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Forensic Toxicology Wednesday, 5/20 Agenda: 1. Lecture on poisons/intro to forensic toxicology 2. Discuss final project and begin sign-up Tomorrow: Continue lecture: alcohol intoxication and learning about sobriety tests
Forensic Toxicology What is it? • The science of detecting and identifying the presence of drugs and poisons in body fluids, tissues, and organs.
Aspects of Forensic Toxicology • Postmortem—medical examiner or coroner • Criminal—motor vehicle accidents (MVA) • Workplace—drug testing • Sports—human and animal • Environment—industrial, catastrophic, terrorism 3
Toxicology Toxic substances may: – Be a cause of death – Contribute to death – Cause impairment – Explain behavior 4
Historical Perspective of Poisoners • Locusta—personal poisoner of Emperor Nero • Lucretia Borgia—father was Pope Alexander VI, known for using arsenic to poison • Madame Giulia Toffana—committed over 600 successful poisonings, including two Popes. • Hieronyma Spara—formed a society to teach women how to murder their husbands AND many others through modern times. 5
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. 6
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 7
Lethal Dose • LD 50: 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 8
Death by Water Hold your wee for a wii • In 2007, a mother tried to win a wii game for her son at a radio show contest – Contestants had to drink a water bottle every 5 minutes without using the bathroom – The mother died of water poisining • 1. 5 to 2. 0 gallons of water can be toxic to your body 9
Toxicity Classes LD 50 (rat, oral) Correlation to Ingestion by 150 lb Adult Human Toxicity <1 mg/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 15 g/kg more than 1 quart relatively harmless 10
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) 11
Symptoms of Various Types of Poisoning Type of Poison Symptom/Evidence • Caustic Poison (lye) • Carbon Monoxide thighs, Sulfuric acid Hydrochloric acid Nitric acid Phosphorous Cyanide Arsenic, Mercury Methyl (wood) or Isopropyl (rubbing) alcohol -Characteristic burns around the lips and mouth of the victim -Red or pink patches on the chest and unusually bright red lividity -Black vomit -Greenish-brown vomit -Yellow vomit Coffee brown vomit. Onion or garlic odor -Burnt almond odor -Pronounced diarrhea -Nausea and vomiting, unconsciousness, possibly blindness • • 12
Toxicology of Alcohol • Alcohol is absorbed through the stomach and intestine • Once absorbed, alcohol is: – Oxidized in liver by alcohol dehydrogenase • turned into acidic acid – Excreted by breath, perspiration, and kidneys (urine) • turned into carbon dioxide and water
Factors that Affect Alcohol Absorption 1. Time of consumption 2. Type of alcoholic beverage 3. Presence of food in stomach
Toxicology of Alcohol • Alcohol intoxication depends on – Amount of alcohol consumed – Time of consumption – Body weight – Rate of alcohol absorption
Fate of Alcohol • Alcohol is absorbed into the bloodstream • Distributed throughout the body’s water • And finally eliminated by oxidation and excretion
Alcohol in the Circulatory System • Measuring the quantity of alcohol in the blood system determines the degree to which someone is drunk • Two methods of making this measurement – Measurement of alcohol content in blood – Measurement of alcohol in breath
Circulation Definitions • Artery: a blood vessel that carries blood away from the heart • Vein: a blood vessel that transports blood toward the heart • Capillary: a tiny blood vessel— walls exchange materials between blood and tissues • Alveoli: small sacs in lungs— exchange vapors between breath and blood
Circulation Con’t • If alcohol is present, it will be passed from the blood into the alveoli where it will be passed on to the mouth and nose during the act of breathing. • Evidence has shown that the ratio of alcohol to alveoli air is approx. 2100 to 1 – This is a basis for relating breath to bloodalcohol concentration.
Analysis of blood alcohol content (BAC) • Breath Tests • Field Sobriety Tests • Blood Tests
Breath Tests • A breath test reflects the alcohol concentration in the pulmonary artery. • One instrument used for breath tests is called The Breathalyzer. • The Breathalyzer is a device for collecting and measuring the alcohol content of alveolar breath.
The Breathalyzer Con’t • The Breathalyzer traps 1/40 of 2100 ml of alveolar breath. • The amount of alcohol in 2100 ml of breath approximates the amount of alcohol in 1 ml of blood – Measures the alcohol concentration present in 1/40 of a ml of blood.
Breathalyzer Con’t • Once the alveolar breath is trapped it is allowed to undergo a chemical reaction: • 2 K 2 Cr 2 O 7 + 3 C 2 H 5 OH + 8 H 2 SO 4 2 Cr 2(SO 4)3 + 2 K 2 SO 4 + 3 CH 3 COOH + 11 H 2 O Potassium Ethyl dichromate alcohol Sulfuric acid Chromium sulfate Potassium Acetic sulfate acid Dihydrogen oxide • The Breathalyzer indirectly determines the quantity of alcohol consumed by measuring the absorption of light by potassium chromate before and after its reaction with alcohol, using the principle of spectrophotometry
Infrared Breath Test Fuel Cell Breath Test • • Infrared light is absorbed A fuel cell converts a when shined on alcohol fuel and an oxidant into an electrical current. – Infrared light passes through a chamber where – The breath alcohol is the fuel and it will interact with the atmospheric oxygen alcohol and cause the light acts as the oxidant. density to decrease. – Alcohol is converted, – The decrease in light generating an electric intensity is proportional to current that is the concentration of proportional to the quantity of alcohol present in the breath. captured breath
These instruments are used more recently because they don’t depend upon chemical reagents and are entirely automated. • Infrared Breath Test uses infrared wavelengths to test for alcohol or other interferences in the breath • Fuel Cell Test converts fuel (alcohol) and oxygen into a measurable electric current
Field Sobriety Testing • Two reasons for the field sobriety test: 1. Used as a preliminary test to ascertain the degree of the suspect’s physical impairment 2. To see whether or not an evidential test is justified.
Field Sobriety Testing Methods • Field sobriety testing consists of a series of psychophysical tests and a preliminary breath test (typically done with a handheld fuel cell tester) • These tests are preliminary and nonevidential in nature. They only serve to establish probable cause requiring a more thorough breath or blood test.
Standardized Field Sobriety Testing The three tests of the SFST are: 1. Horizontal Gaze Nystagmus (HGN), 2. Walk-and-Turn (WAT), 3. One-Leg Stand (OLS). These tests are administered systematically and are evaluated according to measured responses of the suspect.
Test 1: Horizontal Gaze Nystagmus (HGN) • Horizontal Gaze Nystagmus is an involuntary jerking of the eye that occurs naturally as the eyes gaze to the side. – Normal circumstances nystagmus occurs when the eyes are rotated at high peripheral angles. – Impaired by alcohol nystagmus is exaggerated and may occur at lesser angles. – An alcohol-impaired person will also often have difficulty smoothly tracking a moving object. The examiner looks for three indicators of impairment in each eye: • if the eye cannot follow a moving object smoothly • if jerking is distinct when the eye is at maximum deviation, • if the angle of onset of jerking is within 45 degrees of center.
Test 1: Horizontal Gaze Nystagmus (HGN) cont’d • If, between the two eyes, four or more clues appear, the suspect likely has a BAC of 0. 08 or greater. • NHTSA research found that this test allows proper classification of approximately 88% of suspects • https: //www. youtube. com/watch? v=vj. PR 5 Wv. YCx 0
Test 2: Walk and Turn (WAT) (divided attention tasks) • The Walk-and-Turn test and One-Leg Stand test are "divided attention" tests that are easily performed by most unimpaired people. • They require a suspect to listen and follow instructions while performing simple physical movements. • Impaired persons have difficulty with tasks requiring their attention to be divided between simple mental and physical exercises.
Test 2: Walk and Turn (WAT) (divided attention tasks) • In the Walk-and-Turn test, the subject is directed to take nine steps, heel-to-toe, along a straight line. After taking the steps, the suspect must turn on one foot and return in the same manner in the opposite direction. • The examiner looks for 8 indicators of impairment: 1. If the suspect cannot keep balance while listening to the instructions 2. Begins before the instructions are finished 3. stops while walking to regain balance NHTSA research indicates that 79 % of 4. Does not touch heel-to-toe individuals who 5. Steps off the line exhibit two or more 6. Uses arms to balance indicators in the performance of the 7. Makes an improper turn test will have a BAC of 8. Takes an incorrect number of steps. 0. 08 or greater https: //www. youtube. com/watch? v=5 BG 48 Bt 2_u 8&list=PL 379 B 06 AAD 3 E 755 E 3
Test 3: One-Leg Stand (OLS) • In the One-Leg Stand test, the suspect is instructed to stand with one foot approximately six inches off the ground and count aloud by thousands (One thousandone, one thousand-two, etc. ) until told to put the foot down. The officer times the subject for 30 seconds. • The officer looks for 4 indicators of impairment, including: 1. 2. 3. 4. Swaying while balancing, Using arms to balance, Hopping to maintain balance, And putting the foot down. • NHTSA research indicates that 83% of individuals who exhibit two or more such indicators in the performance of the test will have a BAC of 0. 08 of greater • https: //www. youtube. com/watch? v=7 g 7 v. A_qlcko&list=PL 379 B 06 AAD 3 E 755 E 3
And now for the ‘best’ of those soon to be saying goodbye to their license… • https: //www. youtube. com/watch? v=jyd. Bvk 7 R 5 w U • https: //www. youtube. com/watch? v=t. Te. PQi 272 Nc • https: //www. youtube. com/watch? v=p 9 jpwe 6 TDas • https: //www. youtube. com/watch? v=u 78 p_-Jc 1 a. U • https: //www. youtube. com/watch? v=j 6 c_m. WPSd Po&list=RDCGg. Oed. VC 3 RY • https: //www. youtube. com/watch? v=e. GCi. XBJTon Y
Parts of the brain affected by Alcohol • Alcohol 1 st affects the forebrain and moves backward • Last affected is medulla oblongata
Alcohol and the Law • 1939 -1964: intoxicated = 0. 15% BAC • 1965: intoxicated = 0. 10% BAC • 2003: intoxicated = 0. 08% BAC At least we don’t live in France, Germany, Ireland, or Japan (0. 05%) or especially Sweden (0. 02%)!
Alcohol and the Law • Try the drink wheel: http: //www. intox. com/wheel/drinkwheel. asp