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Section 5: Section 5: Preventing Injuries, Saving LivesPreventing Injuries, Saving Lives

Risk, Human Health, and Risk, Human Health, and ToxicologyToxicology

Chapter 14Chapter 14

The Big KillerThe Big Killer

TobaccoTobacco

Health threatsHealth threats

NicotineNicotine

Passive smokingPassive smoking

Costs of smokingCosts of smoking

Anti-smoking programsAnti-smoking programs

Fig. 14-1, p. 327

Risk and HazardsRisk and Hazards RiskRisk - is a measure of your likelihood of - is a measure of your likelihood of

suffering harm from a hazard.suffering harm from a hazard.

ProbabilitiesProbabilities - a mathematical statement about - a mathematical statement about how likely it is that harm will result form a how likely it is that harm will result form a hazard.hazard.

PossibilitiesPossibilities - saying that an event could - saying that an event could happen.happen.

Risk assessmentRisk assessment - estimating how much harm - estimating how much harm a particular hazard can cause to human health.a particular hazard can cause to human health.

Risk managementRisk management - deciding whether to and - deciding whether to and how to reduce a risk and at what cost.how to reduce a risk and at what cost.

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?

Risk Assessment and Risk Risk Assessment and Risk Management Management

Fig. 14-2, p. 328

Major Types of HazardsMajor Types of Hazards

CulturalCultural

BiologicalBiological

ChemicalChemical

PhysicalPhysical

Biological HazardsBiological Hazards Nontransmissible diseases - not caused by living Nontransmissible diseases - not caused by living

organisms and does not spread from person to organisms and does not spread from person to personperson

Transmissible (infectious) diseases - caused by Transmissible (infectious) diseases - caused by living organisms and can spread.living organisms and can spread.

Pathogen - organism that produces disease. Pathogen - organism that produces disease. Carried by air, water, insects, body fluids, other Carried by air, water, insects, body fluids, other vectors, and food.vectors, and food.

Germ resistance to antibioticsGerm resistance to antibiotics

Global Threats from DiseaseGlobal Threats from Disease

TuberculosisTuberculosis

Viral diseasesViral diseases

HIV and AIDS, Influenza, (HBV) hepatitis B virusHIV and AIDS, Influenza, (HBV) hepatitis B virus

MalariaMalaria

Reducing incidences of infectious diseases Fig 14-7Reducing incidences of infectious diseases Fig 14-7

BioterrorismBioterrorism

Fig. 14-3, p. 329

Disease(type of agent)

3.2 millionPneumonia and flu

(bacteria and viruses)

HIV/AIDS(virus)

Diarrheal diseases(bacteria and viruses)

Tuberculosis(bacteria)

Malaria(protozoa)

Hepatitis B(virus)

Measles(virus)

Deaths per year

3.0 million

1.9 million

1.7 million

1 million

1 million

800,000

Seven Seven Deadliest Deadliest

Infectious Infectious Diseases Diseases

Fig. 14-4, p. 331120 40 20 0

100+95-9990-9485-8980-8475-7970-7465-6960-6455-5950-5445-4940-4435-3930-3425-2920-2415-1910-14

5-90-4

Male Female

Population (thousands)

Ag

eWith AIDS

608010 20 100 120806040

Without AIDS

Impact of AIDS on Age Structure of Impact of AIDS on Age Structure of Botswana, Africa Botswana, Africa

Fig. 14-5, p. 331

Distribution of Malaria Distribution of Malaria

Sporozoites penetrate liverand develop into merozoites

Female mosquito bites infected human,ingesting blood that contains Plasmodiumgametocytes

Merozoites enter blood-stream and develop into gametocytes causing malaria and makinginfected person a new reservoir

Female mosquito injects Plasmodium sporozoites into human host

Plasmodiumdevelops inmosquito

Fig. 14-6, p. 332

Life Life Cycle of Cycle of Malaria Malaria

Fig. 14-7, p. 333

Solutions

Infectious Diseases

Increase research on tropicaldiseases and vaccines

Reduce poverty

Decrease malnutrition

Improve drinking water quality

Reduce unnecessary use of antibiotics

Educate people to take all of anantibiotic prescription

Reduce antibiotic use to promotelivestock growth

Careful hand washing by allmedical personnel

Immunize children against major viral diseases

Oral rehydration for diarrhea victims

Global campain to reduce HIV/AIDS

Solutions for Infectious Diseases Solutions for Infectious Diseases

Agent

Smallpox(virus)

Hemorrhagicfever (viruses)

Inhalationanthrax(bacterium)

Botulism(bacterium)

Pneumonicplague(bacterium)

Tularemia(bacterium)

Contagious

Yes

Yes

No

No

Yes

No

Symptoms

Fever, aches, headache, red spots on face and torso

Vary but include fever,bleeding, shock, and coma

Fever, chest pain, difficultybreathing, respiratory failure

Blurred vision, progressiveparalysis, death within 24 hours if not treated

High fever, chills, headache,coughing blood, difficultybreathing, respiratory failure

Fever, sore throat, weak-ness, respiratory stress, pneumonia

Mortality(if untreated)

30%

Varies

90–100%

60–100%

90–100%

30–60%

Existenceof vaccine

Yes

No

Yes

Yes

No

Yes(in testing)

Treatment

Vaccination within 4 days afterexposure, IV hydration

Ebola has no cure, antiviralriboflavin and some antibioticsmay help

Early treatment with Cipro andother antibiotics

Equine antitoxin given early.Intensive care, respirator

Antibiotics

Antibiotics

Fig. 14-8, p. 334

Characteristics of Agents that Could be Used as Biological Characteristics of Agents that Could be Used as Biological Weapons Weapons

Chemical HazardsChemical Hazards Toxic and hazardous chemicals - Toxic and hazardous chemicals - Can cause temporary or permanent Can cause temporary or permanent

harm or death to living organisms.harm or death to living organisms.

Mutagens - Mutagens - cause or increase mutations, or changes, in DNA molecules.cause or increase mutations, or changes, in DNA molecules.

Teratogens - Teratogens - cause harm or birth defects to a fetus or embryo.cause harm or birth defects to a fetus or embryo.

Carcinogens - Carcinogens - chemicals or radiation that cause or promote cancer.chemicals or radiation that cause or promote cancer.

Metastasis - Metastasis - malignant cells break off from tumors and travel to other parts malignant cells break off from tumors and travel to other parts of the body.of the body.

Effects on immune, nervous, and endocrine systemsEffects on immune, nervous, and endocrine systems

Neurotoxins - Neurotoxins - PCB’s, methyl mercury, lead, some pesticides (parathion)PCB’s, methyl mercury, lead, some pesticides (parathion)

Hormonally active agents (HAAs) Hormonally active agents (HAAs) Endocrine disruptors - PCBs, DDT, Endocrine disruptors - PCBs, DDT, and certain herbicidesand certain herbicides

ToxicologyToxicology Toxicity - Toxicity - a measure of how harmful a substance is in causing injury, illness, or death a measure of how harmful a substance is in causing injury, illness, or death

to al living organism.to al living organism.

Dose - Dose - the amount of a substance a person has ingested, inhaled, or absorbed the amount of a substance a person has ingested, inhaled, or absorbed through the skin.through the skin.

Relevance of genetic makeupRelevance of genetic makeup

Multiple chemical sensitivity (MCS) - Multiple chemical sensitivity (MCS) - individuals sensitive to a number of toxins.individuals sensitive to a number of toxins.

Five factors affect the harm caused by a substanceFive factors affect the harm caused by a substance SolubilitySolubility Water-soluble toxins - often inorganicWater-soluble toxins - often inorganic Oil- or fat-soluble toxins - organic (DDT)Oil- or fat-soluble toxins - organic (DDT)

Persistence - DDTPersistence - DDT

Bioaccumulation Bioaccumulation Biomagnification - DDT, PCBBiomagnification - DDT, PCB

Chemical InteractionsChemical InteractionsAntagonistic interactions - reduce harmful effectsAntagonistic interactions - reduce harmful effectsSynergistic interactions - multiplies harmful effectsSynergistic interactions - multiplies harmful effects

ToxicologyToxicology

Acute toxic effects - immediate of rapid reaction to an exposureAcute toxic effects - immediate of rapid reaction to an exposure

Chronic toxic effects - permanent or long-lasting consequences Chronic toxic effects - permanent or long-lasting consequences

““The dose is the poison”The dose is the poison”

Toxicity varies with individualsToxicity varies with individuals

How the human body disposes of chemical toxinsHow the human body disposes of chemical toxins Break it down, Break it down, repair the damage, replace the cellsrepair the damage, replace the cells

Effects of trace levels of toxic chemicalsEffects of trace levels of toxic chemicals

Estimating ToxicityEstimating Toxicity

LD50LD50

Using case reportsUsing case reports

Epidemiological studies (experimental and control groups)Epidemiological studies (experimental and control groups)

Limits of epidemiological studiesLimits of epidemiological studies

Laboratory studies Laboratory studies

Controversies with testing with animalsControversies with testing with animals

Nonthreshold and threshold dose-response modelsNonthreshold and threshold dose-response models

Fig. 14-9, p. 337

LD50

04 8 12 16

Dose (hypothetical units)

Per

cen

tag

e o

f p

op

ula

tio

n k

illed

by

a g

iven

do

se

141062

25

50

75

100

Dose-Response Curve Dose-Response Curve

Table 14-1, p. 337

Toxicity RatingsToxicity Ratings

Fig. 14-10, p. 338

Eff

ect

Dose

Nonlineardose-response

Lineardose-response

No threshold

Eff

ect

Threshold

Thresholdlevel

Dose

Threshold and Nonthreshold Threshold and Nonthreshold Dose-Response Curves Dose-Response Curves

Protection Against Harmful ChemicalsProtection Against Harmful Chemicals

Protecting children from toxic chemicalsProtecting children from toxic chemicals

Why do we know so little about the harmful effects Why do we know so little about the harmful effects of chemicals?of chemicals?

Lack of regulationsLack of regulations

Pollution preventionPollution prevention

Precautionary principlePrecautionary principle

““Innocent until proven guilty” approachInnocent until proven guilty” approach

Persistent organic pollutants (POPs) (“dirty dozen”)Persistent organic pollutants (POPs) (“dirty dozen”)

Risk AnalysisRisk Analysis Risk analysis (risk assessment) - Risk analysis (risk assessment) - Identifying Identifying

hazards and evaluating their associated risks.hazards and evaluating their associated risks. Comparative risk analysis - Comparative risk analysis - ranking risksranking risks Risk management - Risk management - determining the options determining the options

and making decisions about reducing or and making decisions about reducing or eliminating risks.eliminating risks.

Risk communication - Risk communication - informing decisions informing decisions makers and the public about risks.makers and the public about risks.

Poverty: the greatest riskPoverty: the greatest risk Risks from lifestyleRisks from lifestyle

Fig. 14-11, p. 340

Comparative Risk Analysis

Most Serious EcologicalAnd Health Problems

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

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

surface waters

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

Comparative Comparative Risk Analysis Risk Analysis

Estimating Risks from TechnologiesEstimating Risks from Technologies

System reliability (%) = Technology reliability System reliability (%) = Technology reliability xx Human Human reliabilityreliability

Difficulties in estimating reliabilityDifficulties in estimating reliability

““To err is human”To err is human”

Automatic control systemsAutomatic control systems

Fig. 14-12, p. 341

Cause of Death Annual Deaths

11 million (75)Poverty/malnutrition/disease cycle

Tobacco

Pneumonia/flu

Air pollution

HIV/AIDS

Malaria

Diarrhea

Auto accidents

Work related injury

Measles

5 million (34)

3.2 million (22)

3 million (21)

3 million (21)

3 million (21)

1.9 million (13)

1.7 million (12)

1.2 million (8)

1.1 million (8)

1 million (7)

800,000 (5)

Hepatitis B

Number of Deaths Per Year Globally Number of Deaths Per Year Globally

Tuberculosis

Fig. 14-13, p. 342

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 near nuclear plant

6-10 years

5 years

2 years

1 year

7 months

5 months

4 months

4 months

3 months

2 months

1 month

1 month

8 days

5 days

5 days

4 days

1 day

1 day

10 hours

Flu

Air Pollution

6 years

5 months

1 month

7.5 years

HAZARD SHORTENS AVERAGE LIFE SPAN IN THE UNITED STATES BY

Comparison Comparison of Risks of Risks

Perceiving RisksPerceiving Risks

Distorted perceptions of risksDistorted perceptions of risks

Degree of control Degree of control

Fear of the unknown and distrust of the newFear of the unknown and distrust of the new

Whether we voluntarily take the riskWhether we voluntarily take the risk

Whether the risk is catastrophicWhether the risk is catastrophic

Unfair distribution of risksUnfair distribution of risks