READ: Alcohol and Other Toxins

Alcohol

Toxicology of Alcohol

Alcohol Consumption

Alcohol is a colorless liquid that acts as a depressant by suppressing the central nervous system. Within minutes of consumption, alcohol appears in the blood stream and becomes evenly distributed throughout the body. About 20% of the alcohol consumed is absorbed through the stomach and the remaining 80% is absorbed through the small intestine. Once alcohol enters the bloodstream, it is pumped to the lungs and throughout the body. Factors that influence the concentration in the body include the time it takes to consume the drink, the amount of alcohol in the drink, and the number of drinks consumed. Other factors include the age, weight, and gender of the person who is doing the consuming. Interestingly, women metabolize alcohol differently than men. When given the same amount of alcohol, women typically will test with a higher blood alcohol concentration than men. This is due in part to the fact that women have less water in their bodies than men, thus the alcohol is not diluted in the same proportion as in men. Also, women have less response from the alcohol metabolizing enzyme in the stomach known as Alcohol Dehydrogenase, or ADH. Because the enzyme is less effective in women, more alcohol reaches the bloodstream of women after use. It is important to note that these are not simply benign differences between men and women. Because of the difference in alcohol metabolism and decreased efficiency, women are more likely to suffer from alcohol related liver and heart damage!

Alcohol Elimination

 Alcohol is eliminated through two processes: oxidation and excretion. Oxidation, which essentially means that it is combined with oxygen, occurs in the liver by the enzyme ADH. The ADH enzyme turns the alcohol into Acetaldehyde. Acetaldehyde is essentially a poison chemically related to Formaldehyde and can cause damage to your body with repeated exposure. Excretion of alcohol directly occurs in the breath, urine, and sweat. The kidneys convert alcohol to Carbon Dioxide and water. Excretion only accounts for about 2-8% of the alcohol metabolism. The remaining 92+% is metabolised by the body, mainly in the liver.The level of intoxication varies by person due to factors such as body weight, the rate of alcohol absorption, and the time and rate that the alcohol was consumed. This is why some people seem affected in profoundly different ways when drinking the same amount of alcohol.

Testing for Alcohol

Because alcohol is evenly dispersed throughout the body, the amount of alcohol measured in a breath test is directly proportional to the amount of alcohol in the blood stream. Alcohol is excreted, or released from the body without being changed in form, from the lungs through breathing, the pores by sweating, and from the kidneys by urination. This is why alcohol can be smelled on the breath and in the sweat of someone who has recently been drinking it. The body attempts to get rid of it in these ways directly. Alcohol in the blood will pass directly into the alveoli of the lungs where it will be passed out through the mouth and nose as the person breathes. The ratio of alcohol to alveolar breath is approximately 2100 to 1; this is the basis for calculating the Blood Alcohol Content, or BAC. Thus, Breathalyzers, or Breath testers reflect the amount of alcohol that is in the Pulmonary artery at the time of the test. Breath testers use infrared light or fuel cells to measure the concentration of alcohol in the breath and are typically conducted by law enforcement officers in the field. They work by shining an infrared light through the chamber where the breath is captured. As the light passes through the chamber, it will interact with the alcohol and cause the light density to decrease. The decrease in light intensity is proportional to the concentration of alcohol present in the captured breath.

In the Forensic laboratory, toxicologists collect blood, urine, and vitreous humor samples and test them by using gas chromatography. Field sobriety tests are sometimes used in the field by police officers as a type of screening test to either ascertain the level of impairment of the person or to see if further alcohol testing is needed in conjunction with a traffic or legal infraction. Field sobriety tests include various physical tests such as the "walk and turn", "stand on one leg" and "Horizontal Gaze Nystagmus" test. The Horizontal Gaze Nystagmus test is where the eyes will involuntarily jerk as an impaired person looks from one side to the other. When impaired by alcohol, a person has difficulty dividing their attention and maintaining balance; this is the basis for those particular screening tests of sobriety.

Alcohol and the Law

In 1973 a law was adopted by all states that anyone operating a motor vehicle will submit to a test for alcohol intoxication if requested or lose their license. In 2003 every state defined the legal limit of alcohol in the bloodstream to be 0.08 percent for people who are of legal age to drink, which is typically 21 years old. Prior to that, legal limits had been as high as 0.15! See the graph below to see how much more likely a person would be to have an accident with that Blood Alcohol Content or higher! It is important to note that while .08 is the legally accepted level of alcohol in the bloodstream, that it affects each person in different ways. It is also important to note that there are NO acceptable levels of legal alcohol consumption in persons under the age of 21 years of age in the United States.

Georgia Virtual, Forensic Toxicology, CC BY-NC-SA 3.0

The Toxicologist

Role of the Toxicologist

A toxicologist must identify one of thousands of drugs and poisons in given samples. This is often difficult given that they must find nanogram to microgram quantities of the toxin distributed throughout an entire body! In addition, a toxicologist is not always looking for exact chemicals, but for metabolites of desired chemicals. An example of this is Heroin, which converts into a specific type of morphine metabolite within seconds of administration. The metabolites act as a "tracer" for the drug and can be used to reliably indicate that a person has used that drug. In addition to determining which substances are present in the body, a toxicologist must also determine the amount of the substance and the effect that may have had on the body.

 Toxicologists are an important part of Forensic investigations. They are consulted on toxicology evidence to determine if toxins or drugs contributed to a crime or death. Many don't realize that toxicologists actually consult on many other types of criminal cases outside of death investigations. Important pieces of evidence and drug induced behavior in these cases can be evaluated by a toxicologist to provide crucial clues in a case. For example, a Forensic toxicologist may be able to provide testimony or a description of the level of impairment a person may have experienced under the influence of a particular level of drugs or alcohol while driving a car, flying a plane, navigating a ship or operating other heavy machinery. They might also be asked to testify in a case where a sexual assault took place while the victim was under the influence of a date rape drug. Still another example of the role of toxicologists is to determine if illegal drug use is taking place in upper level pro sports or olympic sporting events. Forensic toxicologists analyze samples from the athletes to determine if they are using any of the drugs on the list of banned substances for their particular sport such as steroids, stimulants and diuretics. An athlete found to be using any of the banned substances may be stripped of awards, medals or other titles within the sport. A famous example of this is that of cyclist, Lance Armstrong, who was found to be using several banned substances in order to win his 7 Tour de France titles. He was later stripped of all seven titles due to the doping scandal.

Georgia Virtual, Forensic Toxicology, CC BY-NC-SA 3.0

Other Toxins

Other Toxins

In Toxicology, not all cases involve alcohol or drugs. Some cases involve environmental or biological toxins which cause illness or death in an individual or group. The goal of Forensic Science in these cases is to identify or confirm the identity of the toxin and determine the amount present in the sample. Review some of the most common toxins in the sections below.

Pesticides and Heavy Metals

Pesticides are chemicals that are used to control pests such as weeds, insects, fungus, and rodents. These substances often contain heavy metals and are sometimes used intentionally to poison or murder, but they are also a source of accidental poisonings. Young children are particularly susceptible to accidental poisoning because they will sometimes put objects in their mouths not understanding that they are dangerous. Examples of heavy metals include Mercury, Lead, Arsenic, and Thallium.

When a child is seen for a checkup with their doctor, the parent is often questioned if the child was exposed to any items with lead paint or houses built prior to the 1970s due to Lead plumbing and paint. This is because lead poisoning occurs fairly easily in children who are exposed to relatively small amounts of lead, and this can cause permanent brain damage. Children's toys and furniture are also closely monitored by regulatory agencies to ensure that all paints and coatings are lead free. Other countries from which many products are imported do not have the same Lead standards as the United States, so children's products are often recalled due to unacceptable levels of Lead present in the product. Symptoms of Lead poisoning include abdominal pain, headaches, difficulty concentrating, fatigue, loss of appetite, personality changes, seizures, and coma.

 Mercury is another heavy metal which can be found in common items such as fish. Eating fish with high levels of Mercury can result in a build-up of Mercury in the body. This bioaccumulation of Mercury can cause issues with the sensory organ function (vision, smell, hearing) as well as a lack of coordination. In the image to the right, the Mercury accumulates in greatest concentrations in the larger fish; this is why it is best to avoid eating those fish on a regular basis. Symptoms of Mercury poisoning include a loss of peripheral vision, sensations of "pins and needles" in limbs and around mouth, coordination difficulties, muscle weakness and difficulty with speech or movement.

Arsenic poisoning is most commonly caused by drinking water tainted with Arsenic by organic sources, however there are many documented cases of intentional poisoning as well. Symptoms of Arsenic poisoning include confusion, headaches, drowsiness, severe diarrhea, vomiting and convulsions. A curious clue that may indicate to a clinician or medical examiner to test for Arsenic poisoning is that the breath and urine of an Arsenic poisoned person may smell strongly of garlic.

Thallium is an odorless, colorless and tasteless heavy metal that at one time was common in rat poison and pesticides. It can also be found as a naturally occurring metal in the Earth's crust, in minute amounts in cigarette smoke and as a part of certain medical imaging techniques. Absorption occurs through the skin, by ingestion or inhalation. The symptoms of Thallium poisoning begin as somewhat non-descript with nausea, vomiting and diarrhea. With continued exposure, the victim may lose their reflexes, have convulsions, headaches, psychosis, hair loss, coma and finally death.

 A symptom common to several heavy metal poisonings including Arsenic and Thallium is the presence of "Mee's Lines" on the fingernails. Mee's Lines are horizontal light colored lines across the nail, and are a signal to clinicians and medical examiners to conduct heavy metal toxicology testing. To test for heavy metals a forensic toxicologist generally tests the blood and urine of the victim and may use an indicator called the Reinsch test. The Reinsch test is able to detect the presence of Antimony, Arsenic, Bismuth, Selenium, Thallium and Mercury. Once the presence of a heavy metal is established, a more sophisticated method such as Atomic Absorption Spectrophotometry is used to evaluate the sample. Hair and nail samples can also be used to evaluate for long term heavy metal exposure and poisoning.

Biological Toxins

Exposure to certain biological agents such as certain bacteria, fungi, protozoa, plants, reptiles, amphibians, fish, urchins, starfish, mollusks, and insects can be toxic or even deadly. These toxins are generally unintentional, but they are important to be aware of in a death investigation in terms of toxicology. Some of the most common biological toxins are summarized below.

Tetanus

Sometime called "lockjaw", the bacteria Clostridium tetani is a poisonous bacteria that can cause violent, prolonged muscle spasms. The spasms begin in the jaw and progress to larger muscle groups to the point that the person is often arched and unable to lie flat. Most people are vaccinated against Tetanus and exposure occurs usually as a result of a puncture wound. It is often fatal without treatment and can result in long term health consequences even when treated. Treatment includes medication to get rid of the bacteria, airway support, and a very high protein diet with at least 3500-4000 calories per day to keep up with the metabolic needs after prolonged muscle contraction.

Botulism

 Perhaps the most poisonous biological substance known to exist, Botulism is produced by the bacteriaClostridium botulinum. Humans typically contract it by eating food contaminated with the bacteria, but Botulism is generally considered rare. It causes profound and progressive muscle paralysis and irreversible nerve damage. The paralysis typically begins from the top of the body and travels through the cranial nerves causing paralysis of facial muscles, eyelids drooping, difficulty chewing, difficulty swallowing, difficulty talking, and difficulty breathing as it progresses down the trunk of the body. Eventually the bowels become paralyzed as well. Throughout this progression, the victim retains their mental clarity and senses, though they may lose consciousness from time to time due to difficulty breathing and episodes of "blacking out". Botulism is fatal only about 7% of the time; this is due to advances in the care of people who have contracted Botulism.

Did you know that the Philosopher known as Socrates was sentenced to death for heresy? In the sentencing, he was ordered to drink Hemlock and thus died by his own hand at the order of the court. Hemlock, or Conium, is a very poisonous plant found in the Mediterranean and in Europe. It poisons by way of paralyzing muscles starting from the lower half of the body upward. Once it reaches the lungs, it suppresses respiration and the person is usually unable to breathe due to paralysis in that region. It is fatal in relatively small doses, though with prompt intensive medical treatment (including a ventilator), the chances of survival are vastly improved.

Bioterrorism Agents

Bioterrorism is the deliberate release of disease-causing agents such as bacteria, viruses, and other agents with the intention to harm or kill people, animals or plants (crops). Some bioterrorism agents are found to be naturally occurring, some are engineered to be resistant to antidotes or vaccines so that the impact on the intended population is greater. The disease causing agents are typically spread through the air, water or food supply.

Ricin

 Ricin is a poisonous protein found in the castor bean and is a by-product in the manufacture of Castor Oil. It is lethal even in very small amounts and can be found in the form of a powder, pellet or mist. Exposure can occur by inhalation, ingestion, or injection and death can occur within a few hours. Currently there is no antidote for Ricin poisoning, so treatment is supportive until the poison is out of the body. In June 2013, Shannon Richardson, an aspiring actress with minor roles in "The Walking Dead", "Vampire Diaries", and "The Blind Side" manufactured Ricin from Castor beans she ordered from the internet. She then laced threatening letters addressed to President Barack Obama with the Ricin and mailed them to the White House. She attempted to frame her estranged husband, but was quickly discovered to be the guilty party. She pled guilty in December 2013 with a plea bargain capping her prison sentence at 18 years.

Anthrax

Another deadly bacteria is Bacillus anthracis, which can enter the body via inhalation, ingestion, and absorption. It is naturally found in the soil and typically affects mostly livestock and other animals, but can sicken humans who have contact with infected animals as well. It is not contagious and can't be passed from person to person without direct exposure. Symptoms vary from the less severe itchy blisters or bumps of cutaneous Anthrax to the severe symptoms of Inhalation Anthrax and Gastrointestinal Anthrax. Of the two, Inhalation Anthrax is the most severe and would likely be the most fatal type in an attack. Symptoms of Inhalation and Gastrointestinal Anthrax include fever, dizziness, headache, nausea/vomiting/diarrhea, body aches, extreme fatigue and fainting among others. Exposure can lead to death, especially if ingested. Most recently anthrax was used as a bioterrorism weapon following the September 11, 2001 terrorist attacks in the United States. Anthrax spores were placed into envelopes mailed within the US Postal system. The FBI accused an American scientist named Bruce Ivins of being the sole suspect in the attacks. Dr. Ivins committed suicide and the case was closed, although some doubt that Dr. Ivins acted alone in the attacks or that he was even the actual person responsible for the attacks. The FBI maintains that their investigation yielded sufficient evidence to conclude that Dr. Ivins was the guilty party. In that attack, 22 people were infected and five died. Anthrax is likely to be used as a bioterrorism agent again because it is naturally found in nature which makes it easier to procure and because it can last for long periods in the area where it is released.

Other Common Poisons

 Cyanide is a chemical that combines with other chemicals to form harmful compounds such as Hydrogen Cyanide and Sodium Cyanide. It is found naturally in the environment in certain plants such as almonds, lima beans and spinach in low levels as well as in cigarette smoke and industrial manufacturing. Exposure to cyanide can occur through eating foods containing cyanide, breathing contaminated air, drinking contaminated water or touching contaminated soil. Exposure to Cyanide causes brain and heart damage and can lead to coma or death. A bitter almond smell on the breath of a living person or in the body during autopsy can alert a clinician or medical examiner to the presence of cyanide. Adolf Hitler, his wife Eva Braun Hitler, and the leader of the Nazi SS, Heinrich Himmler, all took Cyanide capsules when captured. Have you ever heard the phrase "Don't drink the Kool-Aid"? The saying stems from a famous case of Cyanide poisoning in 1978 known as the Jonestown Massacre. Jim Jones, leader of the "People's Temple" cult, coerced over 900 of the cult members to commit suicide by drinking Cyanide laced grape generic Kool-Aid.

Georgia Virtual, Forensic Toxicology, CC BY-NC-SA 3.0