Life in Earth is based in the continuous flux of matter represented by the cycles of carbon, nitrogen, phosphorus, sulfur, etc. Mankind has lived in equilibrium with nature along thousands of years. There is no doubt that since the end of the 18th century huge advances have been made in the industrial processes, in agriculture, in livestock, medicine, etc., which have redounded in the improvement of the quality of life. But together with these advances, the generation of huge quantities of residues have reached the biosphere causing problems in the quality of waters, soils and air, that have affected negatively the ecosystems.
Biology in general, and Biotechnology in particular, can contribute to the solving some cases of contamination, and can alleviate the effects of the contaminants in others. For example, a good part of the gas emissions could be reduced by the use if biological filters where organisms eliminate a great variety of organic and inorganic contaminants. We also have to highlight the key role of microorganisms in the treatment of subterranean an surface waters, both in situ and ex situ, which would allow to reduce the amount of nitrates, pesticides, and heavy metals in solution.
The contamination of soils can be eliminated making use of the combined effects of plants and microorganisms, an emerging field in which it is expected to obtain success in the treatment of toxic compounds such as DDT and dioxins. Also, Biotechnology offers the opportunity of designing custom microorganisms with new metabolic capacities that allows them to degrade toxic compounds. Equally, the survival of such recombining microorganisms could be controlled using a biological contention system.