Transcript Chapter 9: Toxicology

Introduction
Forensic toxicology helps determine causeand-effect relationships
between
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Exposure to a drug or other substance
and
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Toxic or lethal effects from that exposure
Forensic Science: Fundamentals & Investigations, Chapter 9
Exposure
People can be exposed to toxic substances:
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intentionally—
by treating illness or relieving pain
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accidentally—
by harmful combinations or overdoses
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deliberately—
by harming or killing others, or
by suicide
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Forensic Science: Fundamentals & Investigations, Chapter 9
Poison—>Murder, Accidental Overdoses,
and Drug Offences
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Poisoning causes less than ½ of 1% of all
homicides
o
Accidental drug overdoses are more
common
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Drug offenders
•
More than 50% of the federal prison population
•
About 20% of the population in state prisons
Controlled Substances
Hallucinogens
Narcotics
Stimulants
Anabolic steroids
Depressants
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5.
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Controlled Substances —Hallucinogens
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o
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Often derived from plants
Affects the user’s perceptions, thinking, self-awareness,
and emotions
Blood 1-3 days, Urine 3-7 +, hair forever
Forensic Science: Fundamentals & Investigations, Chapter 9
Controlled SubstancesNarcotics
Urine
Test
2-3
Days
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Controlled SubstancesStimulants
Increases feelings of energy and alertness, Suppresses
appetite…Afterwards, depression often results
Overdose affects include high blood pressure, agitation,
confusion, seizures
Stimulants tend to be highly addictive
Blood: 5-6 hours or 2-3 days, Urine: 1-7+ days (based on use)
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Controlled Substances- Anabolic
Steroids
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A chemical structure similar to testosterone
Promote cell and tissue growth increasing bone
mass and body muscle.
Popular with weightlifters, bodybuilders, and
other athletes
Controlled Substances —Depressants
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Affects the central nervous system by increasing
a neurotransmitter… causes drowsiness and
slowed brain activity
Relieves anxiety and produces sleep
Side effects include slurred speech and loss of
coordination
Mixing depressants with alcohol and other drugs
increases potency and health risks
Controlled Substances
—Alcohols
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In what way are alcohols toxic?
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How is grain alcohol produced?
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What are the classic symptoms of a
hangover?
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What is the effect of alcohol on the central
nervous system?
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What can chronic alcohol abuse cause?
Forensic Science: Fundamentals & Investigations, Chapter 9
Controlled Substances
—Bacterial Toxins
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Tetanus (also called Lockjaw)
• Produced by the Clostridium tetani bacteria
• Causes violent muscle spasms
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Botulism
• Produced by Clostridium botulinum—botulism
• Paralyzes muscles
• Causes irreversible damage to nerve endings
• Extremely deadly in very small amounts
• Most poisonous biological substance
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Forensic Science: Fundamentals & Investigations, Chapter 9
Controlled Substances
—Pesticides and Heavy Metals
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Forensic Science: Fundamentals & Investigations, Chapter 9
Controlled Substances
—Pesticides and Heavy Metals
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Forensic Science: Fundamentals & Investigations, Chapter 9
Controlled Substances
—Bioterrorism Agents
Ricin
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o
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A poisonous protein in the castor bean
Lethal in extremely small amounts
Enters the body in various ways:
• inhaled as a mist or a powder
• ingested as food or drink
• injected into the body
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Causes death within a few hours
Forensic Science: Fundamentals & Investigations, Chapter 9
Controlled Substances—Bioterrorism
Agents
Anthrax
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o
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Bacillus anthracis, which forms endospores
Spreads to humans from infected animals
Enters the human body through:
• Inhalation; causing breathing problems that usually
result in death
• Ingestion; becoming fatal in 25% to 60% of cases
• Absorption via the skin; leading to death in about
20% of untreated cases
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Forensic Science: Fundamentals & Investigations, Chapter 9