From bags to microplastics: sizing up a pollution problem

Paul Gunton

Paul Gunton · 20 March 2019


Plastic pollution in the oceans is rising up the environmental agenda worldwide, but a news item this week (18 March), an advisory report last week and an IMO paper the week before that have helped to give it a particular focus, prompting this ShipInsight review of current concerns.

The news item reported that the D'Bone Collector Museum in the Philippines had recovered a dead whale last Saturday (16 March) that was found to have 40kg of plastic bags in its stomach, causing it to starve to death. Marine plastic waste is a particular problem in the region, the news item said, citing a 2015 report that credited China, Indonesia, the Philippines, Vietnam and Thailand as accounting for about 60% of all the plastic waste that ends up in oceans.

That is an alarming figure and, in any developing area of research and potential regulation, figures matter. So a report published on 13 March by the Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) that looked into the difficulties of monitoring plastics in the ocean should be welcomed.

GESAMP marks half a century this year of providing advice to the UN system on the scientific aspects of marine environmental protection. Its latest 123-page report, Guidelines for the Monitoring and Assessment of Plastic Litter in the Ocean, says that “the need for greater harmonisation of methods has become more critical with the adoption of the UN Sustainable Development Goals (SDGs).”

Any researchers into marine plastic waste from now should heed GESAMP’s goal of promoting a harmonised approach to sampling programmes so that consistent decisions can be taken.

There can be some practical difficulties in taking samples, however, before any thought can be given to how the data will be analysed. A report published in February 2018 by Eunomia Research and Consulting of the UK for the European Commission’s DG Environment included a remarkable reference to an earlier study that found paint flakes in fish that, their analysis later showed, had come from the two survey vessels conducting the research.

It is not just in fish where hull coatings are posing a problem. Microplastics from marine paint have been detected in the Arctic in recent years, first reported in a study published in October 2015 while, in the same month, another study found that ship paint particles accounted for the majority of microplastics detected in water samples taken along South Korea’s west coast.

It is against this background that IMO published a report, Hull Scrapings and Marine Coatings as a source of Microplastics, on 6 March, funded by the UN Environment-led Global Partnership for Marine Litter. It is a literature study rather than original research, but its findings are dramatic. Over 95% of marine waste consists of plastics, it says, commenting that in the past, although plastics “were previously regarded as an eyesore, but of little significance as a pollutant, it is now recognised that uptake of plastics can impact species and communities directly and that they may bioaccumulate or be directly taken up by humans.”

As for marine coatings, “the issue of plastics has seen limited attention,” it says. The authors found research into how coatings behave in service and which describe how they emit copper and biocides from vinyl and epoxy coatings, but “the research reviewed did not consider microplastics release,” the paper says.

That is starting to change. ShipInsight contacted some of the major paint makers for this article and Hempel’s regulatory affairs manager for health, safety and the environment Gareth Prowse said the company has been following the IMO and EU discussions and has been collaborating on two studies on the topic, at Aalborg University and with the Alfred-Wegener-Institut in Germany.

“Other research states that paint flakes come from a variety of sources, not just the marine coating industry,” he told ShipInsight, in particular shipyards, “where application and removal processes can lead to significant losses of coatings to the environment if they do not conscientiously manage their waste.”

For its part, Hempel is investigating ways to optimise its formulations so that overspray waste is minimised and, in use, “to ensure that potential releases to the environment are controlled as much as possible.”

A director of another manufacturer said that the IMO report had led to some “internal exchanges of ideas” at his company and believed it “has done its job” in bringing this concern to paint makers’ attention as they develop future coatings. But he was unsure what could be done to solve the problem. “It would be a monstrously huge exercise” that would need years of research, he said, to define standards and apply them internationally and locally to develop new coatings.

He also suggested that conflicting environmental risks would have to be balanced against each other. If a ban on paint that could shed microplastics meant that ships had less antifouling capability, “that will cause huge amounts of environmental damage. Paint makers will always say that any antifouling paint is an environment-friendly product because it reduces fuel consumption,” he said.

IMO’s report makes clear that any such choice is a long way off. “This study identified important data gaps and made suggestions for subsequent research into whether ship coatings are an important source of microplastics to the ocean,” its summary says. If they are, it goes on, “the overall relative contribution to ocean microplastics from ship coatings, as well as the individual contributions from the normal use, maintenance and cleaning of coatings, need to be determined as the first step in further research efforts with a view towards informed management.”

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