Presentation on theme: "INTRODUCTION TO TOXICOLOGY"— Presentation transcript:
1 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
3 Toxicology The study of harmful effects of chemicals on living systems The chemicals are called toxicants. (Toxins are toxicants produced by living organisms, ie. Snake venom.)Chemicals may be man-made or naturally-occurring.~9 million patented chemicalsmillions of non-patented chemicals in perfumes and cosmeticseven more are naturally occurring in the environment
5 You are already toxicologists! CONGRATULATIONS!You are already toxicologists!You didn’t pour Drano into your cereal this morning.You only took 2 Tylenol for your headache instead of the whole bottle.You didn’t stand by the bus’s tailpipe and inhale the fumes.You have have already learned a lot about toxicology on your own through life’s lessons.
6 HazardA chemical substance, physical agent, or biological agent that can harm the health of people
7 Exposure Contact with a hazard The hazard must enter the body! ie. A pack of cigarettes in a man’s shirt pocket does not cause him harm because nothing from the cigarettes has entered his body. Once he smokes a cigarette, the smoke has now entered his body through his lungs and can cause harm.
9 Routes of EntryIngestion – chemicals can enter the body by eating or drinkingInhalation – chemicals can be breathed into the lungsAbsorption - chemicals can enter the body by moving through the skinIngestion – From digestive tract, to liver and lymphatic system to bloodstream – ie. Alcohol, drugsInhalation – the inside surface area of the lungs is very large and is a poor chemical barrier; many inhaled chemicals can easily and quickly enter the bloodstream from lung tissue – ie. smokeAbsorption – the skin is a good barrier and protects the body from many hazards, but some substances can penetrate the skin, then enter the bloodstream and be carried to all parts of the body – ie. insect repellent used by the military can be sprayed on clothing, but not on skin
10 Dose Dose is the amount of a chemical that gets inside of your body. Measured in mg of chemical/kg or lb of weight
14 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,Paracelsus is considered “the father of modern toxicology”.Ie. 2 Tylenol are ok, but not a whole bottle; 2 Tylenol are ok for an adult, but not for a baby; small amounts of salt or sugar are ok, but a whole pound at once can kill a person.
15 Most hazardous substances exhibit a “dose-response” relationship 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.AAt low doses - there will be no detectable affectMid-range – damage increases as dose increasesHigh doses – maximum level of damage is reached
16 Dose-Response Curve for Alcohol DeathLabored breathingUnconsciousDeep sleepResponseSleepGiddyAbsorption from the digestive tract is very rapid with peak blood levels attained minutes after ingestion.Typically, it takes one drink an hour to burn off.1 glass of wine = 1 shot = 1 beerNo effectNo effectDose
17 Dose-Response Curve for Vitamin D ToxicHealthyResponseUnhealthyDose
18 Exposure Exposure Frequency – how often Exposure Duration – how long Exposure Concentration – how muchExposure Frequency – a person exposed only once is likely to have a lower dose than a person exposed many times.Exposure Duration - a person exposed for a short time will have a lower dose than a person exposed for a long time.Exposure Concentration – a higher concentration of a hazard generally means a higher dose because there is more of the hazard to enter the body.
20 ToxicityAcute Toxicity – a high toxicant dose over a short period of timeChronic Toxicity – a small dose of a toxicant over a long period of timeAcute Toxicity – ie. A chemical spill; drugs or alcohol ingested in a short period of timeChronic Toxicity – ie. Hazardous material in the air at a factory at which you work; smoking
21 Factors Affecting Toxicity Extrinsic Factors – occur outside the bodyIntrinsic Factors – occur within an individual organismExtrinsic Factors – ie. Temperature, barometric pressure
22 Intrinsic Factors Age Genetic Difference Body Size Age – the old and the very young are more likely to be adversely affected.Genetic Difference – can increase or decrease the tolerance to a toxicant.Body Size – the larger the body size, the less response to a toxicant; this is because the dose is smaller when compared to someone who weighs less but ingested the same amount of toxicant.
23 ControlOur biggest chemical risks are with things we have control over
24 Control Food Exposure to Known Hazards in Daily Lifestyle CigarettesAlcoholPreventable Poisonings
25 Factors Contributing to Cancer Risk in the U.S. Diet ~35%Tobacco ~30%Occupational exposures & pollution ~5%Infection (viruses) ~10%Other ~20%Genetic susceptibilitySun/radiationAlcoholMake wise choices throughout your life and be at lower risk!