Chapter 11 Environmental Hazards and Human Health.

Chapter 11Chapter 11

Environmental Hazards Environmental Hazards and Human Healthand Human Health

Chapter Overview QuestionsChapter Overview Questions

What types of hazards do people face?What types of hazards do people face? What types of disease (biological hazards) What types of disease (biological hazards)

threaten people in developing countries and threaten people in developing countries and developed countries?developed countries?

What chemical hazards do people face?What chemical hazards do people face? How can risks be estimated and recognized?How can risks be estimated and recognized?

Updates OnlineUpdates Online

The latest references for topics covered in this section can be found at The latest references for topics covered in this section can be found at the book companion website. Log in to the book’s e-resources page at the book companion website. Log in to the book’s e-resources page at www.thomsonedu.com to access InfoTrac articles. www.thomsonedu.com to access InfoTrac articles.

InfoTrac: Report Shows 2005 to Be 'Least Bad Year' of AIDS Epidemic. InfoTrac: Report Shows 2005 to Be 'Least Bad Year' of AIDS Epidemic. Lawrence K. Altman. Lawrence K. Altman. The New York Times,The New York Times, May 31, 2006 pA6(L). May 31, 2006 pA6(L).

InfoTrac: Concern Grows Over Increase In Diabetes Around World. Marc InfoTrac: Concern Grows Over Increase In Diabetes Around World. Marc Santora. Santora. The New York Times,The New York Times, June 11, 2006 pA27(L). June 11, 2006 pA27(L).

InfoTrac: Push for New Tactics as War on Malaria Falters. Celia W. InfoTrac: Push for New Tactics as War on Malaria Falters. Celia W. Dugger. Dugger. The New York Times,The New York Times, June 28, 2006 pA1(L). June 28, 2006 pA1(L).

The National Academies: Genetically Altered Bacteria Could Block The National Academies: Genetically Altered Bacteria Could Block Malaria TransmissionMalaria Transmission

Science Daily: Study Shows Promise For Simplified Treatment Of HIV Science Daily: Study Shows Promise For Simplified Treatment Of HIV InfectionInfection

The Gates FoundationThe Gates Foundation

Core Case Study: The Global Core Case Study: The Global HIV/AIDS EpidemicHIV/AIDS Epidemic

According to the World Health Organization According to the World Health Organization (WHO), in 2005 about 42 million people (WHO), in 2005 about 42 million people worldwide (1.1 million in the U.S.) were worldwide (1.1 million in the U.S.) were infected with HIV.infected with HIV.

There is no vaccine for HIV – if you get There is no vaccine for HIV – if you get AIDS, you will eventually die from it.AIDS, you will eventually die from it.

Drugs help some infected people live Drugs help some infected people live longer, but only a tiny fraction can afford longer, but only a tiny fraction can afford them.them.


AIDS has reduced the AIDS has reduced the life expectancy of sub-life expectancy of sub-Saharan Africa from 62 Saharan Africa from 62 to 47 years – 40 years to 47 years – 40 years in the seven countries in the seven countries most severely affected most severely affected by AIDS.by AIDS.

Projected age structure Projected age structure of Botswana's population of Botswana's population in 2020.in 2020.


The virus itself is not deadly, but it cripples The virus itself is not deadly, but it cripples the immune system, leaving the body the immune system, leaving the body susceptible to infections such as Kaposi’s susceptible to infections such as Kaposi’s sarcoma (above).sarcoma (above).

RISKS AND HAZARDSRISKS AND HAZARDS

Risk is a measure of the likelihood that you Risk is a measure of the likelihood that you will suffer harm from a hazard.will suffer harm from a hazard.

We can suffer from:We can suffer from: Biological hazardsBiological hazards: from more than 1,400 : from more than 1,400

pathogens.pathogens. Chemical hazardsChemical hazards: in air, water, soil, and food.: in air, water, soil, and food. Physical hazardsPhysical hazards: such as fire, earthquake, : such as fire, earthquake,

volcanic eruption…volcanic eruption… Cultural hazardsCultural hazards: such as smoking, poor diet, : such as smoking, poor diet,

unsafe sex, drugs, unsafe working conditions, unsafe sex, drugs, unsafe working conditions, and poverty.and poverty.

BIOLOGICAL HAZARDS: BIOLOGICAL HAZARDS: DISEASE IN DEVELOPED AND DISEASE IN DEVELOPED AND

DEVELOPING COUNTRIESDEVELOPING COUNTRIES

Diseases not caused by living organisms Diseases not caused by living organisms cannot spread from one person to another cannot spread from one person to another ((nontransmissible diseasenontransmissible disease), while those ), while those caused by living organisms such as bacteria caused by living organisms such as bacteria and viruses can spread from person to and viruses can spread from person to person (person (transmissibletransmissible or or infectiousinfectious))

Transmissible DiseaseTransmissible Disease

Pathway for infectious disease in humans.Pathway for infectious disease in humans.

PetsLivestock

Wild animals Mosquitoes Food Water

Air

Fetus and babies

Other humans Humans

Transmissible DiseaseTransmissible Disease

WHO estimates that WHO estimates that each year the each year the world’s seven world’s seven deadliest infections deadliest infections kill 13.6 million kill 13.6 million people – most of people – most of them the poor in them the poor in developing developing countries.countries.

Disease (type of agent) Deaths per year

Pneumonia and flu (bacteria and viruses) 3.2 million

HIV/AIDS (virus) 3.0 million

Malaria (protozoa) 2.0 million

Diarrheal diseases (bacteria and viruses) 1.9 million

Tuberculosis (bacteria) 1.7 million

Hepatitis B (virus) 1 million

Measles (virus) 800,000

Case Study: Growing Germ Case Study: Growing Germ Resistance to AntibioticsResistance to Antibiotics

Rabidly producing infectious bacteria are Rabidly producing infectious bacteria are becoming genetically resistant to widely used becoming genetically resistant to widely used antibiotics due to:antibiotics due to: Genetic resistanceGenetic resistance: Spread of bacteria around : Spread of bacteria around

the globe by humans, overuse of pesticides the globe by humans, overuse of pesticides which produce pesticide resistant insects that which produce pesticide resistant insects that carry bacteria.carry bacteria.

Overuse of antibioticsOveruse of antibiotics: A 2000 study found that : A 2000 study found that half of the antibiotics used to treat humans were half of the antibiotics used to treat humans were prescribed unnecessarily.prescribed unnecessarily.

Case Study: The Growing Global Case Study: The Growing Global Threat from TuberculosisThreat from Tuberculosis

The highly infectious tuberculosis (TB) kills The highly infectious tuberculosis (TB) kills 1.7 million people per year and could kill 25 1.7 million people per year and could kill 25 million people 2020.million people 2020.

Recent increases in TB are due to:Recent increases in TB are due to: Lack of TB screening and control programs Lack of TB screening and control programs

especially in developing countries due to especially in developing countries due to expenses.expenses.

Genetic resistance to the most effective Genetic resistance to the most effective antibiotics.antibiotics.

Viral DiseasesViral Diseases

Flu, HIV, and hepatitis B viruses infect and kill Flu, HIV, and hepatitis B viruses infect and kill many more people each year then highly many more people each year then highly publicized West Nile and SARS viruses.publicized West Nile and SARS viruses. The influenza virus is the biggest killer virus The influenza virus is the biggest killer virus

worldwide.worldwide.• Pigs, chickens, ducks, and geese are the major Pigs, chickens, ducks, and geese are the major

reservoirs of flu. As they move from one species to reservoirs of flu. As they move from one species to another, they can mutate and exchange genetic another, they can mutate and exchange genetic material with other viruses.material with other viruses.

Viral DiseasesViral Diseases HIV is the second biggest killer virus HIV is the second biggest killer virus

worldwide. Five major priorities to slow the worldwide. Five major priorities to slow the spread of the disease are:spread of the disease are: Quickly reduce the number of new infections to Quickly reduce the number of new infections to

prevent further spread.prevent further spread. Concentrate on groups in a society that are likely Concentrate on groups in a society that are likely

to spread the disease.to spread the disease. Provide free HIV testing and pressure people to Provide free HIV testing and pressure people to

get tested.get tested. Implement educational programs.Implement educational programs. Provide free or low-cost drugs to slow disease Provide free or low-cost drugs to slow disease

progress.progress.

How Would You Vote?How Would You Vote?

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Should developed and developing nations mount an Should developed and developing nations mount an urgent global campaign to reduce the spread of HIV urgent global campaign to reduce the spread of HIV and to help countries afflicted by the disease?and to help countries afflicted by the disease? a. No. A global AIDS campaign could divert attention a. No. A global AIDS campaign could divert attention

and resources from efforts to combat other serious and resources from efforts to combat other serious threats.threats.

b. Yes. The disease is decimating the populations b. Yes. The disease is decimating the populations and destroying the economies of many developing and destroying the economies of many developing countries. countries.

Case Study: Case Study: Malaria – Death by MosquitoMalaria – Death by Mosquito

Malaria kills Malaria kills about 2 million about 2 million people per year people per year and has and has probably killed probably killed more than all of more than all of the wars ever the wars ever fought.fought.

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

Merozoites enter bloodstream and develop into gametocytes causing malaria and making infected person a new reservoir Plasmodium

develop in mosquito

Sporozoites penetrate liver and develop into merozoites

Female mosquito injects Plasmodium sporozoites into human host.

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

Stepped Art


Economists estimate that spending $2-3 Economists estimate that spending $2-3 billion on malaria treatment may save more billion on malaria treatment may save more than 1 million lives per year.than 1 million lives per year.

Spraying insides of homes with low Spraying insides of homes with low concentrations of the pesticide DDT greatly concentrations of the pesticide DDT greatly reduces the number of malaria cases.reduces the number of malaria cases. Under international treaty enacted in 2002, DDT Under international treaty enacted in 2002, DDT

is being phased out in developing countries.is being phased out in developing countries.


Solutions

Infectious Diseases

Increase research on tropical diseases and vaccines

Reduce poverty

Decrease malnutrition

Improve drinking water quality

Reduce unnecessary use of antibiotics

Educate people to take all of an antibiotic prescription

Reduce antibiotic use to promote livestock growth

Careful hand washing by all medical personnel

Immunize children against major viral diseases

Oral rehydration for diarrhea victims

Global campaign to reduce HIV/AIDS

Ecological Medicine and Ecological Medicine and Infectious DiseasesInfectious Diseases

Mostly because of human activities, Mostly because of human activities, infectious diseases are moving at increasing infectious diseases are moving at increasing rates from one animal species to another rates from one animal species to another (including humans).(including humans).

Ecological (or conservation) medicine is Ecological (or conservation) medicine is devoted to tracking down these connections devoted to tracking down these connections between wildlife and humans to determine between wildlife and humans to determine ways to slow and prevent disease spread.ways to slow and prevent disease spread.

CHEMICAL HAZARDSCHEMICAL HAZARDS

A toxic chemical can cause temporary or A toxic chemical can cause temporary or permanent harm or death.permanent harm or death. MutagensMutagens are chemicals or forms of radiation are chemicals or forms of radiation

that cause or increase the frequency of mutations that cause or increase the frequency of mutations in DNA.in DNA.

TeratogensTeratogens are chemicals that cause harm or are chemicals that cause harm or birth defects to a fetus or embryo.birth defects to a fetus or embryo.

CarcinogensCarcinogens are chemicals or types of radiation are chemicals or types of radiation that can cause or promote cancer.that can cause or promote cancer.

CHEMICAL HAZARDSCHEMICAL HAZARDS

A hazardous chemical can harm humans or A hazardous chemical can harm humans or other animals because it:other animals because it: Is flammableIs flammable Is explosiveIs explosive An irritantAn irritant Interferes with oxygen uptakeInterferes with oxygen uptake Induce allergic reactions.Induce allergic reactions.

Effects of Chemicals on the Immune, Effects of Chemicals on the Immune, Nervous, and Endocrine SystemsNervous, and Endocrine Systems

Long-term exposure to some chemicals at Long-term exposure to some chemicals at low doses may disrupt the body’s:low doses may disrupt the body’s: Immune systemImmune system: specialized cells and tissues : specialized cells and tissues

that protect the body against disease and harmful that protect the body against disease and harmful substances.substances.

Nervous systemNervous system: brain, spinal cord, and : brain, spinal cord, and peripheral nerves.peripheral nerves.

Endocrine systemEndocrine system: complex network of glands : complex network of glands that release minute amounts of hormones into that release minute amounts of hormones into the bloodstream.the bloodstream.

Effects of Chemicals on the Immune, Effects of Chemicals on the Immune, Nervous, and Endocrine SystemsNervous, and Endocrine Systems

Molecules of certain synthetic chemicals Molecules of certain synthetic chemicals have shapes similar to those of natural have shapes similar to those of natural hormones and can adversely affect the hormones and can adversely affect the endocrine system.endocrine system.

Hormone Estrogenlike chemical

Antiandrogen chemical

Receptor

Normal Hormone Process Hormone Mimic Hormone Blocker

Cell

Case Study: Case Study: A Black Day in Bhopal, IndiaA Black Day in Bhopal, India

The world’s worst industrial accident The world’s worst industrial accident occurred in 1984 at a pesticide plant in occurred in 1984 at a pesticide plant in Bhopal, India.Bhopal, India. An explosion at Union Carbide pesticide plant in An explosion at Union Carbide pesticide plant in

an underground storage tank released a large an underground storage tank released a large quantity of highly toxic methyl isocyanate (MIC) quantity of highly toxic methyl isocyanate (MIC) gas.gas.

15,000-22,000 people died15,000-22,000 people died Indian officials claim that simple upgrades could Indian officials claim that simple upgrades could

have prevented the tragedy.have prevented the tragedy.

TOXICOLOGY: ASSESSING TOXICOLOGY: ASSESSING CHEMICAL HAZARDSCHEMICAL HAZARDS

Factors determining the harm caused by Factors determining the harm caused by exposure to a chemical include:exposure to a chemical include: The amount of exposure (dose). The amount of exposure (dose). The frequency of exposure.The frequency of exposure. The person who is exposed.The person who is exposed. The effectiveness of the body’s detoxification The effectiveness of the body’s detoxification

systems.systems. One’s genetic makeup.One’s genetic makeup.


Typical Typical variations in variations in sensitivity to a sensitivity to a toxic chemical toxic chemical within a within a population, population, mostly because mostly because of genetic of genetic variation.variation.

Very sensitive

Majority of population

Very insensitive

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s a

ffe

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Dose (hypothetical units)


Estimating human Estimating human exposure to exposure to chemicals and their chemicals and their effects is very effects is very difficult because of difficult because of the many and often the many and often poorly understood poorly understood variables involved.variables involved.

Water pollutant levels

Air pollutant levelsSoil/dust levels

Food pesticide levels

Nutritional health

Overall health Mathematical Mathematical measurements measurements

& modeling& modeling

?

Lifestyle

Predicted level of toxicant in people

Personal habits

Genetic predisposition

MetabolismAccumulationExcretion

Lung, intestine & skin absorption rates


Children are more susceptible to the effects Children are more susceptible to the effects of toxic substances because:of toxic substances because: Children breathe more air, drink more water, and Children breathe more air, drink more water, and

eat more food per unit of body weight than eat more food per unit of body weight than adults.adults.

They are exposed to toxins when they put their They are exposed to toxins when they put their fingers or other objects in their mouths.fingers or other objects in their mouths.

Children usually have less well-developed Children usually have less well-developed immune systems and detoxification processes immune systems and detoxification processes than adults.than adults.


Under existing laws, most chemicals are Under existing laws, most chemicals are considered considered innocent until proven guiltyinnocent until proven guilty, , and estimating their toxicity is difficult, and estimating their toxicity is difficult, uncertain, and expensive.uncertain, and expensive. Federal and state governments do not regulate Federal and state governments do not regulate

about 99.5% of the commercially used chemicals about 99.5% of the commercially used chemicals in the U.S.in the U.S.

Protecting Children from Toxic Protecting Children from Toxic ChemicalsChemicals

The U.S. Environmental Protection Agency The U.S. Environmental Protection Agency proposed that regulators should assume proposed that regulators should assume children have 10 times the exposure risk of children have 10 times the exposure risk of adults to cancer-causing chemicals.adults to cancer-causing chemicals.

Some health scientists contend that Some health scientists contend that regulators should assume a risk 100 times regulators should assume a risk 100 times that of adults.that of adults.


Some scientists and health officials say that Some scientists and health officials say that preliminary but not conclusive evidence that preliminary but not conclusive evidence that a chemical causes significant harm should a chemical causes significant harm should spur preventive action (spur preventive action (precautionary precautionary principleprinciple).).

Manufacturers contend that wide-spread Manufacturers contend that wide-spread application of the precautionary principle application of the precautionary principle would make it too expensive to introduce would make it too expensive to introduce new chemicals and technologies.new chemicals and technologies.

How Would You Vote?How Would You Vote?

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Should we rely more on the precautionary principle Should we rely more on the precautionary principle as a way to reduce the risks from chemicals and as a way to reduce the risks from chemicals and technologies?technologies? a. No. Assuming that every chemical or technology is a a. No. Assuming that every chemical or technology is a

serious health or environmental threat will lead to serious health or environmental threat will lead to wasteful over-regulation, high costs and hinder the wasteful over-regulation, high costs and hinder the development of critically needed pesticides, plastics, and development of critically needed pesticides, plastics, and other commercial products.other commercial products.

b. Yes. Preventing the commercialization of harmful b. Yes. Preventing the commercialization of harmful chemicals and technologies is better than dealing with the chemicals and technologies is better than dealing with the high costs of medical treatments and environmental high costs of medical treatments and environmental damage. damage.

RISK ANALYSISRISK ANALYSIS

Scientists have Scientists have developed ways to developed ways to evaluate and compare evaluate and compare risks, decide how risks, decide how much risk is much risk is acceptable, and find acceptable, and find affordable ways to affordable ways to reduce it.reduce it.

Comparative Risk Analysis

Most Serious Ecological and Health Problems

High-Risk Health Problems • Indoor air pollution • Outdoor air pollution • Worker chemical exposure • 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 & destruction • Species extinction, loss of biodiversity

Medium-Risk Ecological Problems • Acid 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


Estimating risks from using many Estimating risks from using many technologies is difficult due to unpredictability technologies is difficult due to unpredictability of human behavior, chance, and sabotage.of human behavior, chance, and sabotage.

Reliability of a system is multiplicative:Reliability of a system is multiplicative: If a nuclear power plant is 95% reliable and If a nuclear power plant is 95% reliable and

human reliability is 75%, then the overall human reliability is 75%, then the overall reliability is (0.95 X 0.75 = 0.71) 71%.reliability is (0.95 X 0.75 = 0.71) 71%.


Annual deaths in the U.S. from tobacco Annual deaths in the U.S. from tobacco use and other causes in 2003.use and other causes in 2003.

Cause of Death Deaths

Tobacco use442,000

Accidents101,500 (43,450 auto)

Alcohol use85,000

Infectious diseases

75,000 (16,000 from AIDS)

Pollutants/toxins

55,000

Suicides30,600

Homicides20,622

Illegal drug use

17,000


Number of deaths per year in the world from various Number of deaths per year in the world from various causes. Parentheses show deaths in terms of the causes. Parentheses show deaths in terms of the number of fully loaded 400-passenger jumbo jets number of fully loaded 400-passenger jumbo jets crashing every day of the year with no survivors.crashing every day of the year with no survivors.

Cause of death Annual deaths

Poverty/malnutrition/

disease cycle

11 million (75)

Tobacco 5 million (34)

Pneumonia and flu 3.2 million (22)

Air pollution 3 million (21)

HIV/AIDS

Malaria 2 million (14)

Diarrhea 1.9 million (13)

Tuberculosis 1.7 million (12)

Car accidents 1.2 million (8)Work-related injury

& disease 1.1 million (8)

Hepatitis B 1 million (7)

Measles 800,000 (5)

3 million (21)

Perceiving RiskPerceiving Risk

Most individuals evaluate the relative risk Most individuals evaluate the relative risk they face based on:they face based on: Degree of control.Degree of control. Fear of unknown.Fear of unknown. Whether we voluntarily take the risk.Whether we voluntarily take the risk. Whether risk is catastrophic.Whether risk is catastrophic. Unfair distribution of risk.Unfair distribution of risk.

Sometimes misleading information, denial, Sometimes misleading information, denial, and irrational fears can cloud judgment.and irrational fears can cloud judgment.

RISK RISK ANALYSISANALYSIS

Comparisons of Comparisons of risks people face risks people face expressed in expressed in terms of shorter terms of shorter average life average life span.span.

Shortens average life span in the U.S. byHazard

PovertyBorn male

SmokingOverweight (35%)

Unmarried 5 yearsOverweight (15%) 2 yearsSpouse smoking 1 year

Driving 7 monthsAir pollution 5 months

Alcohol 5 monthsDrug abuse 4 months

Flu 4 monthsAIDS 3 months

Drowning 1 monthPesticides 1 month

Fire 1 monthNatural radiation 8 days

Medical X rays 5 daysOral contraceptives 5 days

Toxic waste 4 daysFlying 1 day

Hurricanes, tornadoes 1 dayLifetime near nuclear plant 10 hours

6 years6–10 years

7.5 years7–10 years

Becoming Better at Risk AnalysisBecoming Better at Risk Analysis

We can carefully We can carefully evaluate or tune out of evaluate or tune out of the barrage of bad the barrage of bad news covered in the news covered in the media, compare risks, media, compare risks, and concentrate on and concentrate on reducing personal risks reducing personal risks over which we have over which we have some control.some control.

Risk Assessment Risk Management

Hazard identification Comparative risk analysis

What is the hazard? How does it compare with other risks?

How much should it be reduced?

Risk reduction

Probability of risk

How likely is the event? Risk reduction strategy

How will the risk be reduced?

Consequences of risk Financial commitment

What is the likely damage?

How much money should be spent?

Chapter 11 Environmental Hazards and Human Health.

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Transcript of Chapter 11 Environmental Hazards and Human Health.