A strong alliance against ‘marine litter’
The pollution of the world’s oceans with rubbish (‘marine litter’) is a challenge that experts across the globe are working to tackle. There is no doubt that this problem must be tackled. The K-sector is also actively committed to getting to the root of the causes and developing solutions. Particular attention is being paid to ‘microplastics’.
During the German-Russian Kuril Kamchatka Biodiversity Studies (KuramBio) [1], several deep-sea expeditions were undertaken in the north-western Pacific between 2010 and 2016. In the course of these expeditions, the participating scientists – including those from from the Senckenberg Research Institute and Natural History Museum in Frankfurt am Main and the Institute for Microbial Ecology at the Helgoland Biological Station, collected sediment samples from the Kuril Trench, which is 2,250 kilometres long and reaches a depth of 10,542 metres at its deepest point. The samples were taken at various depths and subsequently analysed in the laboratory for plastic residues. The result: hardly any sample was free of microplastic particles; by definition, these are plastic particles with a diameter of less than five millimetres. The researchers report that between 14 and 209 of these particles were found per 1,000 grams of dry matter. The greater the depth at which the samples were taken, the more particles were found. The researchers conclude that ocean trenches are veritable microplastic traps. [2]
The findings of the KuramBio studies may prove to be a valuable clue for colleagues at the Geomar Helmholtz Centre for Ocean Research in Kiel. There, researchers had been asking themselves where all the plastic waste polluting the oceans might end up. Studies had in fact revealed that some of it simply disappears from view: the amount of plastic actually found on the sea surface is significantly lower than expected, according to a statement from Geomar. This observation applies in particular to microplastics. Whilst less microplastic is found on the sea’s surface than assumed, it has become apparent that significant quantities of it can be detected at great depths in the ocean.
But how does it get there? Polymer material that is, by its very nature, lighter than water and should float on its surface! Geomar set itself the task of answering this and similar questions. Models were used to simulate how microplastics move in the ocean and what influence biological processes have on the particles’ descent into the deep sea. The results of the modelling shed light on the matter.
Geomar researchers attribute the phenomenon of microplastics sinking in the sea in particular to plankton, which lives near the water’s surface. Plankton refers to the totality of all organisms that float in open water without their own means of propulsion and are carried along by the water current. Plankton – for the sake of completeness – stands at the top of the food chain. It is consumed by smaller marine animals (zooplankton), which in turn serve as food for larger aquatic predators, which are then eaten by even larger animals. At the end of the food chain, ultimately, is humankind.
So how do microplastics end up on the seabed? Answer: It is highly likely that excrement, dead cells or entire organisms bind to the microplastic particles, acting, as it were, as a gathering point or crystallisation point for them. Once loaded in this way, the buoyancy is lost and the microplastic ‘vehicle’ drifts – like snowflakes – down into the depths. Bacteria living there consume the organic cargo and release the polymeric carrier, which either sinks further down or is washed back to the sea’s surface. According to Geomar, however, only one in two particles sinks; in some regions, as few as one in three. The researchers therefore consider the sinking process to be ‘rather ineffective’. Nevertheless, it is effective enough to remove sufficient plastic from the upper water layers. ‘Marine snow’ thus has a major influence on the global distribution of microplastics. [4]
Prevention is better than cure
The phenomenon of ‘marine litter’ and the search for microplastic particles in the sea make one thing clear: it would be better if we did not have to deal with the issue in the first place, and if the oceans – like other ecosystems – were free from any anthropogenic residues. Let’s take a look at the causes of ‘marine litter’:
The majority of plastic pollution ending up in the sea is caused by poorly managed waste. In addition, carelessly discarded packaging, bottles, caps, cigarette filters and much more contribute to the problem. In the past, granules (pellets) used in the manufacture of plastic products have also been found along riverbanks and coastlines. In other words, this is a multifactorial, systemic problem, the solution to which requires action on many fronts. The guiding principle, therefore, is this: just as consumers are required to dispose of their waste properly, the plastics industry, in turn, must use raw materials carefully and ensure that no pellets are lost.
This means that the requirements for potential solutions are, at least in part, already known. The issue has been addressed: European plastics manufacturers have made it their mission to prevent the loss of granules. To this end, the plastics manufacturers’ association ‘PlasticsEurope’ (https://www.plasticseurope.org/) launched the ‘Operation Clean Sweep’ (OCS) programme [5] in 2013. It is aimed at all stakeholders along the supply and value chain, from production, through transport and storage, to compounding and further processing. According to PlasticsEurope, around 500 European companies have so far signed up to the OCS programme, which thus covers 98 per cent of European plastics production [6].
What further steps are being taken to combat the growing problem of marine litter? For example, since 2009, ‘World Oceans Day’ has been observed on 8 June each year. Its introduction dates back to the ‘United Nations Conference on Environment and Development’, which took place on 8 June 1992 in Rio de Janeiro; it is commonly referred to as the ‘Earth Summit’ or the ‘Rio Conference’ [7]. It simply takes a great many stakeholders to ensure the protection of the environment and the oceans and to safeguard them in the long term. The plastics industry is doing its bit. Here are a few examples:
- Around 70 organisations and industry associations from more than 40 countries have signed the ‘Global Declaration for Solutions to Preserve Our Aquatic Systems’ (https://www.marinelittersolutions.com/about-us/joint-declaration/). In it, the plastics industry acknowledges its responsibility and is driving forward solutions to tackle marine litter through more than 350 projects. [8]
- Leading plastics manufacturers from Asia, the Middle East, North and South America, and Europe have joined forces to form the “World Plastics Council” [9] to combat global environmental pollution caused by discarded plastic through innovative approaches.
- More than 35 international corporations and companies have come together under the umbrella of the non-profit organisation (NGO) ‘Alliance to End Plastic Waste’ to work on new approaches and efficient solutions for minimising plastic waste in the environment. To this end, the members are contributing their expertise, their materials and technological know-how, and financial resources. The Alliance has its European headquarters in London, where everything comes together; the members’ decisions are translated into strategies and action plans, which are implemented in close cooperation with strategic partners such as the World Business Council for Sustainable Development (WBCSD) or the United Nations Environment Programme (UNEP). [9]
The convergence of corporate and institutional interests highlights the gravity of the situation; resolving it in a sustainable manner requires commitment, drive and substantial funding. The ‘Alliance to End Plastic Waste’ has placed particular emphasis on tackling the pollution of the world’s oceans with plastic waste. A large proportion of the waste is, in fact, washed into the oceans via tributaries, which brings us back to the beginning of this article. Cutting off the flow of waste via river tributaries is one of the Alliance’s objectives. It therefore supports targeted projects around the world:
- Take ‘Renew Ganges’, for example: this project has set itself the task of clearing rubbish from the 2,600-kilometre-long River Ganges, which is heavily polluted with sewage and harmful substances. The Ganges flows through the great plain south of the Himalayas, one of the most densely populated areas on Earth.
- In Indonesia, meanwhile – the world’s largest archipelago and, with 264 million inhabitants, the fourth most populous country on Earth – the Alliance is supporting the development of a functioning infrastructure for waste collection and recycling. The focus is on projects characterised by sustainability, on damage control, and on changing mindsets and bringing about a paradigm shift.
Plastics are produced to fulfil important tasks and functions. However, used plastics do not belong in the environment, but back into the recycling loop – a priority issue for the plastics industry under the term ‘circular economy’. Mastering this challenge, however, requires a commitment from society as a whole. We are all called upon to play our part in preserving an intact, liveable environment. What is your idea?
[2] Abel et al., Systematic identification of microplastics in abyssal and hadal sediments of the Kuril-Kamchatka Trench, Environmental Pollution (2020) 116095, ISSN 0269-7491, https://doi.org/10.1016/j.envpol.2020.116095
[3] Kumar et al., Analysis of microplastics across a broad size range in commercially important mussels using a combination of FTIR and Raman spectroscopy approaches. Environmental Pollution (2020). https://dx.doi.org/10.1016/j.envpol.2020.116147
[4] Kvale et al., The global biological microplastic particle sink, Scientific Reports (2020). https://doi.org/10.1038/s41598-020-72898-4
[5] Operation Clean Sweep, http://www.opcleansweep.eu/impacts/
[6] PlasticsEurope on Operation Clean Sweep, https://www.plasticseurope.org/de/newsroom/press-releases/pressemitteilungen-2019/neuer-report-zu-operation-clean-sweep-veroeffentlicht
[7] Wikipedia, United Nations Conference on Environment and Development, https://de.wikipedia.org/wiki/Konferenz_der_Vereinten_Nationen_%C3%BCber_Umwelt_und_Entwicklung
[8] Marine Litter Solutions, Solutions for our oceans, https://www.marinelittersolutions.com/
[9] World Plastics Council, https://www.worldplasticscouncil.org
[10] Alliance to End Plastic Waste, https://www.endplasticwaste.org