ENVIRONMENTAL DEGRADATION OF POLYACRYLAMIDES .2. EFFECTS OF ENVIRONMENTAL (OUTDOOR) EXPOSURE

The environmental fate of a polyacrylamide thickening agent (PATA), fo rmulated without and with a glyphosate-surfactant herbicide (GH), was examined under various environmental situations: formulation in surfac e water and ground water, volatility, and soil mobility. Environmental Fate of PATA in Surface Water and Ground Water: PATA was formulated a t four concentrations in distilled-deionized water, three surface wate r samples, and two ground water samples, without and with a GH. Soluti ons were placed in glass bottles, covered with plastic wrap, and expos ed to environmental (outdoor) conditions for 6 weeks. Acrylamide and a mmonium concentration, pH, and bacterial and fungal populations were m easured weekly. All solutions in this portion of the study had a homog eneous milky appearance but by the conclusions of the study were nearl y transparent. The results of this study suggest that polyacrylamide c an degrade to acrylamide under environmental conditions. Statistically , there was no linear correlation between the various parameters measu red. Volatility: PATA was formulated without and with GH. Each solutio n plus an acrylamide standard (positive control) was placed in a glass beaker and exposed to environmental (outdoor) conditions for 6 days. Acrylamide concentration, ammonium concentration, pH, and solution vol ume were measured daily. Acrylamide and ammonium concentrations increa sed during the study in all formulations, except when solutions evapor ated to dryness. pH did not change greatly over the course of the stud y for these samples. Those solutions containing PATA had a homogeneous milky appearance but by the conclusions of the study were nearly tran sparent. This suggests a physical structural change in the polymer. So il Mobility: PATA formulated with GH was also applied to soil columns and soil boxes containing sand, Eudora sandy loam, Eudora sandy clay, and Kohola silt loam. Acrylamide could be detected by Day 2 in all soi l columns. Acrylamide could not be detected in the runoff of any of th e soil boxes. (C) 1997 Academic Press.