British Columbia cruise ships may be endangering aquatic life by using exhaust gas cleaning systems, or scrubbers, to remove sulphur oxides from heavy fuel oil exhaust gases in engines.
A new study has found that these ships dumped nearly 35 million tonnes of effluent into coastal waters over 2017, essentially turning air pollution into marine pollution. Remarkably, the 35 million tonnes of effluent came from just 30 cruise ships, the study found.
The washwater effluent (a mix of water and contaminants from the heavy fuel oil) comes from “open-loop” scrubbers that immediately dispose of acidic washwater tainted with carcinogens and heavy metals into the ocean, as well as “hybrid” systems that allow ship operators to control when discharge is released into the ocean after storing it.
Cruise ships, which account for some 90% of the harmful discharges, use these scrubbers to comply with international sulphur-limit regulations. Yet, several coastal states and ports around the world have banned open-loop scrubber discharge, including California, China and, most recently, Malaysia. Singapore and Fujairah, in the UAE, that intend to ban discharges starting in 2020.
Heavy fuel oil use and scrubber washwater discharges are expected to grow by 35% as more ships, particularly container ships, bulk carriers, and roll-on/roll off ferries, begin to use scrubbers, researchers said.
The study, “A whale of a problem? Heavy fuel oil, exhaust gas cleaning systems, and British Columbia’s resident killer whales,” was released by the International Council on Clean Transportation. It was funded by World Wildlife Fund (WWF) Canada.
Particularly at risk from the contaminants are southern resident killer whales, with only 76 individuals remaining, and northern resident killer whales, threatened with just 309 animals remaining.
“Canada has a responsibility to safeguard our oceans,” announced Andrew Dumbrille, senior specialist of sustainable shipping with WWF-Canada, in conjunction with the new study. “Washwater discharges from open-loop scrubbers pollute habitat and negatively affect wildlife, and an HFO spill would be devastating to coastal communities,” added Dumbrille.
Cruise ships will account for two-thirds of heavy fuel oil use and washwater discharges in 2020 despite the exponential growth in scrubber use in other ship types.
The WWF said that using hybrid- or closed-loop scrubbers in zero-discharge mode would eliminate water pollution emissions from these systems, but the risk of an HFO spill would remain. However, Canadian laws do not prohibit ships from functioning in “open mode” in Canadian waters.