Chapter 8 Toxicology: Poisons and Alcohol

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Chapter 8ToxicologyPoisons and Alcohol

• All substances are poisons. There is none which
  is not. The right dose differentiates a poison
  and remedy.
• Paracelsus (1495-1541). Swiss physician and
  chemist

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Toxicology and Alcohol
Students will learn

• A quantitative approach to toxicology.
• The danger of using alcohol.

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Toxicology and Alcohol
Students will be able to

• Discuss the connection of blood alcohol levels to
  the law, incapacity, and test results.
• Understand the vocabulary of poisons.
• Design and conduct scientific investigations.
• Use technology and mathematics to improve
  investigations and communications.
• Identify questions and concepts that guide
  scientific investigations.
• Communicate and defend a scientific argument.

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Toxicology

• Definitionthe study of the adverse effects of
  chemicals or physical agents on living organisms.
• Types
• Environmentalair, water, soil
• Consumerfoods, cosmetics, drugs
• Medical, clinical, forensic

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Forensic Toxicology

• Postmortemmedical examiner or coroner
• Criminalmotor vehicle accidents (MVA)
• Workplacedrug testing
• Sportshuman and animal
• Environmentindustrial, catastrophic, terrorism

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Toxicology

• Toxic substances may
• Be a cause of death
• Contribute to death
• Cause impairment
• Explain behavior

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Historical Perspective of Poisoners

• Olympiasa famous Greek poisoner
• Locustapersonal poisoner of Emperor Nero
• Lucretia Borgiafather was Pope Alexander VI
• Madame Giulia Toffanacommitted over 600
  successful poisonings, including two Popes.
• Hieronyma Sparaformed a society to teach women
  how to murder their husbands
• Madame de Brinvilliers and Catherine
  DeshayesFrench poisoners.
• AND many others through modern times.

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The Severity of the Problem

• If all those buried in our cemeteries who were
  poisoned could raise their hands, we would
  probably be shocked by the numbers.
• John Harris Trestrail, Criminal Poisoning

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People of Historical Significance

• Mathieu Orfilaknown as the father of forensic
  toxicology, published in 1814 Traite des
  Poisons which described the first systematic
  approach to the study of the chemistry and
  physiological nature of poisons.

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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

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Lethal Dose

• LD50refers 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

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Toxicity Classes
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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)

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Symptoms of Various Typesof Poisoning

• Type of Poison Symptom/Evidence
• Caustic Poison (lye) Characteristic burns around
  the lips and mouth of the
  victim
• Carbon Monoxide Red or pink patches on the chest
  and thighs,
  unusually bright red lividity
• Sulfuric acid Black vomit
• Hydrochloric acid Greenish-brown vomit
• Nitric acid Yellow vomit
• Phosphorous Coffee brown vomit. Onion or garlic
  odor
• Cyanide Burnt almond odor
• Arsenic, Mercury Pronounced diarrhea
• Methyl (wood) or Nausea and vomiting,
  unconsciousness,
• Isopropyl (rubbing) alcohol possibly blindness

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Critical Informationon Poisons

• Form
• Common color
• Characteristic odor
• Solubility
• Taste
• Common sources
• Lethal dose
• Mechanism
• Possible methods of administration
• Time interval of onset of symptoms.

• Symptoms resulting from an acute exposure
• Symptoms resulting from chronic exposure
• 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

John Trestrail from Criminal Poisoning
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To Prove a Case

• Prove a crime was committed
• Motive
• Intent
• Access to poison
• Access to victim
• Death was caused by poison
• Death was homicidal

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Forensic Autopsy

• Look for
• Irritated tissues
• Characteristic odors
• Mees linessingle transverse white bands on
  nails.
• Order toxicological screens
• Postmortem concentrations should be done at the
  scene for comparison
• No realistic calculation of dose can be made from
  a single measurement

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Human Specimens for Analysis

• Blood
• Urine
• Vitreous Humor of Eyes
• Bile
• Gastric contents

• Liver tissue
• Brain tissue
• Kidney tissue
• Hair/nails

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AlcoholEthyl Alcohol (C2H5OH)

• Most abused drug in America
• About 40 of all traffic deaths are
  alcohol-related
• Toxicaffecting the central nervous system,
  especially the brain
• Colorless liquid, generally diluted in water
• Acts as a depressant
• Alcohol appears in blood within minutes of
  consumption 30-90 minutes for full absorption
• Detoxificationabout 90 in the liver
• About 5 is excreted unchanged in breath,
  perspiration and urine

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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

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BACBlood Alcohol Content

• Expressed as percent weight per volume of blood
• Legal limits in all states is 0.08
• Parameters influencing BAC
• Body weight
• Alcoholic content
• Number of beverages consumed
• Time between consumption

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BAC

• Burn off rate of 0.015 per hour but can vary
• Male
• BAC male 0.071 x (oz) x ( alcohol)
• body weight
• Female
• BAC female 0.085 x (oz) x ( alcohol)
• body weight

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Henrys Law

• When a volatile chemical is dissolved in a liquid
  and is brought to equilibrium with air, there is
  a fixed ratio between the concentration of the
  volatile compound in the air and its
  concentration in the liquid this ratio is
  constant for a given temperature. THEREFORE, the
  concentration of alcohol in breath is
  proportional to that in the blood.
• This ratio of alcohol in the blood to alcohol in
  the alveolar air is approximately 2100 to 1. In
  other words 1 ml of blood will contain nearly the
  same amount of alcohol as 2100 ml of breath.

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Field Tests

• Preliminary testsused to determine the degree of
  suspects physical impairment and whether or not
  another test is justified.
• Psychophysical tests3 Basic Tests
• Horizontal gaze nystagmus (HGN) follow a pen or
  small flashlight, tracking left to right with
  ones 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 time.

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The Breathalyzer

• More practical in the field
• Collects and measures alcohol content of alveolar
  breath
• Breath sample mixes with 3 ml of 0.025 K2Cr2O7
  in sulfuric acid and water
• 2K2Cr2O7 3C 2H5OH 8H 2SO4 ? 2Cr2(SO4)3
  2K2SO4 3CH3COOH 11 H2O
• Potassium dichromate is yellow, as concentration
  decreases its light absorption diminishes so the
  breathalyzer indirectly measures alcohol
  concentration by measuring light absorption of
  potassium dichromate before and after the
  reaction with alcohol

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Generalizations

• During absorption, the concentration of alcohol
  in arterial blood will be higher than in venous
  blood.
• Breath tests reflect alcohol concentration in the
  pulmonary artery.
• The breathalyzer also can react with acetone (as
  found with diabetics), acetaldehyde, methanol,
  isopropyl alcohol, and paraldehyde, but these are
  toxic and their presence means the person is in
  serious medical condition.
• Breathalyzers now use an infrared light
  absorption device with a digital read-out. Prints
  out a card for a permanent record.

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More Information

• Read more about Forensic Toxicology from Court
  TVs Crime Library at
• http//www.crimelibrary.com/criminal_mind/forensi
  cs/toxicology/2.html