Environmental “cheat” devices fitted to thousands of ships could render some UK ports unusable by contaminating sediment and increasing the cost of dredging, authorities fear.
Last month, The Independent revealed that the global shipping industry has spent more than $12bn (£9.7bn) on installing devices to comply with new environmental legislation that end up polluting the sea instead of the air.
The systems, known as “scrubbers”, filter harmful sulphur dioxide from exhaust gas, and have been installed on more than 3,700 ships worldwide.
Just 65 of these vessels have had closed-loop scrubbers installed only, a version that stores the extracted sulphur in tanks before discharging it at a safe disposal facility in a port.
The others are able to discharge the waste products, which are acidic and often contain carcinogens including polycyclic aromatic hydrocarbons (PAHs) and heavy metals, into the sea.
Operators at British ports are concerned that the buildup of pollution on the sea bed could be so bad it puts them out of business.
“The main concern from our members is around sediments,” said Mark Simmonds, head of policy and external affairs at the British Ports Association, which represents over 300 UK ports.
“Ports are very worried about risk to sediments in terms of contamination over the long term, which can dramatically increase the cost of dredging.
“We are concerned that we could see situations where polluted sediment puts such a financial burden on ports that it makes them unviable. That is the fear.”
As well as the pollution they emit the devices are large, sometimes weighing 200 tonnes, and increase the amount of fuel a ship consumes.
“These systems are expelling huge volumes of washwater and we still don’t know in absolute terms how much contaminant is being pumped out,” Mr Simmonds told The Independent.
“Our concern is that in enclosed waterways these contaminants will settle in particular areas and pockets.
“We are worried that contaminated sediments will build up in berths and navigation channels over the long term.
“Contamination makes it very difficult for ports to get permission to dispose of the sediment and it can raise the cost of dredging by about 10 times.”
British ports have licences that allow them to dredge as required and if the sediment is uncontaminated then they are free to dispose of it in a designated area in the open sea.
If the sediment fails environmental tests due to contamination then ports are required to treat the sediment using expensive processes before it can be disposed of.
Some ports on the south and east coast of England already spend tens of millions of pounds on dredging every year and would be hit especially hard financially if sediments become contaminated by pollutants from scrubber washwater.
“Ports are in a very delicate situation,” said Lucy Gilliam, a campaigner for Transport and Environment, a Brussels-based NGO.
“Many ports are very dependent on their shipping customers. They’ve got a conflict between the threat to the viability of their port in the long-term future from escalating pollution versus keeping their port open for business in the short term.
“Obviously, there are parts of the shipping industry that are applying pressure on ports to downplay this risk from their ships.”
The British Ports Association says that it is yet to see convincing studies that address its concerns about the impact of scrubber discharge on sediments over a time period of five or 10 years.
“The shipping industry says that the amount that goes into ports is so small that it will not cause any problem, but we have yet to see data that confirms this in the long term,” said Mr Simmonds.
“The UK government is usually very cautious on environmental things – and normally uses the principle that you can’t do anything unless you can prove that it won’t cause any harm.
“Whereas with the shipping industry the IMO [the UN body that regulates international shipping] seem to take the opposite view – you can do this unless you prove it is harmful. For me that is the wrong way around.
“Many ports are working hard to improve water quality and sediment quality and we don’t want to see the progress that has been made already reversed because of increasing volumes of scrubber washwater being discharged.”
The International Council on Clean Transportation (ICCT), a nonprofit organisation that provides scientific analysis to environmental regulators, also believes that the risk of contamination over the long term is a major concern.
“There has been some research on the composition of scrubber discharge and the concentrations and there is some research under way looking at where the contaminants might go – but the really important thing that we haven’t yet gotten a good handle on is the accumulation problem,” said Bryan Comer, a senior researcher at ICCT.
He said IMO guidelines, which are set out in terms of concentrations that are being emitted rather than the absolute quantity of pollutants being discharged, are not fit for purpose.
“Even if a ship is complying with those guidelines, it doesn’t address the issue that you are going to see these contaminants accumulate in the sediment and in the food chain as well,” he said.
Shipping companies that have invested heavily in scrubbers include British-American cruise company Carnival, which has spent more than $500m developing and installing them.
Maersk, the world’s largest container ship and supply vessel operator, has also fitted scrubbers on vessels after initially opposing the technology.
In a statement to The Independent, Roger Frizzell, a spokesman for Carnival, denied claims ship owners have failed to make data on scrubber discharges available to ports or carry out sufficient research into the long-term impact on sediments.
“We have undertaken the installation of these systems with a slow methodical scientific-based approach, ship by ship, over the past several years,” he said.
Maersk said that scrubbers will only be used on a limited number of vessels in its feet.
It added: “While our IMO 2020 fuel sourcing strategy focuses on compliant fuels for the vast majority of our fleet, we have decided to invest in a number of scrubbers to mitigate risk and familiarise with the technology in case it turns out to provide significant cost benefits compared to compliant fuels.”
In a statement the IMO said that its guidelines are under review and all external input and studies will be welcomed.
In a statement to The Independent, the Clean Shipping Alliance, a lobby group for companies that have invested in scrubbing technology, said that discharge from the devices is safe for marine ecosystems.
“There is well documented evidence relating to the composition of scrubber washwater,” a spokesperson said.