Precautions when Transiting MARPOL Special Areas or PSSAs

As with any voyage at sea, the vessel poses environmental risks. These range from garbage and air pollution to potential oil spills from the bunker or cargo tanks. Polar waters, especially Antarctic waters, are considered special areas or areas of particular sensitivity (PSSAs), and as such, additional measures should be taken to ensure that no pollution incidents occur.

Oil Pollution Prevention

Oil pollution is considered the most prevalent threat to polar waters from vessels. Oil is a significant marine pollutant that would considerably impact fragile ecosystems and persist for up to 50 years or more. While there is uncertainty about the long-term effects of oil in icy waters, any oil that becomes frozen within the pack will lead to asymmetric freezing and significant pressure fields that will make clean-up impossible.

The main protections for the environment come from the precautions to be taken following MARPOL Annex 1. As special area protections cover polar waters, strict adherence to oily water separators and correct retention of oily residues will prevent most pollution incidents. Also, areas to be avoided (ATBAs) are published for Arctic and Antarctic waters, and these should be noted and duly avoided. More information on ATBAs can be found in IMO SN.1/Circ.331. This will aid in ensuring that shallow waters or areas of particular susceptibility to pollution damage are not endangered unduly.

Should an oil pollution event occur, there are several ways that the spill can be contained and cleaned by the vessel; booms, drizzit pads, sand and mobile transfer pumps are all useful to contain and quickly pick up any smaller spills. They are not a substitute for correct procedures and safe practices, which are the most effective defence against pollution incidents.

Prevention of Pollution by Garbage, Sewage and Other Pollutants

Pollution by garbage, ballast water, sewage and other ship-generated substances should all be minimised in polar waters, as with other sea areas. While MARPOL regulations may allow for more relaxed discharge criteria for some of these substances, there is a consensus that polar waters (especially the Antarctic waters below 60° South) should remain as "carry in and carry out" for all polluting substances. This methodology would ensure that there are no unintended consequences of pollution in these areas.

Prevention of Pollution by Vessel Emissions

Polluting emissions are all defined under Annex VI of MARPOL. This document sets limits on sulphur and nitrogen oxide emitted by exhausts and prohibits the release of ozone-depleting substances. As with all pollution control measures, these mandatory controls should be adhered to and ensure that any known ATBAs are given a wide berth to ensure compliance with all emission controls.