Pollutants are found in the environment, in their natural state, as
an integral part of the natural environment and living organisms,
but within the limits that are harmless for life. Living organisms
emit certain amount of pollutants, and it happens to all economy
processes as well. However, at the low level of economic
development, neutral economic conditions and in the conditions
of low population density production of pollutants is low, so they
are successfully degraded through natural processes. Thus, the
environment, living organisms and people are unaffected. Unfortunately,
due to the increase in population, urbanization of cities,
economy activities and application of chemicals in industry and
agriculture, nowadays, there is an excessive discharge of pollutants
into the environment and its threat [12].