Risk, Toxicology, and Human Health Brian Kaestner Saint Mary’s Hall Thanks to Miller and Clements
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
er o
f in
div
idu
als
aff
ecte
dN
um
ber
of
ind
ivid
ual
s a
ffec
ted
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
e o
f p
op
ula
tio
n k
ille
d b
y a
giv
en d
ose
Per
cen
tag
e o
f p
op
ula
tio
n k
ille
d b
y a
giv
en d
ose
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