Risk, Toxicology, and Human HealthRisk, Toxicology, and Human Health

Brian Kaestner

Saint Mary’s Hall

Brian Kaestner

Saint Mary’s Hall

Thanks to Miller and ClementsThanks to Miller and Clements

Key ConceptsKey Concepts

Types of hazards people face Types of hazards people face

Methods of toxicology Methods of toxicology

Types and measurement of chemical hazards Types and measurement of chemical hazards

Types and effects of biological hazards Types and effects of biological hazards

Risk estimation, management, and reduction Risk estimation, management, and reduction

Risk and ProbabilityRisk and Probability

RiskRisk

ProbabilityProbability

Riskassessment

Riskassessment

Riskmanagement

Riskmanagement

Hazard identificationWhat is the hazard?

Probability of riskHow likely is the event?

Consequences of riskWhat is the likelydamage?

Risk Assessment Risk Management

Comparative risk analysisHow does it comparewith other risks?

Risk reductionHow much shouldit be reduced?

Risk reduction strategyHow will the riskbe reduced?

Financial commitmentHow much moneyshould be spent?

HazardsHazards

Cultural hazardsCultural hazards

Chemical hazardsChemical hazards

Physical hazardsPhysical hazards

Biological hazardsBiological hazards

DeathsDeathsCause of DeathCause of Death

Tobacco useTobacco use 431,000431,000

Alcohol useAlcohol use

AccidentsAccidents

Pneumonia andPneumonia andInfluenzaInfluenza

SuicidesSuicides

HomicidesHomicides

Hard drug useHard drug use

AIDSAIDS

150,000150,000

95,600 (42,000 auto)95,600 (42,000 auto)

84,40084,400

30,50030,500

19,00019,000

15,00015,000

14,00014,000

ToxicologyToxicology

ToxicityToxicityDosageDosageBioaccumulationBioaccumulationBiomagnificationBiomagnificationSynergismSynergismResponse Response Acute effectAcute effectChronic effectChronic effect

DDT in water0.000003 ppm,Or 3 ppm

DDT in fish-eatingbirds (ospreys)

25 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

VerySensitive

Majorityof population

VerySensitive

00 2020 4040 6060 8080

Dose (hypothetical units)Dose (hypothetical units)

Nu

mb

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f in

div

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aff

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dN

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of

ind

ivid

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PoisonsPoisons

Poison Poison

LD50 LD50

Median lethal dose Median lethal dose25

100100

7575

5050

00 22 44 66 88 1010 1212 1414 1616

Per

cen

tag

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f p

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d b

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ose

Per

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Dose (hypothetical units)Dose (hypothetical units)

LD50

Dose-Response CurvesDose-Response Curves

Dose-response Dose-response Nonthreshold Nonthreshold Threshold Threshold

Nonlineardose-response

Lineardose-response

Thresholdlevel

Eff

ect

Eff

ect

DoseDose

Nonlineardose-response

Lineardose-response

No thresholdNo threshold

Eff

ect

Eff

ect

ThresholdThreshold

DoseDose

Chemical HazardsChemical Hazards

Hazardous chemicalsHazardous chemicalsMutagensMutagensTeratogensTeratogensCarcinogensCarcinogensNeurotoxins Neurotoxins

Precautionary principlePrecautionary principle

Biological Hazards: DiseasesBiological Hazards: Diseases

Nontransmissible dieaseNontransmissible dieaseTransmissible diseaseTransmissible diseasePathogensPathogensVectorsVectorsAntibiotic resistanceAntibiotic resistanceMalariaMalaria

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

eggs

larva pupaadult

NORTHAMERICA

EUROPE

SOUTHAMERICA

AFRICA

ASIA

ASTRALIA

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

Areas with limited risk

Areas where malariaTransmission occurs

Scientists(Not in rank order in each category)

Citizens(In rank order)

High-Risk Health Problems• Indoor air pollution• Outdoor air pollution• Worker exposure to industrial or farm chemicals• Pollutants in drinking water• Pesticide residues on food• Toxic chemicals in consumer products

High-Risk Ecological Problems• Global climate change• Stratospheric ozone depletion• Wildlife habitat alteration and destruction• Species extinction and loss of biodiversity

High-Risk Problems• Hazardous waste sites• Industrial water pollution • Occupational exposure to chemicals• Oil spills• Stratospheric ozone depletion • Nuclear power-plant accidents• Industrial accidents releasing pollutants• Radioactive wastes• Air pollution from factories• Leaking underground tanks

Medium-Risk Ecological Problems• Acid deposition • Pesticides • Airborne toxic chemicals • Toxic chemicals, nutrients, and sediment in surface waters

Medium-Risk Problems• Coastal water contamination• Solid waste and litter• Pesticide risks to farm workers• Water pollution from sewage plants

Low-Risk Ecological Problems • Oil spills • Groundwater pollution• Radioactive isotopes• Acid runoff to surface waters• Thermal pollution

Low-Risk Problems • Air pollution from vehicles • Pesticide residues in foods• Global climate change • Drinking water contamination

Hazard Shortens average life spanin the United States by

7-10Poverty

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

Risk AnalysisRisk Analysis

Risk analysisRisk analysis

Comparative riskanalysis

Comparative riskanalysis

Cost-benefitanalysis

Cost-benefitanalysis

Risk managementRisk management

Risk perceptionRisk perception

Riskprobability

Riskassessment

Riskseverity

Is the riskacceptable?

Acceptable ifbenefitsoutweigh costs

Cost–benefit ExpressedpreferencesAcceptable ifpeople agree toaccept the risks

Naturalstandards

Acceptable ifrisk is notgreater thanthose created bynatural hazard

RevealedpreferencesAcceptable ifrisk is notgreater thanthose currentlytolerated

Environmental Cost Benefit AnalysisEnvironmental Cost Benefit Analysis

-economic cost-sort term-long term

-economic benefits-environmental costs

-short term-long term