The local neighborhood pond fringed with spring green looks attractive, but its muddy bottom is loaded with contaminants. Metro communities from White Bear Lake and Maplewood to South St. Paul are discovering that their storm-water ponds are chemical soups of pesticides, fertilizers, pet wastes, oil, grease and other contaminants. With an estimated 20,000 public storm-water ponds in the metro area, and thousands more privately owned by industries and homeowner associations, state pollution officials say they expect the problem to be widespread. "It took us aback, frankly," said Mark Burch, White Bear Lake's public works director. "Especially when we figured out how much it would cost" to clean up. On Tuesday, the city is poised to adopt the state's first ordinance -- and only the fourth in the nation -- to ban coal-tar sealants spread on driveways and parking lots. The sealants, among the worst culprits in the contamination, contain chemical compounds that are classified as likely carcinogens, and are known as PAHs (polycyclic aromatic hydrocarbons).