Jan 16, 2008, 12:15 pm Geog 361b 1

Introduction: Key ConceptsIntroduction: Key Concepts(Moeller Chapter 1)(Moeller Chapter 1)

Geography 361aGeography 361aEnvironment and HealthEnvironment and Health

• Discussion: Is the world more dangerous?

• Historical Context• Concepts/Definitions

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Context:Context:DiscussionDiscussion

• Is the world more dangerous now than it was 20 years ago?

• What are some useful ways to qualify/refine the question above?

• Break into groups of 4 and discuss.

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ContextContext

• healthier than ever• highest life expectancy ever• awareness of hazards and risk high

– e.g., 46,962 articles on “hazards” in major Canadian dailies 1985 to present.

– (reference: “free trade” – 76,531)

• population “at risk” increasing

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Life ExpectancyLife Expectancy

http://www.undp.org/hdr2003/indicator/indic_1_2_1.html

http://www.cia.gov/cia/publications/factbook/rankorder/2102rank.html

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Life ExpectancyLife ExpectancyTime-trendsTime-trends

For

USA

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Life ExpectancyLife ExpectancyTime-trendsTime-trends

For

Canada

Canada: Life Expectancy at Birth for Males and Females

40455055606570758085

1920-22

1930-32

1940-42

1950-52

1960-62

1970-72

1980-82

1990-92

2000-02

Time Period

Years

s o

f L

ife

Males

Females

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Causes of Death Canada

For

For

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Causes of DeathCauses of Death

Source: Thomas and Hrudey (1997) Risk of Death in Canada

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World Population Growth

Source: http://www.prb.org/

world population clock

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Concepts/DefinitionConcepts/Definition

Environmental Health• “That segment of public health that is

concerned with assessing, understanding, and controlling the impacts of people on their environment and the impacts of the environment on them." (Moeller 1997, 1)

Human Health• emphasis of this course is the latter

half of this definition• former half is an “undercurrent” of

the course

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Concepts/Definitions

Contamination• when substance exceeds capacity of

“environment” to eliminate it• aggregate output of substance

exceeds some sensory or predetermined limit

• e.g., wood fires “allowed” in rural vs urban areas.

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Selective Historical ContextEarly Writings

Hippocrates (460 BC)• On Airs, Waters and Places• winds, seasons and sources of water

important for physician diagnosis• occupational diseases – e.g. “lead

colic” in miners• explanation for decline of Rome?

– water delivery lead pipes/aqueducts

– lead-lined vessels – aristocracy

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Selective Historical ContextOccupational Health

• Georgius Agricola (1556)• De Re Metallica (12 books!)• occupational diseases among miners

– joints, lungs (e.g. silicosis, tuberculosis, lung cancer), eyes

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Selective Historical ContextOccupation and Cancer

• Percival Pott (1775)• First detailed writing

about occupationally-induced cancer

• scrotal cancer in chimney sweeps

• soot + tar + infrequent washing

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Selective Historical Context

• John Snow (1855)• On the Mode of Communication of

Cholera• well intake near sewage outfall

“graph on map to

mark cholera deaths”

Broad Street pump linked to cholera

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• water sanitation dramatically decreased several water borne diseases

Selective Historical Context

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Contamination

Natural Contamination• e.g., sulfur, radionuclides, radon

Anthropogenic Contamination• e.g., CO, pesticides• focus of most attention (not always

deservedly so)

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ScopeScope

Some Problems Studied• toxic chemicals• waste (e.g., toxic, municipal,

radioactive)• workplace stress• built environment• overpopulation• food supplies• acid deposition• global warming• resource depletion• …

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PractitionersPractitioners

Some Disciplines (Multidisciplinary)• toxicologists• epidemiologists• economists• geographers (health, hazards)• sociologists• lawyers• planners• engineers• managers• …

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Defining “Environment”Defining “Environment”

Inner vs Outer Environment• protective barriers between inner and

outer:– skin

– GI tract

– lungs

• which barrier makes humans most vulnerable? Why

• problems with this categorization of “environment”?

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Defining “Environment”Defining “Environment”

Personal vs Ambient Environment• personal = individual control• ambient = outside individual control

• problems with this categorization of environment?

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Cancer Caused by Environmental Exposures

categorize each above as “personal” or “ambient”

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Defining “Environment”

• gaseous, liquid and solid• each linked with particular routes of

exposure to humans• problems?

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Defining “Environment”

Chemical, Biological, Physical, Socioeconomic

• Chemical - contaminants• Biological – disease organisms• Physical – e.g., noise, temperature,

radiation• Socioeconomic – e.g., SES,

environmental justice• problems with this categorization?

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Exercise:Defining “Health”

Define “health”.

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Defining “Health”

WHO (1948)• “Health is a state of complete

physical, mental and social well-being and not merely the absence of disease or infirmity.”

• physical• mental

• social well-being

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Disease Classification

infectious vs non-infectious

• infectious

– e.g., malaria, cholera, diarrhea

– pathogenic organisms

– major killer in the past

– not typically considered an “environment and health” issue (e.g., Nadakavukaren, 2000) – but Walkerton!

– historically mono-causal

• non-infectious

– e.g. cancer, heart disease, asthma

– major killer now

– multi-causal model

– typical environment and health concern these outcomes

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Disease Classification

endemic vs epidemic• endemic

– pathogen carried by many people

– typically not considered an environmental illness issue

– e.g., ?

• epidemic– pathogen carried by many people

– sudden and severe outbreak of a disease in a population

– e.g., ?

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Disease Classification

acute vs chronic• acute

– severe short term disease– or disease/symptoms due to short term

high dose exposure to environmental substance

– QOL: if survive, no long-term effects– e.g., ?

• chronic– long term disease/condition– or disease/condition due to long term

low dose exposure to environmental substance

– QOL: long-term effects often duration of life

– e.g., ?

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Systems Approach

• controlling one form of environment and health problem can lead to other problems

• e.g., chlorination, fluoridation of water

• e.g., pesticides

• risk analysis and cost/benefit analysis helpful

• not strictly a technical problem

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Components of Assessing Environment and Health Problems

1. determine the source of contamination/stress

2. determine how contamination/stress contacts humans

3. measure the resulting effects

4. assess the seriousness of the effects

5. apply controls as necessary

How “social” is this process?

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Models of Environmentand Health

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Models of Environmentand Health: Multicausality

• source: Jones and Moon (1987) Health Disease and Society

• source: Jones and Moon (1987) Health Disease and Society