Transcript Science Fair Project

Toxicology: Poisons and Alcohol
Toxicology: Poisons and Alcohol
Objectives
You will understand:
The danger of using alcohol.
A quantitative approach to toxicology.
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Toxicology: Poisons and Alcohol
Objectives, continued
You 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: Poisons and Alcohol
Historical Perspective of Poisoners
 Execution of Socrates —339 BC, earliest recorded use of poison
which involved an extract of hemlock.
 Development of forensic Toxicology—19th century
 Publication of Traite des poisons-1814. This was the first
systematic approach to the study of the chemistry of poisons
 Marsh Test-1836 James marsh developed a sensitive and reliable
test that detected the presence of arsenic in body tissues and fluids.
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Toxicology: Poisons and Alcohol
Historical Perspective of Poisoners
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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 using poison
 Madame de Brinvilliers and Catherine Deshayes—French
poisoners
AND many others through modern times.
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Toxicology: Poisons and Alcohol
Common poisons used during prehistoric period
 Hemlock- a plant related to carrots which contain an alkaloid
similar to nicotine.
 Monkshood
 Belladonna
 Toxic metal salts
Arsenic is the most commonly used metal salt because it:
a. leaves no trace
b. it is easy to obtain and use
c. the symptoms look like death by natural cause.
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Toxicology: Poisons and Alcohol
Toxicology
Toxicology—the study of the adverse
effects of chemicals or physical
agents on living organisms
Types:
Environmental—air, water, soil
Consumer—foods, cosmetics,
drugs
Medical- clinical, forensic
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Toxicology: Poisons and Alcohol
Applications of Forensic Toxicology
Postmortem-medical examiner
or coroner
Criminal—motor vehicle
accidents (MVA)
Workplace—drug testing
Sports—human and animal
Environment—industrial,
catastrophic, terrorism
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Toxicology: Poisons and Alcohol
Toxicology
Toxic substances may:
Be a cause of death
Contribute to death
Cause impairment or
illness
Explain behavior
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Toxicology: Poisons and Alcohol
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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Toxicology: Poisons and Alcohol
People of Historical Significance
Mathieu Orfila
known as the father of
forensic toxicology
published Traité des
poisons in 1814
His book described the first
systematic approach to the
study of the chemistry and
physiological nature of
poisons
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Toxicology: Poisons and Alcohol
Aspects of Toxicity-Contributing factors
 Dosage-Quantity
 The chemical or physical form of the substance
For example-Arsenic is a metal and is therefore insoluble in stomach
acid, however compounds of arsenic are very poisonous.
 The mode of entry into the body-Absorbed, Ingested, inserted or
injected
 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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Toxicology: Poisons and Alcohol
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
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Toxicology: Poisons and Alcohol
Dosage
Many substances which are harmful when taken in excess are actually
beneficial in trace amounts.
 Arsenic-research indicates that an absence of arsenic stunts
growth
 Arsenic is also used to treat a rare form of cancer
 Botulin-most deadly poison known, 1 gram inhaled could kill more
than 1 million people.
 Botulin is also used by doctors to erase wrinkles and prevent
migraines.
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Toxicology: Poisons and Alcohol
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
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Toxicology: Poisons and Alcohol
LD50 (rat,oral)
substance
4,220 mg/kg
Sodium bicarbonate
3,000 mg/kg
Sodium chloride
763 mg/kg
Arsenic metal
192 mg/kg
caffeine
53 mg/kg
nicotine
48 mg/kg
Arsenic chloride
8.0 mg/kg
Arsenic pentoxide
0.000005-0.0005
mg/kg
Botulin toxin
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Toxicity Classificatio
Correlation to
Ingestion by 150-lb
Adult Human
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Toxicity
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Toxicology: Poisons and Alcohol
Measuring toxicity
 Estimating lethal doses in humans based on those for lab mice,
rats, or rabbits is very uncertain because resistance can be
different among species.
Example: Nicotine is lethal at the following doses for
different species
 Humans=0.9 mg/kg
 Dogs =9.2 mg/kg
 Pigeons=75 mg/kg
 Rats=53 mg/kg
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Toxicology: Poisons and Alcohol
Measuring toxicity
 Toxins-substances that cause injury to the health of a living
organism on contact or ingestion. The term is usually reserved for
natural substances that kill rapidly in small quantities.
 Chronic Exposure-continuing exposure to toxins over a long period of
time which leads to chronic toxicity
 Acute toxicity-effects of a toxin occurring almost immediately after an
exposure
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Toxicology: Poisons and Alcohol
Measuring toxicity
 Synergism- Combined effect of substances exceeds the sum of their
individual effects.
Example: Consuming alcohol with certain antihistamines or
sedatives causes the effect of each substance to be much
stronger.
 Antagonism- Combined effect of substances decreases the sum of
their individual effects.
Example: The drug butorphanol when taken in conjunction with
morphine reduces its effect.
 Chelating agent-an organic compound that complexes with a metal
to form a ring.
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Toxicology: Poisons and Alcohol
Symptoms of Various Types of Poisoning
Type of Poison
Symptom/Evidence
Caustic poison (lye)
Characteristic burns around the lips and
mouth of victim
Red or pink patches on the chest and
thigh, unusually bright red lividity
Black vomit
Greenish-brown vomit
Yellow vomit
Coffee-brown vomit, onion or garlic odor
Burnt almond odor
Extreme diarrhea
Nausea and vomiting, unconsciousness
possibly blindness
Carbon monoxide
Sulfuric acid
Hydrochloric acid
Nitric acid
Phosphorus
Cyanide
Arsenic, mercury
Methyl (wood) or isopropyl
(rubbing) alcohol
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Toxicology: Poisons and Alcohol
Federal Regulatory Agencies
Food and Drug Administration (FDA)-deals with pharmaceuticals,
food additives, and medical devices
Environmental Protection Agency (EPA)-Deals with agricultural and
industrial chemicals released into the environment.
Consumer Product Safety Commission-Concerned with toxins in
consumer products
Department of Transportation (DOT)-Deals with shipment of toxic
chemicals
Occupational Safety and Health Administration (OSHA)-concerned
with exposure to chemicals in the workplace
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Toxicology: Poisons and Alcohol
Critical Information
Form
Common color
Characteristic odor
Solubility
Taste
Common sources
Lethal dose
Mechanism
Possible methods of
administration
Time interval of onset of
symptoms
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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
Kendall/Hunt
Publishing
Company
Criminal Poisoning
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Toxicology: Poisons and Alcohol
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
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Toxicology: Poisons and Alcohol
Forensic Autopsy
Look for:
• Irritated tissues
• Characteristic odors
• Mees lines—single transverse white
bands on nails
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Toxicology: Poisons and Alcohol
Human Specimens for Analysis
Blood
Liver tissue
Urine
Brain tissue
Vitreous humor of eyes
Kidney tissue
Bile
Hair/nails
Gastric contents
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Toxicology: Poisons and Alcohol
Alcohol—Ethyl Alcohol (C2H5OH)
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Most abused drug in America
About 40 percent of all traffic deaths are alcohol-related
Toxic—affecting the central nervous system, especially the brain
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
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Toxicology: Poisons and Alcohol
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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Toxicology: Poisons and Alcohol
BAC: Blood Alcohol Content
 Expressed as percent weight per
volume of blood
 Legal limit in all states is 0.08
percent
Parameters influencing BAC:
• Body weight
• Alcohol content
• Number of beverages consumed
• Time since consumption
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Toxicology: Poisons and Alcohol
BAC Calculation
Burn-off rate of 0.015 percent per hour, but can vary:
Male
BAC = 0.071  (oz)  (% alcohol)
body weight
Female
BAC = 0.085  (oz)  (% alcohol)
body weight
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Toxicology: Poisons and Alcohol
Henry’s 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 2,100 to 1. In other words, 1 ml of blood will contain
nearly the same amount of alcohol as 2,100 ml of breath.
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Toxicology: Poisons and Alcohol
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 time
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Toxicology: Poisons and Alcohol
The Breathalyzer
More practical in the field
Collects and measures alcohol content
of alveolar breath
Breath sample mixes with 3 ml of 0.025 percent K2Cr2O7 in sulfuric acid
and water:
2K2Cr2O7 +3C2H5OH + 8H2SO4  2Cr2(SO4)3 + 2K2SO4 + 3CH3COOH + 11H2O
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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Toxicology: Poisons and Alcohol
Generalizations
 During absorption, the concentration of alcohol in arterial blood is
higher than in venous blood.
 Breath tests reflect alcohol concentration in the pulmonary artery.
 The breathalyzer also can react with acetone (as found in 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
readout. Prints out a card for a permanent record.
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Toxicology: Poisons and Alcohol
People in the News
John Trestrail is a practicing toxicologist who has consulted on many
criminal poisoning cases. He is the founder of the Center for the
Study of Criminal Poisoning in Grand Rapids, Michigan, which has
established an international database to receive and analyze
reports of homicidal poisonings from around the world. He is also
the director of DeVos Children’s Hospital Regional Poison Center.
In addition, he wrote the book Criminal Poisoning, used as a
reference by law enforcement personnel, forensic scientists, and
lawyers.
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Toxicology: Poisons and Alcohol
More Information
Read more about forensic toxicology at truTV’s Crime Library:
http://www.crimelibrary.com/criminal_mind/forensics/toxicol
ogy/2.html
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Toxicology: Poisons and Alcohol
Follow question to “An invisible enemy”
 How long prior to death did Todd start
experiencing symptoms?
 Under normal condition over exposure to
poison kills immediately, why was there a
delay?
 What were symptoms he experienced?
 What was the initial cause of death determined
by the medical examiner?
 What was the actual cause of death?
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Toxicology: Poisons and Alcohol
“ An Invisible Enemy” video question
 What type of poison was used?
 Why is it so difficult to detect this poison in
food?
 Was this a case of acute or chronic poisoning?
 What was the possible motive?
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Toxicology: Poisons and Alcohol
“ An Invisible Enemy” video question
 If you were a forensic witness for the
prosecution, what pieces of evidence would
you provide? Please reference information
from video and give at least three pieces.
 If you were a forensic witness for the
prosecution, what pieces of evidence would
you provide? Please reference information
from video and give at least three pieces.
 An what basis was Cynthia awarded a new
trial?
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Toxicology: Poisons and Alcohol
Toxic follow up questions
 Eric Miller’s symptoms were similar to those
of the ___________________
 What type of poison was used?
 Was Eric’s case one of chronic or acute
poisoning? Explain you answer based on
information from the video
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Toxicology: Poisons and Alcohol
Toxic follow up questions
 What were the possible motives cited for
murder
 What key pieces of evidence points to Ann
Miller as the killer?
 List three of Ann’s action that indicate that she
was guilty of Eric’s murder.
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