Chapter 12

Physical Risks

natural disasters, accidents, excessive radiation exposure from radon, x-rays, or sunlight

Biological Risks

associated with disease

• Disease= any impairment of body functions with a characteristic set of symptoms and signs

Chemical Risks

associated with excessive exposure to

• naturally occurring chemicals (lead and arsenic)

  • Chemicals from anthropogenic sources (pesticides, solvents)

Infectious Diseases

those cause by infectious agents, known as pathogens (malaria, yellow fever, influenza)

Two Disease Categories

Chronic Diseases= slowly impair the normal functioning of a person’s body (cancer, asbestosis)
Acute Disease= rapidly impair the normal functioning of a person’s body (Ebola, Zika)

Plague

• bubonic plague, black death

  • spread by fleas associated with rodents, particularly

(Historically important Infectious Disease)

Malaria

infect hundreds through mosquitos, expected to spread and return to many regions as global warming increases (Historically important Infectious Disease)

Tuberculosis

infected people through coughing or contact with infected sputum (Historically important Infectious Disease)

HIV/AIDS

viral disease can be communicated by blood and other body fluids (Emergent Diseases)

Ebola

a rare virus found in central Africa that causes hemorrhagic fever (Emergent Diseases)

Mad Cow Disease

cause by protein particles; can be transmitted by eating parts of the central nervous system of infected cattle (Emergent Diseases)

Bird Flu

spanish influenza (Emergent Diseases)

West Nile virus

lives in hundreds of species of birds and is transmitted by mosquitos (Emergent Diseases)

Neurotoxins

chemicals that disrupt the nervous system (insecticides, lead, mercury)

Carcinogens

chemicals that cause cancer through inflicting damage to cells (tobacco smoke, asbestos, radon)

Teratogens

chemicals that interfere with the normal development of embryos or fetuses (alcohol, some medications)

Allergens

chemicals that cuase allergic reactions, some of which can be fatal (nuts, penicillin, animal dander)

Endrocrine DIsruptors

chemicals that interfere with the normal functioning of hormonoes in an animal’s bodyLD

LD50

lethal dose that kills 50% of the individuals

ED50

effective dose that cuase 50% of the animals to display the harmful but nonlethal effect(s)

Acute Studies

short term and last only a few days

Chronic Studies

attempt to observe effects of longer-term exposure to a chemical, sometime at low dosages

Epidemiology

a field of science that seeks to study causes patterns of disease in animal and human populations

• uses retrospective (monitor populations who have been exposed to a chemical at some time in the past )

  • uses prospective studies ( monitor populations that might become exposed to chemicals sometime in the future

Synergistic Interactions

when two risks together cause more harm that one would alone

ex. cancer would be much higher for a person who smokes

Bioaccumulation

an increase concentration of a chemical within an organism over time

Biomagnification

the increase in a chemical concentration in animal tissues as the chemival moves up the food chain

Persistence

how long a chemical stays in the environment

Qualitative

making a judgement concerning the perceived relative risks of various decisions or behaviors

Probability

the statistical likelihood of an event actually occurring and the likelihood of that event causing harm