TOXICOLOGY OF ALCOHOL

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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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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 death

Contribute to death

Cause impairment

Explain behavior

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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

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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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Symptoms of Various Types of Poisoning

Symptom/EvidenceCharacteristic 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, unconsciousnesspossibly blindness

Type of PoisonCaustic poison (lye)

Carbon monoxide

Sulfuric acidHydrochloric acidNitric acidPhosphorusCyanideArsenic, mercuryMethyl (wood) or

isopropyl(rubbing) alcohol

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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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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 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 percent in the liver

About 5 percent is excreted unchanged in breath, perspiration, and urine

Introduction• A major branch of

forensic toxicology deals with the measurement of alcohol in the body for matters that pertain to violations of criminal law.

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Rate of Absorption

Depends on:

Amount of alcohol consumed

The alcohol content ofthe beverage

Time taken to consume it

Quantity and type of food present in the stomach

Physiology of the consumer

Toxicology of Alcohol• The analysis of alcohol exemplifies the

primary objective of forensic toxicology—the detection and isolation of drugs in the body for the purpose of determining their influence on human behavior.

• Alcohol, or ethyl alcohol, is a colorless liquid normally diluted with water and consumed as a beverage.

Toxicology of Alcohol• Like any depressant, alcohol principally

effects the central nervous system, particularly the brain.

Alcohol Levels• Factors such as time taken to consume

the drink, the alcohol content, the amount consumed, and food present in the stomach determine the rate at which alcohol is absorbed.

Alcohol Levels• Elimination of alcohol throughout the

body is accomplished through oxidation and excretion.

• Oxidation takes place almost entirely in the liver, while alcohol is excreted unchanged in the breath, urine, and perspiration.

• The extent to which an individual may be under the influence of alcohol is usually determined by either measuring the quantity of alcohol present in the blood system or by measuring the alcohol content in the breath.

Alcohol & Circulatory System• Humans have a closed circulatory system

consisting of a heart, arteries, veins, and capillaries.

Alcohol & Circulatory System• Alcohol is absorbed from the stomach

and small intestines into the blood stream.

• Alcohol is carried to the liver where the process of its destruction starts.

Alcohol & Circulatory System• Blood, carrying alcohol, moves to the

heart and is pumped to the lungs.

Alcohol & Circulatory System• In the lungs, carbon dioxide and alcohol

leave the blood and oxygen enters the blood in the air sacs known as alveoli.

• Then the carbon dioxide and alcohol are exhaled during breathing.