Forensic Toxicology

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Transcript Forensic Toxicology

Forensic Toxicology
11.13.09
Deaths Investigated by
Forensic Toxicologists
 Accidental Poisonings
 Drug Abuse Cases
 Suicidal Poisonings
 Homicidal Poisonings
Main Questions Addressed by
Forensic Toxicologist
 Is a drug or poison present? If so,
what is the substance?
 How much of the substance is
present? Is the concentration great
enough to cause or contribute to
death?
 How was the drug/poison
administered?
Properties of Ideal Poison
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Undetectable by senses
Soluble in water
Delayed effect
Easily obtained
Non-traceable
Symptoms mimic actual disease
Undetectable by scientific instruments
Potent
Potencies of Various
Poisons
 Agent
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Botulinum toxin
Ricin
Strychnine
Sodium arsenite
Sodium cyanide
Thallium
 Lethal Dose
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0.05 mg
0.5 mg
100 mg
200 mg
250 mg
1000 mg
General Classes of
Poisons
 Gases – HCN, CO
 Metallic Poisons – As, Sb, Pb, Li,
Hg, Tl
 Non-volatile organics
 Corrosive poisons – strong acids/bases
 Salts – NaCN
 Alkaloids
 Pesticides
Carbon Monoxide (CO)
 Normal level of 1-3% in body (up to 10%
in smokers)
 Fatal level at autopsy considered to be
>50% for a healthy middle-aged male
 CO prevents Oxygen binding to
hemoglobin (red blood cells)
 Leads to suffocation
 CO victims have “cherry pink color”
Metal Poisons
 Most common – As2O3 (arsenic)
 Death within 24 hours
 Can be given in trace amounts over
long periods of time
 Symptoms:
 Vomiting
 Diarrhea
Alkaloids
 Nitrogen-containing organic base
 Found in Plants and fungi
 Strychnine most common
 Death from muscle over-contraction,
leading to respiratory system failure
 Spasms and convulsions
Pesticides
 Many (most?) of the pesticides we
spray on our lawns, gardens, etc. are
poisonous
 Growing in popularity
 Easy to obtain
 Common enough that it won’t raise
suspicions as quickly if traces found
Toxicological Analysis of
Tissues
A. Collect sample of all body fluids
B. Collect samples from organs and
tissues
C. Begin analysis as quickly as possible
after death due to quick metabolism of
toxins
D. Look for traces of poison OR their
metabolic product (what toxin is
changed into when broken down)
Samples Collected at
Autopsy
 Fluids
 Blood – up to
100mL
 Urine – 100 mL
 Bile – all
available
 Vitreous – all
available
 Gastric contents –
50g
 Soft Tissue
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Liver – 100g
Brain – 100-200g
Kidney – 50g
Lung – 50g
Spleen – 50g
Intentional Poisoning
Trends
 Perpetrator Profile
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Caucasian
Male
Average or above IQ
Underachiever
Personality defect
Non-confrontational
Non-athletic
Neat, orderly,
meticulous
 Loner
 Gender
 Male – 46%
 Female – 39%
 Unknown – 16%
Top 5 Homicidal Poisons
 Arsenic – 31%
 Cyanide – 9%
 Strychnine – 6%
 Morphine – 3%
 Chloroform – 3%
Possible Symptoms
 Constricted/dilated pupils (opioids, organic
phosphates)
 Breath odor (arsenic – smells of garlic)
 Hair loss (Thallium)
 Convulsions (strychnine)
 Paralysis (botulism)
 Coma (depressants, hypnotics)
 Skin color (CO=red, nitrites=blue)
 Skin appearance
 (arsenic – hyperkeratosis, warts)
 (dioxin – chloracne)
TCDD (dioxin) – Chloracne
Poisoning of Victor Yushchenko just before Ukraine presidential election