Toxicology and Human Health Hazard Types 1) Cultural Hazards - work conditions, health/lifestyle(nutrition, behavior) 2) Chemical Hazards - chemicals in air, water, soil, food 3) Physical Hazards - fire, earthquake, volcano, storms 4) Biological Hazards - viruses, bacteria (disease causing agents)

Causes of Death in the U.S. Deaths 442,000 Tobacco use 400,000 Excess weight 101,500 (43,450 auto) Accidents 85,000 Alcohol use 75,000 (14,200 from AIDS) Infectious disease 55,000 Pollutants/toxins 30,600 Suicides Causes of Death in the U.S. 20,622 Homocides 17,000 Illegal drug use

© 2004 Brooks/Cole – Thomson Learning Hazard Shortens average life span in the United States by Figure 19-19 Page 430 Poverty 7-10 years Born male 7.5 years Smoking 6-10 years Overweight (35%) 6 years Unmarried 5 years Overweight (15%) 2 years Spouse smoking 1 year Driving 7 months Air pollution 5 months Alcohol 5 months Drug abuse 4 months Flu 4 months AIDS 3 months Air Pollution 2 months Drowning 1 month Pesticides 1 month Fire 1 month Natural radiation 8 days Medical X rays 5 days Oral contraceptives 5 days Toxic waste 4 days Flying 1 day Hurricanes, tornadoes 1 day Living lifetime near nuclear plant 10 hours

Toxicity of chemicals depends on: 1) Dose 2) Occurrence of exposure 3) Age, sex, health, DNA 4) Water-soluble vs. Fat-soluble 5) Persistence 6) Bioaccumulation 7) Biomagnification 8) Chemical Interactions Poisonous? - if LD50 is 50 mg or less per kilogram of body weight - LD50 - median lethal dose - amount needed in 1 dose to kill 50% of animals

Percentage of population killed by a given dose 100 75 Percentage of population killed by a given dose 50 25 LD50 2 4 6 8 10 12 14 16 Dose (hypothetical units)

Table 9-1 Toxicity Ratings and Average Lethal Doses for Humans Supertoxic Extremely toxic Very toxic Toxic Moderately toxic Slightly toxic Essentially nontoxic LD50 (milligrams per kg of body weight)* Less than 0.01 Less than 5 5–50 50–500 500–5,000 5,000–15,000 15,000 or greater Average Lethal Dose† Less than 1 drop Less than 7 drops 7 drops to 1 teaspoon 1 teaspoon to 1 ounce 1 ounce to 1 pint 1 pint to 1 quart More than 1 quart Examples Nerve gases, botulism toxin, mushroom toxins, dioxin (TCDD) Potassium cyanide, heroin, atropine, parathion, nicotine Mercury salts, morphine, codeine Lead salts, DDT, sodium hydroxide, sodium fluoride, sulfuric acid, caffeine, carbon tetrachloride Methyl (wood) alcohol, ether, phenobarbital, amphetamines (speed), kerosene, aspirin Ethyl alcohol, Lysol, soaps Water, glycerin, table sugar *Dosage that kills 50% of individuals exposed †Amounts of substances in liquid form at room temperature that are lethal when given to a 70.4-kg (155-pound) human

Chemical Hazards 1) Toxic Chemicals - cause 50% fatality 2) Hazardous Chemicals - flammable, explosive, skin/lung irritant 3) Mutagens - causes DNA mutations - leads to genetic disorders 4) Teratogens - causes birth defects - ex. Lead, mercury, cadmium 5) Carcinogens - cancer causing agents

Biological Hazards - lead to: A) Nontransmissable Diseases - nonliving causes (can’t be passed) - heart disease, diabetes, asthma OR B) Transmissable Diseases - caused by organisms (viruses, bacteria) - most deadly: 1) Pneumonia & flu 5) Malaria 2) HIV/AIDS 6) Hepatitis B 3) Diarrheal diseases 7) Measles 4) Tuberculosis

Disease Transmission Affected By: - travel - migration to urban & rural areas - poverty - weather (floods, hurricanes, wind) - introduction of alien species

Viruses Protozoa Bacteria HIV (AIDS) Hepatitis B Smallpox Ebola On this scale, a human hair would be 6 meters (20 feet) wide 1 micrometer Protozoa Plasmodium (malaria) 10 micrometers Bacteria Vibrio cholerae (cholera) Myobacterium tuberculosis (tuberculosis) Treponema pallidum (syphilis) 6 micrometers

Virus Infection Virus Cell membrane Host cell The virus attaches to the host cell. The entire virus may enter or it may inject its genetic material, or genome. Virus Cell membrane Host cell Virus Infection The viral genetic material uses the host cell's DNA to replicate again and again. Each new copy of the virus directs the cell to make it a protein shell. New viruses The new viruses emerge from the host cell capable of infecting other cells. This process often destroys the first cell.

Dengue Fever Painful and sometimes fatal. Carried by four related viruses and strikes during rainy season. 2.5 million people at risk; 50 million new cases a year. Dengue Fever

Malaria Endemic in more than 100 countries. Caused by four protozoa species. 270–500 million new cases and 1 million deaths per year. Malaria

Figure 19-14 Page 425 Malaria Transmission Anopheles mosquito (vector) in aquatic breeding area eggs adult larva pupa Malaria Transmission 1. Female mosquito bites infected human, ingesting blood that contains Plasmodium gametocytes 4. Parasite invades blood cells, causing malaria and making infected person a new reservoir 2. Plasmodium develops in mosquito 3. Mosquito injects Plasmodium sporozoites into human host

Yellow Fever Dreaded for more than 400 years. Viral disease that causes symptoms from mild to severe illness and death. 200,000 new cases and 30,000 deaths a year. Yellow Fever

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

Solutions Infectious Diseases Increase research on diseases Reduce poverty & malnutrition Improve drinking water quality Reduce unnecessary use of antibiotics Careful hand washing Immunize children Global campaign to reduce HIV/AIDS