Dear Editor: Carbon emissions, wastewater discharges and vessel disturbances all have a cumulative impact on coastal marine ecosystems.
This year, the cruise ships that visit Sitka will consume roughly 2 million gallons of fuel.
A single ship with 3,600 passengers generates at least 2,800 tons of CO2 during a seven-day trip, equivalent to 600 gasoline-powered cars driving for an entire year.
On a seven-day journey, a ship of this size dumps 211,000 gallons of treated sewage and 1.7 million gallons of gray water. Some are allowed to dump treated sewage in Alaska waters, even at port; others are required to dump outside three miles.
These ships also dump scrubber wastewater all along their routes.
In 2020, the International Maritime Organization required all ships to either burn low-sulfur fuel or install exhaust cleaning systems (i.e. scrubbers) to remove pollutants from cheaper fuels.
Open-loop scrubbers spray sea water into the ship’s exhaust to remove sulfur oxides, creating acidic wastewater that’s pumped back into the ocean.
Closed-loop systems use fresh water treated with chemicals, and deposit less, but more concentrated wastewater.
What doesn’t go into the air, goes into the water as a pollutant. Scrubber discharge contributes to ocean acidification and contains heavy metals (like mercury and arsenic), and polycyclic aromatic hydrocarbons that are toxic to marine organisms.
On each cruise, a 3,600-passenger ship will generate about 55 million gallons of acidic scrubber wastewater—equal to 84 Olympic-sized swimming pools.
All these effluent discharges are dumped in our waters. They are absorbed by fish, concentrated up the food chain, and some will be consumed by us.
Safeguarding Sitka means keeping our ocean, forests, fish and people safe, well, and thriving. I hope we can acknowledge the environmental consequences of overtourism and choose to throttle back.
I’m voting yes to reducing marine pollution in Sitka. We owe it to our home and to our future.
Devon Calvin, Sitka
