INTRODUCTION TO TOXICOLOGY Background Information for Toxicity Testing

INTRODUCTION TO TOXICOLOGY Background Information for “Toxicity Testing with California Blackworms and Alcohol” Created by Stefani D. Hines with modifications by Debbie Gevirtzman, SWEHSC, University of Arizona

Toxicology • What is it? • How is it used?

Toxicology • The study of harmful effects of chemicals on living systems

Toxicology • • Biology Chemistry Physiology Physics Statistics Immunology Ecology • • Forensic Medicine Clinical Treatments Drug Development Public Health Industrial Hygiene Veterinary Science Agriculture Environmental Science

CONGRATULATIONS! You are already toxicologists!

Hazard • A chemical substance, physical agent, or biological agent that can harm the health of people

Exposure • Contact with a hazard

Routes of Entry

Routes of Entry • Ingestion – chemicals can enter the body by eating or drinking • Inhalation – chemicals can be breathed into the lungs • Absorption - chemicals can enter the body by moving through the skin

Dose • Dose is the amount of a chemical that gets inside of your body. • Measured in mg of chemical/kg or lb of weight

Dose: A Visual Explanation

Who took the largest dose of Tylenol? Weight: 125 lb Tylenol: 300 mg 135 lb 600 mg 20 lb 5 lb 100 mg 50 mg

Calculating Dose: 50 mg 5 lb = 10 mg/lb 300 mg 125 lb = 2. 4 mg/lb

The Dose Makes The Poison “What is it that is not a poison? All things are poisons and nothing is without poison. It is the dose only that makes a thing not a poison. ” Paracelsus, 1493 -1541

Most hazardous substances exhibit a “dose-response” relationship. What does this mean? A. The harm caused by the hazard increases as the amount of hazard entering the body (dose) increases. B. It does not matter how big a dose you receive, you will always have the same amount of harm/sickness. C. Exposure to the hazard always results in harm.

Dose-Response Curve for Alcohol Response Death Labored breathing Unconscious Deep sleep Sleep Giddy No effect Dose

Dose-Response Curve for Vitamin D Response Toxic Healthy Unhealthy Dose

Exposure • Exposure Frequency – how often • Exposure Duration – how long • Exposure Concentration – how much

For a Chemical to Affect You • Exposure • Dose

Toxicity • Acute Toxicity – a high toxicant dose over a short period of time • Chronic Toxicity – a small dose of a toxicant over a long period of time

Factors Affecting Toxicity • Extrinsic Factors – occur outside the body • Intrinsic Factors – occur within an individual organism

Intrinsic Factors • Age • Genetic Difference • Body Size

Control • Our biggest chemical risks are with things we have control over

Control • Food • Exposure to Known Hazards in Daily Lifestyle – Cigarettes – Alcohol • Preventable Poisonings

Factors Contributing to Cancer Risk in the U. S. • • • Diet ~35% Tobacco ~30% Occupational exposures & pollution ~5% Infection (viruses) ~10% Other ~20% – Genetic susceptibility – Sun/radiation – Alcohol

And now, let’s do the blackworm lab!