A STUDY commissioned by Panama into the use of open-loop scrubbers raises “cause for concern” and questions whether ships equipped with the technology are truly equivalent to vessels burning low-sulphur fuel.

The study, carried out by researchers at the Massachusetts Institute of Technology, has been submitted to the International Maritime Organization ahead of this week’s meeting of the pollution prevention and response sub-committee review of the guidelines on scrubbers.

The MIT research involved “an extensive literature review” that compared seven previous studies on the environmental impact of marine scrubbers from Denmark, Germany, the Netherlands, the US and internationally.

There was “an almost complete consensus” that there was cause for concern about pollutants contained in scrubber discharges, the study found.

The effluent was also acidic, which could affect ocean chemistry and marine life.

The study also gave consideration to the equivalency of using scrubbers to burning low-sulphur fuels.

While scrubbers were effective for gaseous sulphur oxides, the study noted that scrubbers may not be as efficient in removing small particulates that are harmful to human health.

“Research is far from conclusive in this area. Certainly, more work is needed,” it said.

But there were “enough indications” that there may be issues with current scrubber designs and regulations “in terms of delivering emissions that are completely equivalent to those of low-sulphur fuel”, they concluded.

The findings are very different in emphasis to those of a new Japanese government study being presented to the IMO this week.

It projects that in 10 years’ time any effects from scrubber use in representative coastal areas around Japan would not be significant enough to warrant prohibition.

The amount of heavy metals entering the sea through scrubber effluent was 100 times less than the limitation on land discharges in Japan.

The Panamanian submission will add to growing calls for a closer look at the effects of scrubbers while at the same time dozens of shipping companies invest in multimillion-dollar programmes to install them on board mainly large vessels.

The European Union has asked the IMO to thoroughly review its guidelines on scrubbers as a matter of urgency, saying that the sooner the issue is sorted out, the less the potential economic impact, both on the industry and the public sector.

According to the EU proposal, the current guidelines do not specify discharge criteria for specific areas and it was “questionable” whether they were fit for purpose given the sharp uptake of scrubbers by owners.

The EU says there is scientific evidence for the “potential toxicity of EGCS water discharges” and argues for the ability to take “appropriate regulatory measures” to protect certain areas from pollution, “which could also include discharge bans from ships using a specific technology”.