About Environmental Toxicology

Since biologist Rachel Carson's 'Silent Spring' in 1962, which expressed concerns with the widespread and indiscriminate use of pesticides, has toxicology taken a greater role in environmental science. What was historically a study that examined the dose measurement of poisons and its effects on human health, environmental toxicology aims to understand the effects of toxic chemicals found in air, water, soil and food on biological systems. The biological systems include any living systems such as humans and other mammals, plants, other organisms and their habitats. Today there is an ever-increasing use of toxic chemicals by industries which have resulted in further pollution of the environment. Exposure at or above certain thresholds will manifest as toxicity. These are chemicals foreign in the environment (xenobiotic) and are also called anthropogenic, man-made, synthetic, pollutant, contaminant, recalcitrant, persistent and toxicant.

 

The multidisciplinary branches of toxicology

Environmental toxicology is a multidisciplinary approach to studying the movement and impact of toxicants and their metabolites in the environment, food chains and structure and functions of biological systems. Samples are often collected where the physical and chemical components help determine the degree of contamination. This depends on lab and field work, finding the source and modelling the fate of contamination and understanding how it moves throughout the organism, how it may be changed and interacting with living cells and tissues, what parts are affected and the health outcomes from exposure. We are increasingly exposed to xenobiotic chemicals and toxicologists will try to measure acceptable levels of exposure so that risk management approaches can be developed.

As environmental toxicology is a broad field of study, many environmental toxicologists will specialise and reports can be peer reviewed to compare predictions and experimental findings. Ecotoxicology, as a subdiscipline of environmental toxicology, integrates the effects of stressors across all levels from the molecular to the whole ecosystem. Ecotoxicology is the integration of toxicology and ecology researching the effects of chemicals at certain concentrations on the population, community and ecosystem so it is known what levels are to be avoided to protect that environment. This becomes important in terms of preserving biodiversity from the threat of toxicity from issues such as salinity, PCB's, heavy metals, pesticides etc. Independent conservation groups or companies will use the information from toxicology research for the remediation of contaminated sites.

The persistence of toxicants and threat of exposure in the environment is an unfortunate by-product of industrial and technological progress. Research for a more thorough understanding can help toxicologists predict the consequences of a toxicant to organisms in the environment or the workplace. The information gathered from environmental toxicology studies adds to the collective knowledge about pollutants and aids environmental protection agencies design better environmental policies and set pollution control standards.