Forensic Toxicology

11.20.08

Deaths Investigated by Forensic

Toxicologists

Deaths Investigated by Forensic

Toxicologists Accidental Poisonings Drug Abuse Cases Suicidal Poisonings Homicidal Poisonings

Main Questions Addressed by

Forensic Toxicologist

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

Properties of Ideal Poison

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

Potencies of Various Poisons

Agent Botulinum toxin

Ricin Strychnine Sodium arsenite

Sodium cyanide

Thallium

Lethal Dose 0.05 mg 0.5 mg 100 mg 200 mg 250 mg 1000 mg

General Classes of Poisons

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)

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 PoisonsMetal Poisons

Most common – As2O3 (arsenic) Death within 24 hours Can be given in trace amounts over long periods of time

Symptoms: Vomiting Diarrhea

AlkaloidsAlkaloids

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

PesticidesPesticides

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

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

Samples Collected at Autopsy

Fluids Blood – up to 100mL

Urine – 100 mL

Bile – all available

Vitreous – all available

Gastric contents – 50g

Soft Tissue Liver – 100g Brain – 100-200g

Kidney – 50g Lung – 50g Spleen – 50g

Intentional Poisoning Trends

Intentional Poisoning Trends

Perpetrator Profile 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

Top 5 Homicidal Poisons

Arsenic – 31% Cyanide – 9% Strychnine – 6% Morphine – 3% Chloroform – 3%

Possible SymptomsPossible 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) – ChloracnePoisoning of Victor Yushchenko just before Ukraine presidential election