Forensic ToxicologyWednesday, 5/20

Agenda:1.Lecture on poisons/intro to forensic toxicology2.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.

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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

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ToxicologyToxic substances may:

– Be a cause of death– Contribute to death– Cause impairment– Explain behavior

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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 husbandsAND many others through modern times.

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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.

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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

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Lethal Dose

• LD50: 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

Death by WaterHold 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

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Toxicity ClassesLD50 (rat,oral) Correlation to Ingestion

by 150 lb Adult HumanToxicity

<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

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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)

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Symptoms of Various Typesof PoisoningType of Poison Symptom/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

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 blood-

alcohol 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:

• 2K2Cr2O7 + 3C2H5OH + 8H2SO4 2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11H2O

• 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

Potassium dichromate

Ethyl alcohol

Sulfuric acid

Chromium sulfate

Potassium sulfate

Acetic acid

Dihydrogen oxide

Infrared Breath Test

• Infrared light is absorbed when shined on alcohol– Infrared light passes

through a chamber where it will interact with the alcohol and cause the light density to decrease.

– The decrease in light intensity is proportional to the concentration of alcohol present in the captured breath

• A fuel cell converts a fuel and an oxidant into an electrical current. – The breath alcohol is

the fuel and atmospheric oxygen acts as the oxidant.

– Alcohol is converted, generating an electric current that is proportional to the quantity of alcohol present in the breath.

Fuel Cell Breath Test

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 non-evidential 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=vjPR5WvYCx0

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

4. Does not touch heel-to-toe

5. Steps off the line

6. Uses arms to balance

7. Makes an improper turn

8. Takes an incorrect number of steps. https://www.youtube.com/watch?

v=5BG48Bt2_u8&list=PL379B06AAD3E755E3

NHTSA research indicates that 79 % of individuals who exhibit two or more indicators in the performance of the test will have a BAC of 0.08 or greater

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 thousand-one, 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. Swaying while balancing,

2. Using arms to balance,

3. Hopping to maintain balance,

4. 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=7g7vA_qlcko&list=PL379B06AAD3E755E3

And now for the ‘best’ of those soon to be saying goodbye to their license…

• https://www.youtube.com/watch?v=jydBvk7R5wU

• https://www.youtube.com/watch?v=tTePQi272Nc• https://www.youtube.com/watch?

v=p9jpwe6TDas• https://www.youtube.com/watch?v=u78p_-Jc1aU• https://www.youtube.com/watch?

v=j6c_mWPSdPo&list=RDCGgOedVC3RY• https://www.youtube.com/watch?

v=eGCiXBJTonY

Parts of the brain affected by Alcohol• Alcohol 1st

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