ENVIRONMENT & HEALTH Dept. of Public Health Faculty of Medicine - Padjadjaran University Bandung.
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Learning Objective:• To explain the basic relationship b/w
environmental factors & health, & how the interrelationship b/w economic development, the environment & health can be seen in an ecosystem framework
• To interpret environmental health in historical context w/ respect to changes in technology, economic development & social organization
• To describe the basic requirements for a healthy environment
• To explain the basic issues & concerns w/ respect to methods of measuring environmental quality, exposure & health effects
• To describe the larger socio-economic issues affecting environmental health
ReferencesReferences
• Yassi A, Kjellström T, de Kok T, Guidotti Yassi A, Kjellström T, de Kok T, Guidotti TL. TL. Basic environmental health. Basic environmental health. Chapter 1: Introduction. New York: Chapter 1: Introduction. New York: Oxford University Press, 2001Oxford University Press, 2001
• Smith KR, Corvalán CF, Kjellström T. Smith KR, Corvalán CF, Kjellström T. How much global ill health is How much global ill health is attributable to environmental factors? attributable to environmental factors? Epidemiology, Epidemiology, September 1999, Vol. September 1999, Vol. 10(5):573-8410(5):573-84
BIRTH, LIFE, DEATH & THE ENVIRONMENT
First human beings faced hostile environment shorter life expectancy To survive, the first humans had to cope w/: the constant search for sufficient food & drinking water while avoiding
plants contained natural toxins or rancid infected meat infections & parasites spread from person to person or animal to
person, via food, drinking water, or insect vectors injuries from falls, fires, & animal attacks cold & hot temperatures, rain, snow, natural disasters & other adverse
events
What is What is ‘environment’‘environment’??
(all) that which is external to the individual human host. (It) can be divided into physical, biological, social, cultural, any or all of which can influence health status in populations (Last, 1995)
• Environmental causes of diseases Environmental causes of diseases would be all those that are not would be all those that are not geneticgenetic
• ‘‘Nature’ vs ‘nurture’Nature’ vs ‘nurture’
• Environmental factors include all Environmental factors include all those that affect the organism those that affect the organism after conception regardless of after conception regardless of whether they are mediated by whether they are mediated by social conditions & individual social conditions & individual choice or through environmental choice or through environmental mediamedia
Ecosystem any spatial or organizational unit which
includes living organisms & nonliving substances interacting to produce exchange of materials b/w the living & nonliving parts
Basic components: abiotic substances producer organisms consumer organisms decomposer organisms
Basic components of an ecosystem
Basic plantnutrients
PRODUCERS• Green plants• Bacteria
PRIMARY CONSUMERS• Herbivores• Plant parasites
SECONDARY CONSUMERS• Omnivores• Carnivores• Animal parasites• Scavengers
DECOMPOSERS• Saprophytic bacteria• Fungi
HEALTH
The scale & nature of human activities
(agricultural, industrial, & energy production, the use & management of water & wastes; urbanization; the
distribution of income & assets within & between countries; the quality of health services; & the extent of protection of
the living, working, & natural environment
Physical & chemical environment
(air, water, food & soil chemical composition including radiation; climate including temperature,
humidity, precipitation, & seasonal changes)
Biological environment(type & distribution of pathogens & vectors, as
well as their habitats)
Source: Yassi et al., 2001 (adapted from WHO 1992)
Sustainable Development
development that meets the needs of the present development that meets the needs of the present without compromising the ability of future without compromising the ability of future generations to meet their own needsgenerations to meet their own needs
(WCED, 1987)(WCED, 1987)
Human beings are at the center of concerns for Human beings are at the center of concerns for sustainable development. They are entitled to a sustainable development. They are entitled to a healthy & productive life in harmony with naturehealthy & productive life in harmony with nature
(UN, 1993)(UN, 1993)
Environmental HealthEnvironmental Health
comprises those aspects of human health, comprises those aspects of human health, including quality of life, that are including quality of life, that are determined by physical, biological, social determined by physical, biological, social and psychosocial factors in the and psychosocial factors in the environmentenvironment
refers to the theory & practice of refers to the theory & practice of assessing, correcting, controlling, & assessing, correcting, controlling, & preventing those factors in the preventing those factors in the environment that can potentially affect environment that can potentially affect adversely the health of present & future adversely the health of present & future generationsgenerations
(WHO, 1993)(WHO, 1993)
Environmental Health Science
• hazards in the environment, their effects on health & the variations in sensitivity to exposures within populations
• development of effective means to protect against hazards in the environment
EEtthhiiccss????
Ethical dilemma
Any control limiting the exploitation of resources may inhibit an individual’s or a community’s attempts to
enhance their standard of living infringing on their rights & freedoms as well as
decreasing their ability to maintain health
VS
Any action to protect the environment & maintain the integrity of the ecosystem is justified regardless of the
impact on human activity & health
UN:1st Order Principle:
Ensuring human survival should be taken as a first-order principle
Universal Declaration of Human Rights (UN, 1948)
‘all people have the right to a standard of living adequate for the health and well-being of themselves & their family, including food, clothing, housing, health care, and the necessary social services’
2nd Order Principle:
Respect for nature & control of environmental degradation
Humans have extraordinary abilities to adapt to and influence their environment to meet their needs Many ways to make the environment healthierEnvironmental health hazards are beyond
the control of the affected individual, e.g.:
• industrial pollution• poor services of drinking water &
sanitation• poor housing & town planning• lax control over eating establishments or
food industry• poor quality roads• poor conditions in the workplace
Historical Perspective• 1st environmental crisis
• 2nd wave of environmental concern
• 3rd wave of environmental concern
Basic Requirements for a Healthy Environment
• Clean air
• Safe & sufficient water
• Adequate & safe food
• Safe & peaceful settlement
• Stable global environment
Some pathways for translation of
epidemiological evidence into policyRegulatory
OHS
Environmental Quality
Drug Safety
Public Health Recommendations
Vaccination
Diet
Smoking
Legal System
Cause of injury
Health-care delivery
Practice guidelines
Outcome assessment
Risk management policies are intended to assure that exposures convey an acceptable level of risk, whether in the WP or the general environment
Quantitative Risk Assessment (NRC, 1983):
• Hazard identification – is there a hazard?• Dose-response – what is the relationship
b/w exposure or dose & risk?• Exposure assessment – what is the
distribution of exposure?• Risk characterization – what is the risk to
the population?
THE PATHWAYS FROM SOURCES & MEDIA OF EXPOSURE TO HEALTH EFFECTS (NRC, 1991)
Air FoodSoilWater
Media of exposure ‘source’
Transport & fate
Routes of entry
InhalationIngestion
Skin
Exposure
Internal dose
Biologically effective dose
Health & comfort effects
Applic
ati
ons
Environmental epidemiology
Risk assessment
Risk management
Intervention, prevention & diagnosis
Physicoharmacokineticmodels
Pharmacodynamicsmodels
Exposure metrics in environmental epidemiology
• Cumulative exposure• Exposure during a susceptibility window• Recent exposure• Time since first exposure• Age at first exposure• Exposure rate• Peak exposure• Exposure above threshold
Concept of DALYa measure for the burden of disease that takes into account premature death & loss of healthy life resulting from disability disabilities: physical or mental
Intended use is to assist:• in setting health service priorities• in identifying disadvantaged groups & targeting of health
interventions• in providing a comparable measure of output for
intervention, program & sector evaluation & planning
One DALY is thus one lost year of healthy life
ESTIMATED GBD FROM SELECTED ENVIRONMENTAL THREATS, 1990 & POTENTIAL WORLDWIDE REDUCTIONS THROUGH INTERVENTION IN THE
WORKPLACE & AMBIENT ENVIRONMENT
Type of environment & principal related diseasesa
Burden from these diseases (millions of DALYs/year)
Reduction achievable
through feasible interventions (%)b
Burden averted by feasible
interventions (millions of
DALYs/year)
Burden averted per 1000
population (DALYs/year)
OCCUPATIONAL 318 - 36 7.1
Cancers 79 5 4 0.8
Neuropsychiatric 93 5 5 0.9
Chronic respiratory 47 5 2 0.5
Musculoskeletal 18 50 9 1.8
Unintentional injury 81c 20 16 3.1
URBAN OUTDOOR AIR
Acute respiratory infections 123 5 6 1.2
Chronic respiratory diseases 47 5 2 0.5
ROAD TRANSPORT
(motor vehicle injuries) 32 20 6 1.2
All the above 473d - 50 10.0
Source: World Bank, 1993
ESTIMATED BURDEN OF DISEASE FROM HOUSEHOLD ENVIRONMENTS IN DEVELOPING COUNTRIES, 1990 & POTENTIAL REDUCTION THROUGH INTERVENTIONS
Principal diseases related to poor
household environmentsa
Relevant environmental
problem
Burden from these diseases in
developing countries (millions
of DALYs/year)
Reduction achievable
through feasible interventions (%)b
Burden averted by feasible
interventions (millions of
DALYs/year)
Burden averted per 1000
population (DALYs/year)
Tuberculosis Crowding 46 10 5 1.2
Diarrheac Sanitation, watersupply, hygiene
99 40 40 9.7
Trachoma Water supply, hygiene
3 30 2 0.3
Tropical clusterd Sanitation, garbage disposal, vector breeding
8 30 2 0.5
Intestinal worms Sanitation, water supply, hygiene
18 40 7 1.7
Respiratory infections
Indoor air pollution, crowding
119 15 18 4.4
Chronic respiratory diseases
Indoor air pollution 41 15 6 1.5
Respiratory tract cancers
Indoor air pollution 4 10 <1 0.1
All of the above 338 - 79 19.4 Sourc
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PROPORTION OF GLOBAL DALYS ASSOCIATED WITH ENVIRONMENTAL EXPOSURES, 1990
% of all DALYs
Global DALYs (thousands)
Environmental fraction (%)
Environmental DALYs (thousands)
All age groups
Age 0-14 years
Acute respiratory infections 116,696 60 70,017 5.0 4.50
Diarrheal diseases 99,633 90 89,670 6.5 6.10
Vaccine-preventable infections 71,173 10 7117 0.5 0.49
Tuberculosis 38,426 10 3843 0.3 0.04
Malaria 31,706 90 28,535 2.1 1.80
Unintentional injuries 152,188 30 45,656 3.3 1.60
Intentional injuries 56,459 NE NE
Mental health 144,950 10 14,495 1.1 0.08
Cardiovascular diseases 133,236 10 13,324 1.0 0.12
Cancer 70,513 25 17,628 1.3 0.11
Chronic respiratory diseases 60,370 50 30,185 2.2 0.57
Total these diseases 975,350 33 320,470 23.0 15.40
Other diseases 403,888 NE NE
Total all diseases 1,379,238 (23) (320,470)
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Links b/w environmental & occupational health
• Importance of the workforceHealthy, well-trained & motivated workforce productivity & wealth
• Linked E & O hazardsThe source of the E & O hazards is often the same
• Common approaches & human resourcesThe scientific knowledge & training required to assess & control EH hazards are generally the same skills & knowledge required to address health hazards within the WP (e.g. toxicology, epidemiology, occupational hygiene, ergonomics & safety engineering
• The workplace as a sentinel for environmental hazardsEH hazards have often been first identified from observations of adverse health effects in workers. Information on OH effects of many toxic exposures has been used to calculate the health risk to the wider community
• Total exposure conceptNot enough to assess the exposure to a hazard from just one source
• Consistency in setting standardsEH standards are usually much stricter than OH standards
• Incentives for preventionAlthough the WP is usually the site of more intense exposures, the impact of these hazards on the general public has often been a major force in stimulating cleanup efforts, both inside the WP & in the surrounding community
Comparison between WHO Health-Based Guidelines for Air in the Workplace &
in the General Environment
ChemicalWP Guideline g/m3
(8-hr mean)
General Environment Guideline g/m3
(annual mean)
Lead 30 – 60 0.5 – 1.0
Cadmium 10 0.01 – 0.02
Manganese 300 1
Mercury 50 1
Formaldehyde 500 100 (24 hours)
Nitrogen dioxide 900 150 (24 hours)
Sulfur dioxide 1300 50
Source: WHO, 1987 & several Technical Reports
OBSTACLES & OPPORTUNITIES• Demographic issues
Size of the population level of consumption• Poverty
The poor usually lack a minimum standard of living (e.g. adequate food, safe & sufficient supplies of water, secure shelter, access to education & health care, & provision for the removal of domestic wastes
• Consumption patternsMajor difference in consumption patterns b/w different countries & b/w different groups within countriesRees & Wackernagel (1992) characterized the land area necessary to sustain current levels of resource consumption & waste discharge by a population as its ecological footprint.The ecological footprints of high income cities are hundreds of times larger than their politic or geographical area & are much larger than the ecological footprints of lower income communities
• Macroeconomic policiesInfluence the use & degradation of natural resources, b/c can affect consumer demand & the prices of natural resourcesThe effects are felt most directly at the level of an individual’s purchasing power
EH Professionals
• EH Officer
• EH Technician
• Environmental Inspector
• Epidemiologist
• Ergonomist
• Health Physicist
• Health Policy Analyst
• Laboratory Analytical Scientist
• Occupational Hygienist• OH Nurse• OEH Physician• OHS Inspector• Sanitary Engineer• Safety Professional• Statisticians• Toxicologist
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