2.  Physical hazards = occur naturally Earthquakes, volcanoes, fires, floods, droughts Can’t prevent them, but can prepare for them Increase our vulnerability by deforesting slopes (landslides), channelizing rivers (flooding), etc. Reduce risk by better environmental choices

3.  Chemical = synthetic chemicals such as pesticides, disinfectants, pharmaceuticals Harmful natural chemicals also exist  Biological = result from ecological interactions Viruses, bacteria, and other pathogens Infectious (communicable, or transmissible) disease can’t avoid risk, but can reduce the likelihood of infection

4.  Cultural = result from the place we live, our socioeconomic status, our occupation, our behavioral choices Smoking, drug use, diet and nutrition, crime, mode of transportation

5.  Super Bugs Super Bugs  Nontransmissible disease: cardiovascular, cancers, asthma, diabetes  Infectious disease: caused by a pathogen  Transmissible disease: infectious disease transmitted from person to person  Infectious diseases no longer leading cause of death: better health care, antibiotics, vaccines

6.  Despite our technology, disease kills most of us  Disease has a genetic and environmental basis Cancer, heart disease, respiratory disorders Poverty and poor hygiene can cause illnesses

7.  Spread disease through: air, water, food, and body fluids= feces, urine, blood, and droplets sprayed by sneezing and coughing  Other major pathways: livestock, wild animals (ie deer), insects  Epidemics and pandemics

8.  Toxic Chemical-can cause temporary or permanent harm or death to humans and animals  Hazardous chemicals: Flammable or explosive Irritating or damaging skin or lungs Interfering with or preventing oxygen uptake or distribution Inducing allergic reactions Affect immune, nervous, and endocrine systems

9.  Mutagens Agents that cause random changes in DNA Mutations of gametes can be passed to offspring  Teratogens Cause birth defects to fetus or embryo Ethyl alcohol, lead, mercury, PCBs, formaldehyde  Carcinogens-cause or promote growth of malignant cells Arsenic, formaldehyde, gamma radiation, radon, chemicals in tobacco smoke, UV radiation

10.  Minamata Disease Minamata Disease  Potent neurotoxin- interferes with nervous system & brain function  Natural Sources- rocks, soil, volcanoes, & vaporization from ocean  Anthropogenic sources- coal power plants, waster incineration, chemical manufacturing plants, metal ore smelters  Mercury converted to methylmercury by bacteria-found in albacore tuna, swordfish, king mackerel, shark, or tilefish

11.  Synthetic chemicals may be altering the hormones of animals  Hormonally Active Agents (HAA)-mimic hormones  Examples: aluminum, atrazine, DDT, mercury, Bisphenol A  There are estrogen mimics, hormone blockers, and thyroid disrupters

12.  Research is controversial  Pose economic threats to chemical manufacturers Banning a top-selling chemical could cost a company millions of dollars Bisphenol-A, found in plastics, can cause birth defects, but the plastics industry protests that the chemical  Studies reporting harm are publicly funded, but those reporting no harm are industry funded

13.  Risk- possibility of suffering harm from a hazard  Probability- how likely it will occur  Risk Assessment Identify hazard Probability of occurrence Assess severity of impact on health, environment, economics

14.  Dose  Frequency of exposure  Who exposed (adult or child)  How well detoxification systems working  Sensitivity to toxin  Solubility  Persistence  Bioaccumulation  Biomagnification

15.  Animal testing  Dose-response curve: results of chemical tests plotted  Median Lethal Dose (LD50)  Nonthreshold dose-response model Any dosage of chemical causes harm that increase with the dosage  Threshold dose-response model Harmful effects occur after reaching a certain dose