Environmental Health PUBH-2053

Dr Natasha K Ex-Asst Prof BUHS

drnatasha1203@gmail.com

Class ScheduleDay Date Class Topic1 20/01/2017 1 Fundamentals of Environmental health

2 Common Factors2 27/01/2017 3 Environment and health Issues

4 Environmental Health Sciences and Public Health

3 3/2/2017 5 Air quality and Pollution6 Ozone

4 10/2/2017 7 Physical Hazards-Noise, Temp,Radiation8 Housing

5 17/02/2017 9 Water quality and pollution10 Arsenic

6 24/02/2017 11 Midterm12 Assignment discussion

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Lecture 1 & 2Fundamentals of Environmental Health

Factors

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Definition of Environment

The circumstances, objects, or conditions by which one is surrounded  or  The complex of climatic, edaphic (soil-based), and biotic factors that act upon an organism or an ecologic community

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PH Def

All that which is external to the individual host. [It] can be divided into physical, biological, social, and cultural factors, any or all of which can influence health status in populations.

• Last, J. M. (Ed.). (1995). A Dictionary of Epidemiology (3rd ed.). New York: Oxford University Press.

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Types

1. Internal environment : Organ, Organ system, tissue etc. of the body

2. External environment : Surroundings to which man is exposedOr1. Built Environment2. Natural Environment3. Social Environment

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Built environment is shaped by:

i. Climate and geologyii.Economyiii.Governmentiv.Culture and fashionv.Technologyvi.CustomersDr NatashaK

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Natural Environment

• The natural environment includes all living and non-living things occurring naturally on Earth.

• Natural environment is often used as a synonym for habitat. For instance, when we say that, the natural environment of giraffes is the savanna.

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Composition Natural Environment

i. The Lithosphere: The lithosphere is the rigid outermost shell of a rocky planet defined on the basis of the mechanical properties.

ii. The Hydrosphere: The hydrosphere refers to the combined mass of water found on, under, and over the surface of the planet. Ocean, rivers, lakes, ponds and as a whole all the water body of the earth.

iii. The Atmosphere: The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through greenhouse effect, and reducing temperature extremes between day and night.Dr NatashaK

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iv. The Biosphere: The biosphere is the global sum of all ecosystems. It can also be termed the zone of life on Earth, a closed system and largely self-regulating.

The biosphere is the global ecological system integrating all living beings

and their relationships

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Social Environment

The social environment refers to the immediate physical and social setting in which people live or in which something happens or develops.

It includes the culture that the individual was educated or lives in, and the people and institutions with whom they interact.

The interaction may be in person or through communication media, even anonymous or one-way and may not imply equality of social status.

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• Social environment includes culture, language, social condition, health, profession, living condition, economic capability of the people in a certain area

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Diseases : Trouble or a condition of the living animal or plant body or one of its parts that impairs the performance of a vital function

Safe :Free from harm or risk , Secure from threat of danger, harm, or loss , Zero risk

Risk :Possibility of loss or injury, peril, the chance of loss; the degree of probability of such loss

Hazards : An environmental hazard is a substance, state or event which has the potential to threaten the surrounding natural environment and / or adversely affect people's health. This term incorporates topics like pollution and natural disasters such as storms and earthquakes

Contaminant : Biological, chemical, physical, or radiological substance (normally absent in the environment) which, in sufficient concentration, can adversely affect living organisms through air, water, soil, and/or food.

Or

A material what doesn’t occur in nature but is introduced by human activity into environment, affecting its composition

Pollutant : is defined as the presence in the environment of one or more substances (contaminants) or combinations of these in such quantities and of such duration that they are or may tend to be injurious to human, plant or animal life or property or that interfere with the comfortable, enjoyment of life or property or the conduct of business or other human activities.

Definitions

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Environmental Health Science

NIEHS charter: “The study of those factors in the environment that affect human health”  

Factors (“pollutants” or “toxicants”) in air, water, soil, or food  

Transferred to humans by inhalation, ingestion, or absorption   Production of adverse health effects

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Contributors to the “Environment

Chemical Air pollutants, toxic wastes, pesticides, VOCs

Biological Disease organisms present in food and water

 Insect and animal allergens

 Physical

Noise, ionizing and non-ionizing radiation  Socioeconomic

Access to safe and sufficient health care Dr NatashaK

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Lecture 3 & 4Health Issues

Public health and Environmental Health Science

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EPIDEMIOLOGICAL TRIAD

ENVIRONMENT   

VECTOR

AGENT HOST

WHO Definition of Environmental Health

Environmental health comprises those aspects of human health, including quality of life, that are determined by physical, biological, social, and psychosocial factors in the environment. It also refers to the theory and practice of assessing, correcting, controlling, and preventing those factors in the environment that can potentially affect adversely the health of present and future generations.

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Environmental Health?

Food

Air

Water

Sunlight

Noise

Soil

Definition: ‘Health Effect…’

• ‘…is the specific damage to health that an environmental hazard can cause an individual person. Often the same hazard can cause a range of different effects of different severity.’ (Yassi et al., 2001)

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Good Things Around Us

There are many things around us that help us stay healthy.

Family &

friends

Beautiful

scenery to look

at

Medicine & vitamins

Oxygen in the air

Nutrients in food

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Interdependence• Health depends on resources. • Good health depends on accessibility to sustainable resources.

• Bad health results from inaccessibility to sustainable resources or exposure to a hazard.

• Sustainable resources and hazards exist in the environment.

• Therefore, quality of health depends on the environment

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Interdependent Environments

• A relational definition of environment is a function of scale, boundaries, spatial proximity and recipient populations

• When considering a global scale, focus is on the effect of an unbounded environment, e.g. air, on all populations anywhere

• When considering local scale, focus is on effect of both a bounded and an unbounded environment, e.g. water and air, on a subpopulation closest to the exposure event

• The local scale is a subpart of the global scale

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Population Perspective of Relations

Individual

Family

Community, nation

Human population

All populations

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Environmental Effects on Health

An individual’s response to an environmental effect is a function of their physical environment, their health state, and their culture.

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Facets of Environmental Health

Environmental epidemiology  Associations between exposure to environmental agents and subsequent development of disease Environmental toxicology Causal mechanisms between exposure and subsequent development of disease Environmental engineering

Factors that govern and reduce exposure  Preventive medicine

Factors that govern and reduce disease development Law Development of appropriate legislation to protect public health Dr NatashaK

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PH def of Environmental health

• Environmental Health is the sub field of public health, concerned with assessing and controlling the impacts of environment on people and the impacts of people on their environment.

• Environmental Health is the science and art dedicated to preventing, reducing and reducing environmental pollution

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Health and Environment Perspective of Relations

PersonalHealth

Family Health

Occupational Health

Public Health

Environmental health

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Related Disciplines

Epidemiologists Risk Assessors Biostatisticians

Toxicologists MicrobiologistsHealth ServiceAdministrators

Social WorkersBehavioral

PsychologistsPublic Health

Educators

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Interdisciplinary Roles•To implement the systematic approach, role players are needed

•Three major classes of role players are: the environmental health problem investigators, the environmental problem responders and the health problem responders

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Interdisciplinary RolesEnvironmental health problem investigators : monitors populations to identify health trends, in an attempt to distinguish that which is harmful from that which is harmlessEnvironmental problem responders:measures the range of effects of health trends to characterize

degrees of adverse intensityHealth problem responders :identify potential hazards, potential pathways of hazards, and populations susceptible to hazardsDr NatashaK

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ENVIRONMENTAL IMPACT • Environment

• (Physical, biological and psychosocial)

• Human activities health of individual

33The Core Concepts

Contamination /pollution/hazard/toxicity

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The Toxicological Paradigm

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35Dr NatashaK

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Exposure is

The total amount of a hazard that comes in direct contact with your

body.Dr NatashaK

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The 3 parts of exposure

TheSource

of the hazard(bus exhaust)

TheEnvironmental

Pathway(air)

TheContact

(inhaled fumes)

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Which route will the hazards take?

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Route #1: InhalationInhalation:

Breathing. When chemicals enter the body through this route of exposure, they can get stuck in the lungs and/or be taken up into the bloodstream.

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Route #2: IngestionIngestion:

Swallowing (usually by eating or drinking). When chemicals enter the body through this route of exposure, they can easily be taken up into the bloodstream.

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Route #3: Dermal Absorption

Dermal Absorption:Absorbing a chemical through any part of the skin, including the eyes. When chemicals come in contact with the skin, they can sometimes enter the bloodstream through this route of exposure.

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ExposureX

XWhat is dose?X X

X

X X

X = hazard

Dose

Dose is the amount of a hazard that actually enters your body.

XX

XXX

X

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Dose can depend on…Duration of Exposure:How long?

Frequency of Exposure: How often?

Body Size:How big or small

are you?

M L

S S

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Duration of Exposure

might not have any harmful effects.

30 minutes of sun exposure

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Duration of Exposure

might be very harmful indeed!

But 4 hours of sun exposure

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Dose can depend on how big or small you are. To understand how, let’s take three different size flasks and fill them with water. Imagine each one represents a different human body - one small, one medium, and one large.

Dose & Body Size

LMs s

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Now we will take a dropper of an imaginary hazardous substance and put 3 drops in each flask. What will happen? How will each flask look after the 3 dark purple drops have been added?

A Dose Experiment

LMsDr NatashaK

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The larger the dose, the more extreme the response will be.

Dose/Response Relationship

1 can of pop in 15 minutes

3 cans of pop in 15 minutes

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Hazards/Pollution/Contamination/ Toxicities

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Pollutants (again)

Primary pollutants - enter the environmental media directly as a result of some manmade or natural activity or processSecondary Pollutants- are formed in the environmental media when primary pollutantsand other atmospheric constituents undergo chemical reactions eg. Photochemical oxidants

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Classification of Pollutants

MaterialsSubstances

Energy

Organic Chemicals

inorganic Chemicals

Solidse.g.

Plastics

Liquidse.g.Oils

Gasese.g.

Carbons of Low mol. Wt.

Solidse.g.

Fluorides

Liquidse.g.

Mercury

Gasese.g.

Sulphur dioxide

Heat e.g.Waste heat in the cooling water from a power station

Sounde.g.

noise

Radiation e.g.

Gamma radiation

from a source

Microorganismse.g. bacteria, virus

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Pollution Indicators : Some Indicators of environmental pollution: Changes in the chemical and physical constituents, energy patterns, radiation level, Abundances of organisms, Damage of ozone layer Increase in atmospheric temperature and CO2

layer

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Three major causes of pollution:

- Industrialization -        Urbanization-        Over-population

Industrialization - Industrial emissions pollute air - Industrial wastes, pollute soil, water and air - Industrial effluents, pollute water and soil - Industrial accidents, pollute soil, water and air

Urbanization-   Concentration of excessive population- Overcrowding- Excessive solid and liquid waste- Pressure on water supply-    Motor vehicle emission- Migration of people from rural to the urban

Over population- Earth resources can sustain up to 1500-1600 crore population- Over exploitation of land, water, mineral resources, disturbance of ecological balance- Increased use of chemical fertilizer, pesticides, cause soil pollution, soil degradation

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On the basis of nature of the Pollutant: Environmental pollution may be divided into 4 groups:

- Water pollution - Air pollution - Soil pollution - Noise pollution

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Causes of Environmental Pollution in Bangladesh

- Over population- Low literacy rate - Development without proper planning- Unplanned urbanization- Improper application of insecticides/pesticides and chemical fertilizers- Unplanned industrial estates- Untreated industrial waste disposal- Excessive destruction of forests and cutting trees for fuel- Emissions from increasing number of motor vehicles- Unhygienic excreta disposal- Increase migration from rural to urban- Excessive use of natural resources including over withdrawal of under ground water.

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Hazards

A hazard is anything in the environment that can hurt you or

make you sick.

Bacteria &

viruses Harmful chemical

s

Loud noises

Tobacco

smokeStress

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Biological hazardsThese are living organisms or their products that are harmful to humans

A. Water-borne diseases are diseases that are transmitted in drinking water1. Examples are polio virus, hepatitis A virus, Salmonella, Shigella, cholera, amoebic dysentery, Giardia, and Cryptosporidium.2. These disease organisms are shed into the water in feces, and can produce illness in those who consume untreated, contaminated water.3. Our municipal water treatment facilities are usually able to purify water by removing these agents or killing them by disinfecting the water.

B. Food-borne diseases are diseases transmitted in or on food1. Examples of food-borne agents are the bacteria Salmonella, serotype enteritidis, Escherichia coli 0157:H7, as well as other agents.2. To protect against food-borne diseases, sanitarians from local health departments routinely inspect food service establishments (restaurants) and retail food outlets (supermarkets) to verify that food is being stored and handled properly.

C. Vector-borne diseases are those transmitted by insects or other arthropods1. Examples are St. Louis encephalitis and La Crosse encephalitis transmitted by mosquitoes and plague and murine typhus transmitted by fleas.2. Improper environmental management can cause vector-borne disease outbreaks.

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II. Chemical hazards result from mismanagement or misuse of chemicals resulting in an unacceptable risk to human health

A. Pesticides are chemicals that have been manufactured for the purpose of reducing populations of undesirable organisms (pests)

1.Examples of categories of pesticides are herbicides and insecticides.2. Most pesticides kill non-target organisms as well as the target, or pest species.3. The wise use of pesticides can protect human health and agricultural crops.

B. Environmental tobacco smoke (ETS) is an environmental hazard produced by millions that smoke1. Diseases associated with ETS include lung cancer and perhaps heart disease.2. ETS contains 4, 000 substances.3. The EPA has classified ETS as a Class A carcinogen.4. Smoking has been increasingly restricted from public buildings and from many private work sites.5. Regulation of smoking seems to be the best approach to controlling this pollutant

•

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Chemicals in the Environment

• Roughly 70,000 different synthetic chemicals are on the global market; many others are emitted as by-products of their production, use, or disposal

• Production of synthetic organic chemicals (e.g., dyes, plastics, solvents) has increased from less than 0.15 billion kilograms (1935) to more than 150 billion kilograms (1995)

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II. Physical hazards include airborne particles, humidity, equipment design and radiation

A. Radon contamination results from over exposure to radon gas.B. Noise :Unwanted sound (the most simple). Another definition is

“Wrong Sound, in the wrong place, at the wrong time.”C. Humidity and Temperature :

D. Radiation

E. Equipment Design….Occupational Health

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III. Psychological hazards are environmental factors that produce psychological changes expressed as stress, depression, hysteria.

• IV. Sociological hazards are those that result from living in a society where one experiences noise, lack of

privacy and overcrowding.Population growth may be a sociological hazard.

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V. Site and Location Hazards

Natural disasters are geographical and meteorological events of such magnitude and proximity to communities that they produce significant damage and injuries.

1. Examples are cyclones, earthquakes, floods, hurricanes, tornadoes, typhoons, and volcanic eruptions.

2. The magnitude of devastation of these events can sometimes be great.

3. Biological, psychological and sociological hazards may increase following a natural disaster.

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64ToxicToxic means

Toxicology is the study of poisons.

Toxicity is a measure of how dangerous a chemical is.

poisonous or dangerous

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65A Toxicity ScaleToxicity Rating Signal Words on Package Symbol on Package

Highly Toxic DANGER or POISON

Moderately Toxic WARNING

Slightly Toxic CAUTION

Not Toxic none

Safe

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Symbols

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66Toxic air

Health Hazard

Toxic environment

Biohazard

Biohazard-Radiation

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68Individual SusceptibilityWhy are these

people more likely to be harmed by

exposure to a hazard than the man below?

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69Individual Susceptibility

Pregnant women and their developing babies

Elderly people whose defense mechanisms are less efficient

Infants and children who are still developing

Sick people who have weakened immune systems

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70Genes & SusceptibilityYour genes can also make you more or less susceptible to harm from an environmental hazard. For example, some people are more likely to get sick when they are exposed to certain kinds of pesticides.

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72What are the risks & benefits?

12 3

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73Risks & BenefitsWhat are the risks and benefits when fruit

growers use pesticides on their crops?

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74Risks & Benefits

RISKSBENEFITS•No bugs!

•Better looking fruit that is more visually appealing

•Bigger crops so farmers can make more profit

•People ingest pesticides with the

fruit and get sick

•Pesticides get into dirt and water

•Animals ingest pesticides and get

sickDr NatashaK

Public Health Environmental Issue

• Do you think that environmental issues are among the top three public health issues in this country?

• What criteria do you use to identify an important public health issue?

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Traditional Public Health Approach

• Define the problem •  • Identify and characterize the parameters governing the problem •  • Design appropriate PH interventions •  • Implement and evaluate the interventions •

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Another Possible Approach

• Define the health parameters of importance •  • Identify the problems most impacting the health parameters •  • Identify and characterize the parameters governing the problem •  • Design appropriate PH interventions •  • Implement and evaluate the interventions Dr NatashaK

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What is environmental justice?

Environmental Justice (EJ) means that everyone has a right to live in an environment that doesn’t make them sick, regardless of their race, culture, or income.

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80The EJ ProcessWho is

producing the hazard?

Who is being

exposed?

Who are the decision makers?

Establish a dialog between the

decision makers, scientists, and

the affected community.

Empower community

members to bring about change.

Share information and decisions with

community members.

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Systematic Approach

• In the absence of a universal definition of ‘good health’, at least a universal concept of adverse health effect, e.g. sick, illness, dysfunctional, ‘not normal’ or ‘not well’, must exist such that understanding the concept results in a response

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• In order to identify and investigate adverse states of health, a fundamental systematic approach of health problem identification and characterization must exist and be implemented

This approach is summarized as follows:Determine the source and nature of hazards Determine the exposure pathwayMeasure the effectsApply controls however possible

(Moeller, 1992)

Vulnerable group

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84How can you take action?

Write a letter to a

newspaper

Call or write an elected

official

Organize a community meeting

Inform your neighbors

Make a documentary

about the problem

Create a petition and

get signatures

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Problem Solving Paradigm

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Selecting PrioritiesRisk assessment

The determination of the probability that an adverse effect will result from a defined exposure • Hazard identification • Exposure assessment • Dose-response assessment •  Risk characterization•Pure “science” activities

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86Risk management

The process of weighing policy alternatives and selecting the most appropriate regulatory actions based on the results of risk assessment and social, economic, and political concerns

Intervention models

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Environmental health Science

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Thank you for today

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