Environmental Health What is the relationship between the health of the planet and our own health?
Types of Environmental Health Hazards • Environmental health hazards can be biological, social, chemical, physical. Can you think of any environmental health hazards that exist here in Latrobe, PA? • Biological: Viruses, bacteria, and other organisms that cause disease • Social: Lifestyle choices that endanger health • Chemical:Harmful artificial and natural chemicals in the environment • Physical: Natural disasters and ongoing natural phenomena, such as UV radiation, that can cause health problems
Identifying hazards in the environment is just one part of environmental health. Scientists also want to understand how these hazards affect people. Epidemiology Toxicology The study of how poisonous substances affect an organism’s health Toxicity is a measure of how harmful a substance is. Toxicologists look at toxicity by determining dose-response relationships. • The study of disease in human populations—how and where they occur and how they can be controlled • Often involves studying large groups over long periods • Can determine statistical associations between health hazards and effects, but can’t prove the hazards actually caused the effects
Individual Responses • People respond differently to environmental hazards making it difficult to predict with certainty how hazards may affect specific people. • Sensitivity to hazards varies with age, sex, weight, and immune system health. • People with health issues like asthma, compromised immune systems are more sensitive. • Many diseases have genetic as well as environmental factors. • Much research has proven that breast cancer can be caused by either emvironmental or genetic factors…and if caught early can be curable. Did You Know?Thalidomide, a drug that currently shows promise for treatment of Alzheimer's, AIDS, and some cancers, caused thousands of severe birth defects when it was used as an anti-nauseal in the 1950s and 60s.
Risk AssessmentScientists try to determine how likely it is that a given hazard will cause harm. With chemical hazards, scientists determine toxicity, human exposure, frequency of exposure, concentration of exposure, etc. • Risk: The probability that a hazard will cause harm • Risk assessment: The process of measuring risk • Takes into account: • The type of hazard • How frequently humans will be exposed to it • How sensitive people are to it
Tuberculosis-causing bacteria Three quarters of infectious disease deaths are caused by five types of diseases: respiratory infections, AIDS, diarrheal diseases, tuberculosis, and malaria. Biological and Social Health Hazards in the Environment
Infectious Diseases • Caused by pathogens • Spread by human and animal contact and through contaminated food and water • Cause of almost half of all deaths in developing nations • Covering your mouth when you cough, washing your hands often, and staying home from school if you’re sick help prevent the spread of infectious disease. Did You Know?In 2002, AIDS killed about 2 million people worldwide— almost equal to the entire population of Arkansas.
Emerging Diseases • Diseases appearing in the human population for the first time or suddenly beginning to spread rapidly • Humans have little or no resistance, and no vaccines have been developed. • Facilitated by increasing human mobility, growing antibiotic resistance, and environmental changes
Responding to Emerging Diseases • World Health Organization (WHO): Monitors health events worldwide and coordinates international responses to emerging diseases • Centers for Disease Control and Prevention (CDC): Responds to emerging diseases in the United States; the CDC developed pandemic plans to deal with the spread of the H1N1 flu virus. Click HERE: History of Pandemics H1N1 Virus
Social Hazards • Some social hazards are easier to avoid than others. • Examples of social hazards include smoking, being exposed to secondhand smoke, living near an old toxic waste site, working with harmful chemicals, and eating fatty foods.
Chemicals are all around us, and all of them can be harmful to our health in large enough amounts. In other words, “The dose makes the poison.” Chemical Health Hazards in the Environment
Chemical Hazards • Any chemical can be harmful in large enough amounts. • A pollutant is something released into the environment that has some harmful impact on people and other organisms. • Chemical hazards are not necessarily pollutants, and pollutants are not necessarily chemical hazards.
Types of Chemical Hazards • Carcinogens: Cancer-causing chemicals • Chemical mutagens: Chemicals that cause genetic mutations • Teratogens: Chemicals that harm embryos and fetuses • Neurotoxins: Chemicals that affect the nervous system • Endocrine disruptors: Chemicals that interfere with the endocrine system • Allergens: Chemicals that over-activate the immune system Dust mite protein is a common allergen.
Sources of Outdoor Chemical Hazards • In the air: Natural sources, such as volcanic eruptions, or human sources, such as pesticides • In the ground: Pesticide use, improper disposal of electronics, etc. • In the water: Chemical runoff from land or direct drainage of toxic substances into water
A landslide caused by the Great Sichuan Earthquake in Sichuan Province, China Although we cannot prevent most natural disasters, there are steps that scientists, engineers, governments, and citizens can take to resist damage and deal with the aftermath. Physical Health Hazards in the Environment
Physical Hazards • Physical hazards in the environment can pose health risks to humans. • Earth Quakes, Volcanos, Storms, and Avalanches are just some examples of natural disasters that can create environmental hazards. • We see biological hazards, chemical hazards, and social hazards result from natural disasters when they strike. • Although we cannot prevent these disasters, we can decrease our vulnerability to them.
Bioaccumulation and Biomagnification • Bioaccumulation: The buildup of toxic substances in the bodies of organisms • Biomagnification: The increased concentration of toxic substances with each step in a food chain • Persistent organic pollutants are biomagnified and stay in the environment for long periods of time and over long distances. CLICK HERE: Mercury in fish
One third of death and disease in the least developed nations is a direct result of environmental causes.
Review Questions: Please answer ALL • What are the 4 types of environmental hazards? • What is the difference between epidemiology and toxicology? • Does everyone respond to environmental hazards in the same way? Why or why not? • How does the health of the environment influence biological hazards such as infectious disease? • How are social hazards linked to environmental impacts? • Make a chart listing each of the chemical hazard categories. Locate a specific example for each. ie: carcinogen example = xxxx • Find an example of something that is a bioaccumulator in humans and in the environment. • Explain the relationship between the health of the environment and the health of humans on the planet. Are they linked?