Toxicology

ToxicologyPoison is any substance that can harm or kill.

Toxicology is the study of poisons.

Forensic Toxicology is the study of postmortem signs of the poisoning.

Toxicology The idea of poison came from the Greek

word, “toxicon,” which referred to poison arrows, and it is the root of “intoxicated,” which to the Greeks meant being sickened by poisoned arrows.

History of Poisonings The Greeks also developed a form of

capital punishment via poison with Hemlock, which was given to Socrates for corrupting the Athenian youth.

History of Poisonings 700 A.D. an Arab chemist turned arsenic into an

odorless, tasteless powder that was impossible to trace in the body until centuries later.

During the Renaissance, poisoning became an art form, inspiring subtle ways

to dispense with people via such items as poison rings, swords, knives, letters, and even lipstick.   

Poisoning societies developed, as did family businesses that relied on poison-for-hire as their trade. 

History of PoisoningsThe Council of Ten in Venice in 1419 poisoned people for a fee, using a mercury-based compound and various forms of arsenic. 

In Venice and Rome, there were even schools for people to learn how to do this.

History of PoisoningsPoison is the weapon of choice for women. Historically, more women than men have been mass or serial poisoners. Locusta, in Ancient Rome, was Nero’s

personal poisoner and the first documented serial killer.   She helped Nero to murder his brother with cyanide, and she also murdered several of his wives.

History of PoisoningsIn the 17th century, Italy’s Madam Toffana: used poison over 600 times, either

directly by her or indirectly by those to whom she sold her arsenic concoction.   

was allegedly involved with poisoning two popes.

Role of ToxicologistsDetect and identify

presence of drugs and poisons

body fluidsTissuesorgans

Role of Toxicologists Work in crime laboratories and medical

examiners’ offices May also reach into hospital laboratories

and health facilities to identify a drug overdose or monitor the intake of drugs

Major branch: measurement of alcohol in the body (violations of criminal law)

Toxicology of Alcohol

Toxicology of Alcohol• Primary objective of forensic

toxicologyAlcohol analysisDetection and isolation of

drugs in the bodyDetermine the influence of

alcohol on human behavior.

Toxicology of AlcoholAlcohol (ethanol, ethyl

alcohol)Colorless liquid Normally diluted with waterConsumed as a beverage

CNS depressant

Alcohol LevelsElimination of alcohol throughout the bodyOxidation: in the liverExcretion: unchanged in breath, urine, perspiration

Alcohol LevelsMeasure

Blood alcoholAlcohol content in the breath: direct proportion to the blood concentration

Alcohol LevelsAlcohol appears in the blood within

minutesSlowly increases in concentration

while it is being absorbed from the stomach (20%) and the small intestine

All the alcohol absorbed until the maximum alcohol level is reached in the blood

Alcohol LevelsPost absorption period begins Concentration slowly decreases until a zero level is again reached

Alcohol LevelsFactors influencing rate of

absorptionTime taken to consume the

drinkAlcohol contentAmount consumedFood present in the stomach.

Alcohol & Circulatory SystemClosed circulatory system consisting of a heart, arteries, veins, and capillaries

Alcohol absorbed from the stomach and small intestines

Carried to the liver where the process of its destruction starts

Alcohol & Circulatory SystemBlood, carrying alcohol, moves to

the heart, pumped to the lungsCarbon dioxide and alcohol

leave the bloodOxygen enters the blood in the

air sacs (alveoli)Carbon dioxide, alcohol exhaled

Breath Test Instruments Operate on the principle of infrared light

absorption Becoming increasingly popular within

the law enforcement community Designed to capture a set volume of

breath Captured breath is exposed to infrared

light

Breathalyzer Works by measuring the amount of

potassium dichromate destroyed.

Breathalyzer It is a glass ampoule containing:

Potassium dichromate Sulfuric acid WaterIn the chemical reaction with ethyl alcohol, the potassium dichromate gets used up.

OHCOOHCHSOKSOCrSOHOHHCOCrKr

2342342

4252722

1132)(2832

Considerations in Breath Testing Unit must measure alveolar breath (deep lung

breath) 1.5 liters breath needed

Avoid measuring mouth alcohol Regurgitation Belching Recent intake of alcohol Alcohol mouthwash

No foreign material 15-20 minutes before test Duplicate measurements within a few minutes

Field Sobriety Testing

Field Sobriety Testing Estimate motorist’s degree of physical

impairment by alcohol Evidential test for alcohol justified? Preliminary breath-alcohol content

Portable, handheld, roadside breath tester Contains fuel cell the oxidizes alcohol Produces electrical current proportional to

alcohol content

Field Sobriety TestingNystagmus Test Horizontal gaze nystagmus test Involuntary jerking as eye moves to side Subject unaware of jerking 0.10 % blood alcohol jerking before

movement of 45 degrees

Field Sobriety Testing Comprehension of two instructions Walk and turn

Stand heel to toe Walk nine steps heel-toe Turn around Repeat

One-leg stand Balance standing with heels together Stand on one leg 30 seconds Count aloud while standing

Analysis for Blood Alcohol

Analysis for BloodGas Chromatography TestingMost widely used approach for

determining alcohol levels in blood

Blood must beDrawn under medically

accepted conditionsBy a qualified individual

Gas Chromatography- Con’tNonalcoholic disinfectant be

applied before the suspect’s skin penetrated with a sterile needle or lancet

PreservationAnticoagulant and a

preservative addedSealed in an airtight container

and stored in a refrigerator

Links used History of Poisonings:

http://www.trutv.com/library/crime/criminal_mind/forensics/toxicology/5.html