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What is the relationship between environmental health & our own health?

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Environmental Health is the study of how environmental factors affect human health & our quality of life. Any factor that threaten of are harmful to human health are called hazards.

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Environmental hazards can be biological, social, chemical or physical.

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Biological Hazards: Viruses, bacteria, & other organisms in the environment that cause harm to humans are classified as biological hazards. Pathogens infect humans & make us sick.

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Social Hazards: Hazards that result from where we live, our jobs or our lifestyle choices. Ex: smoking-increases you risk of lung cancer or living beside a factory where illegal chemicals are being released

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Chemical Hazards: Chemicals in the environment that harm human health. They can by synthetic or produced by organisms. Ex: disinfectants to clean your kitchen

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Physical Hazards: Physical process that pose threat to our health including natural disasters. Ex: UV radiation from sun

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Epidemiology & Toxicology are two scientific fields that help us understand how, where & to what extent environmental hazards affect our health.

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Epidemiology is the study of disease in human population. Epidemiologists are scientist that study how & where disease occurs & how to control them.

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Toxicology is the study of how poisonous substances affect an organisms health. A substances toxicity determines how harmful a substance is to an organism.

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Toxicity is determined by two factors: What the substance is How much of the substance is needed to cause harm

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Toxicity is determined by measuring the response a substance produces at different doses. A dose is the amount of substance an organism is exposed to. This includes the amount & time exposed.

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The response is the effect an organism show as a result of exposure.

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The relationship between the different doses & the response they generate is called the dose- response relationship. Determining this relationship is difficult in humans.

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Every person is different. Two people can drink contaminated water & have two different reactions. Below are some reasons why people react differently.

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Sensitivity: People with health issues may be more sensitive to hazards. Sensitivity can also vary w/age, sex & weight. Babies & older people are more sensitive that adults.

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Genetics: Many diseases have both genetics & environmental factors. Environmental factors can increase the risk of developing the disease

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Risk Assessment is the process of measuring the chance that an environmental hazard will cause harm.

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1)Risk is the likelihood that that a given hazard will cause harm. 2)The process of measuring risk is called risk assessment.

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You encounter biological hazards EVERY DAY! Biological hazards are the second leading cause of death worldwide.

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Infectious Disease are caused by pathogens, such as viruses & bacteria. Infectious diseases account for nearly 30% of all deaths each year.

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Infectious disease spread through the human population in different ways. Pathogens can be spread by human, water or food, or by other organisms.

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Humans Some disease can be spread directly from one human to another. For example: touching, biting, or contact w/bodily fluids.

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HIV and TB are two diseases that can be transmitted from person to person.

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Water or food Some pathogens spread when people eat contaminated food or drink. Cholera is disease caused by a bacterium in water.

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It makes people sick when they drink the contaminated water. The person may experience intense diarrhea and vomiting. You can die from the cholera.

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Other Organisms Organism carries the pathogen and passes it to a person. The organisms do not suffer from the disease but passes on the pathogen to humans.

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Malaria is a disease that is transmitted by this way. A female mosquito picks up the pathogen & when it bites an infected person & then transmits it when it bites a non-infected person.

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Emerging Disease is a disease that has appeared in the human population for the first time or has existed but is increasing rapidly or spreading around the world. Ex: Swine flu

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Increasing mobility people are more mobile so the disease is being spread more easily

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Antibiotic resistance - bacteria becoming resistant to the antibiotics b/c of natural selection.

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Some bacteria survive after being exposed to the drug. They reproduce & create more bacterial resistant to the antibiotic.

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Changing environment When we cut down trees, we may come into contact w/ animals that spread disease. Climate change can also encourage the spread of disease.

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Social Hazards - some can be avoided while other cannot. You might live near an old toxic waste dumpa hazard difficult to change. You may choose to eat unhealthy foods.a change YOU can make!

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All chemical hazards can be dangerous in large enough quantities. A chemical hazard is anything that may harm human health.

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Chemical Hazard vs. Pollution Pollution is matter or energy that is released into the environment, causing negative effects that impact people, wildlife & other parts of the environment

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Example: oil in poison ivy. This is a chemical hazard b/c it can cause itchy rash on humans but not a pollutant because it doesnt harm the environment.

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Types of Chemical Hazards Chemical hazards can cause cancer, birth defects & improper function of human body systems.

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Carcinogens: Chemicals that cause cancer are known carcinogens. Cancer is a disorder where cells grow uncontrollably.

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Cancer does have a genetic component but can be influenced by environmental factors.

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Chemical Mutagens are substances that cause genetic changes or mutations in the DNA or an organism. Ex: benzenesecond hand smoke, gasoline & air pollution

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Teratogens are chemicals that harm embryos & fetuses. Example: thalidomide, alcohol

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Neurotoxins Chemicals that affect the nervous system. Neurotoxins are various heavy metals such as lead, mercury & cadmium.

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Allergens Substances that over activate the immune system causing a response when one is not necessary. Examples: mold, bacteria, animal proteins

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Endocrine Disruptors is a chemical that interferes with the endocrine system or hormones.

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Hormones regulate our body functions like growth & development. Small children are at the greatest risk b/c they are developing. Example: PCBs

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Our homes & buildings may contain chemical hazards including asbestos, radon, volatile organic compounds, carbon monoxide & lead. Indoor pollution is not always easy to detect

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Asbestos is a mineral that forms long think fibers. It is used as insulation to muffle sounds and keep heat in.

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When disturbed, these fibers can be inhaled & may go into lung tissue. This may cause cancer & asbestosis.

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Radon is a colorless, odorless, highly toxic radioactive gas. This gas is made naturally when uranium in rock, soil & water decay.

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Radon is detected w/a special kit & can be vented out of the building.

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Volatile Organic Compounds (VOCs) is a diverse group of indoor pollutants. These chemicals contain carbon and are released into the air by plastics, perfumes & pesticides.

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We are unsure how they affect our health b/c we are exposed to them in such low levels. Formaldehyde is an exception.

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Carbon Monoxide is a colorless & odorless gas. Low exposure can cause headaches, nausea, dizziness & fatigue.

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Higher exposure can impair vision, chest pains, lower brain function & death. Carbon monoxide can lead from stoves, car exhaust & tobacco smoke.

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You can protect yourself with a carbon monoxide detector.

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Lead is another indoor hazard. Lead can be in the air, drinking water, contaminated soil, dust & lead-based paint.

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Lead poisoning can lead to learning problem. When ingested, lead poisoning can damage the brain, liver, kidneys & stomach.

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Hazardous Waste is waste with characteristics that make it harmful to human health and the environment

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CORROSIVE Chemical action can burn or destroy living tissue & other material brought into contact

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Ignitable, flammable, or combustible Easily set on fire

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Explosive- explode when exposed to heat, sudden shock, pressure or certain chemical substance

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Toxic - Hazardous substance that causes adverse effects to living things or environment

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Less toxicCAUTIONMild hazard WarningModerate hazard More toxicDANGER POISON Extremely toxic, flammable, corrosive

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There are chemical hazards in the air, on land, and in the water.

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These contaminants include antibiotics, detergents, drugs, disinfectants, solvents, perfumes and other substances.

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Hazards in the air Chemicals in the air can travel by wind & impact an area far away from the beginning point.

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Volcanic eruptions & human activity can release chemical hazards in the air.such as carbon monoxide, sulfur dioxide, etc.

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Hazards on Land Chemical hazards can enter the soil in many ways. Using pesticides put chemicals directly in the land.

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Also improper disposal of electronic devices can add heavy metals like lead in the soil

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Hazards in Water Many chemicals are soluble in water and enter the organisms tissues through drinking or absorption.

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Chemicals can enter the water in many different ways. Runoffwater runs off the land & picks up everything in its path.

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Hazards can also be released directly into the water.

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Toxic chemicals accumulate in organisms as they feed on one anotherthis is called biomagnification!

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When the toxic substance builds up large concentrations in the bodies of organisms it is called bioaccumulation

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Persistent Organic Pollutants (POPs) are the chemicals that magnify through the food web & cause adverse health effects for humans.

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POPs can be carried long distances by water & wind. Ex. DDT, PCBs

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The use of POPs has led to an international treaty. As of 2009, 152 countries have signed the Stockholm Convention on POPs agreeing to reduce the use of the top 12.

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The average American household uses about 18 pounds of hazardous waste each year.

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Natural Disasters can affect the Earths surface, human lives and property.

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Earthquakes: earth shakes due to tectonic plates scraping against one another

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Landslide: rock and soil slide down a slope usually after an earthquake

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Tsunami: a large ocean wave caused by an earthquake at the bottom of the ocean

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Volcano: opening in the Earths crust through which lava, ash and gases are ejected

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Tornadoes: type of windstorm in which a funnel of air drops down from a storm cloud touches the Earth

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Hurricanes: a powerful storm that forms over the ocean in the tropics

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Avalanche: mass of snow sliding down a slope