1. Chapter 6
FORENSIC TOXICOLOGY

2. Toxicology
Toxicology—the study of the adverse effects of chemicals or physical agents on living organisms. Video
Types:
Environmental—air, water, soil
Consumer—foods, cosmetics, drugs
Medical, clinical, forensic

3. Toxicologists
Toxicologists are charged with the responsibility for detecting and identifying the presence of drugs and poisons in body fluids, tissues, and organs. Video
Toxicologists not only work in crime laboratories and medical examiners’ offices, but may also reach into hospital laboratories and health facilities to identify a drug overdose or monitor the intake of drugs. Careers video

4. Mathieu Orfilia – Father of Tox
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.

5. Intoxicant vs. Poison:
An intoxicant such as alcohol requires that a relatively large amount be added to be lethal.
A poison, like cyanide, requires a relatively small amount to be fatal.

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

7. Environmental Example: Love Canal New York
An example of where forensic toxicology impacts the population is the Love Canal Disaster. Video

8. Toxicology
Toxic substances may:
*Be a cause of death
*Contribute to death
*Cause impairment
*Explain behavior

9. Life Example: Carbon Monoxide:
Video Link

10. Aspects of Toxicity Dosage
The chemical or physical form of the substance
The mode of entry into the body
Body weight and physiological conditions of the victim, including age and sex
The time period of exposure
The presence of other chemicals in the body or in the dose

11. Lethal Dose
LD50 refers to the dose of a substance that kills half the test population, usually within four hours. Testing is usually done on animals that compare well to humans metabolism.
Expressed in milligrams of substance per kilogram of body weight

12. Toxicity Classification
LD50 (rat,oral)
Correlation to Ingestion by 150-lb Adult Human
Toxicity
<1 mg/kg
a taste to a drop
extreme
1–50 mg/kg
to a teaspoon
high
50–500 mg/kg
to an ounce
moderate
500–5,000 mg/kg
to a pint
slight
5–15 g/kg
to a quart
practically nontoxic
Over 15 g/kg
more than 1 quart
relatively harmless

13. Symptoms of Various Types of Poisoning
Type of Poison
1. Caustic poison (lye) Characteristic burns around the lips and mouth of victim
2. Carbon monoxide Red or pink patches on the chest and thigh, unusually bright red lividity
3. Sulfuric acid Black vomit
4. Hydrochloric acid Greenish-brown vomit
5. Cyanide- Seizures, Burnt almond odor
6. Arsenic diarrhea, vomiting, blood in the urine, cramping muscles, stomach pain, and convulsions.
7. Methyl (wood) or isopropyl (rubbing) alcohol Nausea and vomiting, unconsciousness possibly blindness

14. To Prove a Case Prove a crime was committed Motive Intent
Access to poison
Access to victim
Death was homicidal
Death was caused by poison

15. Alcohol—Ethyl Alcohol (C2H5OH)
Most abused drug in America
About 40 percent of all traffic deaths are alcohol-related. Acts as a depressant
Toxic—affecting the central nervous system, especially the brain
Colorless liquid, generally diluted in water
Alcohol appears in blood within minutes; 30–90 minutes for full absorption
Detoxification—about 90 percent in the liver

16. Introduction
A major branch of forensic toxicology deals with the measurement of alcohol in the body for matters that pertain to violations of criminal law.

17. Rate of Absorption Depends on: Amount of alcohol consumed
The alcohol content of
the beverage
Time taken to consume it
Quantity and type of food
present in the stomach
Physiology of the consumer
About 5 percent is excreted unchanged in breath, perspiration, and urine

18. Toxicology of Alcohol
The analysis of alcohol exemplifies the primary objective of forensic toxicology—the detection and isolation of drugs in the body for the purpose of determining their influence on human behavior.
Alcohol, or ethyl alcohol, is a colorless liquid normally diluted with water and consumed as a beverage.
Like any depressant, alcohol principally effects the central nervous system, particularly the brain.

19. Alcohol on the Breath
A major branch of forensic toxicology deals with the measurement of alcohol in the body for matters that pertain to violations of criminal law.

20. Alcohol & Circulatory System
Humans have a closed circulatory system consisting of a heart, arteries, veins, and capillaries.

21. Alcohol & Circulatory System
Alcohol is absorbed from the stomach and small intestines into the blood stream.
Alcohol is carried to the liver where the process of its destruction starts.

22. Alcohol & Circulatory System
Blood, carrying alcohol, moves to the heart and is pumped to the lungs.

23. Alcohol & Circulatory System
In the lungs, carbon dioxide and alcohol leave the blood and oxygen enters the blood in the air sacs known as alveoli.
Then the carbon dioxide and alcohol are exhaled during breathing.

24. Toxicology of Alcohol
The analysis of alcohol exemplifies the primary objective of forensic toxicology—the detection and isolation of drugs in the body for the purpose of determining their influence on human behavior. Video
Alcohol, or ethyl alcohol, is a colorless liquid normally diluted with water and consumed as a beverage.

25. Breath Testers
Breath testers that operate on the principle of infrared light absorption are becoming increasingly popular within the law enforcement community.

26. Toxicology of Alcohol
Like any depressant, alcohol principally effects the central nervous system, particularly the brain.

27. Alcohol Levels
Then the alcohol concentration slowly decreases until a zero level is again reached.
Factors such as time taken to consume the drink, the alcohol content, the amount consumed, and food present in the stomach determine the rate at which alcohol is absorbed.

28. Alcohol Levels
Elimination of alcohol throughout the body is accomplished through oxidation and excretion.
Oxidation takes place almost entirely in the liver, while alcohol is excreted unchanged in the breath, urine, and perspiration.
The extent to which an individual may be under the influence of alcohol is usually determined by either measuring the quantity of alcohol present in the blood system or by measuring the alcohol content in the breath.

29. Alcohol Levels
Experimental evidence has verified that the amount of alcohol exhaled in the breath is in direct proportion to the blood concentration.

30. Alcohol and Law
The American Medical Association and the National Safety Council have been able to exert considerable influence in convincing the states to establish uniform and reasonable blood-alcohol standards.
Between 1939 and 1964 a person having a blood-alcohol level in excess of 0.15 percent w/v was to be considered under the influence, which was lowered to 0.10 percent by 1965.
In 1972 the impairment level was recommended to be lowered again to 0.08 percent w/v. It remains there today.

31. Alcohol and Law
To prevent a person’s refusal to take a test for alcohol consumption, the National Highway Traffic Safety Administration recommended an “implied consent” law.
Adopted by all states by 1973, this law states that the operation of a motor vehicle on a public highway automatically carries with it the stipulation that a driver will submit for a test for alcohol intoxication if requested or be subject to loss of the license.

32. Breath Testers
Many types of breath testers are designed to analyze a set volume of breath.
The captured breath is exposed to infrared light.

33. Breath Testers
It’s the degree of the interaction of the light with alcohol in the captured breath sample that allows the instrument to measure a blood alcohol concentration in breath.
Some breath testing devices also use fuel cells.

34. Field Testing
Law enforcement officers typically use field sobriety tests to estimate a motorist’s degree of physical impairment by alcohol and whether or not an evidential test for alcohol is justified.
The horizontal gaze nystagmus test, walk and turn, and the one-leg stand are all considered reliable and effective psychophysical tests.

35. Gas Chromatography Testing
Gas chromatography offers the toxicologist the most widely used approach for determining alcohol levels in blood.

36. Gas Chromatography Testing
Blood must always be drawn under medically accepted conditions by a qualified individual.
It is important that a nonalcoholic disinfectant be applied before the suspect’s skin is penetrated with a sterile needle or lancet.
Once blood is removed from an individual, its preservation is best ensured when it is sealed in an airtight container after an anticoagulant and a preservative have been added and stored in a refrigerator.

37. The Confirmation Step
The GC separates the sample into its components, while the MS represents a unique “fingerprint” pattern that can be used for identification.
Once the drug is extracted and identified, the toxicologist may be required to provide an opinion on the drug’s effect on an individual’s natural performance or physical state.