Environmental & Occupational Toxicology Flashcards by VERNARD DOMINIC ALOYON

Q

is the branch of pharmacology that encompasses the deleterious effects of chemicals on biologic systems.

A

Toxicology

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Q

Toxic chemicals in the environment

A

Pollutants
Agricultural chemicals
Solvents

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Q

Toxic chemicals in the environmen

Types of Pollutants

A

Air
Environmental

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Q

Toxic chemicals in the environmen

Types of Agricultural Chcemicals

A

pesticides
herbicides

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Q

Toxic chemicals in the environmen

Types of Solvents

A

Halogenated aliphatic hydrocarbons
aromatic
hydrocarbons

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Q

Toxic chemicals in the environmen

Types of air pollutants

A

CO
SO2
NO2
O3

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Q

Toxic chemicals in the environmen

Types of environmental pollutants

A

PCBs
dioxins
asbestos
metals

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Q

Toxic chemicals in the environmen

Types of Pesticides

A

Chlorinated hydrocarbons
cholinesterase inhibitors
botanical

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Q

Toxic chemicals in the environmen

Types of Herbicides

A

Chlorophenoxy acids
glyphosate
bipyridyl

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Q

AIR POLLUTANTS

The major air pollutants in industrialized countries include:

Classification and Prototypes

A

carbon monoxide
sulfur oxides
hydrocarbons
particulate matter
nitrogen oxides

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Q

AIR POLLUTANTS

carbon monoxide accounts for about ____ of the total
amount of air pollutants

Classification and Prototypes

A

50%

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Q

AIR POLLUTANTS

sulfur oxides accounts for about ____ of the total amount of air pollutants

Classification and Prototypes

A

18%

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Q

AIR POLLUTANTS

hydrocarbons accounts for about ____ of the total amount of air pollutants

Classification and Prototypes

A

12%

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Q

AIR POLLUTANTS

particulate matter accounts for about ____ of the total amount of air pollutants

Classification and Prototypes

A

10%

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Q

AIR POLLUTANTS

nitrogen oxides accounts for about ____ of the total amount of air pollutants

Classification and Prototypes

A

6%

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Q

AIR POLLUTANTS

Air contaminants are regulated in the ______________

Classification and Prototypes

A

United States by the Environmental Protection Agency (EPA)

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Q

AIR POLLUTANTS

Carbon monoxide (CO) is an odorless, colorless gas that competes avidly with oxygen for _________

Carbon monoxide (CO)

A

hemoglobin

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Q

AIR POLLUTANTS

The affinity of CO for hemoglobin is more than _____-fold greater than that of oxygen.

Carbon monoxide (CO)

A

200

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Q

AIR POLLUTANTS

The
threshold limit value of CO for an 8-h workday is

Carbon monoxide (CO)

A

25 parts per
million (ppm)

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Q

AIR POLLUTANTS

in heavy motor vehicle traffic, the concentration of CO may _________

Carbon monoxide (CO)

A

exceed 100 ppm.

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Q

AIR POLLUTANTS

CO causes ________

Carbon monoxide (CO)

Effects

A

tissue hypoxia

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Q

AIR POLLUTANTS

Headache occurs first,
followed by confusion, decreased visual acuity, tachycardia, syncope, coma, seizures, and death.

Carbon monoxide (CO)

Effects

A

tissue hypoxia

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Q

AIR POLLUTANTS

Collapse and syncope occur when approximately 40% of hemoglobin has been converted to _________

Carbon monoxide (CO)

Effects

A

carboxyhemoglobin

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Q

AIR POLLUTANTS

Prolonged hypoxia can result in irreversible damage to the _________ and _________

Carbon monoxide (CO)

Effects

A

brain and the myocardium.

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# AIR POLLUTANTS Exposure of a pregnant woman to elevated CO levels at critical fetal developmental periods may cause __________ or _____________ | Carbon monoxide (CO) ## Footnote Effects

- fetal death - serious and irreversible but survivable birth defects.

# AIR POLLUTANTS ________ and ________ are the main features of treatment | Carbon monoxide (CO) ## Footnote Treatment

- Removal of the source of CO - 100% oxygen

# AIR POLLUTANTS accelerates the clearance of carbon monoxide. | Carbon monoxide (CO) ## Footnote 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 ## Footnote Effects

sulfurous acid

# AIR POLLUTANTS this acid is responsible for most of the pathologic effects. | Sulfur Dioxide ## Footnote Effects

sulfurous acid

# AIR POLLUTANTS the primary sign of exposure (especially in individuals with asthma) | Sulfur Dioxide ## Footnote Effects

Conjunctival and bronchial irritation

# AIR POLLUTANTS Presence of 5–10 ppm in the air is enough to cause severe ___________ | Sulfur Dioxide ## Footnote Effects

bronchospasm

# AIR POLLUTANTS Heavy exposure may lead to delayed _________ | Sulfur Dioxide ## Footnote Effects

pulmonary edema

# AIR POLLUTANTS Chronic low-level exposure may aggravate ____________. | Sulfur Dioxide ## Footnote Effects

cardiopulmonary disease

# AIR POLLUTANTS ____________ and _________ constitute the major treatment | Sulfur Dioxide ## Footnote 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 ## Footnote 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 ## Footnote Effects

acute pulmonary edema

# AIR POLLUTANTS Irritation of the ________, ________, and, _______ is common. | Nitrogen Oxides ## Footnote 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 ## Footnote effect

automobile and truck traffic emissions.

# AIR POLLUTANTS Measures to reduce _________ and _________ are important. | Nitrogen Oxides ## Footnote 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 ## Footnote Effects

0.01–0.1 ppm

# AIR POLLUTANTS _________ may be impaired at higher concentrations | Ozone ## Footnote Effects

Pulmonary function

# AIR POLLUTANTS Chronic exposure leads to __________, __________, ___________, and ___________. | Ozone ## Footnote Effects

- bronchitis - bronchiolitis - pulmonary fibrosis - emphysema

# AIR POLLUTANTS Measures that reduce _________ and _________ are emphasized. | Ozone ## Footnote 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 ## Footnote Effects

CNS depressants

# SOLVENTS The _______ of excessive exposure are nausea, vertigo, locomotor disturbances, headache, and coma | Aliphatic Hydrocarbons ## Footnote Effects

acute effects

# SOLVENTS Chronic exposure leads to ____________ and _________ | Aliphatic Hydrocarbons ## Footnote Effects

- hepatic dysfunction - nephrotoxicity

# SOLVENTS Long-term exposure to ___________ or _________ has caused peripheral neuropathy. | Aliphatic Hydrocarbons ## Footnote Effects

- tetrachloroethylene - trichloroethane

# SOLVENTS __________ is the only specific treatment available | Aliphatic Hydrocarbons ## Footnote Treatment

Removal from exposur

# SOLVENTS ___________ must be treated with support of vital signs | Aliphatic Hydrocarbons ## Footnote 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 ## Footnote Effects

CNS depression with ataxia and coma.

# SOLVENTS Long-term exposure to benzene is associated with __________ and ________ | Aromatic Hydrocarbons ## Footnote Effects

- hematotoxicity (thrombocytopenia, aplastic anemia, pancytopenia) - hematologic cancers (leukemia)

# SOLVENTS Most national and international organizations classify ________ as a known human carcinogen | Aromatic Hydrocarbons ## Footnote Effects

benzene

# SOLVENTS ___________ and __________ are not carcinogenic. | Aromatic Hydrocarbons ## Footnote Effects

- Toluene (methylbenzene) - xylene (dimethylbenzene)

# SOLVENTS ___________ is the only specific way to reduce toxicity | Aromatic Hydrocarbons ## Footnote Treatment

Removal from exposure

# SOLVENTS _________ is managed by support of vital signs. | Aromatic Hydrocarbons ## Footnote 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 ## Footnote 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 ## Footnote Effects

- sodium channels - action potentials

# PESTICIDES _____ is usually the first sign of acute toxicity and may progress to seizures. | Chlorinated Hydrocarbons ## Footnote Effects

Tremor

# PESTICIDES Chronic exposure of animals to these pesticides is __________. | Chlorinated Hydrocarbons ## Footnote Effects

tumorigenic

# PESTICIDES The toxicologic impact of long-term exposure in humans is ________ | Chlorinated Hydrocarbons ## Footnote 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 ## Footnote 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 ## Footnote 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 ## Footnote 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 ## Footnote Effects

signs and symptoms

# PESTICIDES The most common cause of death is _____________ | Cholinesterase Inhibitors ## Footnote Effects

respiratory failure.

# PESTICIDES ________ is used in large doses to control muscarinic excess | Cholinesterase Inhibitors ## Footnote Treatment

Atropine

# PESTICIDES ________ is used to regenerate cholinesterase | Cholinesterase Inhibitors ## Footnote Treatment

pralidoxime

# PESTICIDES ____________ may be necessary until sufficient cholinesterase has been regenerated. | Cholinesterase Inhibitors ## Footnote Treatment

Mechanical ventilation

# PESTICIDES Nicotine has the same effects on __________ in insects as in mammals and probably kills by the same mechanism | Botanical Insecticides ## Footnote Nicotine

nicotinic cholinoceptors

# PESTICIDES Treatment is _________. | Botanical Insecticides ## Footnote Nicotine

supportive

# PESTICIDES This plant alkaloid pesticide causes __________ when ingested and __________ after direct contact with exposed body surfaces. | Botanical Insecticides ## Footnote Rotenone

- gastrointestinal distress - conjunctivitis and dermatitis

# PESTICIDES Treatment is _________ | Botanical Insecticides ## Footnote Rotenone

supportive.

# PESTICIDES The most common toxic effect of this mixture of plant alkaloids is __________ | Botanical Insecticides ## Footnote Pyrethrum

contact dermatitis

# PESTICIDES Ingestion or inhalation of large quantities may cause ____________ and ________ | Botanical Insecticides ## Footnote Pyrethrum

- CNS excitation (including seizures) - peripheral neurotoxicity

# PESTICIDES Treatment is supportive with __________ if necessary. | Botanical Insecticides ## Footnote 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 ## Footnote Effects

5-enolpyruvylshikimate-3-phosphate synthase

# HERBICIDES Glyphosate exposure causes significant ___________ and can be ____ when ingested in large quantities. | Glyphosate ## Footnote 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 ## Footnote Effects

ingested

# HERBICIDES After ingestion, the initial effect is ___________ with ___________ and __________. | Paraquat ## Footnote 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 ## Footnote Effects

- pulmonary fibrosis - death.

# HERBICIDES Because of the _________, prompt prevention of absorption is important | Paraquat ## Footnote 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 ## Footnote Treatment

Gastric lavage

# HERBICIDES Once the paraquat is absorbed, treatment is successful in fewer than ____ of cases. | Paraquat ## Footnote Treatment

50%

# HERBICIDES Antioxidants such as ________- and _______ might be beneficial through free radical-scavenging, anti-inflammatory actions. | Paraquat ## Footnote 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 ## Footnote 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 ## Footnote Source

electrical equipment

# ENVIRONMENTAL POLLUTANTS PCBs are among the most ______ organic compounds known. | Polychlorinated Biphenyls ## Footnote Source

stable

# ENVIRONMENTAL POLLUTANTS they are poorly ________ and ___________ | Polychlorinated Biphenyls ## Footnote Source

- metabolized - lipophilic.

# ENVIRONMENTAL POLLUTANTS They are therefore highly persistent in the environment, and they accumulate in the _________ | Polychlorinated Biphenyls ## Footnote Source

food chain

# ENVIRONMENTAL POLLUTANTS In workers exposed to PCBs, the most common effect is _______ | Polychlorinated Biphenyls ## Footnote Effects

dermatotoxicity | (acne, erythema, folliculitis, hyperkeratosis)

# ENVIRONMENTAL POLLUTANTS Less frequently, mild increases in _________ and elevated __________ have been observed. | Polychlorinated Biphenyls ## Footnote 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 ## Footnote 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 ## Footnote Source

by-products

# ENVIRONMENTAL POLLUTANTS They are chemically stable and highly resistant to ____________ | Dioxins ## Footnote Source

environmental degradation.

In __________, exposure to TCDD causes a wasting syndrome, hepatotoxicity, immune dysfunction, teratogenicity, and cancer. | Dioxins ## Footnote 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 ## Footnote Effect

- dermatitis - chloracne

# ENVIRONMENTAL POLLUTANTS Epidemiologic evidence suggests that the dioxins also have _____ and _______ effects in humans. | Dioxins ## Footnote Effect

- carcinogenic - teratogenic

# ENVIRONMENTAL POLLUTANTS Asbestos is a group of naturally occurring long, flexible mineral fibers, most commonly containing _______. | Asbestos ## Footnote Source

silicon

# ENVIRONMENTAL POLLUTANTS Asbestos has been used widely in _________ and _________ | Asbestos ## Footnote 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 ## Footnote 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 ## Footnote Source

banned

# ENVIRONMENTAL POLLUTANTS Inhalation of asbestos fibers can cause a fibrotic lung disorder called ________, which is characterized by shortness of breath. | Asbestos ## Footnote Effects

asbestosis

# ENVIRONMENTAL POLLUTANTS Asbestos is also associated with several cancers including _______, ____________, and _________ | Asbestos ## Footnote 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