Forensic toxicology plays an exceptionally vital role in linking victim deaths to drug use, poisonings, and the detection of foreign chemicals and toxins in the human body. The utilization of analytical chemistry and a few chemical tests can tell investigators if the victim was under the influence of any drugs or even poisoned, by studying samples of blood, urine, hair and even bodily fluids. Forensic toxicologists detect and identify the foreign chemicals in the body, the concentration of these chemicals, and link these findings to possible drug overdose, poisoning and even suicide which help investigators greatly, as they can guide their investigation in reference to the toxicology panel. However, discovering ingested substances in the human body isn’t as easy as it seems.
According to Katherine Ramsland of Court TV, “determining the substance ingested is often complicated by the bodies natural processes, as it is rare for a chemical to remain in its original form once in the body.” “For example, heroin is almost immediately metabolized into another substance and further to morphine, making detailed investigation into factors such as injection marks and chemical purity necessary to confirm diagnosis.” Overall, the collection of bodily samples, the technology of screening and confirmation tests and the detection and classification process has improved significantly in the past years, and thanks to technology, it has assisted investigators in solving some of the most complicated crimes.
In order to process a toxicology panel, it is necessary to obtain a sample from the human body. Samples can be taken in the forms of urine, blood, hair, saliva and bodily fluids such stomach contents, semen and vitreous humour from the eye. Urine samples are the easiest way of collection from a live person, and can also be collected from the deceased. They are typically utilized for on-site drug testing in employees and athletes, and sometimes used as post-accident drug tests. However, trace amounts of toxins and drugs only record in the urine for about two weeks post-ingestion. Blood samples, possibly the most informative sample, provides toxicologists with a full panel, and is even more important in DUI cases since it reveals the blood alcohol level of individuals and again, assists the investigators in solving the current investigation. Samples of hair give toxicologists a much more further look back, for hair samples can give evidence of long term addictions or higher dose abuse.
“Chemicals in the bloodstream may be transferred to the growing hair and stored in the follicle, providing a rough timeline of drug intake events. Head hair grows at rate of approximately 1 to 1.5 cm a month, and so cross sections from different sections of the follicle can give estimates as to when a substance was ingested.” (Levine, “Forensic Toxicology”) Amazingly, there have been tests done to show that the darker and coarser the hair, the more drug will be found in the hair. So if two people consumed the same amount of drugs, the person with the darker and coarser hair will have more drug in their hair than the lighter haired person when tested. This raises issues of possible racial bias in substance tests with hair samples. Stomach contents are another considerable inspection that must be completed with every autopsy.
The contents provide the toxicologists and investigators with the nature of their last meal, by studying the digestion process, it can give you a time frame of when this meal was ingested and therefore the victim died after the meal was ingested. Also, undigested pills can also be found in the stomach, which gives information of a possible pharmaceutical overdose, possible poisoning or even links to a synergistic effect on the body. Overall, the specimens that can be studied by toxicologists assist investigations greatly and expose information that would have never been known by naked-eye observations.
According to C. Klaasen and his book “Principles of Toxicology and Treatment of Poisoning”, toxicology tests come in two steps: screening tests and confirmation tests. “Screening tests allow the processing of specimens for a wide range of toxins in a short time. Any positive indications from the screening tests must be verified with a confirmation test.” Some screening tests include physical tests (boiling point, melting point), crystal tests (treatment with chemical reagent to produce crystals) and chemical spot tests (treatment with chemical reagents to produce color change). Once these screening tests are confirmed, confirmation tests must be performed as a mass spectrometry, which “a combination of gas chromatography/mass spectrometry which is generally accepted as the confirmation test of choice.
Each toxin has a known mass spectra, or “fingerprint”, which is infallible proof of its presence at the chemical level.” (Klaasen, 136) Usually, toxicologists are not one to give an opinion of whether the toxin levels were enough to cause death, the defense usually calls upon medical experts who must be physicians (expert witnesses) to determine if the levels are indeed high enough to cause death. Yet, low-level, trace amounts of drugs and toxins truly cause battles between the experts.
Overall, drug overdose, suicide and poisoning are the three most common occurrences a toxicologist faces. Toxicology is significantly important in determining the cause of death, and the tests performed can uncover large amounts of information about how this person died, either it be a homicide, overdose or suicide. Investigators guide their investigations based on the results from the toxicology panel, and granted if toxicologists did not have access to the science and technology they do today, we would find ourselves solving much less cases and running into many more problems.
Klaasen, C. (1996). “Principles of Toxicology and Treatment of Poisoning”
Levine, A. (1993). “Forensic Toxicology” Journal of Analytical Chemistry