Explain How the Properties of Pollutants Affect the Way in Which They Cause Environmental Damage

The term pollution is used to describe a wide variety of events and processes that do harm to the environment and living organisms. Pollution is usually caused by human activities and results in the release of materials or forms of energy that do harm by causing changes that would not have normally occurred. The behaviour of the pollutant is controlled by the properties of the pollutants and the features of the environment into which they are released. In order to mitigate the problems associated with pollution the properties of the pollutants need to be understood and need to be considered before the pollutant in released in the environment.

Toxicity is the measure of how poisonous a material is. A toxic substance is one which harms biological processes such as damaging proteins, especially enzymes. The higher the toxicity, the greater damage is caused. DDT was widely used as an insecticide post WWI and is highly toxic. DDT prevents normal passage of nerve impulses between nerve cells by inhibiting enzyme action. DDT has now been banned from agricultural uses since 2001.

Specificity is the measure of the differing toxicity of a substance to different types of organism. A substance which is toxic to one organism may not be toxic to another. For instance, in order to reduce environmental problems, farmers should seek to use specific pesticides which are only toxic to target species to avoid harming non-target species. Neonicotinoids are less toxic to birds and mammals than they are to insects. However, they are still toxic to beneficial insects such as bees.

Persistence is a measure of how long it takes for a pollutant to chemically break down. The more persistent the pollutant is the more likely it will build up to concentrations which could cause more damage or they are more likely to travel further and therefore cause an effect over a larger area. CFCs are very chemically stable and therefore persist in the environment – they take between 20-100 years to break down. CFCs were banned under the Montreal Protocol 1987 but still remain in the atmosphere and continue to damage the ozone layer.

Biodegradability is the process of chemical breakdown.