Forensic Toxicology - An Overview

The branch of forensics that deals with the examination of biological samples to determine the presence of drugs and poisonous substances is known as Forensic Toxicology. It analyzes the samples collected as evidence from the crime scene and the body of the deceased to know the cause of the death. Toxicologists conduct various tests to determine the level of intoxicants present in the human body and their adverse effects on it. These experts work in close collaboration with the medical examiners and crime investigators. Apart from this, they also testify in the court of law and present their findings of the concerned case.

What is Forensic Toxicology?

Under this branch of forensics, students are taught the effect of chemicals and toxins on human bodies, animals, and the environment. These people are involved directly in the case investigation only in cases where a person dies after consuming some toxic substances. They examine the drug present in the body through blood and urine tests.

What Do Toxicologists Do?

The role of these experts is quite important in the field of crime investigation. There are cases when the victim is dead and the police can’t determine the actual cause behind his/her demise. In such cases, these experts conduct sample tests on the corpse and try to identify the cause of the death. They identify the presence of chemicals in the body that lead to his death. The role of toxicologists has been mentioned below:

• They provide information regarding the effects of drugs and other toxic chemicals on the human body and animals to law enforcement agencies,
• They testify in the court of law and present their opinion on the case as an expert,
• They present their findings and present them as evidence to the court,
• In cases where the deceased died because of a drug overdose, they determine whether it was accidental or a planned murder,
• Apart from this, they also furnish information regarding the potential effects of a substance on the mental and physical health of a person,
• These are the same people who determine the level of alcohol consumed by the person before the death.

Areas of Investigation:

Though there are so many areas these experts investigate to identify the presence of toxins and chemicals but a few of them are the important ones. Here we have mentioned the most important areas investigated by these experts:

• Drink and Drive Cases: The cases of drink and driving are common across the world. Road accidents and deaths because of such cases are increasing continuously and increasing road safety concerns. These experts analyze the body of the deceased in case of road accidents to determine whether the deceased was under the influence of alcohol or not. They do so by examining their urine and blood samples during the post-mortem. Thus, they present their findings to the police and assist in the crime investigation.
• Suspicious Death Investigation: In cases where it becomes quite difficult to identify the cause of death during the police investigation, these experts are called for help. These people examine the body and identify the cause and manner of sudden death. They try to identify whether it was a natural death or it was because of a violent attack that led to the internal injuries. They study the wounds and injury patterns on the body of the deceased and hence conclude the cause of death.
• Drug Aided Crimes: Crimes committed under the influence of drugs or intoxicating substances are also investigated by these experts. Crimes such as theft, sexual assault, harassment, blackmailing, etc fall under this category. In cases of sexual assault, these experts collect the samples of the victim and the accused to find the presence of drugs in their bodies.

Also Read: Is forensic science a good career?

Techniques Used In Toxicology:

In the investigation of drug content in the human and animal body various techniques are used by these experts. These techniques involve various tests such as:

• Immunoassay Screening: This test detects the diseases through biochemical tests conducted on body fluids like blood and urine. This analysis works on the principle of antigen and antibody reaction and measures the presence and amount of drug present in the body.
• Mass Spectrometry: It is used to detect the presence of toxins and poisonous substances in the body tissues, fibers collected from the crime scene, metals, etc. It is used for the quick analysis of the samples collected to identify the presence of known and unknown substances.
• High-Performance Liquid Chromatography: This test is used to identify the presence of various components in the liquid present at the crime site or such liquids collected from the crime scene as evidence. It reveals the identity of components present in the liquid and their ratio in it.
• Gas Chromatography: It is a technique used to separate volatile mixtures. It can be used for the components that can be vaporized using heat that too without decomposition. It is used to know whether the deceased had consumed alcohol before his death or not.

Forensic Toxicology Syllabus:

The syllabus for toxicology may vary from college to college but some common subjects are taught across all such institutes. Here we have mentioned the toxicology syllabus below in the table:

Serial No.	Subjects	Syllabus
1.	Basics of Toxicology	Toxicology and its branches, Basics of forensic toxicology, Scope of forensic toxicology, Application of forensic toxicology, Significance of findings, Techniques used, Analysis and tests used in investigation, Post-mortem Toxicology, Human performance toxicology, etc.
2.	Collection & Preservation of Toxicological Evidences	Collection and preservation of samples like blood and urine.
3.	Plant Poisons	Classification of plant poisons, Fatal dose and period, Symptoms, Poisons in plant, Its Treatment & Analysis.
4.	Animal Poisons	Animal Poison classification, Fatal period and dose, Symptoms involved Analysis of toxins, and Treatment.
5.	Metallic Poisons	Types of metallic poison, Fatal dosage, Symptoms of poisoning, Analysis & Treatment of drug intake.
6.	Acidic & Alkali Poisons	Types, Deadly Dose and Period, Signs, Screening and Treatment.
7.	Neutral Poisons	Neutral Poison Classification, Untreatable dose and period, Its signs & symptoms, Examination and Treatment.

How Do They Work?

These experts work with medical examiners and determine the presence of chemicals in the body of humans and animals. They aim at determining the amount of toxins given to the victim so that the victim can be treated accordingly on time. These people use various analytical techniques to identify the drugs and poisonous chemicals in the samples collected as evidence. After getting the desired findings they present them to the police investigators and sometimes also appear in the court to testify.

Career Options:

The scope of forensics is wide and these experts can work in a range of sectors including private and government. Some of the industries they can work in are mentioned below in the table:

Serial No.	Career Options
1.	Government and Private Forensic Laboratories
2.	Government and Private Hospitals
3.	Crime Branch
4.	Police Departments
5.	Universities

Samples used in toxicology studies:

Toxicologists conduct various tests to analyze the presence of toxins and other harmful chemicals in the samples collected. The samples that are analyzed by these experts are given below:

• Urine: One of the most common samples that are tested for drug presence is urine. It can be tested in both cases i.e. ante mortem and post mortem. Though it is one of the best samples for drug screening there is one loophole in it. The reports do not predict the presence of toxins unless it was consumed at the time of sample collection.
• Blood: A range of tests can be performed on the blood samples hence it is widely used for the examination. The blood test is sufficient enough to furnish information about all kinds of drugs that might be consumed by the person before death. This test is also useful in case of gaseous or volatile material poisoning, but the condition is the samples must be collected immediately. In drunken driving cases also where the person is no more, these experts collect the blood samples and measure the alcohol content.
• Hair: It is not known by most people that hair can also reveal the drug history of a person. The texture and color of hair can reveal about the exposure of a person to drugs. This test is common in medical insurance cases; these experts conduct tests to verify the statements made by the applicant. It is because hair can hold the drugs for a long period. These chemicals are stored in the hair follicle thus providing information about the timeline of drug intake.
• Oral fluids: Another important sample used in forensic investigation by toxicologists is the oral fluid. As these samples can be collected easily without interfering with someone’s privacy, they prove to be an ideal source of evidence for investigations. In recent years, it has gained popularity because it is easy to identify the presence of drugs through these fluids.

Application of Forensic Toxicology:

This field has a wide range of application as it involves the determination of the presence of poison and intoxicating agents in the body. Here we have mentioned some of the most important applications of toxicology:

• It studies the presence of illegal and legal drugs.
• It identifies the presence of poison and hazardous chemicals.
• It studies the chemical composition of substances found during investigation.
• It helps in testing the presence and quantity of drugs and alcohol.
• It determines the drug overdoses.
• It helps in the investigation of cases involving drug-facilitated sexual assault
• Along with the determination of the presence of drugs in the body of the deceased, it also helps in identifying the drug given to the victim to treat him
• It helps in post-mortem investigations

References:

• https://en.wikipedia.org/wiki/Forensic_toxicology
• https://nij.ojp.gov/topics/forensics/forensic-toxicology#: ~:text=Forensic%20toxicology%20is%20the%20analysis,is above%20a%20harmful%20level
• https://www.sciencedirect.com/topics/pharmacology- toxicology-and-pharmaceutical-science/ forensic-toxicology
• https://pubmed.ncbi.nlm.nih.gov/20358697/