Fifty-four U.S. environmental groups called on the EPA yesterday to crack down on pollution from cruise ships, with a formal petition that asks the agency to close loopholes in Clean Water Act regulations that allow the ships to dump millions of gallons of pollutants directly into sensitive waters. Cruise ships can legally discharge untreated waste water from laundries, showers, sinks, and galleys anywhere in the seas, and they can dump human waste and food more than three miles from shore. On one typical weeklong voyage, a cruise ship with 3,000 passengers and crew members generated 1 million gallons of untreated waste water, 200,000 gallons of sewage, 25,000 gallons of oil-contaminated water, and eight tons of garbage, according to a report by enviro group Bluewater Network.