Ballast Water: Convention Not Good Enough for the Arctic?

IMO's Marine Environment Protection Committee (MEPC) is meeting for its 69th session this week, and one paper submitted for discussion relates to bioinvasions in Arctic waters.

Friends of the Earth International has submitted a paper that describes what is presently known about the risks, pathways and potential control strategies for ship-mediated bioinvasions in the Arctic. The paper calls for either more stringent discharge standards for ballast water treatment systems used in Arctic waters than currently specified in the IMO Ballast Water Management Convention or a move to shore-based ballast water treatment.

The paper has been prepared by Dr Andrew N. Cohen of the Center for Research on Aquatic Bioinvasions in California. 

The number of bioinvasions in the Arctic is low compared to other regions. Eight bioinvasions that appear to be the result of transport are reported north of the Arctic Circle. Wider definitions that include more southerly waters such as the Aleutian Islands boost the number to 26 or 37.

Coastal Norway, Iceland, the Faroe Islands and south Alaska appear to be hotspots for invasions, although this could be because the waters have been the subject of more study compared to, for example, Greenland where no bioinvasions have been reported. Islands may be susceptible to a higher rate of invasion, and differences in shipping, tourism, aquaculture and the development of shoreside infrastructure could also be important.

Ecological theory and evidence suggest that the relatively low biological diversity of the Arctic’s marine waters should result in low biotic resistance, says Cohen, making the Arctic susceptible to bioinvasions.

Cohen considered ballast water exchange, noting that it appears to be on the way out as a method for invasive species control. “This may be a good thing since it has limited and somewhat uncertain effectiveness, in certain cases may increase the risk of introductions, depending on where exchange occurs, is very difficult to monitor and enforce and appears to have unresolved and potentially serious safety issues.”

Ballast water treatment systems that meet the requirements of the IMO Ballast Water Management Convention can’t be assumed to reduce concentrations of bacteria, viruses and small protests to safe levels, states Cohen. Some treatment systems can even increase the concentrations of these organisms by killing zooplankton that eat bacteria and by killing organisms and thereby increasing the nutrients that fuel bacterial growth.

Therefore, Cohen recommends that any consideration for developing discharge standards beyond the Convention should consider organisms under 10 microns in size including bacteria and viruses.

Additionally, Cohen notes that only a quarter of the IMO-approved treatment systems that were reviewed had conducted any land-based type approval tests in waters colder than 5°C and none conducted any shipboard type approval tests in waters colder than 5°C.

Land-based treatment processes using conventional drinking water treatment processes might be able to achieve considerably higher levels of treatment than the best shipboard treatment systems, states Cohen. They could also be more reliable, adaptable and probably safer.

“One big advantage is that it would be much easier to monitor the discharges of a small number of treatment plants on shore than a much larger number of treatment plants installed on and moving around on ships (and easier to take enforcement actions.) Compliance monitoring of shipboard treatment is extremely challenging, and no one has yet developed a plan for how to do it effectively.”

Cohen notes that the establishment of LNG export terminals and other natural resource export terminals in the Arctic provides an opportunity to implement shore-based treatment.