Almost everyone is familiar with the use of poison to commit murder. Movies such as the 1944 film “Arsenic and Old Lace” make it seem easy to trick a victim into consuming a deadly substance. But how can investigators tell when the cause of a victim’s death is poisoning?
It turns out that bodies contain a wealth of information about the toxic substances they have been exposed to. This includes recreational drugs as well as substances used with sinister intentions. A forensic science specialist called a forensic toxicologist has the knowledge to analyze a body to figure out if any toxic substances are present and whether they had and what effect they had on the person.
The applications of this field range from drug testing for employees and athletes to analyzing the cause of a murder victim’s death.
How exactly does forensic toxicology work?
That is, how do tissues and fluids from a body reveal whether toxic substances contributed to that person’s death? It turns out that when a substance enters the body, it enters all the different systems in the body. So, samples from the body contain evidence of any outside substances that the victim has eaten, breathed, or taken intravenously. Forensic toxicologists use principles from chemistry and pharmacology to determine which substances a victim was exposed to based on the amount and type of chemicals they find in the samples. Sometimes, chemical levels can even reveal an attempted cover up.
For example, criminals often try to cover up a murder by setting a fire. But if forensic toxicologists don’t find carbon monoxide in a victim’s blood, they know he or she must not have breathed the smoke and other byproducts of the fire, and was therefore not alive when the fire first started.
In the context of crime scene investigation, forensic toxicology is the process of analyzing the type and amount of each toxic substance that is present in a sample, and whether those chemicals had any effect on the person. This process is not straightforward, because the toxic substances do not stay in their original form once they enter the body. They are generally severely diluted and, in some cases, get metabolized into other forms.
The forensic toxicologist doesn’t go to the crime scene, but often receives important information about chemicals found by the crime scene investigator, mainly in the form of pill bottles or residues.
This information can help the forensic toxicologist understand what might have happened to the victim and figure out which tests to perform on the samples when they arrive in the lab. Forensic toxicologists generally perform two types of tests as they try to identify a toxic substance:
– Screening tests, which are short tests used to quickly assess the likelihood that the sample contains a particular substance.
– Confirmation tests, which are detailed tests used to verify a positive screening test.
Once the forensic toxicologist has confirmed the nature of the toxic substance, it is time to write a full report about the analysis and its conclusions. If the toxicological evidence is used in a case that goes to trial, the forensic toxicologist may be required to testify in court about the work.
If you are looking for an inspiring and captivating career, forensic toxicology may be just what you’re looking for!
About the author: Emily Nelson earned an M.S. in Electrical Engineering from the Massachusetts Institute of Technology before beginning her career as a science writer.