Alcohol & Poisons

Poison—a chemical that can harm the body if ingested, absorbed, or breathed in sufficiently high concentrations. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 2

History of Toxicology (Obj 9.1) Early 1700’s—first use of chemistry to detect poisons Early 19th century—toxicology became a new scientific discipline Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 3

France in 1840—Charles Lafarge trial involved testing for arsenic Charles Lafarge became ill and died. His wife Marie was accused of killing him with rat poison. Yrs earlier, chemist, James Marsh, developed a test to detect arsenic, the major ingredient in rat poison. The Marsh test helped investigators find traces of arsenic in food at the Lafarge home, but were not able to detect the poison in Lafarge’s body. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 4

The leading authority in medical toxicology at that time, Mathieu Orfila, was called in to retest Lafarge’s exhumed body. Orfila found traces of arsenic in Lafarge’s body. The soil surrounding the body was also tested and no traces of arsenic were found, disproving claims by the defense that poison had been absorbed into the body after burial. Marie Lafarge was convicted of murder. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 5

Forensic toxicologists— study the legal and medical aspects of alcohol, drugs, poisons, and toxins in bodily fluids. Toxicologists and pathologists work together because many autopsies involve analysis of body fluids and tissues for the detection of poisons or drugs. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 6

Alcohol (Obj 9.2, 9.3) In everyday speech, alcohol usually refers to the ethanol used in alcoholic beverages (beer, wine, or liquor.) In chemistry, alcohols are a group of substances with a hydroxyl (–OH) group. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 7

Alcohol Some alcohols are used as solvents and can be found in antifreeze, perfumes, fuels, hairspray, and medications. All alcohols are toxic in sufficient quantities As little as 30 mL of methanol can kill When ingested, propanol, or rubbing alcohol, causes decreased heart rate, dizziness, and internal hemorrhage. Ethanol, the alcohol in alcoholic beverages, can be fatal if consumed in large quantities. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 8

Alcohol in the Body Ethanol (ethyl alcohol)-colorless liquid obtained from fermented grains or fruits Initial reaction-euphoria but alcohol is actually a depressant (a chemical that slows the heart rate and brain activity and causes drowsiness) Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 9

Absorption of alcohol in the body begins when it: Diffuses through the stomach and small intestine into the bloodstream 1st, the person feels less inhibited, happy and talkative (the part of the brain that controls inhibitions is depressed) As more alcohol is absorbed, the person begins to lose coordination and to become confused (the part of the brain responsible for learning and memory becomes affected) Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 10

Alcohol in the Body In the liver, alcohol is metabolized, or broken down, by the enzyme alcohol dehydrogenase (ADH). The resulting product is acetaldehyde. The acetaldehyde is broken down into carbon dioxide and water. The liver can normally metabolize one or two alcoholic drinks (15 to 30 mL/hr). 90% of the ingested alcohol is converted to carbon dioxide and water. 10% is excreted from the body in the breath, perspiration, and urine. When a person drinks more alcohol than the liver can metabolize, the excess alcohol is distributed to the tissues of the body. Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 11

BLOOD ALCOHOL CONCENTRATIONS AND STAGES OF INTOXICATION Determining the amount of alcohol in a person’s blood is a good indication of the level of intoxication the person is experiencing. A blood alcohol concentration (BAC) of 0.08 means there are 8 g of alcohol to every 10,000 mL of blood or 0.08g of alcohol for every 100mlof blood. 12

Stages of Intoxication Alcohol affects different people differently Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 13 ConcentrationBehavior 0.01 to 0.05Normal behavior 0.03 to 0.12euphoria, talkative, less inhibited, more confident, loss of motor skills 0.09 to 0.25blurred vision, loss of balance & coordination, sleepiness to 0.30slurred speech, dizziness & disorientation, emotional & confusion, increased tolerance for pain & respiratory system may be affected.

Stages of Intoxication (cont.) Alcohol affects different people differently Forensic Science II: Physiology of Alcohol and Poisons, Chapter 9 © 2012 Cengage Learning. All Rights Reserved 14 ConcentrationBehavior 0.25 to 0.40standing and walking is very difficult; vomiting, loss of bladder control to 0.50impaired respiratory & circulatory systems, difficulty breathing, drop in body temperature, coma & possibly death. Over 0.45Potentially fatal due to respiratory arrest.