To be a toxicologist takes more than knowing the smell of bitter almonds

by Dr BOJAN FLAKS PhD DSc CBiol FIBiol FRCPath, of InfoResearch International TOXICOLOGY IS the science of poisons.

It is the study of the adverse effects of chemicals on living organisms, including the study of symptoms, mechanisms, treatments and detection of the poisoning of people or animals.

It is defined by the Oxford English Dictionary as: “...that department of pathology or medicine which deals with the nature and effects of poisons. So Toxicologist, a person versed in t[oxicology]”.

The American Heritage Dictionary of the English Language defines it as:

“The study of the nature, effects, and detection of poisons and the treatment of poisoning.”

Definitions of toxicologist include:

“One who studies the nature and effects of poisons and their treatment” (wordnet.princeton.edu/perl/webwn) and “A scientist trained to examine the nature of the adverse effects of chemicals on living organisms and assess the probability of their occurrence” (science.education.nih.gov/supplements/nih2/chemicals/other/glossary/glossary3.htm).

Those definitions imply that a toxicologist requires considerably more knowledge and expertise than the ability to read a material safety data sheet or to be aware of regulatory occupational exposure limits for chemicals. It is relevant to consider some of the criteria adopted by British and other bodies concerned with toxicology training and accreditation.

In the UK, the Royal College of Pathologists considers toxicology to be a specialty within the wider field of pathology. The College’s Core Training Programme for Toxicology aims to produce trained toxicologists able to provide expert opinions in their specialty option and who should have developed the appropriate skills to lead a department, if required.

Examinations are offered in six subspecialty areas of toxicology: systematic toxicology, histopathology and comparative pathology, mechanisms of toxicology, metabolism and pharmacokinetics, chemical pathology, haematology and immunology, genetic toxicology and reproductive toxicology. The core training programme covers the areas common to all six options. Over a minimum three-year period the trainee should acquire or develop:

1: Specialised factual knowledge about the mechanisms of toxicity in relation to the chosen specialty option in toxicology; an understanding of how to perform mechanistic investigations; awareness of national and international requirements/guidelines on appropriate studies for safety evaluation.

2: Interpretative skills so that a relevant specialist opinion can be derived from raw data.

3: Technical knowledge, gained from close acquaintance with laboratory experimentation, so that a methodology appropriate to toxicological investigations can be selected, relevant experiments designed and quality control and quality assurance procedures implemented.

4: Research and development experience; to develop and be able to demonstrate a critical assessment of bexperimental data and published work. Those skills are important to allow the trainee to contribute, in a team and individually, to the development of toxicology. Familiarity with laboratory organisation, laboratory methods and technical limitations is a prerequisite in determining the quality of experimental data.

5: The life-long habits of learning: reading, literature searches, consultation with colleagues, attendance at scientific meetings and the presentation of their own scientific work as part of their continuing professional development.

In addition the trainee should acquire data management skills, management skills, familiarity with relevant aspects of health and safety requirements, including COSSH, and oral and written communication skills, through publication of papers, production of scientific reports and presentation of data at scientific meetings.

Based on the experience of trainees from academia and industry and in the absence of specific full-time training posts in toxicology, candidates are advised by the College that they are unlikely to satisfy the training requirements for the Part I examination for MRCPath within less than five years of obtaining their primary academic qualifications.

Toxicology is described by the British Toxicology Society as: “...the study of how harmful effects may occur in humans, other animals, plants and the environment and how they can be avoided or minimised.”

The UK Register of Toxicologists, sponsored by the Institute of Biology and the British Toxicology Society, was established in 1993.

Applications to join the register are open to experienced scientists engaged in the field of toxicology.

Registered toxicologists are required to have an acceptable education leading to an appropriate qualification, together with any additional training required to achieve the necessary competence to practice their profession.

Requirements for registration include:

• A broad-based written examination such as DIBT, DRCPath, DABT or equivalent qualification, or an honours degree in a relevant science (taken over a minimum three-year period from a UK university or its equivalent) and at least five years subsequent relevant toxicological experience. The applicant: “Must be currently engaged in the practice of toxicology and be of good professional standing.”

• Assessment for suitability for registration, eg by published works, confidential reports or reviews and through evidence of CPD.

Those applying must name two senior toxicologists as referees, who can confirm the experience and current employment of the applicant.

A toxicological consultant can provide reports for commercial clients on the adverse health effects of chemicals which the company uses, manufactures or of which it disposes, and might be involved in toxicity testing of a new product. He can interpret and summarise the results of toxicological studies for purposes of litigation, serving as an expert witness in litigation involving the alleged adverse effects of chemicals on human health or the environment. He can also advise lawyers on the development of factual evidence and the strengths or weaknesses of the opponents’ case and determine cause and effect relationships.

It should be noted that forensic toxicology is a distinct area of analytical chemistry, rather than pathology. The forensic toxicologist does not generally have expertise in the adverse health effects of chemicals: his expertise lies in the detection and quantification of exogenous chemicals in bodily tissues and fluids. Although he should be aware of the general toxic properties of chemicals, he is not qualified to evaluate their causation of damage to health in the absence of the training and experience expected of a toxicologist.

Similarly, an occupational health and safety expert will be aware that, among other potential hazards, toxic chemicals may be present in the working environment, and will be aware of the current regulations governing their exposure limits. He will be able to determine and advise on the degree to which exposure to such chemicals has occurred in a workplace and whether these regulations have been observed. However, following the criteria of the bodies involved in toxicology training and/or accreditation, he will not have the necessary specific expertise to be able to offer expert toxicological advice, particularly on issues of causation.

Those criteria make it obvious that attendance at a short (day or weekend) course in toxicology cannot possibly provide sufficient training. To those exclusions I would add that membership of a governmental committee concerned with toxicity issues, or the tenure of an administrative position in an institution which carries out toxicological activities, do not per se confer toxicological expertise. In addition, the fact that an individual is a qualified and registered physician does not equip him to act as a toxicologist or to enable him to act as an expert witness in toxicology. The Royal College of Pathologists recognises that toxicological expertise requires specialised knowledge and experience not held by pathologists in general.

I am aware from personal experience that it is not unknown for individuals to have claimed to be toxicologists for the purpose of acting as expert witnesses in litigation, while lacking the necessary qualifications and experience.

Frequently that goes unchallenged because the lawyers involved and the court, as laymen, are not usually aware of the recognised criteria. A lay jury, not unnaturally, is even less likely to be aware of them.