Anthropogenic metabolic process

Material flow models should be used as instruments, to create decision bases for the control of anthropogenic metabolic processes. They are to contribute particularly to the early recognition of region-relevant material modification. In particular, the material modifications connected with the introduction of new goods can be measured over appropriate code zones of the system (Baccini and Bader 1996). 

Sulfur dioxide is produced by both natural and anthropogenic sources. The most important of the natural sources are volcanic eruptions, which account for about 40 percent of all natural emissions of the gas. Since volcanic eruptions are episodic events, the amount of sulfur dioxide attributable to this source in any one year varies widely. Other natural sources of the gas are forest fires and other natural burns, biological decay, and certain metabolic processes carried out by living organisms, especially marine plankton and bacteria. Natural sources release about 27.5 million short tons (25 million metric tons) of sulfur dioxide per year. 

Phenol is produced through both natural and anthropogenic processes. It is naturally occurring in some foods, human and animal wastes, and decomposing organic material, and is produced endogenously in the gut from the metabolism of aromatic amino acids. Phenol has been isolated from coal tar, but it is now synthetically manufactured (EPA, 2002). Currently, the largest use of phenol is as an intermediate in the production of phenolic resins, which are used in the plywood, adhesive, construction, automotive, and appliance industries. Phenol is also used in the production of synthetic fibers such as nylon and for epoxy resin precursors such as bisphenol-A. 

Biological properties Organic matter is a source of nutrients to plants, due to its cation-exchange capacity it provides metabolic energy for soil biological processes (e.g., bacterial) and contributes to ecosystem resilience, because it enhances the ecosystem s ability to recover from natural or anthropogenic perturbations. 

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