Process contamination can occur directly or indirectly. IE directly pollutants are directly toxic and disturbing impact on human health, animals and plants or disrupt the ecological balance of good water, air or soil. Indirect process, IE some of these chemicals react in the air, water and land, causing pollution.
Pollutants have immediate impact, for example in the form of direct health problems (acute disease), or would be perceived after the period of time (chronic diseases). Actually, nature has the ability to cope with pollution (self recovery), but nature has its limitations. Once the limit is exceeded, then the pollutant will be in a fixed nature or accumulated and then have an impact on human, material, animals, plants and ecosystems.
