Ch. 8 Toxicology

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Transcript Ch. 8 Toxicology

Toxicology: Poisons and
Toxicology—the study of the adverse effects of
chemicals or physical agents on living
Environmental—air, water, soil
Consumer—foods, cosmetics, drugs
Medical, clinical, forensic
Forensic Toxicology
Postmortem—medical examiner
or coroner
Criminal—motor vehicle
accidents (MVA)
Workplace—drug testing
Sports—human and animal
catastrophic, terrorism
Toxic substances may:
Be a cause of death
Contribute to death
Cause impairment
Explain behavior
Historical Poisoners
Olympias—a famous Greek poisoner
Locusta—personal poisoner of Emperor Nero
Lucretia Borgia—father was Pope Alexander VI
Madame Giulia Toffana—committed over 600
successful poisonings, including two popes
• Hieronyma Spara—formed a society to teach
women how to murder their husbands
• Madame de Brinvilliers and Catherine Deshayes—
French poisoners
• AND many others through modern times.
• Mathieu Orfila—known as the father of
forensic toxicology, published in 1814
Traité des poisons which described the
first systematic approach to the study of
the chemistry and physiological nature of
Aspects of Toxicity
1. Dosage
2. The chemical or physical form of the
3. The mode of entry into the body
4. Body weight and physiological
conditions of the victim, including age
and sex
5. The time period of exposure
6. The presence of other chemicals in the
body or in the dose
Lethal Dose
LD50 refers to the dose of a substance
that kills half the test population,
usually within four hours
Expressed in milligrams of substance per
kilogram of body weight
Toxicity Classification
Federal Regulatory Agencies
Food and Drug Administration (FDA)
Environmental Protection Agency (EPA)
Consumer Product Safety Commission
Department of Transportation (DOT)
Occupational Safety and Health
Administration (OSHA)
Symptoms of Various Types of
Type of Poison
Caustic poison (lye)
Characteristic burns around the lips and
mouth of victim
Carbon monoxide
Red or pink patches on the chest and
thigh, unusually bright red lividity
Sulfuric acid
Black vomit
Hydrochloric acid
Greenish-brown vomit
Nitric acid
Yellow vomit
Coffee-brown vomit, onion or garlic odor
Burnt almond odor
Arsenic, mercury
Extreme diarrhea
Methyl (wood) or isopropyl
(rubbing) alcohol
Nausea and vomiting, unconsciousness
possibly blindness
Critical Information
Common color
Characteristic odor
Common sources
Lethal dose
Possible methods of administration
Time interval of onset of symptoms
Symptoms resulting from an acute
Symptoms resulting from chronic
Disease states mimicked by poisoning
Notes relating to the victim
Specimens from victim
Analytical detection methods
Known toxic levels
Notes pertinent to analysis of poison
List of cases in which poison was used
Human Specimens for Analysis
• Blood
• Urine
• Vitreous humor of
• Bile
• Gastric contents
• Liver tissue
• Brain tissue
• Kidney tissue
• Hair/nails
Alcohol—Ethyl Alcohol (C2H5OH)
• Most abused drug in America
• About 40 percent of all traffic deaths are alcohol-related
• Toxic—affecting the central nervous system, especially the
• Colorless liquid, generally diluted in water
• Acts as a depressant
• Alcohol appears in blood within minutes of consumption;
30–90 minutes for full absorption
• Detoxification—about 90 percent in the liver
• About 5 percent is excreted unchanged in breath,
perspiration, and urine
Rate of Absorption of Alcohol
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
BAC: Blood Alcohol Content
• Expressed as percent weight per volume of
• Legal limit in all states is 0.08 percent
Parameters influencing BAC:
• Body weight
• Alcohol content
• Number of beverages consumed
• Time since consumption
BAC Calculation
Burn-off rate of 0.015 percent per hour, but can
0.071  (oz)  (% alcohol)
body weight
0.085  (oz)  (% alcohol)
body weight
Field Tests
• Preliminary tests—used to determine the degree of
suspect’s physical impairment and whether or not
another test is justified
• Psychophysical tests—three basic tests:
• Horizontal gaze nystagmus (HGN): follow a pen or small
flashlight, tracking left to right with one’s eyes. In
general, wavering at 45 degrees indicates 0.10 BAC.
• Nine-step walk and turn (WAT): comprehend and
execute two or more simple instructions at one time
• One-leg stand (OLS): maintain balance; comprehend
and execute two or more simple instructions at one