Chapter 6 Toxicology: Poisons and Alcohol “All substances are poisons. There is none which is not....

Chapter 6

Toxicology:Poisons 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

A quantitative approach to toxicology.

The danger of using alcohol.

Students will learn:

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Toxicology and Alcohol

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.

Students will be able to:

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Toxicology

Definition—the study of the adverse effects of chemicals or physical agents on living organisms.

Types:Environmental—air, water, soilConsumer—foods, cosmetics, drugsMedical Forensic

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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

Toxic substances may:Be a cause of deathContribute to deathCause impairmentExplain behavior

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Historical Perspective of 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.

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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 Orfila—known 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

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

Chapter 6

Death by WaterHold your wee for a wii

In 2007, a mother tried to win a wii game for her son at a radio show contest

Contestants had to drink a water bottle every 5 minutes without using the bathroom

The mother died of water poisining12

Chapter 6

How much water is too much water?

1.5 to 2.0 gallons can be toxic to your body

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Toxicity Classes

LD50 (rat,oral) Correlation to Ingestion by 150 lb Adult Human

Toxicity

<1mg/kg a taste to a drop extremely

1-50 mg/kg to a teaspoon highly

50-500 mg/kg to an ounce moderately

500-5000 mg/kg to a pint slightly

5-15 g/kg to a quart practically non-toxic

Over 15g/kg more than 1 quart relatively harmless

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Federal Regulatory Agencies

Food and Drug Administration (FDA)

Environmental Protection Agency (EPA)

Consumer Product Safety CommissionDepartment 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 lines—single 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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Alcohol—Ethyl Alcohol (C2H5OH)

Most abused drug in America About 40% of all traffic deaths are alcohol-related Toxic—affecting 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 Detoxification—about 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:

MaleBAC male = 0.071 x (oz) x (% alcohol)

body weight Female

BAC female = 0.085 x (oz) x (% alcohol) body weight

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Field Tests Preliminary tests—used to determine the degree of

suspect’s physical impairment and whether or not another test is justified.

Psychophysical tests—3 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.

Chapter 6

Implied Consent Law

Driver must consent to tests or lose license

Implemented to prevent refusal to take breath test on grounds of self incrimination

Chapter 6

Mouth Alcohol

Alcohol present in a breath test subject’s mouth Presence of mouth alcohol causes the concentration

detected in exhaled breath to be higher then the actual blood concentration

Sources include Regurgitation Belching Recent intake of an alcoholic beverage Recent gargling of alcohol containing mouthwash

Chapter 6

Forensics 4/1/13

Welcome back! Any good spring break stories?

Don’t forget to turn in extra credit assignment Midterm Friday: includes CH 6 quiz

(toxicology) CH. 8 blood, CH. 5 Drugs CH 6 supp questions are due this Fri 4/5/12

(Bring your textbook Wednesday)29

Chapter 6

Case Study

Read the Case Study: Death by Tylenol

Answer the following questions as a group:

1. Where did this event take place?

2. What is Product Tampering ?

3. How do you think the investigators determined the capsules contained a quantity of poison “ten thousand times what was needed to kill an average person” ?

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Chapter 6

The Metabolism of alcohol

Metabolism:

The transformation of a chemical in the body to other chemicals to facilitate its elimination from the body

Happens in three steps: absorption, distribution and elimination

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Chapter 6

Absorption

Alcohol enters the blood stream by passing across the wall of the stomach and small intestine

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Chapter 6

Distribution

The alcohol becomes evenly distributed throughout the watery parts of the body (including the blood and the brain)

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Chapter 6

Elimination

Alcohol is eliminated in two ways:

1.oxidation: the combination of alcohol with oxygen to produce carbon dioxide and water (oxidation occurs in the liver)

2. excretion: elimination of alcohol from the body in an unchanged state (breath and urine)

95% of consumed alcohol eliminated through oxidation

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Chapter 6

Alveoli

Small sacks in the lungs that exchange oxygen, carbon dioxide and other gases with the blood

Carbon dioxide and other volatile chemicals (alcohol) are then expelled through the nose and mouth

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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 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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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 water2K2Cr2O7 + 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

Chapter 6

The Breathalyzer

More modern breathalyzers don’t use chemicals

1. Infrared Light Absorption: Alcohol present in a subject’s breath reacts with a particular wavelength of inrared light

2. The Fuel Cell: a chemical reaction involving alcohol produces electricity (electrons)

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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.

Chapter 6

Forensics 4/2/13

Don’t forget to bring your textbook Wednesday/Thursday so that you can work on your CH 6 questions and prepare for your midterm Friday!

Midterm Friday: Primarily on CH 6 with questions from CH 5 (drugs) and CH 8 (blood)

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Chapter 6

A man of 185 lbs drinks three shots (1.5 oz/shot) of Jack Daniels 80 proof (40%) in an hour.

1. What is his BAC?

2. Is it ok for him to drive home? Explain

3. What is the BAC if the above person is a woman?

4. Why the difference from male to female for BAC?

Chapter 6

Rank from most to least intoxicated and explain your reasoning.

John 200lb had eight 8oz drinks on a full stomach.

Frank 170 lb had four 8oz drinks on an empty stomach

Gary 240 lb had six 8oz drinks on an empty stomach

Stephan 180 lb had six 8oz drinks on a full stomach

Chapter 6

Blood Samples

Clean injection site with non-alcohol astringent Need preservative and refrigeration Over time alcohol breaks down

Chapter 6

Blood Samples

Forensic Laboratories use gas chromatography to determine blood-alcohol content

Compare alcohol peaks with KNOWN blood- alcohol standards

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Chapter 6

Hair samples

The only viable option if it is necessary to ascertain whether a subject has been abusing a drug over a longer period of time

( drugs remain in blood stream for 24 hours and in urine for up to 72 hours)

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Chapter 6

Hair Samples

Hair is nourished by blood flowing close to the hair root

Drugs present in blood become permanently trapped in hair’s protein structure

Can date the presence of drugs dating back over a period of weeks, months and sometimes years

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Chapter 6

Case Study

Read the case study: Joann Curly: Caught by hair

Answer the following questions as a group:

1. If Bobby’s urine showed high levels of thallium in his body, does this indicate recent or distant exposure?

2. How did investigators determine that Bobby wasn’t exposed to the poison at work?

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Chapter 6

Match the organization to the concerns

Organizations

1) FDA 2) EPA 3) Consumer Product Safety Commission 4) DOT 5) OSHA

Concerns

a. Toxins in consumer products

b. Exposure to chemicals in the work place

c. Agricultural and industrial chemicals

d. Pharmaceuticals, food additives and medical devices

e. Shipment of toxic chemicals

Chapter 6

More Information on alcohol

http://www.intox.com/t-AboutAlcohol.aspx http://www.intox.com/t-Physiology.aspx

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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, forensic scientists and lawyers.

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More Information

Read more about Forensic Toxicology from Court TV’s Crime Library at:

http://www.crimelibrary.com/criminal_mind/forensics/toxicology/2.html