What is Forensic Toxicology?

The field of forensic science has come a long way – this is particularly true in the area of forensic toxicology, which is both fascinating and important for many applications. Forensic toxicology deals with the investigation of toxic substances, environmental chemicals or poisonous products. If you have ever been asked to take a drug test for work or you know someone who has, then you are already familiar with one of the applications of forensic toxicology. The toxicology part refers to the methods used to study these substances. Forensic toxicology is actually a bit of a mix of many other scientific disciplines such as chemistry, pathology and biochemistry. It also shares ties with some of the environmental sciences.

Using Forensic Toxicology Today

Forensic toxicologists perform toxicology screens, which involve looking for unusual chemicals in the body.

Currently, this area of forensics has evolved to mean the study of illegal drugs and legal ones such as alcohol. Forensic toxicology can even identify poisons and hazardous chemicals. The chemical makeup of each substance is studied and they are also identified from different sources such as urine or hair. Forensic toxicology deals with the way that substances are absorbed, distributed or eliminated in the body – the metabolism of substances. When learning about drugs and how they act in the body, forensic toxicology will study where the drug affects the body and how this occurs.

Obtaining Samples for Toxicology Testing

Before toxicology testing can go forward, samples need to be taken. You might be surprised to know just how many parts of your body can produce samples that are effective for identifying drugs. One example is urine, which is commonly used in forensic toxicology. It’s an easy sample to obtain and relatively rapid and non-invasive. It can show substances even several weeks after their ingestion. One example would be the drug marijuana, which can be detected even two weeks following use of the drug. When a urine sample is taken, however, there are sometimes rules and regulations around how the sample is collected. If the testing was related to workplace drug testing, a person could substitute a sample from someone else that would then show a negative result. For this reason, there are sometimes parameters around reasonable supervision when a person has to provide a urine sample.

Blood samples are another body sample used for forensic toxicology. A huge range of toxic substances can be tested from a blood sample. You may already be familiar with blood alcohol testing used to assess if a person was driving under the influence of alcohol. This type of testing is important in assessing if a driver is above the legal limit and it is also used to prove a case in court.

Hair samples are a good way to test for substance abuse that has occurred over the long-term. After a person ingests a chemical, it ends up in the hair, where it can provide forensic toxicologists with an estimate of the intensity and duration of drug use. Hair testing is even offered quite widely by companies that allow you to mail in a hair sample and check off the drugs you want checked. Saliva is another way that forensic toxicologists can test for drugs. It does, however, depend on the drug in terms of identifying its concentration. One of the more unusual sounding but interesting ways that the human body can be used for forensic toxicology involves the gastric contents in a deceased person. During the autopsy, a sample of the person’s gastric contents can be analysed, which then allows the forensic toxicologist to assess if the person took any pills or liquids before their death. The brain, liver and spleen can even be used during toxicology testing.

Forensic Toxicology Applications

While there are many uses for forensic toxicology testing, the most familiar one to most people is likely to be drug and alcohol testing. This type of testing is commonly performed in the transportation industry and in workplaces. Another use is for drug overdoses, whether these are intended or accidental. People who drive with a blood alcohol concentration over the accepted legal limit can also be assessed through toxicology testing. Another application of forensic toxicology relates to sexual assault that involves the use of drugs. Various drugs are used today for the purposes of rendering the victim unable to fight the attacker, who then proceeds to sexually assault the victim. Through toxicology testing, a victim can find out what drug was given and can then be treated accordingly.

There are a lot of substances and poisons in our world – many of which impact how we function in work and society. For some people, these substances can influence their death. Fortunately, forensic toxicology testing allows forensic scientists to identify substances and determine a pattern of use. In this way, a forensic toxicologist can provide closure on the ‘what if’ of a person’s drug habits or perhaps some mystery surrounding their death.

This article first appeared on Explore Forensics on the 4th of September 2014 and was authored by Ian Murnaghan – BSc (hons), MSc.

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