Toxicology (Impact of poisons)

Hazards Biological – pathogens (diseases), pollen, animals Cultural – Smoking, diet, drugs Physical – natural disasters Chemical : Mutagens – alter DNA Teratogens – cause birth defects Carcinogens – cause cancer

Biological Hazards Nontransmittable disease: Any disease that cannot be spread directly from one person to another Transmittable Disease: Any disease that can be spread directly by person or living organism Chronic conditions like heart disease or diabetes Can be spread by bacteria, protozoan, or virus Acute conditions like influenza, HIV, strep throat, smallpox

6 deadliest infectious diseases Acute respiratory infections (pneumonia and flu) HIV/AIDS Diarrheal diseases (typhoid fever, rotavirus) Tuberculosis Malaria Measles

Spread of transmittable disease Air travel Migration to urban areas and rural areas Hunger/malnutrition/water access Increased rice cultivation Increased water exposure Accidental introduction of insect vectors (Vectors carry disease – ticks, fleas) Migration – which disease is prone to develop in each area

Leading causes of death In developing countries, infectious disease (AIDS, malaria, flu,) In developed countries = chronic conditions (heart disease)

Toxicology Toxicity – measure of how harmful a substance is Toxic if it kills 50% of test population Hazardous – causes harm Harmfulness depends on several factors: Dosage over time Exposure Who is exposed How well body’s detox systems work Genetic makeup to determine sensitivity to a toxin

Other ways harm can be caused by a substance Solubility : Water soluble toxins = water supplies Oil or fat soluble toxins = body tissues and cells Persistence How long substance remains in toxic form in environment

Bioaccumulation / biomagnification Bioaccumulation – accumulation of a toxin within tissues of a lower organism in a food chain Biomagnification – exposure to higher levels of toxins by consuming toxins from multiple prey organisms

Interactions Antagonistic interaction – reduce harmful response Ex. Vitamins E and A interact to reduce body’s response to carcinogens Synergistic effect – multiplies harmful effect Alcohol and prescription meds

Response Response = type and amount of health damage due to exposure Acute effect – immediate/rapid harmful reaction to an exposure (allergic reaction) Chronic effect – permanent or long lasting consequence (liver or kidney damage from drinking for 10 years)

Poison The LD50 is the median lethal dose or the amount of a chemical received in one dose that kills 50% of test population in a 14 day period The LC50 is the concentration of chemical that would kill 50% of the test population in 14 days **Don’t write** - the AP exam will present these as the same thing

Some example toxicities (Do not write) Nerve gas – less than one drop Morphine – 7 drops to 1 tsp Aspirin – 1 ounce to 1 pint Water – essentially nontoxic, but too much would kill you For me – 2133 cups of decaf coffee, 265 cans of Coke Zero, 11944 Hershey’s Kisses

Dose Response Curve – shows dosage affect on group

Dose Response Curve Nonthreshold –any dosage of a toxic chemical will cause harm that increases with dosage Threshold dose-response model – there is a threshold or a line before any detectable damage can occur (b/c body can combat to an extent)