Vancouver, Canada (GLOBE-Net) - Greenhouse gas emissions from marine vessels have received special attention of late, but as the maritime shipping industry continues to grow, other forms of pollution from ships are creating problems that require urgent attention. 

In the past 15 years, seaborne trade has increased by 50% and continued high rates of growth are expected.  The rise in trade between the North America and Asia (particularly with China) has increases greatly the number of vessels navigating the Pacific, which in turn is exacerbating many environmental problems. The include sulfur and nitrogen emissions from dirty fuels; the release of untreated wastewater effluents; and the transport of toxins, contaminants and invasive species from ballast water.

Air Pollution

The United Nations International Marine Organization (IMO), the leading international body on marine policy, estimates that by 2010, up to 40% of air pollution over land could come from ships.

Seagoing vessels are currently responsible for an estimated 14% of emissions of nitrogen and 16% of the emissions according to the Pew Oceans Commission.  The main culprit is the unrefined diesel fuel, also called bunker fuel, used for marine shipping which contains sulfur content of 2.5% by weight.

"They use the waste products from the refinery, so the refineries make clean fuel for cars, for inland boats, and the rest they simply dump into the tanks of ships going to sea," says Irene Blooming, a spokeswoman for the European environmental coalition Seas at Risk.

According to the IMO, in 2005, maritime activities produced more than 1,444 gross tonnes of diesel particulate matter containing sulfur and an additional 3,109 gross tonnes of fine particulate matter such as dust, dirt, soot and smoke.

Such diesel exhaust has been classified by United States Environmental Protection Agency (EPA) as a likely human carcinogen. According to the EPA airborne sulphur is a major cause of acid rain and the associated particulate matter has been linked to severe respiratory ailments. 

These emissions are particularly dangerous to coastal communities, where pollutant concentrations at their highest.  Research has shown that residents of such areas are at an increased risk of illnesses.

Puget Sound, for example, a major shipping route in the Pacific North West, is in the top 5% of the nation for potential cancer risk, according to the US Environmental Protection Agency.  Approximately 78% of the potential cancer risk comes from marine emissions.

A report release by the American Chemical Society in November of 2007 suggests as many as 60,000 people living in coastal communities along major shipping routes died from lung and heart complaints as a result of high sulfate emissions from ships in 2002.  That number could reach 82,000 by 2015 the study says.

Ballast Water

When a larger vessel, such as a container ship or an oil tanker unloads cargo, sea-water is pumped into compartments in the hull. Similarly, when a larger vessel is being loaded it discharges sea-water from these compartments. This process is meant to help stabilize and balance a ship.

Although there is potential for pollution from ballast water, the larger concern comes from the transportation of alien and invasive species into aquatic ecosystems.  When entering a new ecosystem, these species can quickly take over and extirpate native organisms.

"The potential and real impacts of aquatic nuisance species on our environment, food supply, economy, health and overall biodiversity are universally accepted as costly, significant and growing," said Capt. Mike Blair, chief of the US Coast Guard’s office of operating and environmental standards.

This has been a particular problem in the Great Lakes, the world’s largest freshwater system, linked to the ocean and ocean faring vessels by the St. Lawrence Seaway. Ballast water has been responsible for both the Sea Lamprey and the outbreak of the Zebra Mussel in southern Ontario freshwater bodies. Combined both species have decimated local fish species and cost billions of dollars in damages to both the United States and Canada.

Searching for Solutions

Action is being taken to address the problem, but it has been slow due to the complexity of the issue.  For shipping laws to work, international consensus is required however most current international regulations on fuels are voluntary.

Any port that moves too aggressively to reduce pollution also runs the risk of driving away business.  The end result is economic losses while essentially relocating the pollution elsewhere but not eliminating it.

For example a law adopted in 2004 by the IMO to help reduce the threat of invasive species resulting from ballast water has only been ratified by 12 countries, representing just 3.64% of the world’s shipping, resulting in little action to curb the problem.

Many solutions have also been technological in nature, through the development of cleaner fuels and more efficient engines.  The IMO for instance, recently revised MARPOL Annex VI, the global regulatory regime dealing with sulfur emissions from ships.  The revisions include progressively lower sulphur limits in what are now referred to as sulphur emission control areas (SECA), heavily populated, coastal areas.

Rich nations are more capable of affording such technology solutions; however poor nations are unable to do the same.  Cleaner, low sulfur fuels are nearly double the cost of the existing bunker fuel that ships currently use.

To compound the problem, outdated, high polluting vessels may be turned away from ports with more stringent regulations, causing further economic hardship to poor countries by restricting exports.

"International regulation is the only way to bring in the use of cleaner fuels and ensure there is no competitive disadvantage when using it," said Arthur Bowring, of the Hong Kong Ship Owners Association.

Enforcing shipping laws also poses a practical problem, as marine vessels can operate unmonitored on the ocean.

Current ballast water management regulations require applicable ships to conduct a mid-ocean ballast water exchange. This ballast water exchange is intended to flush out most coastal water, along with coastal organisms, and replace it with water from the open ocean but there is no guarantee this is being done on a regular basis.

If the situation is to improve, stricter legislation and greater international collaboration is required according to experts.

"Ship pollution affects the health of communities in coastal and inland regions around the world, yet pollution from ships remain one of the least regulated parts of our global transportation system," said Dr. James Corbett Associate Professor of Marine Policy at the University of Delaware.  "With more than half the world’s population living in coastal regions and freight growth outpacing other sectors, shipping emissions will need to meet stricter control targets."