It is hard to say, as many cruise lines do not keep records. Consider this: "Imagine the cumulative effect of what gets dumped into the sea from ships that carry 4,500 passengers. They are like huge floating cities 10 stories high. If you calculate 600,000 passengers in just one summer season cruising the Alaska's Inside Passage dumping 200,000 gallons of wastewater daily - that's millions of gallons a year. There are many cruise ships throughout the world's waters, all contributing to the massive amounts of pollution impacting ocean health and species. Ships are transporting non-native species and pathogens in their ballast waters and discharging them in waters at destination ports. These exotic species can take over the native species and cause catastrophic changes in marine ecosystems and biodiversity. Many cruise ships fly under "flags of convenience," registering the ships under a variety of foreign countries that have little or no environmental regulation or enforcement of pollution control. Major cruise lines have been fined millions of dollars for falsifying records, installing illegal bypass lines, and dumping oil, sewage, garbage and hazardous toxic wastes into our oceans and waterways". Also, "AND, there's the ILLEGAL dumping: From 1993 to 1998, cruise ships were involved in 87 confirmed cases of illegal discharges of oil, garbage and hazardous wastes into U.S. waters. In 1998 and 1999 Royal Caribbean Cruises Ltd. was fined more than $26 million for fleet wide practices of discharging oil-contaminated waste, regularly and routinely discharging without a permit wastewater contaminated by pollutants, and making false statements to the Coast Guard". Source: These links: http://www.thepetitionsite.com/takeaction/929852289?ltl=1161710876 http://www.eco-pros.com/humanimpact.htm

Marcie Keever, director of the Clean Vessels Campaign of Friends of the Earth says a one week voyage on a cruise ship produces 210,000 gallons of sewage, a million gallons of gray water (runoff from sinks, baths, showers, laundry and galleys), 25,000 gallons of oily bilge water, 11,550 gallons of sewage sludge and more than 130 gallons of hazardous wastes.