America's obsession with single-serving water is creating ugly mountains of cheap plastic bottles in landfills nationwide & a public relations headache for a segment of the packaging industry struggling with the three-headed hydra of escalating oil prices, rising environmental concerns, & health fears. The big question is whether manufacturers of glass bottles can capitalize on the plastic-bottle industry's problems by persuading customers to come home to glass. Firms like Owens-Illinois Inc., the world's largest manufacturer of glass bottles, are beginning to get inquiries from baby-bottle makers responding to consumer fears about a chemical compound called bisphenol-A. "There are opportunities," said Joe Cattaneo, who represents glass manufacturers & their suppliers as president of the US-based Glass Packaging Institute.