Environmental & Occupational Toxicology Flashcards
is the branch of pharmacology that encompasses the deleterious effects of chemicals on biologic systems.
Toxicology
Toxic chemicals in the environment
- Pollutants
- Agricultural chemicals
- Solvents
Toxic chemicals in the environmen
Types of Pollutants
- Air
- Environmental
Toxic chemicals in the environmen
Types of Agricultural Chcemicals
- pesticides
- herbicides
Toxic chemicals in the environmen
Types of Solvents
- Halogenated aliphatic hydrocarbons
- aromatic
hydrocarbons
Toxic chemicals in the environmen
Types of air pollutants
- CO
- SO2
- NO2
- O3
Toxic chemicals in the environmen
Types of environmental pollutants
- PCBs
- dioxins
- asbestos
- metals
Toxic chemicals in the environmen
Types of Pesticides
- Chlorinated hydrocarbons
- cholinesterase inhibitors
- botanical
Toxic chemicals in the environmen
Types of Herbicides
- Chlorophenoxy acids
- glyphosate
- bipyridyl
AIR POLLUTANTS
The major air pollutants in industrialized countries include:
Classification and Prototypes
- carbon monoxide
- sulfur oxides
- hydrocarbons
- particulate matter
- nitrogen oxides
AIR POLLUTANTS
carbon monoxide accounts for about ____ of the total
amount of air pollutants
Classification and Prototypes
50%
AIR POLLUTANTS
sulfur oxides accounts for about ____ of the total amount of air pollutants
Classification and Prototypes
18%
AIR POLLUTANTS
hydrocarbons accounts for about ____ of the total amount of air pollutants
Classification and Prototypes
12%
AIR POLLUTANTS
particulate matter accounts for about ____ of the total amount of air pollutants
Classification and Prototypes
10%
AIR POLLUTANTS
nitrogen oxides accounts for about ____ of the total amount of air pollutants
Classification and Prototypes
6%
AIR POLLUTANTS
Air contaminants are regulated in the ______________
Classification and Prototypes
United States by the Environmental Protection Agency (EPA)
AIR POLLUTANTS
Carbon monoxide (CO) is an odorless, colorless gas that competes avidly with oxygen for _________
Carbon monoxide (CO)
hemoglobin
AIR POLLUTANTS
The affinity of CO for hemoglobin is more than _____-fold greater than that of oxygen.
Carbon monoxide (CO)
200
AIR POLLUTANTS
The
threshold limit value of CO for an 8-h workday is
Carbon monoxide (CO)
25 parts per
million (ppm)
AIR POLLUTANTS
in heavy motor vehicle traffic, the concentration of CO may _________
Carbon monoxide (CO)
exceed 100 ppm.
AIR POLLUTANTS
CO causes ________
Carbon monoxide (CO)
Effects
tissue hypoxia
AIR POLLUTANTS
Headache occurs first,
followed by confusion, decreased visual acuity, tachycardia, syncope, coma, seizures, and death.
Carbon monoxide (CO)
Effects
tissue hypoxia
AIR POLLUTANTS
Collapse and syncope occur when approximately 40% of hemoglobin has been converted to _________
Carbon monoxide (CO)
Effects
carboxyhemoglobin
AIR POLLUTANTS
Prolonged hypoxia can result in irreversible damage to the _________ and _________
Carbon monoxide (CO)
Effects
brain and the myocardium.
AIR POLLUTANTS
Exposure of a pregnant woman to elevated CO levels at critical fetal developmental periods may cause __________ or _____________
Carbon monoxide (CO)
Effects
- fetal death
- serious and irreversible but survivable birth defects.
AIR POLLUTANTS
________ and ________
are the main features of treatment
Carbon monoxide (CO)
Treatment
- Removal of the source of CO
- 100% oxygen
AIR POLLUTANTS
accelerates
the clearance of carbon monoxide.
Carbon monoxide (CO)
Treatment
Hyperbaric oxygen
AIR POLLUTANTS
Sulfur dioxide (SO2) is a colorless, irritating gas formed from the _____________
Sulfur Dioxide
combustion of fossil fuels.
AIR POLLUTANTS
SO2 forms __________ on contact with moist
mucous membranes
Sulfur Dioxide
Effects
sulfurous acid
AIR POLLUTANTS
this acid is responsible for most of the pathologic effects.
Sulfur Dioxide
Effects
sulfurous acid
AIR POLLUTANTS
the primary sign of exposure (especially in
individuals with asthma)
Sulfur Dioxide
Effects
Conjunctival and bronchial irritation
AIR POLLUTANTS
Presence
of 5–10 ppm in the air is enough to cause severe ___________
Sulfur Dioxide
Effects
bronchospasm
AIR POLLUTANTS
Heavy exposure may lead to delayed _________
Sulfur Dioxide
Effects
pulmonary edema
AIR POLLUTANTS
Chronic
low-level exposure may aggravate ____________.
Sulfur Dioxide
Effects
cardiopulmonary disease
AIR POLLUTANTS
____________ and _________ constitute the major treatment
Sulfur Dioxide
Treatment
- Removal from exposure to SO2
- relief of irritation and inflammation
AIR POLLUTANTS
Nitrogen dioxide (NO2), a brownish irritant gas, is the principal member of this group. It is formed in _________
Nitrogen Oxides
fires and in silage on farms.
AIR POLLUTANTS
NO2 causes __________ and _____________
Nitrogen Oxides
Effect
- deep lung irritation
- pulmonary
edema
AIR POLLUTANTS
Farm workers exposed to high concentrations of the gas
within enclosed silos may die rapidly of ____________
Nitrogen Oxides
Effects
acute pulmonary edema
AIR POLLUTANTS
Irritation of the ________, ________, and, _______ is common.
Nitrogen Oxides
effect
eyes, nose, and throat
AIR POLLUTANTS
Today, the most
common source of human exposure to oxides of nitrogen, including NO2, is _______ and __________
Nitrogen Oxides
effect
automobile and truck traffic emissions.
AIR POLLUTANTS
Measures to
reduce _________ and _________ are important.
Nitrogen Oxides
Treatment
inflammation and pulmonary edema
No specific treatment is available.
AIR POLLUTANTS
Ozone (O3) is a bluish irritant gas produced in ____________ and _________
Ozone
- air and water
purification devices - electrical fields
AIR POLLUTANTS
Exposure to __________ may cause irritation
and dryness of the mucous membranes
Ozone
Effects
0.01–0.1 ppm
AIR POLLUTANTS
_________
may be impaired at higher concentrations
Ozone
Effects
Pulmonary function
AIR POLLUTANTS
Chronic exposure
leads to __________, __________, ___________, and ___________.
Ozone
Effects
- bronchitis
- bronchiolitis
- pulmonary fibrosis
- emphysema
AIR POLLUTANTS
Measures that
reduce _________ and _________ are emphasized.
Ozone
Treatment
- inflammation
- pulmonary edema
No specific treatment is available
SOLVENTS
Solvents used in industry and solvents to clean clothing are a major
source of direct exposure to ________ and also contribute to
air pollution.
hydrocarbons
SOLVENTS
This group includes __________ such as carbon tetrachloride, chloroform, and trichloroethylene.
cAliphatic Hydrocarbons
halogenated solvents
SOLVENTS
Solvents are potent ___________.
Aliphatic Hydrocarbons
Effects
CNS depressants
SOLVENTS
The _______ of excessive exposure are nausea, vertigo, locomotor disturbances, headache, and coma
Aliphatic Hydrocarbons
Effects
acute effects
SOLVENTS
Chronic exposure leads to
____________ and _________
Aliphatic Hydrocarbons
Effects
- hepatic dysfunction
- nephrotoxicity
SOLVENTS
Long-term exposure to ___________ or _________ has caused peripheral neuropathy.
Aliphatic Hydrocarbons
Effects
- tetrachloroethylene
- trichloroethane
SOLVENTS
__________ is the only specific
treatment available
Aliphatic Hydrocarbons
Treatment
Removal from exposur
SOLVENTS
___________ must be treated with
support of vital signs
Aliphatic Hydrocarbons
Treatment
Serious CNS depression
SOLVENTS
__________,_________, and _________ are important aromatic hydrocarbons.
Aromatic Hydrocarbons
- Benzene
- toluene
- xylene
SOLVENTS
Acute exposure to any of these hydrocarbons leads
to __________
Aromatic Hydrocarbons
Effects
CNS depression with ataxia and coma.
SOLVENTS
Long-term exposure to
benzene is associated with __________ and ________
Aromatic Hydrocarbons
Effects
- hematotoxicity (thrombocytopenia, aplastic anemia, pancytopenia)
- hematologic cancers (leukemia)
SOLVENTS
Most national and international
organizations classify ________ as a known human carcinogen
Aromatic Hydrocarbons
Effects
benzene
SOLVENTS
___________ and __________ are not
carcinogenic.
Aromatic Hydrocarbons
Effects
- Toluene (methylbenzene)
- xylene (dimethylbenzene)
SOLVENTS
___________ is the only specific way to
reduce toxicity
Aromatic Hydrocarbons
Treatment
Removal from exposure
SOLVENTS
_________ is managed by support of vital signs.
Aromatic Hydrocarbons
Treatment
CNS depression
PESTICIDES
The 3 major classes of pesticides are
Classification and Prototypes
- chlorinated hydrocarbons
- acetylcholinesterase inhibitors
- botanical agents
PESTICIDES
DDT and its analogs
Classification and Prototypes
chlorinated hydrocarbons
PESTICIDES
carbamates,
organophosphates
Classification and Prototypes
acetylcholinesterase inhibitors
PESTICIDES
nicotine, rotenone, pyrethrum alkaloids
Classification and Prototypes
botanical agents
PESTICIDES
These agents are persistent, poorly metabolized, lipophilic chemicals that exhibit significant bioaccumulation.
Chlorinated Hydrocarbons
PESTICIDES
Chlorinated hydrocarbons block physiologic inactivation in the _________ of nerve membranes and cause uncontrolled firing of _________.
Chlorinated Hydrocarbons
Effects
- sodium channels
- action potentials
PESTICIDES
_____ is usually the first
sign of acute toxicity and may progress to seizures.
Chlorinated Hydrocarbons
Effects
Tremor
PESTICIDES
Chronic exposure of animals to these pesticides is __________.
Chlorinated Hydrocarbons
Effects
tumorigenic
PESTICIDES
The toxicologic
impact of long-term exposure in humans is ________
Chlorinated Hydrocarbons
Effects
unclear
PESTICIDES
Although no relationship has been shown in humans between the risk of breast cancer and serum levels of DDT metabolites, recent evidence suggests an association with _________ and ____________
Chlorinated Hydrocarbons
Effects
- non-Hodgkin’s lymphoma
- testicular cancer.
PESTICIDES
Because of their extremely long ______ in organisms and in the environment (years), their use in North America and Europe has been
curtailed.
Chlorinated Hydrocarbons
Treatment
half-lives
No specific treatment is available for the acute toxicity
PESTICIDES
The ________ and ___________ are effective pesticides with short environmental half-lives. These inexpensive drugs are heavily
used in agriculture.
Cholinesterase Inhibitors
- carbamates (eg, aldicarb, carbaryl)
- organophosphates
(eg, dichlorvos, malathion, parathion)
PESTICIDES
cholinesterase inhibitors increase ______ and ________
Cholinesterase Inhibitors
Effects
- muscarinic
- nicotinic cholinergic activity
PESTICIDES
The _________ include pinpoint pupils, sweating, salivation, bronchoconstriction, vomiting and diarrhea, CNS stimulation followed by depression, and muscle fasciculations, weakness, and paralysis.
Cholinesterase Inhibitors
Effects
signs and symptoms
PESTICIDES
The most common cause of death is
_____________
Cholinesterase Inhibitors
Effects
respiratory failure.
PESTICIDES
________ is used in large doses to control muscarinic excess
Cholinesterase Inhibitors
Treatment
Atropine
PESTICIDES
________ is used to regenerate cholinesterase
Cholinesterase Inhibitors
Treatment
pralidoxime
PESTICIDES
____________ may be necessary until sufficient cholinesterase has been regenerated.
Cholinesterase Inhibitors
Treatment
Mechanical ventilation
PESTICIDES
Nicotine has the same effects on __________ in insects as in mammals and probably kills by the same mechanism
Botanical Insecticides
Nicotine
nicotinic cholinoceptors
PESTICIDES
Treatment is _________.
Botanical Insecticides
Nicotine
supportive
PESTICIDES
This plant alkaloid pesticide causes __________ when ingested and __________ after direct contact with exposed body surfaces.
Botanical Insecticides
Rotenone
- gastrointestinal distress
- conjunctivitis and dermatitis
PESTICIDES
Treatment is _________
Botanical Insecticides
Rotenone
supportive.
PESTICIDES
The most common toxic effect of this mixture of plant alkaloids is __________
Botanical Insecticides
Pyrethrum
contact dermatitis
PESTICIDES
Ingestion or inhalation of
large quantities may cause ____________ and ________
Botanical Insecticides
Pyrethrum
- CNS excitation (including seizures)
- peripheral neurotoxicity
PESTICIDES
Treatment is supportive with __________ if necessary.
Botanical Insecticides
Pyrethrum
anticonvulsants
HERBICIDES
The 2 most important members of this group are
Chlorophenoxy Acids
- 2,4-dichlorophenoxyacetic acid
- 2,4,5-trichlorophenoxyacetic
acid (Agent Orange)
HERBICIDES
2,4,5-Trichlorophenoxyacetic
acid is longer used because it is often contaminated during manufacturing with ________ and _________
Chlorophenoxy Acids
dioxin and other polychlorinates
HERBICIDES
Large doses of these drugs cause muscle ________ and _________
Chlorophenoxy Acids
hypotonia and coma
HERBICIDES
Longterm exposure has been associated with an increased risk of ___________
Chlorophenoxy Acids
nonHodgkin’s lymphoma
HERBICIDES
Glyphosate is the principle ingredient in _________ and is now the most widely used herbicide in the world
Glyphosate
Roundup brand weed killer
HERBICIDES
Its target, ___________, a key
enzyme involved in aromatic amino acid biosynthesis in plants.
Glyphosate
Effects
5-enolpyruvylshikimate-3-phosphate synthase
HERBICIDES
Glyphosate exposure causes significant ___________ and can be ____ when ingested in large quantities.
Glyphosate
Effects
- eye and skin
irritation - fatal
cHERBICIDES
Treatment
Glyphosate
Supportive, no specific treatment is available.
HERBICIDES
Paraquat, a _________, is used extensively to kill weeds on farms and for highway maintenance
Paraquat
bipyridyl herbicide
HERBICIDES
The compound is relatively nontoxic unless ______
Paraquat
Effects
ingested
HERBICIDES
After ingestion, the initial effect is ___________ with
___________ and __________.
Paraquat
Effects
- gastrointestinal irritation
- hematemesis and bloody stools
HERBICIDES
Within a few days, signs of pulmonary impairment occur and are usually progressive, resulting in severe
___________ and _________
Paraquat
Effects
- pulmonary fibrosis
- death.
HERBICIDES
Because of the _________, prompt prevention of absorption is important
Paraquat
Treatment
delayed pulmonary toxicity
activated charcoal, Fuller’s earth
HERBICIDES
________ is not recommended, as it may promote aspiration from
the stomach into the lungs.
Paraquat
Treatment
Gastric lavage
HERBICIDES
Once the paraquat is absorbed,
treatment is successful in fewer than ____ of cases.
Paraquat
Treatment
50%
HERBICIDES
Antioxidants such as ________- and _______ might be beneficial
through free radical-scavenging, anti-inflammatory actions.
Paraquat
Treatment
- acetylcysteine
- salicylate
HERBICIDES
However, the best supportive treatment, including dialysis,
still results in less than 50% survival after ingestion of as little
as __________.
Paraquat
Treatment
50–500 mg/kg
Chemical compounds that contribute to environmental pollution
include the polychlorinated biphenyls, dioxins, asbestos, and the
heavy metals
ENVIRONMENTAL POLLUTANTS
ENVIRONMENTAL POLLUTANTS
the polychlorinated biphenyls (PCBs) were used extensively in manufacturing ________ until their potential for environmental damage was recognized.
Polychlorinated Biphenyls
Source
electrical equipment
ENVIRONMENTAL POLLUTANTS
PCBs are
among the most ______ organic compounds known.
Polychlorinated Biphenyls
Source
stable
ENVIRONMENTAL POLLUTANTS
they are
poorly ________ and ___________
Polychlorinated Biphenyls
Source
- metabolized
- lipophilic.
ENVIRONMENTAL POLLUTANTS
They are therefore highly
persistent in the environment, and they accumulate in the
_________
Polychlorinated Biphenyls
Source
food chain
ENVIRONMENTAL POLLUTANTS
In workers exposed to PCBs, the most common
effect is _______
Polychlorinated Biphenyls
Effects
dermatotoxicity
(acne, erythema, folliculitis, hyperkeratosis)
ENVIRONMENTAL POLLUTANTS
Less frequently, mild increases in _________ and elevated __________ have been observed.
Polychlorinated Biphenyls
Effects
- plasma triglycerides
- liver enzymes
ENVIRONMENTAL POLLUTANTS
The polychlorinated dibenzo-p-dioxins (dioxins) are a large group of related compounds of which the most important
is _______________
Dioxins
Source
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)
ENVIRONMENTAL POLLUTANTS
The dioxins have appeared in the environment as unwanted _______ of the chemical industry
Dioxins
Source
by-products
ENVIRONMENTAL POLLUTANTS
They are chemically stable and highly resistant to ____________
Dioxins
Source
environmental degradation.
In __________, exposure to TCDD causes a wasting syndrome, hepatotoxicity, immune dysfunction, teratogenicity,
and cancer.
Dioxins
Effects
laboratory animals
ENVIRONMENTAL POLLUTANTS
In humans, the most common signs of toxicity are _________ and _______, which are cystic acneiform lesions that typically form on the face and upper body
Dioxins
Effect
- dermatitis
- chloracne
ENVIRONMENTAL POLLUTANTS
Epidemiologic evidence suggests that
the dioxins also have _____ and _______ effects in humans.
Dioxins
Effect
- carcinogenic
- teratogenic
ENVIRONMENTAL POLLUTANTS
Asbestos is a group of naturally occurring long, flexible
mineral fibers, most commonly containing _______.
Asbestos
Source
silicon
ENVIRONMENTAL POLLUTANTS
Asbestos has
been used widely in _________ and _________
Asbestos
Source
manufacturing and building.
ENVIRONMENTAL POLLUTANTS
Because it is poorly_________ and ________, it is highly persistent in the
environment and accumulates in the food chain.
Asbestos
Source
- metabolized
- lipophilic
ENVIRONMENTAL POLLUTANTS
Many countries
have ______ all use of asbestos because of its toxicity and strictly
regulate handling of preexisting asbestos building products.
Asbestos
Source
banned
ENVIRONMENTAL POLLUTANTS
Inhalation of asbestos fibers can cause a fibrotic lung
disorder called ________, which is characterized by shortness of
breath.
Asbestos
Effects
asbestosis
ENVIRONMENTAL POLLUTANTS
Asbestos is also associated with several cancers including _______, ____________, and _________
Asbestos
Effects
- lung cancer
- mesothelioma
- cancers of the gastrointestinal tract.
High-Yield Terms to Learn
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
There is concern that exposure to ___________ may increase reproductive cancers, impair fertility,
and have teratogenic effects
Endocrine disruptors
Chemicals in the environment that have estrogen-like or antiandrogen activity or disrupt thyroid function.
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
