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Chapter 8 Toxicology: Poisons and Alcohol

“All substances are poisons. There is none which is not. The right dose differentiates a poison and remedy.” —Paracelsus (1495-1541). Swiss physician and chemist. Chapter 8 Toxicology: Poisons and Alcohol. Toxicology and Alcohol. A quantitative approach to toxicology.

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Chapter 8 Toxicology: Poisons and Alcohol

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  1. “All substances are poisons. There is none which is not. The right dose differentiates a poison and remedy.” —Paracelsus (1495-1541). Swiss physician and chemist Chapter 8Toxicology:Poisons and Alcohol

  2. Toxicology and Alcohol • A quantitative approach to toxicology. • The danger of using alcohol. Students will learn: Kendall/Hunt Publishing Company

  3. Toxicology and Alcohol Students will be able to: • Discuss the connection of blood alcohol levels to the law, incapacity, and test results. • Understand the vocabulary of poisons. • Design and conduct scientific investigations. • Use technology and mathematics to improve investigations and communications. • Identify questions and concepts that guide scientific investigations. • Communicate and defend a scientific argument. Kendall/Hunt Publishing Company

  4. Toxicology Definition—the study of the adverse effects of chemicals or physical agents on living organisms. Types: Environmental—air, water, soil Consumer—foods, cosmetics, drugs Medical, clinical, forensic Kendall/Hunt Publishing Company

  5. Forensic Toxicology Postmortem—medical examiner or coroner Criminal—motor vehicle accidents (MVA) Workplace—drug testing Sports—human and animal Environment—industrial, catastrophic, terrorism Kendall/Hunt Publishing Company

  6. Toxicology Toxic substances may: • Be a cause of death • Contribute to death • Cause impairment • Explain behavior Kendall/Hunt Publishing Company

  7. Historical Perspective of Poisoners Olympias—a famous Greek poisoner Locusta—personal poisoner of Emperor Nero Lucretia Borgia—father was Pope Alexander VI Madame GiuliaToffana—committed over 600 successful poisonings, including two Popes. HieronymaSpara—formed a society to teach women how to murder their husbands Madame de Brinvilliers and CatherineDeshayes—French poisoners. AND many others through modern times. Kendall/Hunt Publishing Company

  8. The Severity of the Problem “If all those buried in our cemeteries who were poisoned could raise their hands, we would probably be shocked by the numbers.” —John Harris Trestrail, “Criminal Poisoning” Kendall/Hunt Publishing Company

  9. People of Historical Significance Mathieu Orfila—known as the father of forensic toxicology, published in 1814 “Traite des Poisons” which described the first systematic approach to the study of the chemistry and physiological nature of poisons. Kendall/Hunt Publishing Company

  10. Aspects of Toxicity Dosage The chemical or physical form of the substance The mode of entry into the body Body weight and physiological conditions of the victim, including age and sex The time period of exposure The presence of other chemicals in the body or in the dose Kendall/Hunt Publishing Company

  11. Lethal Dose LD50—refers to the dose of a substance that kills half the test population, usually within four hours Expressed in milligrams of substance per kilogram of body weight Kendall/Hunt Publishing Company

  12. Toxicity Classes LD50(rat,oral) Correlation to Ingestion by 150 lb Adult Human Toxicity <1mg/kg a taste to a drop extremely 1-50 mg/kg to a teaspoon highly 50-500 mg/kg to an ounce moderately 500-5000 mg/kg to a pint slightly 5-15 g/kg to a quart practically non-toxic Over 15g/kg more than 1 quart relatively harmless Kendall/Hunt Publishing Company

  13. Federal Regulatory Agencies Food and Drug Administration (FDA) Environmental Protection Agency (EPA) Consumer Product Safety Commission Department of Transportation (DOT) Occupational Safety and Health Administration (OSHA) Kendall/Hunt Publishing Company

  14. Symptoms of Various Typesof Poisoning Type of PoisonSymptom/Evidence Caustic Poison (lye) Characteristic burns around the lips and mouth of the victim Carbon Monoxide Red or pink patches on the chest and thighs, unusually bright red lividity Sulfuric acid Black vomit Hydrochloric acid Greenish-brown vomit Nitric acid Yellow vomit Phosphorous Coffee brown vomit. Onion or garlic odor Cyanide Burnt almond odor Arsenic, Mercury Pronounced diarrhea Methyl (wood) or Nausea and vomiting, unconsciousness, Isopropyl (rubbing) alcohol possibly blindness Kendall/Hunt Publishing Company

  15. Critical Informationon Poisons Form Common color Characteristic odor Solubility Taste Common sources Lethal dose Mechanism Possible methods of administration Time interval of onset of symptoms. Symptoms resulting from an acute exposure Symptoms resulting from chronic exposure Disease states mimicked by poisoning Notes relating to the victim Specimens from victim Analytical detection methods Known toxic levels Notes pertinent to analysis of poison List of cases in which poison was used —John Trestrail from “Criminal Poisoning” Kendall/Hunt Publishing Company

  16. To Prove a Case Prove a crime was committed Motive Intent Access to poison Access to victim Death was caused by poison Death was homicidal Kendall/Hunt Publishing Company

  17. Forensic Autopsy Look for: Irritated tissues Characteristic odors Mees lines—single transverse white bands on nails. Order toxicological screens Postmortem concentrations should be done at the scene for comparison No realistic calculation of dose can be made from a single measurement Kendall/Hunt Publishing Company

  18. Human Specimens for Analysis Blood Urine Vitreous Humor of Eyes Bile Gastric contents Liver tissue Brain tissue Kidney tissue Hair/nails Kendall/Hunt Publishing Company

  19. Alcohol—Ethyl Alcohol (C2H5OH) Most abused drug in America About 40% of all traffic deaths are alcohol-related Toxic—affecting the central nervous system, especially the brain Colorless liquid, generally diluted in water Acts as a depressant Alcohol appears in blood within minutes of consumption; 30-90 minutes for full absorption Detoxification—about 90% in the liver About 5% is excreted unchanged in breath, perspiration and urine Kendall/Hunt Publishing Company

  20. Rate of Absorption Depends on: amount of alcohol consumed the alcohol content of the beverage time taken to consume it quantity and type of food present in the stomach physiology of the consumer Kendall/Hunt Publishing Company

  21. BACBlood Alcohol Content Expressed as percent weight per volume of blood Legal limits in all states is 0.08% Parameters influencing BAC: Body weight Alcoholic content Number of beverages consumed Time between consumption Kendall/Hunt Publishing Company

  22. BAC Burn off rate of 0.015% per hour but can vary: Male BAC male = 0.071 x (oz) x (% alcohol) body weight Female BAC female = 0.085 x (oz) x (% alcohol) body weight Kendall/Hunt Publishing Company

  23. Henry’s Law When a volatile chemical is dissolved in a liquid and is brought to equilibrium with air, there is a fixed ratio between the concentration of the volatile compound in the air and its concentration in the liquid; this ratio is constant for a given temperature. THEREFORE, the concentration of alcohol in breath is proportional to that in the blood. This ratio of alcohol in the blood to alcohol in the alveolar air is approximately 2100 to 1. In other words 1 ml of blood will contain nearly the same amount of alcohol as 2100 ml of breath. Kendall/Hunt Publishing Company

  24. Field Tests Preliminary tests—used to determine the degree of suspect’s physical impairment and whether or not another test is justified. Psychophysical tests—3 Basic Tests Horizontal gaze nystagmus (HGN): follow a pen or small flashlight, tracking left to right with one’s eyes. In general, wavering at 45 degrees indicates 0.10 BAC. Nine Step walk and turn (WAT): comprehend and execute two or more simple instructions at one time. One-leg stand (OLS): maintain balance, comprehend and execute two or more simple instructions at one time. Kendall/Hunt Publishing Company

  25. The Breathalyzer More practical in the field Collects and measures alcohol content of alveolar breath Breath sample mixes with 3 ml of 0.025 % K2Cr2O7 in sulfuric acid and water 2K2Cr2O7 + 3C2H5OH+ 8H 2SO4 2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11 H2O Potassium dichromate is yellow, as concentration decreases its light absorption diminishes so the breathalyzer indirectly measures alcohol concentration by measuring light absorption of potassium dichromate before and after the reaction with alcohol Kendall/Hunt Publishing Company

  26. Generalizations During absorption, the concentration of alcohol in arterial blood will be higher than in venous blood. Breath tests reflect alcohol concentration in the pulmonary artery. The breathalyzer also can react with acetone (as found with diabetics), acetaldehyde, methanol, isopropyl alcohol, and paraldehyde, but these are toxic and their presence means the person is in serious medical condition. Breathalyzers now use an infrared light absorption device with a digital read-out. Prints out a card for a permanent record. Kendall/Hunt Publishing Company

  27. More Information Read more about Forensic Toxicology from Court TV’s Crime Library at: http://www.crimelibrary.com/criminal_mind/forensics/toxicology/2.html Kendall/Hunt Publishing Company

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