Forensic Toxicology

Dr. Harold Shipman• In 1998, family members found Kathleen Grundy, an 81

year old who was in good health dead on her couch.• They soon learned that her will had been recently

changed, leaving all of her money to Dr. Shipman. Forgery was quickly discovered and her body was exhumed and a toxicological analysis of the remains showed a lethal quantity of morphine.

• Investigations of Shipman’s deceased patients began. He killed at least 236 people over 24 years with overdoses of heroin or morphine.

• Dr. Shipman hung himself in jail in 2004.

Toxicologist

• An individual whose job is to detect and identify drugs and poisons in body fluids, tissues, and organs

• Toxicology is the study of drugs and poisons in body fluids, tissues, and organs.

History• Ancient Egyptians and Grecians reported

poisonings due to herbs, plants and food.

• Opium, arsenic and hydrocyanic acid were used throughout Europe during the middle ages.

History• Philippus Theophrastus Aureolus Bombastus

von Hohenheim (or Paracelsus) observed that any substance could be a poison, depending on its dose

• “ What is there that is not poison? All things are poison and nothing without poison. Solely the dose determines that a thing is not a poison”

History• In the U.S., forensic toxicology did not develop

until the early 20th century.

• Dr. Alexander Gettler is considered this country’s first forensic toxicologist.

Postmortem Forensic Toxicology• Suspected drug intoxication cases • Homicides• Arson fire deaths• Motor vehicle fatalities• Deaths due to natural causes

Postmortem Forensic Toxicology• Death Investigations

– Coroner

– Medical Examiner

Postmortem Forensic Toxicology• Specimens

– Blood – from the heart and from the femoral or jugular veins

– Vitreous humor– Urine– Bile– Liver– Other – lung, spleen, stomach contents or brain

Postmortem Forensic Toxicology• Analytical Process

– Separation

– Identification

– Confirmation

– Quantitation

Postmortem Forensic Toxicology• Analytes

– Volatiles (Carbon Monoxide, Cyanide, and Alcohols)

– Drugs

– Metals

Alcohol

• Alcohol, or ethyl alcohol, is a colorless liquid normally diluted with water and consumed as a beverage.

• Alcohol appears in the blood within minutes.• Many factors determine the rate at which

alcohol is absorbed into the bloodstream.– Time to consume – Alcohol content of beverage– Presence of food

Ethanol

• Absorption– Means of absorption

• Dermal• Inhalation• IV• Oral

Ethanol

• Elimination

– 5-10% in the urine

– Saliva, expired air and sweat

– **Liver (enzymatic oxidation to acetaldehyde, acetic acid and carbon dioxide)

Blood Alcohol Concentration (BAC)

• How much alcohol is present in a person’s system

• It takes hours for alcohol to be eliminated from the blood, longer depending on how much alcohol was ingested

Stages of Acute Alcohol Intoxication*

*Reprinted by permission of K.M. Dubowski, 1997.

Death from respiratory arrestDeath0.45+

Possible deathImpairment of circulation and respirationSubnormal temperatureDepressed or abolished reflexesComplete unconsciousness; coma; anesthesiaComa0.35-0.50

Impaired consciousness; sleep or stuporVomiting; incontinence of urine and fecesMarked muscular incoordination; inability to stand or walkMarkedly decreased response to stimuliGeneral inertia; approaching loss of motor functionsStupor0.25-0.40

Apathy, lethargy

Increased muscular incoordination; staggering gait; slurredspeech

Increased pain threshold

Disturbances of vision (diplopia, etc.) and of perception ofcolor, form, motion, dimensions

Exaggerated emotional states (fear, rage, grief, etc.)Disorientation, mental confusion; dizzinessConfusion0.18-0.30

DrowsinessSensory-motor incoordination; impaired balance

Reduced visual acuity, peripheral vision, and glarerecovery

Decreased sensory response; increased reaction timeImpairment of perception, memory, and comprehensionEmotional instability; loss of critical judgmentExcitement0.09-0.25

Loss of efficiency in critical performance testsSlowed information processingBeginning of sensory-motor impairmentDiminution of attention, judgment, and controlIncreased self-confidence; decreased inhibitionsMild euphoria, sociability, talkativenessEuphoria0.03-0.12

Impairment detectable by special testsBehavior nearly normal by ordinary observationInfluence/effects not apparent or obviousSub clinical0.01-0.05

Clinical Signs/Symptoms

Stage ofAlcoholicInfluence

Blood-AlcoholConcentrationg/100mL

Alcohol and the Law

• .08 % Blood Alcohol concentration is the legal measure of drunk driving

• The 5th Amendment of the US Constitution guarantees all citizens protection against self-incrimination (being forced to make an admission that would prove guilt).

• So a law was put into effect essentially stating that by choosing to drive you give consent for BAC testing or will lose your license (usually for a year).

Tylenol Murders

• In 1982, 2 firefighters were casually talking about 4 recent deaths in the area when they realized that they had all taken Tylenol.

• They reported this to police and before the investigation was complete 3 more people were killed with the poison-laced Tylenol.

• The Tylenol was filled with potassium cyanide.• The poison was determined to be added outside

of the factory and is still unsolved.

Postmortem Forensic Toxicology• Metals

– Aluminum– Arsenic– Iron– Mercury– Lead– Thallium

Heavy Metal poisoning is not as common today because of the heavy regulation of these substances because of environmental laws.

Carbon Monoxide Poisoning

• Very common• Usually from automobile exhaust

Techniques used by the Toxicologist

• Alcohol, Marijuana, and Cocaine account for 90% of all the drugs/poisons encountered in the toxicology lab.

• Many different procedures are used to try and detect drugs and poisons.

Acids and Bases

• Drugs/poisons fall into certain levels of acidity• Acids=a compound capable of donating a

Hydrogen ion• Bases=a compound capable of accepting a

hydrogen ion• pH scale=used to express the acidity of

basicity of a substance.

pH Scale

Screening and Confirmation

• Screening=quick test to determine if a drug/poison is present– TLC Chromatography, gas chromatography,

immunoassay• Confirmation=a more specialized test to

identify the type of drug– Gas Chromatography combined with Mass

Spectrometer, yields a unique ‘fingerprint’ of the drug or poison.

Significance of Toxicological Findings

• Toxicologists can determine:– What was present in a victim’s system (or a living

person)– How much was present– The probable state of the person’s behavior based

on the known substances– If the use was prolonged or sudden