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Forensic science TOXICOLOGY AND ALCOHOL. The study of Poisons and how they affect the human body. Toxicology. Toxicology — the study of the adverse effects of chemicals or physical agents on living organisms… Poisons Types: Environmental — air, water, soil

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forensic science toxicology and alcohol
  • The study of Poisons and how they affect the human body.


Toxicology—the study of the adverse effects of chemicals or physical agents on living organisms… Poisons


Environmental—air, water, soil

Consumer—foods, cosmetics, drugs

Medical, clinical, forensic

mathieu orfila 1787 1853
Mathieu Orfila(1787-1853)
  • “Father of Toxicology”
  • He gave the subject its first formal treatment in 1813 in his book Traitédes poisons, also called Toxicologiegénérale.(General Toxicology)
  • Wrote about the detection of poisons & their effects on animals.

Forensic Toxicology

Postmortem—medical examiner

or coroner

Criminal—motor vehicle

accidents (MVA)

Workplace—drug testing

Sports—human and animal


catastrophic, terrorism



Toxic substances may:

Be a cause of death

Contribute to death

Cause impairment

Explain behavior


Aspects of Toxicity

Dosage – Has 5 factors:

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


Lethal Dose

LD50refers to the dose of a substance that kills 50% of the test population, usually within four hours

Expressed in milligrams of substance per kilogram of body weight


Toxicity Classification

Link to LD 50 table


World’s Worst Industrial

Accident: Bopal India

In 1984 at the Union Carbide India pesticide plant in Bhopal,. Over 500,000 people were exposed to methyl isocyanate gas and other chemicals. The toxic substance made its way in and around the shanty towns located near the plant. The government of India confirmed a total of 3,787 deaths related to the gas release.[3] Others estimate 8,000 died within two weeks and another 8,000 or more have since died from gas-related diseases



What is the World’s

Deadliest Snake?

The deadliest snake is a Belcher's Sea-snake. It takes only 0.02 milligrams of venom to kill a person. They usually injects around 35 milligrams and that can kill around 15,000 people with one bite. Death can happen within 2 minutes.


Where are more people

killed by Snakes?

An estimated 12,000 people die annually from Cobra bites in India. It is possible that under the right conditions a person could die from a cobra bite in 30 minutes


Symptoms of Various Types of Poisoning


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

Type of Poison

Caustic poison (lye)

Carbon monoxide

Sulfuric acid

Hydrochloric acid

Nitric acid



Arsenic, mercury

Methyl (wood) or isopropyl

(rubbing) alcohol


Famous Poisons

Hemlockor Conium is a highly toxic flowering plant indigenous to Europe and South Africa. It was a popular one with the ancient Greeks, who used it to kill off their prisoners. For an adult, the ingestion of 100mg of conium or about 8 leaves of the plant is fatal – death comes in the form of paralysis, your mind is wide awake, but your body doesn’t respond and eventually the respiratory system shuts down. Probably the most famous hemlock poisoning is that of Greek philosopher, Socrates. Condemned to death for impiety in 399 BC, he was given a very concentrated infusion of hemlock.


Famous Poisons

Arsenic has been called “The King of Poisons”, for its discreetness and potency – it was virtually undetectable, so it was very often used either as a murder weapon or as a mystery story element. But that’s until the Marsh test came and signaled the presence of this poison in water, food and the like. However, this king of poisons has taken many famous lives: Napoleon Bonaparte and Simon Bolivar to name a few. On another note, arsenic, like belladonna, was used by the Victorians for cosmetic reasons. A couple of drops of the stuff made a woman’s complexion white and pale.


Famous Poisons

If you’re watching Sherlock Holmes, then you’ll know about this one. The Botulinum toxin causes Botulism, a fatal condition if not treated immediately. It involves muscle paralysis, eventually leading to the paralysis of the respiratory system and, consequently, death. The bacteria enter the body through open wounds or by ingesting contaminated food. By the way, botulinum toxin is the same stuff used for Botox injections!


Famous Poisons

Cyanide seems to be extremely popular (spies use cyanide pills to kill themselves when caught) and there are plenty of reasons for this. Firstly, it is found in a great variety of substances like almonds, apple seeds, apricot kernel, tobacco smoke, insecticides, and pesticides. Murder in this case can be blamed on a household accident, such as ingestion of pesticide – a fatal dose of cyanide for humans is 1.5 mg per kilogram of body weight. Secondly, it’s a rapid killer: depending on the dose, death occurs within 1 to 15 minutes. Hydrogen cyanide gas was used by Nazi Germany for mass murders in gas chambers during the Holocaust.


Famous Poisons


There are three forms of mercury which are extremely dangerous. Elemental mercury is the one you can find in glass thermometers, it’s not harmful if touched, but lethal if inhaled. Inorganic mercury is used to make batteries, and is deadly only when ingested. And finally, organic mercury is found in fish, such as tuna and swordfish (consumption should be limited to 170g per week), but can be potentially deadly over long periods of time. A famous death caused by mercury is that of Amadeus Mozart, who was given mercury pills to treat his syphilis.


Famous Poisons


The name of this plant is derived from Italian and means beautiful woman. That’s because it was used in the middle-ages for cosmetic purposes – diluted eye-drops dilated the pupils, making the women more seductive (or so they thought). Also, if gently rubbed on their checks, it would create a reddish color, what today would be known as blush! This plant seems innocent enough, right? Well, actually, if ingested, a single leaf is lethal and that’s why it was used to make poison-tipped arrows. The berries of this plant are the most dangerous – consumption of ten of the attractive-looking berries is fatal.


To Prove a Case of Poisoning

Prove a crime was committed:

1. Motive ?

2. Intent?

3. Access to poison?

4 Access to victim?

5. Death was homicidal?

6. Death was caused by poison?

pattern of poisoning
Pattern of poisoning
  • Chemical products, most often swallowed by children include household cleaners (bleach, detergents) fuel (kerosene, paraffin), cosmetics, medicines, paints and products for household repairs and household pesticides.
  • Bites and stings of animals and insects, and ingestion of poisonous plants and seeds also considerably account for outdoor poisoning in children.
poisoning in children
  • Poison is a substance that causes harm if it gets into the body.
  • The poisoning in children could occur due to diverse causes and could be classified as
    • accidental,
    • homicidal or
    • suicidal.
  • Erroneous administration of over dosage of drugs by the parents or by the medical staff is also frequent.
accidental poisoning
Accidental Poisoning
  • Accidental poisoning in children is a global problem. The relative importance of poisoning as a cause of childhood morbidity and mortality increases when malnutrition and infections are brought under control.
  • Accidental poisoning is the twelfth leading cause of admissions in pediatric wards in India and accounts for about one percent of the hospitalized patients. Most cases of accidental poisoning are preventable. Continuing morbidity and mortality due to accidental poisoning is serious challenge to the pediatricians and public health officials.
acute or chronic exposure
Acute or Chronic Exposure
  • Acute exposure is a single contact that lasts for seconds, minutes or hours, or several exposures over about a day or less. Chronic exposure is contact that lasts for many days, months or years.
  • A poison may get into the body through ingestion, inhalation (gas, vapors, dust, fumes, smoke, spray), skin contact (pesticides), or injection (bites and stings, drug injection
carbon monoxide
Carbon Monoxide
  • Carbon monoxide poisoning can happen when fires, stoves, heaters or ovens are used in rooms, huts which do not have proper ventilation to let the gas out.

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, Acts as a depressant, especially the brain.

Colorless liquid, generally diluted in water

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


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 oxidation starts.
  • It also goes through the circulatory system into the lungs where it is exhaled as a gas.

Alcohol Effects upon the body

As can be seen, the effects of alcohol upon the body are not good. With repeated exposure, general health declines.


Alcohol Breaks down to Acetaldehyde

In humans, acetaldehyde is a carcinogen and is the reason for hang overs. It causes drowsiness, delirium, hallucinations and loss of intelligence. Exposure may also cause severe damage to the mouth, throat and stomach; accumulation of fluid in the lungs, chronic respiratory disease, kidney and liver damage, throat irritation, dizziness, reddening and swelling of the skin


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.
  • Estimated costs of alcohol related crashes in 2000 were over $114 b ($51 billion in monetary costs, $63 b in quality of life losses)


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

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


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

BAC Calculation

Your liver oxidizes alcohol to filter it out of the body. This Burn-off rate is 0.0015 percent per hour, (but can vary)

Healthy liver metabolizes about

0.5 oz = 15 ml of alcohol per hour





0.071  (oz)  (% alcohol)

body weight

0.085  (oz)  (% alcohol)

body weight

what s a standard drink
What's a "standard" drink?

Many people are surprised to learn what counts as a drink. In the United States, a "standard" drink is any drink that contains about 0.6 fluid ounces or 14 grams of "pure" alcohol. Although the drinks below are different sizes, each contains approximately the same amount of alcohol and counts as a single standard drink.

blood alcohol legal limits
Blood Alcohol legal limits

Legal maximum BAC in USA is

.08% or 0.8 grams/kilogram

• 1 beer = 0.6 oz alcohol = 14 grams

• 150 lb adult = 68 kg

• 63% body weight from blood = 42.8 kg

• 14/42800 = 0.000327or 0.327 grams/kg or .0327%

• 2.5 beers produces BAC of about 0.083%

blood alcohol concentrations
Blood Alcohol concentrations

.020 - light to moderate drinkers begin to feel some effects

* .040 - most people begin to feel relaxed

* .060 - judgment is somewhat impaired, people are less able to make rational

decisions about their capabilities (for example, driving)

* .080 - there is a definite impairment of muscle coordination and driving skills;

this is legal level for intoxication in all states

* .10 - there is a clear deterioration of reaction time and control; this is legally

drunk in most states

* .120 - vomiting usually occurs. Unless this level is reached slowly or a person

has developed a tolerance to alcohol

* .150 - balance and movement are impaired. This blood-alcohol level means

the equivalent of 1/2 pint of whiskey is circulating in the blood stream

* .300 - many people lose consciousness

* .400 - most people lose consciousness; some die

* .450 - breathing stops; this is a fatal dose for most people

what is blood alcohol concentration
What is blood alcohol concentration:

What is blood alcohol concentration?

• Ratio of amount of alcohol in the blood to the amount of blood.

• 1 gram of alcohol per kilogram of blood is a ratio of 1/1000 or 0.001 alcohol/blood.

• 0.001 alcohol/blood concentration is 0.10%

blood alcohol calculator
Blood Alcohol Calculator


how many drinks in different examples
How many drinks in different examples?

In the United States, a "standard" drink is any drink that contains about 0.6 fluid ounces or 14 grams of "pure" alcohol. Below is the approximate number of standard drinks in different sized containers of

now your turn
Now your Turn

Find the BAC for a 255-lb man who, in 2 hours, has drunk 13 beers. (Assume that each beer is 12 oz with a 4.5% alcohol content.) Round your answer to the nearest thousandth.

  • BAC = 0.071  (oz)  (% alcohol)
  • body weight

BAC = 0.071 x 12 oz x 13 beers x 4.5%

255 lbs

= 0.19%


Alcohol Levels

  • Experimental evidence has verified that the amount of alcohol exhaled in the breath is in direct proportion to the blood concentration.

Field Testing

  • Law enforcement officers typically use field sobriety tests to estimate a motorist’s degree of physical impairment by alcohol and whether or not an evidential test for alcohol is justified.
  • The horizontal gaze nystagmus test, walk and turn, and the one-leg stand are all considered reliable and effective psychophysical tests.

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

Breath Testers

  • It’s the degree of the interaction of the light with alcohol in the captured breath sample that allows the instrument to measure a blood alcohol concentration in breath.
  • Some breath testing devices also use fuel cells.

Modern Breath Testers

  • Breath testers that operate on the principle of infrared light absorption are becoming increasingly popular within the law enforcement community.


One of the first breathalyzers used chemical reactions to measure alcohol in 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.



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.


Breath Testers

  • Many types of breath testers are designed to analyze a set volume of breath.
  • The captured breath is exposed to infrared light.
  • Can be built into cars.
  • Car can’t start if drunk.

Field Testing

  • A portable, handheld, roadside breath tester may be used to determine a preliminary breath-alcohol content.

Gas Chromatography Testing

  • Gas chromatography offers the toxicologist the most widely used approach for determining alcohol levels in blood.

Alcohol and Law

  • The American Medical Association and the National Safety Council have been able to exert considerable influence in convincing the states to establish uniform and reasonable blood-alcohol standards.
  • Between 1939 and 1964 a person having a blood-alcohol level in excess of 0.15 percent w/v was to be considered under the influence, which was lowered to 0.10 percent by 1965.

Alcohol and Law

  • In 1972 the impairment level was recommended to be lowered again to 0.08 percent w/v.
  • Starting in 2003, states adopted the 0.08 percent
  • Commercial drivers are allowed only 0.04% because of the possible dangers of driving large and hazardous payloads.

Alcohol and Law

  • To prevent a person’s refusal to take a test for alcohol consumption, the National Highway Traffic Safety Administration recommended an “implied consent” law.
  • Adopted by all states by 1973, this law states that the operation of a motor vehicle on a public highway automatically carries with it the stipulation that a driver will submit for a test for alcohol intoxication if requested or be subject to loss of the license.