Forensic Toxicology

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  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  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  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 – As 2 O 3 (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  Liver – 100g  Brain – g  Kidney – 50g  Lung – 50g  Spleen – 50g

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  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