Biological contamination - accidental or due to human activities penetration exploited ecosystems and technological devices alien to them on plants, animals and microorganisms (bacteriological), and often has a negative impact in mass outbreaks alien species. Especially pollute companies that produce antibiotics, enzymes, vaccines, serums, and other, that is, the industrial enterprises of biosynthesis, which are present in the emissions of the living cells of microorganisms. To biological contamination can also be considered intentional and accidental introductions, over-expansion of living organisms

Thus, in the presence of urban landfills, the late harvesting of household waste have led to the numerical growth of commensal animals: rats, insects, pigeons, crows, and so on. One of the problems of cities - the pollution of the atmosphere. This introduction into the atmosphere or her education in physical and chemical agents and substances, due to both natural and anthropogenic factors.