1. Forensic Toxicology

3. Toxicology
Toxicology—the study of the adverse effects of chemicals or physical agents on living organisms.
(In other words: combination of chemistry and physiology that deals with drugs, poisons, and other toxic substances and how these substances effect living organisms.)
Types:
Environmental—air, water, soil
Consumer—foods, cosmetics, drugs
Medical, clinical, forensic

4. Toxicologists What do they do?
Detect and identify the presence of drugs and poisons in body fluids, tissues, and organs.
Where do they work?
Crime Labs
ME Offices
Hospital labs & Health Facilities
Identify drug overdoses
Monitor intake of drugs

5. Mathieu Orfilia- Father of Toxicology
The father of toxicology was Mathieu Orfilia in the early 1800’s .
His work mainly centered around arsenic.
It was relatively easy to get because it was the rat poison of the day and was the favorite murder weapon among poor people.

6. Intoxicant vs. Poison
Intoxicant – need a relatively large amount in order to be lethal
Ex. Alcohol
Poison - requires a relatively small amount to be fatal
Ex. Cyanide

7. Forensic Toxicology can be found in…
Postmortem—medical examiner or coroner
Criminal—motor vehicle accidents (MVA)
Workplace—drug testing
Sports—human and animals
Environment—industrial, catastrophic, terrorism.

8. Toxicology plays a major part in forensics at three levels
A criminalist may be asked to see if a person’s behavior has been influenced by a drug
A forensic team may examine evidence to see whether a suspect has been manufacturing illicit compounds
Forensic experts will look for evidence that a toxic substance has killed a person

9. Toxic Substances may… Be the cause of death Contribute to death
Cause impairment
Explain Behavior

10. Looking for Poisons
Most poisons don’t visibly change the body. The medical examiner won’t notice most cases until fluids and tissue sample are examined in the lab

11. Biotransformation
When chemicals enter the body, the body reacts by breaking it down in order to eliminate it
For example… if you inject something like heroin, the body will break it down into the morphine originally used to produce it. Looking for heroin is futile but if you find morphine, you have found signs of heroin
We call these products metabolites

12. What are the clues?
Ingested toxins show up in the stomach, intestines, or liver
Inhaled gases are concentrated in the lungs
Toxins that are ingested intramuscularly concentrate themselves around the injection site
Drugs that re given intravenously are directly absorbed into the blood bypassing the stomach and liver. Concentrations are found throughout the body, low in the stomach and liver, high in the blood stream

13. Best Tissues to Sample for Poisons
Blood
Most Useful
Shows chemical and metabolites
Blood levels show what was going on in the body at TOD
Urine
Easy to obtain
High concentrations
Kidneys are along elimination route
Stomach Contents
Digestion stops at the moment of death

14. Best Tissues to Sample for Poisons
Liver
Toxin “sponge” of your body
Can reflect levels of toxins that blood may not reveal
Vitreous Humor (eyeball fluid)
Slow to decay
Retain toxins longer than most other organs
Hair
Chemicals take abut 5 days to show in the core of a hair shaft
Insects
toxins accumulate in the bodies of insects that feed off of decomposed bodies

15. Determining the Manner and Cause of Death
Natural- ex. heart attack
Accidental- ex. Children putting things in their mouths, misreading labels, mixing different chemicals
Suicidal- ex. CO poisoning, drug overdose
Homicidal- ex. Purposeful tampering, weapons

16. Most Abused Drug: Alcohol
Blood-alcohol levels are directly proportional to the degree of intoxication
Expressed in grams of alcohol/100 mL of blood)
Alcohol is absorbed through the stomach and small intestines
Rate of absorption
Total time taken to consume
Alcoholic content
Amount consumed
Body weight
Stomach contents

17. How do we get it out of our bodies?
Oxidation
Takes Place in the liver
Excretion
Breath
Urine
Perspiration

18. How do we test for it? Breathalyzer Field Sobriety Pupil Dilation
Walk and Turn (heel to toe)
One leg standing and counting
Finger to Nose “thing”

19. Legal Limit
Maximum Blood Alcohol Level is 0.08% for drivers age 21 and up
Maximum Blood Alcohol Level is 0.02% if the driver in under 21