Environmental Health What is the relationship between environmental health & our own health?
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.
Biological Hazards: Viruses, bacteria, & other organisms in the environment that cause harm to humans are classified as biological hazards. Pathogensinfect humans & make us sick.
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
Chemical Hazards: Chemicals in the environment that harm human health. They can by synthetic or produced by organisms. • Ex: disinfectants to clean your kitchen
Physical Hazards: Physical process that pose threat to our health including natural disasters. Ex: UV radiation from sun
Epidemiology & Toxicology are two scientific fields that help us understand how, where & to what extent environmental hazardsaffect our health.
Epidemiology is the study of disease in human population. Epidemiologists are scientist that study how & where disease occurs & how to control them.
Toxicology is the study of how poisonous substances affect an organism’s health. A substance’s toxicity determines how harmful a substance is to an organism.
Toxicity is determined by two factors: • What the substance is • How much of the substance is needed to cause harm
Toxicity is determined by measuring the response a substance produces at differentdoses. A dose is the amount of substance an organism is exposed to. This includes the amount & time exposed.
The relationship between the different doses & the response they generate is called the dose-response relationship. Determining this relationship is difficult in humans.
Every person is different. Two people can drink contaminated water & have two different reactions. Below are some reasons why people react differently.
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.
Genetics: Many diseases have both genetics & environmental factors. Environmental factors can increase the risk of developing the disease
Risk Assessment is the process of measuring the chance that an environmental hazard will cause harm.
1)Risk is the likelihood that that a given hazard will cause harm. 2)The process of measuring risk is called risk assessment.
You encounter biological hazards EVERY DAY! Biological hazards are the second leading cause of death worldwide.
Infectious Disease are caused by pathogens, such as viruses & bacteria. Infectious diseases account for nearly 30% of all deaths each year.
Infectious disease spread through the human population in different ways. Pathogens can be spread by human, water or food, or by other organisms.
Humans – Some disease can be spread directly from one human to another. For example: touching, biting, or contact w/bodily fluids.
HIV and TB are two diseases that can be transmitted from person to person.
Water or food – Some pathogens spread when people eat contaminated food or drink. Cholera is disease caused by a bacterium in water.
It makes people sick when they drink the contaminated water. The person may experience intense diarrhea and vomiting. You can die from the cholera.
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.
Malariais a disease that is transmitted by this way. A female mosquito picks up the pathogen & when it bites an infected person & then transmitsit when it bites a non-infected person.
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
Increasing mobility – people are more mobile so the disease is being spread more easily
Antibiotic resistance - bacteria becoming resistant to the antibiotics b/c of natural selection.
Some bacteria survive after being exposed to the drug. They reproduce & create more bacterial resistant to the antibiotic.
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.
Social Hazards - some can be avoided while other cannot. You might live near an old toxic waste dump…a hazard difficult to change. You may choose to eat unhealthy foods….a change YOUcan make!
Chemical Hazards All chemical hazards can be dangerous in large enough quantities. A chemical hazardis anything that may harm human health.
Chemical Hazard vs. Pollution Pollution is matter or energy that is released intothe environment, causing negative effects that impact people, wildlife & other parts of the environment
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 doesn’t harm the environment.
Types of Chemical Hazards Chemical hazards can cause cancer, birth defects & improper function of human body systems.
Carcinogens: Chemicals that cause cancer are known carcinogens. Cancer is a disorder where cells grow uncontrollably.
Cancer does have a genetic component but can be influenced by environmental factors.
Chemical Mutagens – are substances that cause genetic changes or mutations in the DNA or an organism. • Ex: benzene…second hand smoke, gasoline & air pollution
Teratogens – are chemicals that harm embryos & fetuses. • Example: thalidomide, alcohol
Neurotoxins – Chemicals that affect the nervous system. Neurotoxins are various heavy metals such as lead, mercury & cadmium.
Allergens – Substances that over activate the immune system causing a responsewhen one is not necessary. Examples: mold, bacteria, animal proteins
Endocrine Disruptors – is a chemical that interferes with the endocrine system or hormones.
Hormonesregulate our body functions like growth & development. Small children are at the greatest risk b/c they are developing. • Example: PCBs
Indoor Chemical Hazards • Our homes & buildings may contain chemical hazards including asbestos, radon, volatile organic compounds, carbon monoxide & lead. Indoor pollution is not always easy to detect
Asbestos is a mineral that forms long think fibers. It is used as insulation to muffle sounds and keep heat in.
When disturbed, these fibers can be inhaled & may go into lungtissue. This may cause cancer & asbestosis.