Forensic toxicology is a sub-branch of forensic chemistry which applies the knowledge, principles, and methodologies associated with a specialized field of toxicology for the criminal justice system. Forensic toxicology deals with the harmful aspects of chemicals, poisons, and other toxic substances on humans and animals.

Toxicology is the branch of chemistry that deals with the identification and analysis of the toxic substances. It involves the study of the impacts of the chemicals on living organisms.

It includes the study of symptoms, mechanism, treatment, and detection of chemical substances in biological evidence such as bodily fluids and tissues. Toxicology is also called a science of poison. A poison is a substance which when it comes in contact with skin, inhaled or ingested is capable of producing detrimental effects on the body of the recipient depending upon its dose.

The amount of the toxic agent capable of causing death is called a lethal dose (LD). The effect of the toxic substance or poison on the individual depends upon the age, sex, habits, route of administration, and health of such individuals.

For example, children and older age individuals because of lack of immunity are more susceptible for the poisons than the young adults, and females are more susceptible than males, healthy individuals may be more resistant over the diseased, and poison if taken intravenously through injections is more dangerous than the one taken orally. The expertise of forensic toxicology is utilized to find the cause of death, cases related to homicides, suicides, and drug addiction.

A Brief History

Toxicologist Paracelus also called the father of modern toxicology, in the 16th century proposed that any drug or medicine if taken erratically can be poisonous. He proposed the relationship between the dose and response of drugs and poisons on humans. In the 17th century, Joseph Plenic proposed that the detection and identification of poisons in the organs of the dead body is the true sign of poison ingestion.

Mathieu Orfila in the 19th century developed a scientific chemical test for the identification of the poisons; he also determined the cause and effect of a particular poison on animals for determining the lethality. James Marsh in 1813 developed a test called a Marsh test for the identification of Arsenic in the body tissues; this test is used for homicidal and accidental arsenic poisoning cases.

At the end of World War II, the invention and application of instrumentation techniques for the quantitative estimation of poison begun. In 1850, British chemist Jean Servials Stas extracted Nicotine an alkaloid poison from the human tissues. After some time the German chemist named as Friedrich Otto improved this technique and used this test for the identification and estimation of several alkaloid poisons such as

Narcotine (C 22 H 23 NO 7 )

Morphine (C 17 H 19 NO 3 )

Codeine (C 18 H 21 NO 3 )

Strychnine (C 21 H 22 N 2 O 2 ) , and others.

The test is named a Stas-Otto test, and it is still in use.

Significance And Applications Of Forensic Toxicology

Forensic toxicology deals with the following:

It involves the examination and estimation of the poison or drug substances in the human or animal biological materials such as blood, urine, vomit, viscera, and hair.

It involves the examination of unknown powder, pills, and medicinal capsules, tablets, syringes, and vials to establish their chemical identity.

It deals with the identification of plant alkaloids like nicotine, strychnine, croton, others in the tissues of the deceased.

It establishes the cause of death by occupational poisoning hazards. It helps in the determination of the quantity of alcohol in the blood, urine samples in drink, and drive cases.

It helps in detecting poisons in the foodstuff and potable water. It describes the cause and effect of the poison on different parts of the body when taken through the skin, injection, and oral routes.

It describes the effect of the dose of a particular substance in causing detrimental impacts.

It includes the remedies for the treatment of the persons who accidentally or intentionally get affected by the poisons.

It determines the fate of poison in the body.

Establishing the identity of the animal toxicant responsible for death like a scorpion, snake, fishes, insects, and other animals.

Determining the cause of death by examining the post mortem staining, odour from the body, examining the natural orifices, injection and bite marks, the colour of skin, nails, and hair.

Collection And Preservation Of The Toxicological Evidence

The material to be collected in the cases of poisoning typically is of two types these can be biological or non-biological. The biological material includes the blood, vomit, saliva, stomach wash, intestine, nails, bones, brain, liver, kidney, teeth, lungs, spleen, hair, and cerebrospinal fluid should be collected in the glass bottles, and paper envelops.

The suspected utensils and the food placed in them should be collected and sealed with a polybag. In the case of an animal bite, the tissues surrounding the bite mark should be collected.

Sufficient quantities of each viscera material should be collected. Like, it should include the whole content of the stomach, 100cm of the small intestine, liver with a quantity of 1 kg, half part of each kidney.

Saturated saline or rectified spirit should be used as a preservative but rectified spirit should not be used in the case of phenol, phenol, paraldehyde, and phosphorus poisoning a saturated solution of sodium chloride is used.

Blood and urine should be preserved in sodium fluoride solutions.

Quantity of preservative should be equal to the quantity of the organ. Bottles should be properly sealed so that volatile poisons or preservatives do not get evaporated.

Separation And Identification Techniques Commonly Used In Forensic Toxicology Laboratories

The forensic toxicology laboratories utilize several experimentation procedures to isolate, identify, and estimate the suspected poison sample. The method varies with the type and quantity of the test sample available.

Volatile poisons can be extracted from the steam distillation process, and later identification is done by gas chromatography. The non- volatile organic poisons are first treated with suitable solvents, later can be identified by the thin layer or gas chromatographic techniques.

Modern instrumental techniques such as HPLC (high-performance liquid chromatography), gas chromatography combined with mass spectrometry (GC-MS) can be used to identify and quantify the poison available in trace amounts.

Other techniques like Radio-Immuno Assay (RIA), Enzyme-Linked Immunosorbent Assay (ELISA) are reliable techniques for the identification of drugs and poisons in biological materials such as blood, urine, saliva, and others.

Educational Requirements To Become a Forensic Toxicologist

At the basic level, a forensic toxicologist is expected to have a bachelor’s degree in basic science like biology, chemistry, clinical chemistry, and biochemistry. A specialized degree in forensic toxicology is not required. The coursework of the study should include disciplines such as toxicology, and pharmacology. But specialized courses in forensic toxicology are available at the postgraduate level.

Such courses can give a thorough knowledge of the presentation of toxicological evidence in the court of law. The American Board of Forensic Toxicology (ABFT) offers certificates courses in the field of forensic toxicology, which requires a three-year full-time bachelor’s degree as eligibility to opt for these courses. These courses include

Diploma in Forensic Toxicology

Diploma in Forensic Alcohol Toxicology

Diploma in Forensic drug Toxicology

Fellow Forensic Toxicology .

ABFT also offers fellowship to students who have completed their doctoral-level programs. The coursework of forensic toxicology specialized course must include subjects like general toxicology, principles of forensic science, types of toxicological evidence, an overview of handling and collection of toxicological pieces of evidence.

It also includes knowledge of the relation of other fields of natural and forensic science with forensic toxicology like forensic botany, forensic entomology, and forensic medicine, chemical and instrumental tests and procedures, and applied statistics for data analyses.

Specialized Fields In Forensic Toxicology

According to the National Institute for Standards and Technology (NIST), there are four specialized fields in the forensic toxicology, these are

Doping Test

Drug Testing

Human Performance Toxicology

Death Investigation.

Examples of tests involved in Forensic Toxicology:

A doping test is required to be done to prove that the driver was drunk while driving a vehicle, which could be a possible culprit of the accident.

Drug testing is done to prove that the culprit was in the influence of the drug on the commission of offenses such as theft, rape, and heinous crime like murder. Also, to identify the drugs obtained from the drug peddlers.

Human performance toxicology involves the observation of the impact of the drug on the health of a drug abuser, treatment of patients of rehabilitation centers.

Role Of a Forensic Toxicologist

Generally, the profession of the forensic toxicologist is laboratory oriented. They are trained to work with chemicals, the latest technology instruments, and the latest laboratory standards. Forensic toxicologists perform tests on samples collected by the crime scene investigators.

Their jobs involve the testing of the presence of illicit drugs, poisons, prescription drugs, alcohol, biological fluid, and tissue samples. Some of them are engaged in examining and conducting autopsy procedures.

Such experts are summoned in courts to present their testimony in cases related to toxicological evidence. But forensic toxicologists can obtain a place in the private sector too such as industrial labs, universities, and hospitals.

Forensic toxicologists can pursue a carrier in training and educating bachelors, masters, Ph.D., and other higher education pursuing students. They can also use their knowledge and skills in research and publication.