Environmental Hazards and Human Health By Brittney Jones CHAPTER 18 Environmental Hazards and Human Health By Brittney Jones

What types of hazards do people face? We can suffer from -biological hazards: from more than 1,400 pathogens than can infect people (bacteria, viruses, parasites, protozoa and fungi) -chemical hazards: from chemicals in air, water, soil, and food -physical hazards: fires, earthquakes, volcanic eruption, flood, tornado, and hurricane -cultural hazards: smoking, unsafe working conditions, poor diet, drugs, drinking etc.

What types of disease (biological hazards) threaten people in developing and developed countries? Rapid producing infectious bacteria are becoming genetically resistant to widely used antibiotics Tuberculosis kills 1.7 million people per year and could kill 25 million more people by 2020 The worlds three most widespread and dangerous viruses are influenza (biggest killer), HIV, and hepatitis B Malaria kills about 2 million people a year

Disease (type of agent) Deaths per year Pneumonia and flu (bacteria and viruses) 3.2 million HIV/AIDS (virus) 3.0 million Malaria (protozoa) 2.0 million Diarrheal diseases (bacteria and viruses) 1.9 million Tuberculosis (bacteria) 1.7 million Hepatitis B (virus) 1 million Measles (virus) 800,000 Fig. 18-5, p. 420

infectious bacteria are becoming genetically resistant to widely used antibiotics Genetic resistance: Spread of bacteria around the globe by humans, overuse of pesticides which produce pesticide resistant insects that carry bacteria. Overuse of antibiotics: A 2000 study found that half of the antibiotics used to treat humans were prescribed unnecessarily.

What chemical hazards do people face? Toxic chemical can cause temporary or permanent harm or death to humans or animals Hazardous chemical harms human or animals because its flammable or explosive so it can irritate or damage skin and lungs mutagens are chemicals or forms of radiation that cause harm or birth defects to fetus or embryo (ethyl alcohol, chlorine, PCB’s, tobacco smoke, etc.) Carcinogens are chemicals that cause cancer (chromium, PCB’s, benzene, etc) Long term exposure to some chemicals at low doses may disrupt the body’s immune, nervous and endocrine systems.

How can risks be estimated ad recognized? Scientists have developed ways to evaluate and compare risks, decide how much risk and acceptable and find affordable ways to reduce it Risk assessment: involves deciding whether or how to reduce a particular risk to a certain level and at what cost Risk analysis: involves identifying hazards and evaluate their associating risks, ranking risks, determining options and making decisions about reducing or eliminating risks and informing decision makers and public about the risks. Estimating risks from using many technologies is difficult because of the unpredictability of human behavior, chance and sabotage.

EXTRA VOCAB Risk: the possibility of suffering harm from a hazard that can cause injury, disease, death, economic loss or environmental damage. Non-transmissible disease: not caused by living organisms and does not spread from one person to another Transmissible disease: an infection, pathogen, virus, or parasite invades the body and multiplies in its cells and tissues Toxicology: the science that examines the effects of harmful chemicals on humans, wildlife, and ecosystems Toxicity: a measure of how harmful a substance is in causing injury, illness, or death to a living organism