of hemoglobin has been converted to
_______________.
40; carboxyhemoglobin
T or F: Exposure of a pregnant woman to elevated CO levels at critical fetal developmental periods may cause fetal death or serious and irreversible but survivable birth defects.
T
__________ _______ accelerates the clearance of carbon monoxide.
Hyperbaric oxygen
a colorless, irritating gas formed from the combustion of fossil fuels.
Sulfur Dioxide
SO2 forms _________ ______ on contact with moist mucous membranes
Sulfurous Acid
Primary sign of SO2 exposure
Conjunctival and bronchial irritation (esp in individuals w/ asthma)
Presence of ___-___ ppm of SO2 in the air is enough to cause severe bronchospasm.
5; 10
Heavy exposure to SO2 may lead to
delayed pulmonary edema
Chronic low-level exposure to SO2 may aggravate:
cardiopulmonary disease
a brownish irritant gas, is the principal
member of this group; formed in fires and in silage on farms
Nitrogen Oxide
causes deep lung irritation and pulmonary edema.
NO2
The most cost common source of human exposure to oxides of nitrogen
automobile and truck traffic emissions
a bluish irritant gas produced in air and water purification devices and in electrical fields
Ozone
Exposure to ___–___ ppm of O3 may cause irritation and dryness of the mucous membranes.
0.01-0.1
The increasing concentration of a substance in the environment as the result of environmental persistence and physical properties (eg, lipid solubility) that leads to accumulation in biologic tissues
Bioaccumulation
Although the concentration of a contaminant may be virtually undetectable in water, it may be magnified hundreds or thousands of times as the contaminant passes up the food chain
Biomagnification
Study of the toxic effects of chemical and physical agents on populations and communities of living organisms within defined ecosystems
Ecotoxicology
Chemicals in the environment that have estrogen-like or antiandrogen activity or disrupt thyroid function.
They may increase reproductive cancers, impair fertility,
and have teratogenic effects
Endocrine disruptors
The area of toxicology that deals with the effects of agents found in the environment; regulated by the
Environmental Protection Agency (EPA) in the United States
Environmental toxicology
The area of toxicology that deals with the toxic effects of chemicals found in the workplace; regulated by the Occupational Safety and Health Administration (OSHA) in the United States
Occupational toxicology
The amount of exposure to a given agent that is deemed safe for a stated time period. It is higher for shorter periods than for longer periods
Threshold limit value
Aliphatic hydrocarbons are also known as
halohydrocarbons
Examples of halohydrocarbons
carbon tetrachloride
chloroform
trichloroethylene
Solvents are potent CNS __________ (stimulants or depressants)
depressants
Chronic exposure to aliphatic hydrocarbons leads to
hepatic dysfunction and nephrotoxicity
solvents that cause peripheral neuropathy
tetrachloroethylene and trichloroethane
important aromatic hydrocarbons
Benzene
Toluene
Xylene
aromatic hydrocarbon associated with hematotoxicity and various types of hematologic cancers like leukemia
Benzene
aromatic hydrocarbon that is a known human carcinogen
benzene
aka methylbenzene
Toluene
aka dimethylbenzene
Xylene
3 major classes of pesticides
Chlorinated hydrocarbons
Acetylcholinesterase inhibitors
Botanical agents
persistent, poorly metabolized, lipophilic chemicals that exhibit significant bioaccumulation
Chlorinated Hydrocarbons
Chlorinated hydrocarbons block physiologic inactivation in the _______ channels of nerve membranes
sodium
usually the first sign of acute chlorinated hydrocarbon toxicity
Tremor
T or F: Chronic exposure of animals to chlorinated hydrocarbon pesticides is tumorigenic.
T
associated with non-Hodgkin’s lymphoma and testicular cancer
Chlorinated Hydrocarbons
effective pesticides with short environmental half-lives
Carbamates
T or F: Carbamates are cholinesterase inhibitors
T
________ _________ increase muscarinic and nicotinic cholinergic activity.
Cholinesterase inhibitors
The signs and symptoms include pinpoint pupils, sweating,
salivation, bronchoconstriction, vomiting and diarrhea, CNS
stimulation followed by depression, and muscle fasciculations,
weakness, and paralysis.
Cholinesterase inhibitors
most common cause of death of cholinesterase inhibitors
respiratory failure
used in large doses to control muscarinic excess
Atropine
used to regenerate cholinesterase
Pralidoxime
Botanical insecticides
Nicotine
Rotenone
Pyrethrum
has the same effects on nicotinic cholinoceptors in insects as in mammals and probably kills by the same mechanism
Nicotine
plant alkaloid pesticide that causes gastrointestinal distress when ingested and conjunctivitis and dermatitis after direct contact
Rotenone
plant alkaloids that can cause contact dermatitis as well as CNS excitation and peripheral neurotoxicity in large quantities
Pyrethrum
The compound in Agent Orange
2,4,5-trichlorophenoxyacetic acid
2,4-dichlorophenoxyacetic acid and 2,4,5-trichlorophenoxyacetic acid are members of
Chlorophenoxy Acid (herbicide)
the principle ingredient in Roundup brand weed killer
Glyphosate
the most widely used herbicide in the world
Glyphosate
a key enzyme involved in aromatic amino acid biosynthesis in plants
5-enolpyruvylshikimate-3-phosphate synthase,
a bipyridyl herbicide used extensively to kill weeds on farms and for highway maintenance
Paraquat
herbicide that is relatively nontoxic unless ingested
Paraquat
the initial effect is gastrointestinal irritation with hematemesis and bloody stools
Paraquat
prompt prevention of absorption of Paraquat is done by
activated charcoal, Fuller’s earth
Chemical compounds that contribute to environmental pollution
polychlorinated biphenyls
dioxins
asbestos
heavy metals
were used
extensively in manufacturing electrical equipment until their
potential for environmental damage was recognized
Polychlorinated Biphenyls
are among the most stable organic compounds known
PCBs
poorly metabolized and lipophilic, therefore highly persistent in the environment; accumulate in the
food chain
PCB and Asbestos
most common effect of PCB exposure among workers
dermatoxicity
Used in insulation and fire retardancy
PCBs
aka dioxins
polychlorinated dibenzo-p-dioxins
most important dioxin
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)
causes a wasting syndrome, hepatotoxicity, immune dysfunction, teratogenicity, and cancer
TCDD
cause cystic acneiform lesions
Dioxins
is a group of naturally occurring long, flexible mineral fibers, most commonly containing silicon
Asbestos
can cause a fibrotic lung disorder
inhalation of Asbestos fiber
a lung disorder characterized by shortness of breath
asbestosis
associated with mesothelioma
Asbestos
