by Andrea CampbellQ: Can you tell me more about toxicology and what a forensic toxicologist is all about?
A: The busiest department in a crime lab, hands down, has to be forensic toxicology. This science is essentially a specialty area of analytical chemistry, so think vials, jars, and lots of machinery to test them when you consider this area's discipline.
Toxicology, per se, is the science of adverse effects of chemicals, either natural or man-made, on living organisms. The job of a toxicologist is to detect and identify foreign chemicals in the body, with a particular emphasis on toxic or hazardous substances. There are several sub-groups of toxicology expert: a descriptive toxicologist performs toxicity tests to evaluate the risk that exposure poses to humans; a mechanistic toxicologist attempts to determin
e how substances exert deleterious effects on living organisms; and the regulatory toxicologist judges whether or not a substance has low enough risk to justify making it available to the public.
Toxins
then, are materials that threaten the life of living things. Poisons are a subgroup of toxins. Toxic materials can come in many forms such as gas, liquids, solids, animal, mineral and vegetable. Toxins can be ingested, inhaled or absorbed through the skin and organs. Some toxins have medicinal value and, if this is the case, the amount that is taken is significant to health, but—if abused, may cause irreparable damage. Toxins may have antidotes, but some do not.
Some toxins may disguise or mask themselves, whereas some are identifiable by their symptoms. Here are a couple of examples of toxins and their symptoms:
e how substances exert deleterious effects on living organisms; and the regulatory toxicologist judges whether or not a substance has low enough risk to justify making it available to the public.Toxins
then, are materials that threaten the life of living things. Poisons are a subgroup of toxins. Toxic materials can come in many forms such as gas, liquids, solids, animal, mineral and vegetable. Toxins can be ingested, inhaled or absorbed through the skin and organs. Some toxins have medicinal value and, if this is the case, the amount that is taken is significant to health, but—if abused, may cause irreparable damage. Toxins may have antidotes, but some do not.Some toxins may disguise or mask themselves, whereas some are identifiable by their symptoms. Here are a couple of examples of toxins and their symptoms:
Acids (nitric, hydrochloric, sulfuric) = Burns around mouth, lips, nose
Aniline (hypnotics, nitrobenzene) = Skin of face and neck quite dark
Atropine (Belladonna, Scopolamine) = Pupil of eye dilated
Arsenic (metals, mercury, copper, etc.) = Severe, unexplained diarrhea
Carbon Monoxide = Skin is bright cherry red
Cyanide = Quick death, red skin, odor of peach
Nicotine = Convulsion
Opiates = Pupil of eye contracted
And so forth.
The true incidence of poisoning in the United States is unknown. Approximately 2 mill
ion cases are voluntarily reported to poison control centers each year, and officially, a rather steady figure of about 700 deaths by poisoning is reported each year. Children under age 6 account for the majority of poisonings reported, but adults account for the majority of deaths by poisoning, most of which is intentional rather than accidental.
Some common reported poisons are: household cleaning supplies, antidepressant medications, analgesics (aspirin, acetaminophen), street drugs, cough and cold remedies, cardiovascular drugs, plants, alcohol, gases and fumes, pesticides, asthma therapies, industrial chemicals, sedatives, food poisoning, insects and other animals.
It is not easy to distinguish toxic from nontoxic substances. A key principle in toxicology is the dose-response relationship. The toxic effects of substances are not side effects. "Side effects" are defined as non-deleterious, such as dry mouth, for example. Toxic effects are the undesirable results of a direct effect, like the result of too much stress on the body; in other words, the body is upset by physical, chemical or biological agents and it manifests itself as a reaction. Toxic reactions are classified as one of three reactions: pharmacological—with injury to the central nervous system; pathological—with injury to the liver; and genotoxic—causing the creation of benign or malignant neoplasms or tumors.
ion cases are voluntarily reported to poison control centers each year, and officially, a rather steady figure of about 700 deaths by poisoning is reported each year. Children under age 6 account for the majority of poisonings reported, but adults account for the majority of deaths by poisoning, most of which is intentional rather than accidental.Some common reported poisons are: household cleaning supplies, antidepressant medications, analgesics (aspirin, acetaminophen), street drugs, cough and cold remedies, cardiovascular drugs, plants, alcohol, gases and fumes, pesticides, asthma therapies, industrial chemicals, sedatives, food poisoning, insects and other animals.
It is not easy to distinguish toxic from nontoxic substances. A key principle in toxicology is the dose-response relationship. The toxic effects of substances are not side effects. "Side effects" are defined as non-deleterious, such as dry mouth, for example. Toxic effects are the undesirable results of a direct effect, like the result of too much stress on the body; in other words, the body is upset by physical, chemical or biological agents and it manifests itself as a reaction. Toxic reactions are classified as one of three reactions: pharmacological—with injury to the central nervous system; pathological—with injury to the liver; and genotoxic—causing the creation of benign or malignant neoplasms or tumors.
For certification as a toxicologist, an individual must possess a Ph.D. or doctorate in one of the natural sciences. Undergraduate degrees must also be in either biology or chemistry, usually. Certification is bestowed by the American Board of Forensic Toxicology and the expert may use the title of “Diplomate,” which must be renewed every three years. Board-certified toxicologists will never face difficulties qualifying as an expert witness. State crime laboratories may not have a toxicologist on staff, their functions being performed by a criminalist, a biochemist, a forensic biologist or other technician. These personnel would typically have a Bachelor’s or Master’s degree in any of the sciences.
A forensic toxicologist is normally presented with preserved samples of body fluids, stomach contents, and organ parts. They will have access to the coroner’s report which should contain information on various signs and symptoms as well as other postmortem data. The toxicologist needs a thorough knowledge of how the body alters or metabolizes drugs because few substances leave the body in the same state as when they entered.
Hooray for toxicologists, an overworked group and a much needed discipline in the realm of forensic science.
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