1 Red numbers indicate the number of 747 Jumbo Jets crashing
every day of the year with no survivors! Annual Deaths and Their
Causes
Slide 3
What are Risks? Risk is the possibility of suffering harm from
a hazard that can cause injury, disease, economic loss or
environmental damage.Risk is the possibility of suffering harm from
a hazard that can cause injury, disease, economic loss or
environmental damage. What are some different hazards?What are some
different hazards?
Slide 4
Toxic Chemicals Fatal to over 50% of test subjects at given
concentrationsFatal to over 50% of test subjects at given
concentrations Can be Industrial or Agricultural Ex: Dioxin,
mercury cyanide, benzene chloroform Kill cell or impair their
function
Slide 5
Hazardous Chemicals Flammable or explosiveFlammable or
explosive Irritating to skin or lungsIrritating to skin or lungs
Interfere with oxygen uptakeInterfere with oxygen uptake Induction
of allergic reactionsInduction of allergic reactions Interference
with endocrine (hormone) systemInterference with endocrine
(hormone) system
Slide 6
Mutagens Chemicals or radiation that cause mutationsChemicals
or radiation that cause mutations Can cause cancer or congenital
(present at birth) defects.Can cause cancer or congenital (present
at birth) defects.
Slide 7
Carcinogens Chemicals, radiation or viruses that cause
malignant (cancerous) tumors.Chemicals, radiation or viruses that
cause malignant (cancerous) tumors. Cancer: Cells cannot regulate
their growth, divide uncontrollably, and metastasize (break off
from tumors and travel to other parts of the body).Cancer: Cells
cannot regulate their growth, divide uncontrollably, and
metastasize (break off from tumors and travel to other parts of the
body).
Slide 8
Carcinogens 2nd highest cause of death in the U.S.2nd highest
cause of death in the U.S. Rates of cancer survival are increasing
as treatment gets betterRates of cancer survival are increasing as
treatment gets better
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Teratogens Chemicals, radiation, viruses that cause birth
defects during pregnancyChemicals, radiation, viruses that cause
birth defects during pregnancy ex. Alcohol Fetal Alcohol Syndrome
(FAS)- mental defects, developmental delays, behavioral
problemsFetal Alcohol Syndrome (FAS)- mental defects, developmental
delays, behavioral problems
Slide 10
Neurotoxins Metabolic poisons attack nervesMetabolic poisons
attack nerves Anesthetics (Ether, Chloroform)Anesthetics (Ether,
Chloroform) Chlorinated hydrocarbons (DDT)Chlorinated hydrocarbons
(DDT) Heavy metals (Lead, Mercury)Heavy metals (Lead, Mercury)
Organophosphates (Malathion)Organophosphates (Malathion) Carbamates
(Sevrin)Carbamates (Sevrin) Toxic and fast actingToxic and fast
acting
Slide 11
Ionizing Radiation Radiation with enough energy that it can
remove tightly bound electrons from the orbit of an atom, causing
the atom to become charged or ionized. Health Effects: Beyond
certain thresholds, radiation can impair the functioning of tissues
and/or organs and can produce acute effects such as skin redness,
hair loss, radiation burns.
Slide 12
Heavy-Metal Poisoning Minimata Disease or Mad as a Hatter
Mercury is Fat SolubleHeavy-Metal Poisoning Minimata Disease or Mad
as a Hatter Mercury is Fat Soluble
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Asphyxiants Interfere with oxygen uptakeInterfere with oxygen
uptake Passive: carbon dioxide, methanePassive: carbon dioxide,
methane Active: carbon monoxide (replaces oxygen in hemoglobin),
hydrogen cyanide, hydrogen sulfideActive: carbon monoxide (replaces
oxygen in hemoglobin), hydrogen cyanide, hydrogen sulfide
Slide 14
Figure 10-4 Hormone Mimics and Disrupters These chemicals
prevent natural hormones from attaching to their receptors.
(dioxins, PCBs, plastics, pesticides, lead, mercury, BPA)
Slide 15
Respiratory Fibrotic Agents Irritants that damage lung tissue
and cause formation of scar tissue with limits lung
capacityIrritants that damage lung tissue and cause formation of
scar tissue with limits lung capacity ex. Coal dust causing black
lung (coal) asbestosis, brown lung (cotton)
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Cultural Hazards SmokingSmoking Nations leading cause of
preventable deathNations leading cause of preventable death # of
deaths equal to 3 jumbo jets crashing every day (1,150/day)# of
deaths equal to 3 jumbo jets crashing every day (1,150/day) only 1
in ten can quitonly 1 in ten can quit 30-40% of cancers caused by
smoking.30-40% of cancers caused by smoking.
Slide 17
Physical Hazards Ionizing Radiation Ionizing Radiation
Electromagnetic radiation with enough energy to damage body
tissues. Radiation knocks loose electrons from a cellular chemical
altering cell functionRadiation knocks loose electrons from a
cellular chemical altering cell function Genetic DNAGenetic DNA
Somatic - TissueSomatic - Tissue
Slide 18
Persistence and Chemical Interactions Persistence - how long a
chemical remains in the environmentPersistence - how long a
chemical remains in the environment
Slide 19
Chemical Interactions Antagonistic reactions - interfere with
the effects of or stimulate the breakdown of other chemicals
antioxidantsAntagonistic reactions - interfere with the effects of
or stimulate the breakdown of other chemicals antioxidants Additive
effects - effects are added togetherAdditive effects - effects are
added together Synergistic effects - when combination is worse than
added effectsSynergistic effects - when combination is worse than
added effects
Slide 20
Magnification (additive) Bioaccumulation: The build up of a
substance in an individual organisms tissueBioaccumulation: The
build up of a substance in an individual organisms tissue
Biomagnification : Increase in concentration of a toxin as it
passes up the food chain.Biomagnification : Increase in
concentration of a toxin as it passes up the food chain.
Slide 21
Biological Hazards transmissible by living
organisms.transmissible by living organisms. Pathogens spread by
air, water, food, body fluids such as bacteria, virus, protozoa,
parasites. Non-transmissible does not spread from person to
personNon-transmissible does not spread from person to person such
as most cancers, heart disease, diabetes. Etc.
Slide 22
Who Performs Risk Analysis? The EPA (Environmental Protection
Agency)The EPA (Environmental Protection Agency) Began in 1970s to
estimate cancer risks as a result of exposure
Slide 23
What are the 4 steps? 1. Risk assessment 2. Dose-response
assessment 3. Exposure assessment 4. Risk characterization
Slide 24
1. Risk Assessment Determining types of hazardsDetermining
types of hazards Probability that each will occurProbability that
each will occur How many people will be exposedHow many people will
be exposed How many will suffer serious harmHow many will suffer
serious harm
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1. Risk Assessment Two methods:Two methods: Epidemiology -
tracks how sickness spreads through community - can establish links
Animal testing - gives more immediate results (remember cats and
Minimata?)
Slide 26
2. Dose-Response Assessment Dose and Response Relationship:Dose
and Response Relationship: Dose- amount of substance someone has
taken in Acute exposure - single doseAcute exposure - single dose
Chronic exposure - long-term exposureChronic exposure - long-term
exposure
Slide 27
2. Dose-Response Assessment Response - type and amount of
damage Acute effect - immediate or rapid reaction to exposureAcute
effect - immediate or rapid reaction to exposure Chronic effect -
permanent or long-lasting effectChronic effect - permanent or
long-lasting effect
Slide 28
Dose- Response Curves Linear relationship for some carcinogens
Threshold There is a minimal dosage necessary for a response Linear
there is an immediate response (example: smoke inhalation)
Threshold there is no immediate response. Levels must build up in
the system (example: mercury poisoning)
Slide 29
Range of Tolerance All species have:All species have: Minimum
and maximum levels of tolerance to any environmental factor in
order to live. They will not live outside that level. They will
exist in fewer numbers at the edges of the range.
Slide 30
Solubility Solubility is the quantity of a particular substance
that can dissolve in a particular solventSolubility is the quantity
of a particular substance that can dissolve in a particular solvent
One of the most important characteristics determining how a toxin
will move through a body or environmentOne of the most important
characteristics determining how a toxin will move through a body or
environment
Slide 31
Solubility Water-soluble compounds move rapidly in environments
and throughout the body.Water-soluble compounds move rapidly in
environments and throughout the body. Ex: Vitamins: B-complex and
CEx: Vitamins: B-complex and C Fat-soluble compounds have trouble
getting into body, but once in, readily penetrate cells and are
accumulated over time.Fat-soluble compounds have trouble getting
into body, but once in, readily penetrate cells and are accumulated
over time. Ex: Vitamins A, Lead, DDT, MercuryEx: Vitamins A, Lead,
DDT, Mercury
Slide 32
Measuring Toxicity Lethal Dose - LD 50Lethal Dose - LD 50
Amount of a chemical that is required in one dose to kill 50% of
test population in 14 days
Slide 33
Exposure hazard: Exposure hazard: more people exposed the
greater the risk closer the people to the source the greater the
risk. 3. Exposure Assessment Estimation of intensity, duration, and
frequency of human exposure to hazardEstimation of intensity,
duration, and frequency of human exposure to hazard
Slide 34
4. Risk Characterization Pull together all information in first
three steps to determine magnitude of the risk and its accompanying
uncertaintiesPull together all information in first three steps to
determine magnitude of the risk and its accompanying
uncertainties
