The panel, in a preliminary report from November, found that none of the advanced wastewater treatment systems on ships operating in Alaska waters could consistently meet water quality standards at the point of discharge for "constituents of concern" â¿¿ ammonia, copper, nickel and zinc.

Parnell, in his transmittal letter, said the advanced systems being used "are significantly more effective and produce a higher quality discharge than most municipal systems."

"Even without incremental improvements to cruise ship wastewater quality, aquatic life and human health are protected through provisions in the current cruise ship General Permit that restrict the location of discharge and when ships must be under way before they discharge," he wrote.

Gershon Cohen, project director with the Campaign to Safeguard America's Waters, said the proposal isn't based on the best available science.

"The best science for what puts people and marine ecosystems at risk are the Water Quality Standards," he said in an email. "Using public waters to dilute waste isn't good science, it's simply risk management. It is saying, how much risk are 'we' willing to take on to not require a polluter to clean up their discharges."

He also said a science advisory panel, "refused to acknowledge" some treatment devices work better than others and that combinations of technologies could reduce emissions below the water quality standards at a "minimum" cost to each ship.

Guy Archibald, mining and clean water coordinator for the Southeast Alaska Conservation Council, said he's not sure what the rush is to "rescind" the 2006 initiative, which has already been modified. For example, in 2010, the Legislature passed a reduction in the cruise passenger head tax. The move was aimed at attracting more ships â¿¿ which Parnell says it has â¿¿ and at settling a lawsuit with the Alaska Cruise Association, which it also did.

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