Current tools for removal of hazardous materials from environments

Vimal Chandra Pandey, Vijai Singh
Contd from previous issue
Holdgate (1979) defined environmental pollution as the introduction by man, into the environment, of substances or energy liable to cause interference with legitimate uses of environment. Singh (1991) has defined pollution in a very simple manner, i.e., “Disequilibrium condition from equilibrium condition in any system.” This definition may be applied to all types of pollution ranging from physical to economic, political, social, and religious. Over the past couple of decades, various sources of pollution were identified that altered the composition of water, air, and soil of the environment. The substances that cause pollution are known as pollutants. A pollutant can be any chemical (toxic metal, radionuclides, organophosphorus compounds, gases) or geochemical substance (dust, sediment), biological organism or product, or physical substance (heat, radiation, sound wave) that is released intentionally or inadvertently by man into the environment with actual or potential adverse, harmful, unpleasant, or inconvenient effects. Such undesirable effects may be direct (affecting man) or indirect, being mediated via resource organisms or climate change. Depending on the nature of pollutants and also subsequent pollution of environmental components, the pollution may be categorized as follows:
1. Air Pollution, 2. Water Pollution, 3. Soil/Land Pollution, 4. Noise Pollution, 5. Radioactive Pollution, 6. Thermal Pollution.  
Among these types of pollution, air pollution is the main type threatening the environment, humans, plants, animals, and all living organisms.