Introduction to Toxicology: Occupational and Environmental Flashcards
Basic principles of toxicology
- Mechanism of exposure
- Toxicological effects
a. Recognition
b. Prevention
c. Treatment
Exposure to chemicals maybe through the environment (air, water, soil, food) and/or occupational.
Occupational & Environmental Toxicology
T/F: Most common chemicals are those used in households, personal care and consumer products; those used in agriculture and industry
T
What systems are affected by Occupational & Environmental Toxicology?
CNS, liver & kidney, Reproductive system
Signs and symptoms for chronic chemical poisoning of chemicals may be non-specific and may manifest as
headaches, nauseas, vomiting, dizziness, irritation of the skin, eyes and mucous membranes
F; acute chemical poisoning
Effects of Occupational & Environmental Toxicology
Depending on dose, duration of exposure, vulnerability of individuals
This area of toxicology deals with chemicals found in the
workplace
Occupational Toxicology
Handles cases involving Occupational & Environmental Toxicology
Occupational Medicine Specialists and Toxicologists
T/F: Treatment is available for Occupational & Environmental Toxicology.
T
Occupational toxicology identifies?
- Agents of concern
- Acute & chronic diseases
- Conditions for safe use
- Preventive measures
- Treatment
- Surveillance
Who established RA 11058 or the Labor Code of the PH?
Occupational Safety and Health Standards (OSHS)
Standards for specific materials of particularly
serious toxicity
Permissible Exposure Limits (PELs): ppm
Only serves as a guide
or reference points in the evaluation of potential
workplace exposures in the absence of OSHA requirements; it is still not implemented
Threshold limit values (TLVs)
Deals with the deleterious impact of chemical pollutants in the environment, on living organisms
Environmental toxicology / Ecotoxicology
Toxic effects of chemical and physical agent on
populations and communities of living
organisms within defined ecosystems
Environmental toxicology / Ecotoxicology
Transfer pathways of those agents and interactions with the environment
Environmental toxicology / Ecotoxicology
● Concerned with the impact on populations of living
organisms or on ecosystems
● Includes air, soil or water
Environmental toxicology / Ecotoxicology
Environmental toxicology / Ecotoxicology is a product of?
- Industrialization
- Technologic development
- Urbanization
Ability of chemical agent to cause injury / disease in a
given situation or setting
Hazard
Something that can potentially cause harm
Hazard
Likelihood that a hazard will cause harm
Risk
Potential to cause harm
Hazard
Expected frequency of the occurrence of an undesirable effect arising from exposure to a chemical
or physical agent
Risk
Inhalation and dermal
Atmospheric pollutants
Hazard + exposure
Risk
Routes of Exposure in Industrial
Inhalational > Transdermal Route > Oral
Water and soil pollutants are absorbed through
○ Inhalation
○ Ingestion
○ Transdermal
Inhalation, ingestion, dermal
Water and soil pollutants
● Single or multiple exposure over a brief period of time
● (Ex.) accidental discharge
Acute exposure
● Single or multiple exposure over a longer period of time
● (Ex.) repetitive handling of chemical (done by laboratory technicians)
Chronic exposure
↑ dose = _ effect
↑
Physically remove the hazard
Elimination
replace the hazard
Substitution
isolate people from the hazard
engineering controls
Protect the worker with Personal Protective Equipment
PPE
Most effective in Hierarchy of Controls
Elimination
change the way people work
Administrative controls (Policies)
Least effective in Hierarchy of Controls
PPE
Polychlorinated biphenyls
Persistent organic pollutants (POPs)
Furans
Persistent organic pollutants (POPs)
Dioxins
Persistent organic pollutants (POPs)
Methyl mercury discharges causes __________.
neurotoxicity
T/F: Poorly degraded chemicals (by abiotic or biotic pathways) exhibit environmental persistence and can accumulate
T
Environmental considerations
Degradability, bioaccumulation, transport and biomagnification
Organochlorine pesticides
bioaccumulate in body fat causes endocrine disruption, neurological disorders, and carcinogenesis
Lipophilic substances
T/F: Biodegradable are biotic
F; abiotic
↓ degraded = _ capacity to accumulate in the environment
↑
causative agent Minamata disease
Methylmercury
0ccurs when the metabolism of a chemical is low, thus preventing it from being excreted out since it cannot be turned into water
soluble or excretable form
Bioaccumulation
Pollutants having the widest
environmental impact are poorly degradable
Bioaccumulation
Relatively mobile in air, water, and soil
Bioaccumulation
Concentrates the chemical in organisms higher on the food chain
Biomagnification
n entails several organisms
Biomagnification
Colorless, tasteless, odorless and non-irritating gas
Carbon monoxide / CO
Byproduct of incomplete combustion
Carbon monoxide / CO
Sources of Carbon monoxide / CO
→ Unvented kerosene and gas space heaters
→ Leaking chimneys and furnaces
→ Back-drafting from furnaces
→ Gas water heaters
→ Wood stoves and Fireplaces
→ Gas stoves
→ Generators and other gasoline powered equipment
→ Automobile exhaust and attached garages
→ Tobacco Smoke
most famous source of carbon monoxide (CO)
Automobile exhaust and attached garages
● Easily absorbed through the lungs
● Exposure may be acute or chronic
● Has teratogenic potential
Carbon monoxide / CO
T/F: Carbon Monoxide combines tightly but reversibly with oxygen-binding site of Hemoglobin (Hb)
T
Sources of Carbon Monoxide in a home
→ Car left running in attached garage
→ Clogged chimney
→ Corroded or Disconnected Water Heater Vent Pipe
→ Gas or Wood-burning Fireplace
→ Cracked or Loose Furnace Exchanger
→ Improperly installed Kitchen Range or Vent
→ Operating a Grill indoors or in a Garage
→ Portable Kerosene or Gas Heaters
CO + oxygen-binding site of hemoglobin (Hb) = ?
Carboxyhemoglobin
cannot transport oxygen
Carboxyhemoglobin
CO has affinity of about ___ times that of oxygen
220
Interferes with the dissociation of oxygen from the remaining oxyhemoglobin as a result of the Bohr effect.
Carboxyhemoglobin
T/F: The presence of carboxyhemoglobin increases oxygen transfer to the tissues
F; decreases
What organs with the highest oxygen demand are most seriously
affected?
- Brain
- Heart
- Kidneys
carries oxygen and carbon dioxide
hemoglobin
T/F: Presence of carbon monoxide causes oxygen to not be carried in and out of the body
T
Complete combustion
Carbon dioxide (CO2)
Incomplete combustion
Carbon monoxide (CO)
Symptoms of Hypoxia
● Psychomotor impairment
● Headache and tightness in the temporal area
● Confusion and loss of visual acuity
● Tachycardia, tachypnea, syncope, and coma
● Deep coma, convulsions, shock, and respiratory failure
Hypoxia is aggravated by
● Heavy labor
● High altitude and ambient temperature
● Smoking exposure
● Cardiorespiratory diseases
Principle sign of carbon monoxide
Hypoxia
1st step of treatment when carbon monoxide is inhaled
Colorless irritant gas generated primarily by the combustion of sulfur-containing fossil fuels
Sulfur Dioxide
Treatment for Hypoxia
Remove from source of CO
Give high conc of O2
Hypothermic therapy
Principal source of urban SO2
Burning of coal, both for domestic heating and in coal-fired power plants
Site of principal effect for sulfur dioxide
upper respiratory tract
Clinical effect if sulfur dioxide is INHALED
- Causes bronchial constriction
- Produces profuse bronchorrhea
- Parasympathetic reflexes and altered smooth muscle tone
Clinical outcome of Sulfur Dioxide
acute irritant asthma
Signs and symptoms of SO2 intoxication
- Irritation of the eyes, nose, and throat
- Reflex bronchoconstriction
- Increased bronchial secretions
Exposure to 5 ppm SO2 for 10 minutes
Increased resistance to airflow
Exposures of 5-10 ppm SO2
Cause severe bronchospasm
Severe exposure of SO2
Delayed-onset pulmonary edema
Cumulative effects from chronic low-level exposure of SO2
Aggravation of chronic cardiopulmonary disease
Treatment for SO2
Depends on therapeutic maneuvers used to treat irritation of the respiratory tract and asthma
NO2 is found in
Fresh silage
Diesel equipment
Automobile and truck traffic emissions
Brownish irritant gas sometimes associated with fires
Relatively insoluble deep lung irritant
Nitrogen Oxides NO2
Most common source of human exposure to oxides of nitrogen
Automobile and truck traffic emissions
Capable of producing pulmonary edema and acute adult respiratory distress syndrome (ARDS)
Nitrogen Oxides
Inhalation damages the lung infrastructure that produces the surfactant necessary to allow smooth and low-effort lung alveolar
expansion
Nitrogen Oxides
This cell appears to be the cells chiefly affected by acute low to moderate inhalation exposure of Nitrogen oxide
Type 1 cells of the alveoli
Intoxication of NO2 is associated with
○ Silo-Filler’s Disease
○ Non-allergic Asthma
○ “Twitchy Airway Disease”
Acute intoxication of NO2 symptoms
○ Irritation of eyes and nose, cough
○ Mucoid or frothy sputum production
○ Dyspnea and chest pain
○ Pulmonary edema
○ Fibrotic destruction of terminal bronchioles
Chronic exposure of NO2
emphysematous changes
Bluish irritant gas naturally found in the earth’s atmosphere
Ozone (O3) and other oxides
Ozone (O3) and other oxides are found in
○ Burning of fossil fuel
○ Emission from power plants, motor vehicles
and other sources of high heat compounds
○ High-voltage electrical equipment and air and
water purification systems
○ Agriculture
Sources of Ozone
● Area sources
● Oil and gas
● Biogenic sources
● Off-road engines
● On-road vehicles
● Non-road engines
● Point sources
Clinical effects of Ozone
Shallow, rapid breathing and decrease in pulmonary compliance
Clinical effects of Acute Ozone Exposure
○ Irritation and dryness to throat
○ Changes to visual acuity
○ Substernal pain and dyspnea
○ Acute Respiratory Distress Syndrome (ARDS)
Clinical effects of Chronic Ozone Exposure
○ Chronic bronchitis
○ Bronchiolitis
○ Emphysema
Treatment for Ozone exposure
No specific treatment for acute O3 intoxication
