Presentation on theme: "Toxicology. Poison is any substance that can harm or kill. Toxicology is the study of poisons. Forensic Toxicology is the study of postmortem signs."— Presentation transcript:
Poison is any substance that can harm or kill. Toxicology is the study of poisons. Forensic Toxicology is the study of postmortem signs of the poisoning.
Toxicology The idea of poison came from the Greek word, “toxicon,” which referred to poison arrows, and it is the root of “intoxicated,” which to the Greeks meant being sickened by poisoned arrows.
History of Poisonings The Greeks also developed a form of capital punishment via poison with Hemlock, which was given to Socrates for corrupting the Athenian youth.
History of Poisonings 700 A.D. an Arab chemist turned arsenic into an odorless, tasteless powder that was impossible to trace in the body until centuries later. During the Renaissance, poisoning became an art form, inspiring subtle ways to dispense with people via such items as poison rings, swords, knives, letters, and even lipstick. Poisoning societies developed, as did family businesses that relied on poison-for-hire as their trade.
History of Poisonings The Council of Ten in Venice in 1419 poisoned people for a fee, using a mercury- based compound and various forms of arsenic. In Venice and Rome, there were even schools for people to learn how to do this.
History of Poisonings Poison is the weapon of choice for women. Historically, more women than men have been mass or serial poisoners. Locusta, in Ancient Rome, was Nero’s personal poisoner and the first documented serial killer. She helped Nero to murder his brother with cyanide, and she also murdered several of his wives.
History of Poisonings In the 17th century, Italy’s Madam Toffana: used poison over 600 times, either directly by her or indirectly by those to whom she sold her arsenic concoction. was allegedly involved with poisoning two popes.
Role of Toxicologists Detect and identify presence of drugs and poisons body fluids Tissues organs
Role of Toxicologists Work in crime laboratories and medical examiners’ offices May also reach into hospital laboratories and health facilities to identify a drug overdose or monitor the intake of drugs Major branch: measurement of alcohol in the body (violations of criminal law)
Toxicology of Alcohol
Primary objective of forensic toxicology Alcohol analysis Detection and isolation of drugs in the body Determine the influence of alcohol on human behavior.
Toxicology of Alcohol Alcohol (ethanol, ethyl alcohol) Colorless liquid Normally diluted with water Consumed as a beverage CNS depressant
Alcohol Levels Elimination of alcohol throughout the body Oxidation: in the liver Excretion: unchanged in breath, urine, perspiration
Alcohol Levels Measure Blood alcohol Alcohol content in the breath: direct proportion to the blood concentration
Alcohol Levels Alcohol appears in the blood within minutes Slowly increases in concentration while it is being absorbed from the stomach (20%) and the small intestine All the alcohol absorbed until the maximum alcohol level is reached in the blood
Alcohol Levels Post absorption period begins Concentration slowly decreases until a zero level is again reached
Alcohol Levels Factors influencing rate of absorption Time taken to consume the drink Alcohol content Amount consumed Food present in the stomach.
Alcohol & Circulatory System Closed circulatory system consisting of a heart, arteries, veins, and capillaries Alcohol absorbed from the stomach and small intestines Carried to the liver where the process of its destruction starts
Alcohol & Circulatory SystemCirculatory System Blood, carrying alcohol, moves to the heart, pumped to the lungs Carbon dioxide and alcohol leave the blood Oxygen enters the blood in the air sacs (alveoli) Carbon dioxide, alcohol exhaled
Breath Test Instruments Operate on the principle of infrared light absorption Becoming increasingly popular within the law enforcement community Designed to capture a set volume of breath Captured breath is exposed to infrared light
Breathalyzer Works by measuring the amount of potassium dichromate destroyed.
Breathalyzer It is a glass ampoule containing: Potassium dichromate Sulfuric acid Water In the chemical reaction with ethyl alcohol, the potassium dichromate gets used up.
Considerations in Breath Testing Unit must measure alveolar breath (deep lung breath) 1.5 liters breath needed Avoid measuring mouth alcohol Regurgitation Belching Recent intake of alcohol Alcohol mouthwash No foreign material minutes before test Duplicate measurements within a few minutes
Field Sobriety Testing
Estimate motorist’s degree of physical impairment by alcohol Evidential test for alcohol justified? Preliminary breath-alcohol content Portable, handheld, roadside breath tester Contains fuel cell the oxidizes alcohol Produces electrical current proportional to alcohol content
Field Sobriety Testing Nystagmus Test Horizontal gaze nystagmus testnystagmus test Involuntary jerking as eye moves to side Subject unaware of jerking 0.10 % blood alcohol jerking before movement of 45 degrees
Field Sobriety Testing Comprehension of two instructions Walk and turn Walk and turn Stand heel to toe Walk nine steps heel-toe Turn around Repeat One-leg stand Balance standing with heels together Stand on one leg 30 seconds Count aloud while standing
Analysis for Blood Alcohol
Analysis for Blood Gas Chromatography Testing Most widely used approach for determining alcohol levels in blood Blood must be Drawn under medically accepted conditions By a qualified individual
Gas Chromatography- Con’t Nonalcoholic disinfectant be applied before the suspect’s skin penetrated with a sterile needle or lancet Preservation Anticoagulant and a preservative added Sealed in an airtight container and stored in a refrigerator
Links used History of Poisonings: al_mind/forensics/toxicology/5.html al_mind/forensics/toxicology/5.html