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
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
Sports—human and animal
Toxic substances may:
Be a cause of death
Contribute to death
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
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
Link to LD 50 table
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. Others estimate 8,000 died within two weeks and another 8,000 or more have since died from gas-related diseases
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.
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
Characteristic burns around the lips and
mouth of victim
Red or pink patches on the chest and
thigh, unusually bright red lividity
Coffee-brown vomit, onion or garlic odor
Burnt almond odor
Nausea and vomiting, unconsciousness
Type of Poison
Caustic poison (lye)
Methyl (wood) or isopropyl
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.
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.
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!
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.
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.
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.
Prove a crime was committed:
1. Motive ?
3. Access to poison?
4 Access to victim?
5. Death was homicidal?
6. Death was caused by poison?
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
As can be seen, the effects of alcohol upon the body are not good. With repeated exposure, general health declines.
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
Amount of alcohol consumed
The alcohol content of
Time taken to consume it
Quantity and type of food
present in the stomach
Physiology of the consumer
Expressed as percent weight per volume of blood
Legal limit in all states is 0.08 percent
Parameters influencing BAC:
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)
0.085 (oz) (% alcohol)
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.
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%
.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?
• 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%
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
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 x 12 oz x 13 beers x 4.5%
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:
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 + 8H2SO42Cr2(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.