Risk, Toxicology and Human Health

Risk, Toxicology Risk, Toxicology and and

Human HealthHuman Health

AP Environmental AP Environmental ScienceScience

Chapter 8Chapter 8

Human HealthHuman Health•Health is a state of complete Health is a state of complete

physical, mental, social and physical, mental, social and spiritual well-being and not spiritual well-being and not merely the absence of disease merely the absence of disease or infirmity (disability)or infirmity (disability)

oror• The ability to lead a socially and The ability to lead a socially and

economically productive lifeeconomically productive life

Holistic Concept of Holistic Concept of HealthHealth

• This concept recognizes the This concept recognizes the strength of social, economic, strength of social, economic, personal freedom and personal freedom and environmental influences on healthenvironmental influences on health

• DeterminantsDeterminants– HeredityHeredity– Health and family welfare services Health and family welfare services – EnvironmentEnvironment– Life-styleLife-style– Socio-economic conditionsSocio-economic conditions

DiseaseDisease•Disease results from the Disease results from the

complex interaction between complex interaction between man, an agent and the man, an agent and the environmentenvironment

•Ecological point of view – Ecological point of view – “maladjustment of the human “maladjustment of the human organism to the environment”organism to the environment”

Epidemilogical TriadEpidemilogical TriadAny EnvironmentAny Environment

Vector (how infected: Vector (how infected: water, pollution, insect, water, pollution, insect,

contact)contact)

Pathogen:Pathogen:

(Virus/bacteria) (Virus/bacteria) (Organism)(Organism)

AgentAgent

HostHost

Key ConceptsKey Concepts• Types of HazardsTypes of Hazards• Exposure AssessmentExposure Assessment

• Risk estimation, management, and Risk estimation, management, and reductionreduction

Types of HazardsTypes of Hazards•Biological HazardsBiological Hazards

–These are living organisms or their products that are harmful to humans

Biological HazardsBiological Hazards•Water-borne diseasesWater-borne diseases

– Transmitted in drinking waterTransmitted in drinking water•Disease organisms shed into Disease organisms shed into water in feceswater in feces

•Can produce illness in those who Can produce illness in those who consume untreated, contaminated consume untreated, contaminated waterwater


– municipal water treatment municipal water treatment facilities are usually able to facilities are usually able to purify water purify water •removing these agents by removing these agents by filtrationfiltration

•killing them by disinfectionkilling them by disinfection


– Examples Examples •Polio virusPolio virus•Hepatitis A virusHepatitis A virus•SalmonellaSalmonella•ShigellaShigella•CholeraCholera•Amoebic dysenteryAmoebic dysentery•GiardiaGiardia•CryptosporidiumCryptosporidium

E. coli outbreak in E. coli outbreak in WalkertonWalkerton• In May 2000 the small community of In May 2000 the small community of

Walkerton, Ontario was laid waste by a Walkerton, Ontario was laid waste by a toxic strain of toxic strain of E. coli:0157E. coli:0157. . – The contamination came from the public The contamination came from the public

water supply. water supply. – Six people died in the first week including a Six people died in the first week including a

two year old daughter of a local medical two year old daughter of a local medical doctor. doctor.

– Four new cases surfaced in late July, all very Four new cases surfaced in late July, all very young children. young children.

– Over a thousand innocent people were Over a thousand innocent people were infected.infected. bss.sfsu.edu/ehines/geog600/ Freshwater%20and

%20ocean%20Pollution.ppt

Waterborne Waterborne BacteriaBacteria

Escherichia coli Vibrio sp.Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

• Disease symptoms usually are Disease symptoms usually are explosive emissions from either explosive emissions from either end of the digestive tractend of the digestive tract

Waterborne Waterborne ProtozoansProtozoans

Giardia sp.**P. Darben

Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

• Disease symptoms are usually Disease symptoms are usually explosive emissions from either explosive emissions from either end of the digestive tractend of the digestive tract

Waterborne Waterborne Human Human VirusesViruses

Hepatitis A virus Hepatitis E virus

Norwalk virus* Rotavirus**F. Williams

Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

Indicator TestsIndicator Tests

Total coliform[Endo agar]

Fecal coliform[m-FC agar]

Fecal streptococci[M-enterococcus]

Prescott et al., MicrobiologyBarbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio

Case Study on Case Study on Eradicating Eradicating

DracunculiasisDracunculiasis

Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ HaywardWater and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward

Guinea Worm Guinea Worm DiseaseDisease• People have suffered from Guinea Worms People have suffered from Guinea Worms

for centuries – the “fiery serpent” was for centuries – the “fiery serpent” was mentioned in the biblementioned in the bible

• People are infected by drinking water People are infected by drinking water that contain the larvae in a tiny that contain the larvae in a tiny freshwater crustacean called Cyclopsfreshwater crustacean called Cyclops

• A year later, larvae mature into 3 feet A year later, larvae mature into 3 feet worms that emerge through skin blistersworms that emerge through skin blisters

• This is such a This is such a painful processpainful process that men that men and women can’t work, children can’t and women can’t work, children can’t attend schoolattend school

Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward

http://www.pmeh.uiowa.edu/fuortes/63111/GUINEA/

The Guinea The Guinea Worm Worm grows grows

down the down the leg and its leg and its sex organs sex organs appear at appear at the ankle the ankle or on the or on the

foot foot usually, usually, bursting bursting when it when it senses senses water, water,

releasing releasing ova.ova.

Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward

• No vaccine for Guinea No vaccine for Guinea worm is available.worm is available.

• People do not seem to People do not seem to build up any resistance build up any resistance and the disease can be and the disease can be reinfected over and reinfected over and over.over.

• No research is being No research is being conducted for any conducted for any vaccine or cure.vaccine or cure.

• Worms are removed Worms are removed slowly each day by slowly each day by winding around a stick.winding around a stick.

http://www.pmeh.uiowa.edu/fuortes/63111/GUINEA/Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward

Biological HazardsBiological Hazards•Food–borne diseasesFood–borne diseases

– To protect against food-borne To protect against food-borne diseasedisease•local health departments local health departments

– inspect inspect »food service establishments food service establishments (restaurants) (restaurants)

»retail food outlets (supermarkets)retail food outlets (supermarkets)»processing plantsprocessing plants

–verify that foodverify that food»stored stored »handled properlyhandled properly

Biological HazardsBiological Hazards•Food-borne diseasesFood-borne diseases

– Examples Examples •Salmonella, serotype Salmonella, serotype enteritidisenteritidis–Eggs or undercooked chickenEggs or undercooked chicken–ReptilesReptiles

•Escherichia coli 0157:H7Escherichia coli 0157:H7–SpinachSpinach–Undercooked meatUndercooked meat

»Jack in the BoxJack in the Box

Biological HazardsBiological Hazards•Vector-borne diseasesVector-borne diseases

– Transmitted by insects, Transmitted by insects, other arthropods and other arthropods and other animals including other animals including humanshumans

– Improper environmental Improper environmental management can cause management can cause vector-borne disease vector-borne disease outbreaksoutbreaks


– Examples Examples •MosquitoesMosquitoes

–MalariaMalaria–St. Louis encephalitis St. Louis encephalitis –La Crosse encephalitis La Crosse encephalitis –West Nile VirusWest Nile Virus

•FleasFleas–Bubonic plague Bubonic plague – Murine typhus Murine typhus

3. Mosquito injects Plasmodium sporozoites into human host

2. Plasmodium develops in mosquito

1. Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes

4. Parasite invades blood cells, causing malaria and making infected person a new reservoir

Anopheles mosquito (vector)in aquatic breeding area

eggslarva

pupaadult

Fig. 16.10, p. 409

Areas in which malaria hasdisappeared, been eradicated,or never existed

Areas with limited risk

Areas where malariaTransmission occurs


– Examples Examples •HumansHumans

–SARSSARS–Tuberculosis Tuberculosis –HIVHIV–GonorrheaGonorrhea–SyphilisSyphilis–ChlamydiaChlamydia–Etc.Etc.

Deaths per100,000 people

<2.5

2.5-10

10-35

35-70

70-100

100+

Tuberculosis epidemic, kills about 2 million people a year.


– Greatest viral health Greatest viral health threat to human life are threat to human life are virulent flu strainvirulent flu strain•1918 Swine Flu1918 Swine Flu

–Killed 20 – 30 millionKilled 20 – 30 million•Today flu kills Today flu kills

–1 million per year worldwide1 million per year worldwide–20,000 in the U.S.20,000 in the U.S.

Spread of DiseasesSpread of Diseases• Increases international travelIncreases international travel• Migration to urban areasMigration to urban areas• Migration to uninhabited areas and Migration to uninhabited areas and

deforestationdeforestation• Hunger and malnutritionHunger and malnutrition• Increased rice cultivationIncreased rice cultivation• Global warmingGlobal warming• Hurricanes and high windsHurricanes and high winds• Accidental introduction of insect Accidental introduction of insect

vectorsvectors• FloodingFlooding

Reducing Spread of Reducing Spread of DiseasesDiseases

• Increase research on tropical diseases Increase research on tropical diseases and vaccinesand vaccines

• Reduce poverty and malnutritionReduce poverty and malnutrition• Improve drinking waterImprove drinking water• Reduce unnecessary use of antibioticsReduce unnecessary use of antibiotics• Educate people on taking antibioticsEducate people on taking antibiotics• Reduce antibiotic use in livestockReduce antibiotic use in livestock• Careful hand washing by medical staffCareful hand washing by medical staff• Slow global warmingSlow global warming• Increase preventative health careIncrease preventative health care

Types of HazardsTypes of Hazards•Biological HazardsBiological Hazards

•Chemical HazardsChemical Hazards– Harmful chemicals in the air, Harmful chemicals in the air,

water, soil, and foodwater, soil, and food– Most human have small amounts Most human have small amounts

of about 500 synthetic chemicalsof about 500 synthetic chemicals

Hazardous Hazardous ChemicalsChemicals

•Methods to determine threatMethods to determine threat–Case StudiesCase Studies

•MD with actual patient recordMD with actual patient record

Case StudiesCase StudiesIn-depth, longitudinal examination of a In-depth, longitudinal examination of a

single instance or eventsingle instance or event• 18 year- old, 5-8, 145 pound healthy 18 year- old, 5-8, 145 pound healthy male male

– CircumstancesCircumstances• Collapsed on 2/4/07 at 4:30 PM while in the Collapsed on 2/4/07 at 4:30 PM while in the

kitchenkitchen• Ambulance rushed him to VHH where he died of Ambulance rushed him to VHH where he died of

cardiac arrest a little after 5 PMcardiac arrest a little after 5 PM• Toxicology results – negativeToxicology results – negative• Brain Aneurysm Brain Aneurysm

– HistoryHistory• Broken neck at age 7Broken neck at age 7• Hit by car June of 2005Hit by car June of 2005

Pesticide EffectsPesticide Effects•http://www.pbs.org/wnet/nature/http://www.pbs.org/wnet/nature/

episodes/frogs-the-thin-green-episodes/frogs-the-thin-green-line/video-agricultures-effect-on-line/video-agricultures-effect-on-frogs/4848/frogs/4848/

•The effect of atrazine on The effect of atrazine on amphibians and eventually amphibians and eventually humans.humans.


•Methods to determine threatMethods to determine threat– Case StudiesCase Studies

•MD with actual patient recordMD with actual patient record

–EpidemiologyEpidemiology•Health officials investigating case Health officials investigating case studies studies

EpidemiologyEpidemiology• Study of the distribution and Study of the distribution and

causes of disease in populationscauses of disease in populations– how many people or animals have a how many people or animals have a

diseasedisease– the outcome of the disease the outcome of the disease

(recovery, death, disability, etc.)(recovery, death, disability, etc.)– the factors that influence the the factors that influence the

distribution and outcome of the distribution and outcome of the diseasedisease

Epidemiology of Epidemiology of RabiesRabies

• In 2001, 49 states, the District of In 2001, 49 states, the District of Columbia, and Puerto Rico Columbia, and Puerto Rico reported 7,437 cases of rabies in reported 7,437 cases of rabies in animals and no cases in humans to animals and no cases in humans to CDC CDC

• The total number of reported cases The total number of reported cases increased by 0.92% from those increased by 0.92% from those reported in 2000 (7,369 cases)reported in 2000 (7,369 cases)


•Wild animals accounted for Wild animals accounted for 93% of reported cases of rabies 93% of reported cases of rabies in 2001in 2001

•Outbreaks of rabies infections Outbreaks of rabies infections in terrestrial mammals like in terrestrial mammals like raccoons, skunks, foxes, and raccoons, skunks, foxes, and coyotes are found in broad coyotes are found in broad geographic regions across the geographic regions across the United StatesUnited States


Geographic boundaries of currently Geographic boundaries of currently recognized reservoirs for rabies in recognized reservoirs for rabies in

terrestrial mammalsterrestrial mammals


•Domestic species accounted for Domestic species accounted for 6.8% of all rabid animals 6.8% of all rabid animals reported in the United States in reported in the United States in 20012001

•The number of reported rabid The number of reported rabid domestic animals decreased domestic animals decreased 2.4% from the 509 cases 2.4% from the 509 cases reported in 2000 to 497 in 2001reported in 2000 to 497 in 2001


•Successful vaccination Successful vaccination programs that began in the programs that began in the 1940s caused a decline in dog 1940s caused a decline in dog rabies in this countryrabies in this country

•But, as the number of cases of But, as the number of cases of rabies in dogs decreased, rabies in dogs decreased, rabies in wild animals increased rabies in wild animals increased


Human rabiesHuman rabies• Declined from 100 or more each year Declined from 100 or more each year

to an average of 1 or 2 each yearto an average of 1 or 2 each year• Programs Programs

– Animal control and vaccination Animal control and vaccination programs begun in the 1940's have programs begun in the 1940's have practically eliminated domestic dogs as practically eliminated domestic dogs as reservoirs of rabies in the United Statesreservoirs of rabies in the United States

– Effective human rabies vaccines and Effective human rabies vaccines and immunolglobins have been developed immunolglobins have been developed


•Methods to determine threatMethods to determine threat– Case StudiesCase Studies

•MD with actual patient recordMD with actual patient record– EpidemiologyEpidemiology

•Health officials investigating case Health officials investigating case studies studies

–Laboratory InvestigationsLaboratory Investigations•Substances that are fatal to more Substances that are fatal to more than 50% of the test animals (LD50) than 50% of the test animals (LD50) at a given concentrationat a given concentration

Laboratory Laboratory InvestigationsInvestigations

•Animal StudiesAnimal Studies– Populations of lab animals Populations of lab animals

usually rodentsusually rodents– Measured doses under controlled Measured doses under controlled

conditionsconditions– Takes two to five yearsTakes two to five years– Costs $200,000 to $2,000,000 Costs $200,000 to $2,000,000

per substanceper substance•Newer methodsNewer methods


•Newer methodsNewer methods– BacteriaBacteria– Cell and tissue cultureCell and tissue culture

•Appropriate tissueAppropriate tissue•Stem cellsStem cells

– Chicken egg membraneChicken egg membrane

Fig. 16.5, p. 400

100

75

50

25

02 4 6 8 10 12 14 16

Per

cen

tag

e o

f p

op

ula

tio

n k

illed

by

a g

iven

do

se

Dose (hypothetical units)

LD50

Why?Why?

Fig. 16.3, p. 398

VerySensitive

Majorityof population

lowSensitivity

0 20 40 60 80

Dose (hypothetical units)

Nu

mb

er o

f in

div

idu

als

affe

cted


•Validity ChallengedValidity Challenged– Human physiology is differentHuman physiology is different– Different species react different Different species react different

to same toxinsto same toxins•Mice die with aspirinMice die with aspirin

– Species can be selected Species can be selected depending on physiological area depending on physiological area •Pigs circulatory very similar to Pigs circulatory very similar to humanshumans

ToxicityToxicityToxicity LD50 Lethal Dose Examples

Super < 0.01 less than 1 drop dioxin, botulismmushrooms

Extreme <5 less than 7 drops heroin, nicotine

Very 5-50 7 drops to 1 tsp. morphine, codeine

Toxic 50-500 1 tsp. DDT, H2SO4, Caffeine

Moderate 500-5K 1 oz.-1 pt. aspirin, wood alcohol

Slightly 5K-15K 1 pt. ethyl alcohol, soaps

Non-Toxic >15K >1qt. water, table sugar

(LD50 measured in mg/kg of body weight)


•Why so little is known of toxicityWhy so little is known of toxicity– Only 10% of at least 75,000 Only 10% of at least 75,000

commercial chemicals have been commercial chemicals have been screenedscreened

–~~2% determined to be carcinogen, 2% determined to be carcinogen, teratogen or mutagenteratogen or mutagen

– >1000 new synthetic chemicals >1000 new synthetic chemicals added per yearadded per year

– >99.5% of US commercial >99.5% of US commercial chemicals are NOT regulatedchemicals are NOT regulated

Dose-Response Dose-Response CurvesCurves

Nonlineardose-response

Lineardose-response

Thresholdlevel

Eff

ect

Eff

ect

DoseDose

Nonlineardose-response

Lineardose-response

No thresholdNo threshold

Eff

ect

Eff

ect

ThresholdThreshold

DoseDose

Fig. 16.6, p. 401

Chemical HazardsChemical Hazards•Hazardous ChemicalsHazardous Chemicals

•MutagensMutagens– Chemicals (and ionizing Chemicals (and ionizing

radiation) that changes DNA or radiation) that changes DNA or RNA in cellsRNA in cells

Chemical HazardsChemical Hazards•Hazardous ChemicalsHazardous Chemicals•MutagensMutagens

–TeratogensTeratogens•Chemicals, radiation, or viruses Chemicals, radiation, or viruses that cause birth defects while the that cause birth defects while the human embryo is gestating, human embryo is gestating, especially in the first three monthsespecially in the first three months

TeratogensTeratogens•Examples:Examples:

– RubellaRubella– Mercury in waterMercury in water– Fetal alcohol syndromeFetal alcohol syndrome– Crack babiesCrack babies– MethamphetamineMethamphetamine

Ocean Pollution: Mercury Ocean Pollution: Mercury and Minamata Diseaseand Minamata Disease• Mercury has many Mercury has many

industrial uses but industrial uses but is extremely toxic is extremely toxic

• A chemical plant A chemical plant released large released large quantities of quantities of mercury into mercury into Minamata Bay, Minamata Bay, JapanJapan

• Residents who ate Residents who ate highly highly contaminated fish contaminated fish suffered suffered neurological neurological disease and birth disease and birth disordersdisorders

bss.sfsu.edu/ehines/geog600/ Freshwater%20and%20ocean%20Pollution.ppt


– TeratogensTeratogens

–CarcinogensCarcinogens

CarcinogensCarcinogens•Causative agentsCausative agents

– Chemicals – Tobacco smokeChemicals – Tobacco smoke– Radiation – Pilots and cosmic radiationRadiation – Pilots and cosmic radiation– Viruses – HPV and cervical cancerViruses – HPV and cervical cancer

•Texas Governor mandated vaccination of Texas Governor mandated vaccination of all School females with Merck’s HPV all School females with Merck’s HPV vaccinevaccine

•Promote growth of malignant Promote growth of malignant tumorstumors

CarcinogensCarcinogens•Latent PeriodLatent Period

– Long time lapse between exposureLong time lapse between exposure•SmokingSmoking•EatingEating•Lifestyle choices – laying in sunLifestyle choices – laying in sun

– SymptomsSymptoms•Lung cancerLung cancer•AIDSAIDS•MelanomaMelanoma


– TeratogensTeratogens– CarcinogensCarcinogens

•Hormonally Active Hormonally Active AgentsAgents

Hormonally Active Hormonally Active AgentsAgents

•Estrogen-like chemicalsEstrogen-like chemicals– Alter developmentAlter development

•Early pubescenceEarly pubescence•Low sperm countLow sperm count•Runts in wildlifeRunts in wildlife

– Examples of hormone mimicsExamples of hormone mimics•PCBPCB•Organophosphates pesticidesOrganophosphates pesticides•Industrial solventsIndustrial solvents

Hormone

Receptor

Cell

Normal Hormone Process

Normal Mimic Hormone Blocker

Estrogen- like chemical Antiandrogen chemical


– TeratogensTeratogens– CarcinogensCarcinogens

•Hormonally Active AgentsHormonally Active Agents•Precautionary PrinciplesPrecautionary Principles

Precautionary Precautionary PrinciplePrinciple

•Better safe than sorryBetter safe than sorry–Two scenariosTwo scenarios

•Assume new chemicals guilty Assume new chemicals guilty – Humans are not guinea pigs– Humans are not guinea pigs

•Most Chemicals not toxic and Most Chemicals not toxic and too expensive to testtoo expensive to test


•BioaccumulationBioaccumulation–An increase in An increase in concentration of a concentration of a chemicals in specific chemicals in specific organs or tissues in organs or tissues in organisms organisms


•BiomagnificationBiomagnification– Increase in concentration in Increase in concentration in organismsorganisms•DDTDDT•PCBPCB•Slowly degradable, fat-soluble Slowly degradable, fat-soluble chemicalschemicals

– At successively higher trophic At successively higher trophic levels of food chains or in fatty levels of food chains or in fatty tissuetissue

DDT in fish-eatingDDT in fish-eatingbirds (ospreys)birds (ospreys)

25 ppm25 ppm

DDT in largeDDT in largefish (needle fish)fish (needle fish)2 ppm2 ppm

DDT in smallDDT in smallfish (minnows)fish (minnows)0.5 ppm0.5 ppm

DDT inDDT inzooplanktonzooplankton0.04 ppm0.04 ppm

DDT in waterDDT in water0.000003 ppm,0.000003 ppm,Or 3 ppmOr 3 ppm

Types of HazardsTypes of Hazards•Biological HazardsBiological Hazards•Chemical HazardsChemical Hazards

•Physical Hazards Physical Hazards – Ionizing radiation, airborne particles, equipment design, fire, earthquake, volcanic eruptions, flood, tornadoes, and hurricanes

Physical HazardsPhysical Hazards•Example: Radon Example: Radon

– Source:Source:•Arises naturally from Arises naturally from decomposition of uranium in the decomposition of uranium in the earthearth

•Occurs at dangerous levels in some Occurs at dangerous levels in some buildings and homesbuildings and homes

– Can cause lung cancerCan cause lung cancer– Test kits available for under $20Test kits available for under $20

Types of HazardsTypes of Hazards•Biological HazardsBiological Hazards•Chemical HazardsChemical Hazards•Physical HazardsPhysical Hazards•Cultural HazardsCultural Hazards

–SociologicalSociological–PsychologicalPsychological

Cultural HazardsCultural Hazards•SociologicalSociological

– result from living in a society result from living in a society where one experiences noise, where one experiences noise, lack of privacy and lack of privacy and overcrowdingovercrowding•Population growth Population growth

– Beyond carrying capacity when Beyond carrying capacity when environmental resources can environmental resources can support no further growthsupport no further growth

Cultural HazardsCultural Hazards•Psychological Psychological

– Environmental factors that Environmental factors that produce psychological produce psychological changes expressed as stress, changes expressed as stress, depression, hysteriadepression, hysteria

Key ConceptsKey Concepts• Types of HazardsTypes of Hazards

• Exposure AssessmentExposure Assessment• Methods of toxicologyMethods of toxicology

• Risk estimation, management, and Risk estimation, management, and reductionreduction

Exposure Exposure AssessmentAssessment

4 important considerations4 important considerations1. Route 1. Route 2. Magnitude 2. Magnitude 3. Duration of exposure3. Duration of exposure4. Frequency4. Frequency

Key ConceptsKey Concepts• Types of HazardsTypes of Hazards

• Exposure AssessmentExposure Assessment

• Risk estimation, management, Risk estimation, management, and reductionand reduction

Risk AnalysisRisk AnalysisRisk AnalysisRisk Analysis•How can risks be estimated, How can risks be estimated,

managed and reduced?managed and reduced?

Risk Analysis Risk Analysis involves…involves…

•Identifying hazardsIdentifying hazards•Evaluate risksEvaluate risks•Ranking risksRanking risks•Determining options and Determining options and

deciding course of actiondeciding course of action•Informing policy makers and Informing policy makers and

public about riskspublic about risks

Risk AnalysisRisk AnalysisRisk AnalysisRisk AnalysisRisk The possibility of suffering harm from a hazard

that can cause injury, disease, economic loss, or environmental damage. Risk is Expressed in terms of probability, a mathematical statement about How likely it is that some event or effect will occur.

Risk=Exposure X Harm

Risk The possibility of suffering harm from a hazard

that can cause injury, disease, economic loss, or environmental damage. Risk is Expressed in terms of probability, a mathematical statement about How likely it is that some event or effect will occur.

Risk=Exposure X Harm

Fig. 16.2, p. 297

Fig. 16.14, p. 412

Riskprobability

Riskassessment

Riskseverity

Is the risk acceptable?

Acceptable ifbenefitsoutweigh costs

Cost–benefit Expressedpreferences

Acceptable ifpeople agree toaccept the risks

Naturalstandards

Acceptable ifrisk is notgreater thanthose created bynatural hazard

Revealedpreferences

Acceptable ifrisk is notgreater thanthose currentlytolerated

Risk Analysis Risk Analysis UsefulnessUsefulness

•Organize and analyze available Organize and analyze available scientific informationscientific information

• Identify significant hazardsIdentify significant hazards•Focus on areas that warrant Focus on areas that warrant

more researchmore research

Risk Analysis Risk Analysis UsefulnessUsefulness

•Help regulators decide how Help regulators decide how money for reducing risks money for reducing risks should be allocated, should be allocated,

•Stimulate people to make Stimulate people to make more informed decisions about more informed decisions about health and environmental health and environmental goals and priorities.goals and priorities.

Risk PerceptionRisk Perception• If chance of death is 1 in 100,000 If chance of death is 1 in 100,000

people are not likely to be people are not likely to be worried or change behavior.worried or change behavior.

•Most of us do a poor job of Most of us do a poor job of assessing relative risks from assessing relative risks from hazards around us.hazards around us.

Risk PerceptionRisk Perception•Most people deny the high-risk Most people deny the high-risk

activities they voluntarily enjoyactivities they voluntarily enjoy– Motorcycles (1 in 50)Motorcycles (1 in 50)– Smoking (1 in 300 pack a day Smoking (1 in 300 pack a day

smokers, by 65)smokers, by 65)– Hang-gliding (1 in 2,500)Hang-gliding (1 in 2,500)

What do you What do you think are the think are the highest risk highest risk

hazards in the hazards in the U.S.?U.S.?

Fig. 16.1, p. 396

DeathsCause of Death

Tobacco use 431,000

Alcohol use

Accidents

Pneumonia andInfluenza

Suicides

Homicides

Hard drug use

AIDS

150,000

95,600 (42,000 auto)

84,400

30,500

19,000

15,000

14,000

Fig. 16.15, p. 414

Hazard Shortens average life spanin the United States by

7-10 yearsPoverty

Born male

Smoking

Overweight (35%)

Unmarried

Overweight (15%)

Spouse smoking

Driving

Air pollution

Alcohol

Drug abuse

AIDS

Drowning

Pesticides

Fire

Natural radiation

Medical X rays

Oral contraceptives

Toxic waste

Flying

Hurricanes, tornadoes

Living lifetime nearnuclear plant

7.5 years

6 years

6 years

5 years

2 years

1 year

7 months

5 months

5 months

4 months

3 months

1 month

1 month

1 month

8 days

5 days

5 days

4 days

1 day

1 day

10 hours

Yet some of these people are Yet some of these people are terrified of dying from…terrified of dying from…

• Commercial plane crashCommercial plane crash– 1 in 4.6 million1 in 4.6 million

• Train crash Train crash – 1 in 20 million1 in 20 million

• Snakebite Snakebite – 1 in 36 million1 in 36 million

• Shark attack Shark attack – 1 in 300 million1 in 300 million

Each year 99.1% of Each year 99.1% of the people on Earth the people on Earth

do not diedo not die..Average life expectancy Average life expectancy continues to increase. continues to increase.

BibliographyBibliography1. Humayun, Ayesha, “Introductory Lecture on Environment and Health” @

http://www.publichealth.pitt.edu/supercourse/SupercoursePPT/17011-18001/17961.ppt

2. Bent Flyvbjerg, “Five Misunderstandings About Case-Study Research,” Qualitative Inquiry, Volume 12, Number 2, April 2006 219-245 @ http://flyvbjerg.plan.aau.dk/Publications2006/0604FIVEMISPUBL2006.pdf

3. Centers for Disease Control: National Center for Infectious Disease, “Epidemiology of Rabies,” @ http://www.cdc.gov/ncidod/dvrd/rabies/Epidemiology/Epidemiology.htm

4. http://bss.sfsu.edu/ehines/geog600/Freshwater%20and%20ocean%20Pollution.ppt 5. Barbara E. Moore, Ph.D., Department of Biology, University of Texas at San Antonio @

http://www.texastmdl.org/presentations/Pathogen Issues I final.ppt

6.6. Water and Sanitation – Critical Elements in Development - Mike Lee CSU @ HaywardWater and Sanitation – Critical Elements in Development - Mike Lee CSU @ Hayward

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