ABSTRACT
All fossil fuels contain sulfur, and when these fuels are combusted the sulfur present is released into the atmosphere, contributing to air pollution in the form of "acid rain." Current air quality standards have already placed strict limitations on the amounts of sulfurous air emissions allowed, and these regulations may well become even more stringent in the future. Unlike the metabolism of inorganic sulfur, the metabolism of organic sulfur is not known to serve as a source of energy for bacteria. Moreover, inorganic sulfur generally exists in coal in the form of discrete particles or crystals of pyrite, whereas organic sulfur occurs as an integral part of the molecular coal matrix and is not readily accessible for microbial attack. The sulfur bioavailability assay is useful because it is much more sensitive than chemical/physical assays for sulfate or other sources of sulfur.
