Striving to defang the poisoned chalice

Aerial spraying of endosulfan on the cashew plantations in Kasaragod has caused untold misery to people. Proper toxicological studies prevent such tragedies.  

A cynic once said, “Even water is poison.” Perhaps, what he meant was that taking too much of water in one go may kill you. Read what Paracelsus (1493-1541), a Swiss alchemist, is supposed to have proclaimed: “All substances are poisons — the difference is in the dose.”

We are all being regularly exposed to a variety of toxic chemicals since the application of chemical technology is widespread. But the risk or extent of harm depends on the dose, the degree of exposure, and other variables.

The scientific study of poisons, their nature, and effects is termed toxicology. It deals with the detection of poisons and the treatment for poisoning. In many workplaces, a usual occupational hazard is the presence of toxic materials — arsenic, lead, mercury, nickel, asbestos, carbon monoxide, hydrogen sulphide, ethyl alcohol acetone, acetic acid, benzene, naphthalene, phenol, vinyl chloride, polychlorinated biphenyls, pesticides, aniline, and cyanides.

Knowing what is poison and what is not is tricky. For instance, metallic nickel or chromium may not pose any hazard. But nickel tetracarbonyl is a highly toxic gas. So also chromium in the hexavalent state, used in many industries, may cause cancer.

What has to be appreciated is the mechanism employed by the body to absorb poison. In general, fat-soluble liquids are readily absorbed through the skin and fat-soluble vapours are readily absorbed through the lungs. Water-soluble lead compounds are usually found in red blood cells, whereas fat-soluble compounds will concentrate in the central nervous system. The liver may sometimes convert toxins into harmless substances. The kidney may excrete toxins. Lungs will eliminate toxins. Some organs will resist their absorption.

Toxins have different kinds of effect on the body. For instance, detergents cause dermatitis and cement produces irritation. Strong acids cause burns. Certain chemicals cause headache, drowsiness, nausea, or unconsciousness. A poisonous gas, such as carbon monoxide, may asphyxiate you to death. Sodium cyanide, used widely in the processing of gold and silver, may prove to be fatal if not handled with care. Many allergens cause skin problems and asthma. Long exposure to certain chemicals may lead to cancer. Radiation has several genetic effects. Human foetus may be at risk when the mother works in environments with radiation hazard.

The Indian Institute of Toxicology Research, working under the Council of Scientific and Industrial Research, studies toxicology and related subjects in depth and brings out several useful findings.

It was started in 1965 as the Industrial Toxicology Research Centre. The present name was adopted in 2008. The institute has a “city campus” at Mahatma Gandhi Marg, Lucknow – 226 001 and the Gheru campus on the Lucknow-Kanpur highway at the 17th kilometre. It website is

The objectives of the institute include

Safety evaluation of chemicals used in industry, agriculture, and everyday life.

Remedial and preventive measures to safeguard health and environment from pollutants.

Prevention of occupational health hazards caused by exposure in chemical industries, mines, agricultural fields, and environment.

Simple and rapid diagnostic tests for disorders caused by industrial and environmental chemicals.

Collection, storage, and dissemination of information on toxic chemicals.

Helping regulatory bodies to formulate guidelines for safe use of chemicals and pollutants. As a leader in toxicology research, the institute endeavours to mitigate problems of human health and environment. The institute keeps a motto: “Safety to environment and health and service to industry.” It undertakes research in different areas of toxicology, including the following:

Impact of industrial and environmental chemicals on human health and ecosystem; and environmental monitoring of pollutants in air, water, and soil.

The growth in toxicology research has interesting dimensions. Classical studies in animal experimentation gave way to “omic” technologies in the interdisciplinary area of biology. (“Omics” represents a collection of newfangled or newest technologies). The concepts of biomarkers, mathematical modelling, and predictive toxicology are significant.

The spread of toxicology to encompass new developments, including nanomaterials and genetically modified products, calls for fresh approaches in research.

Research groups

The five research groups in the institute are:

Nanomaterial toxicology

Environmental toxicology

Food, drug, and chemical toxicology

Regulatory toxicology

Systems toxicology and health risk assessment

Nanotechnology, which is expected to bring in the second industrial revolution, will spread to all realms of human endeavour. Toxicology research should necessarily ready itself to meet the new challenges posed by the increasing application of nanotechnology. Several countries manufacture and market a variety of nanotech-based consumer products, including cosmetics and food. Since nanomaterials may cross cellular barriers, exposure to flora and fauna may go unrestricted. The institute focusses on the areas of safety and toxicity evaluation of nanomaterials and their impact assessment.

Industries release several chemicals into the environment. New chemical entities, genetically modified organisms, and engineered nano-materials cause pollution.

Compounds caused by human activity are called anthropogenic compounds. Such compounds released into the environment have potential effects on organisms. These effects are studied in environmental toxicology. We have to create ways to predict toxic potency and exposure levels of chemicals.

There are ethical as well as economic concerns over animal testing. The effectiveness of the existing remediation strategies will have to be determined and refined.

Application of technology in various forms in agriculture and food preservation has the inherent risk of introducing hazardous elements in food. Use of insecticides, additives for preservation, and emergence of genetically modified food cause growing concern about food safety. Careless handling of food during its production or storage may lead to contamination. Deliberate adulteration of food by unscrupulous commercial operators poses serious problems. Studies and monitoring of toxicity and safety data are essential in the interest of food safety.

Regulations are essential to ensure that the presence of toxic chemicals and other materials do not pose hazards to people. The manufacture, marketing, transport, storage, labelling, classification, and usage of various industrial chemicals, agro-chemicals, pharmaceuticals, cosmetics, and items of food have to be brought under regulatory toxicology. Creation and validation of correct specifications will help regulatory decisions. Competent technical manpower is necessary for the safety evaluation of biotechnologically-derived products, gene-therapy, stem-cell therapy, safety and toxicity screening, environmental impact assessment, wastewater technologies, and so on. Continuing research has to back up the efforts.

Chemical substances that are foreign to a biological system are called xenobiotics. We should understand how xenobiotics affect human health. Systems toxicology and health-risk assessment aims at applying a system biology approach to predict the effects of xenobiotics and identify adverse health outcomes.

The results of such studies and research can be applied for controlling the adverse effects of toxins.

Related Topics
This article is closed for comments.
Please Email the Editor

Printable version | Nov 27, 2020 10:48:46 PM |

Next Story