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chromatograph (GC). Results demonstrate that the loss of TPH corcelates well with the <br />production of COz. <br />When petroleum or petroleum products enter the environment, they are subjected to various <br />weathering processes that alter their chemical and physical nature. Biodegradation of petroleum <br />pollutants by microorganisms is a major process mediating the fate of oil in the environment (4). <br />The chemical nature of petroleum and refined hydrocarbons and compounds, such as naphthoic <br />acids, phenols, thiols, and heterocyclic nitrogen, sulfur, and oxygen (NSO) compounds, as well as <br />some metalloporphyrins (5) presents a challenge to microorganisms. Extensive degradation of a <br />petroleum mixture generally requires the combined activities of several different microbial <br />populations (4). <br />Fate of Polyacrylamide <br />A major constituent of many of the formulations for ATM is polyacrylamide (PAM), <br />which has been used to control soil erosion and hold water in desert soils. Polyacrylamides are <br />synthetic polymers made of acrylamide or acrylamide and acrylic acid (3). <br />Once exposed to the environment, polyacrylamide polymers are capable of translocating <br />through different soil compositions under field conditions (32; 24). However, they can bind to <br />particulate matter such as clay particles (33). Polyacrylamides may undergo biodegradation to <br />mineralized forms such as COZ and NH3. Degradation of PAMs in soil systems can be expected to <br />occur with time as a result of mechanical degradation, chemical and biological hydrolysis, <br />sunlight, salt and temperature effects (34; 36) at a rate that has been estimated to be about 10% <br />per year (6). Release of [he acrylamide monomer has not been observed in degradation studies <br />(13). In the manufacture of Polyacrylamides, maximum residual acrylamide levels range between <br />0.05-0.5% depending on the intended use of the product (13). Polyacrylamides are non-toxic <br />because of their inability to pass biological membranes (27). <br />Fate and Toxicity of Acrylamide Monomer <br />One of the important components of polyacrylamide is acrylamide, which is a vinyl <br />monomer with a solubility of 212 g/100 ml water (37). Acrylamide is a potential groundwater <br />contaminant. It is a known neurotoxin to man (14; 29). Animal testing has demonstrated that <br />acute exposure primarily affects the central nervous system and that chronic, subacute exposure <br />can damage the peripheral, as well as the central, nervous system. <br />A major source of acrylamide in the environment is the release of residual acrylamide <br />monomer from the polymers. Studies by Croll et al. (13) showed that industries employing <br />polyacrylamide or acrylamide-acrylic acid copolymers as flocculating agents, without exception, <br />discharged acrylamide into the environment in amounts far exceeding the maximum allowed <br />levels for potable water, which is 0.5 ppb (35). <br />New information on acrylamide has been recently reported in food technology by Coughlin <br />(12). Five international research groups have separately confirmed a major Maillard reaction <br />pathway for acrylamide formation. Using elegant radiolabeling experiments, they conclusively <br />