Marine Plastic Pollution: why is it a global concern? And how technology can help?

Sandra Ramos

C. Marisa R. Almeida

  ⁽²⁾CIIMAR- Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, PORTUGAL

1. Current situation of plastic and microplastic pollution

Plastic is undoubtedly one of the most significant innovations of the last century. With its exceptional properties such as durability, resistance, and inertness, it has become a widely used material. This associated with its low production costs and versatile nature lead to an unprecedented overuse of plastic, resulting in an alarming amount of plastic waste in our ocean.

Marine plastic pollution has become a global concern in recent years, as the magnitude of the problem has become increasingly clear. Plastic pollution is the accumulation of plastic materials in the natural environment, particularly in the ocean. Plastics do not biodegrade, but rather break down into smaller particles. Nowadays, plastic debris is one of the most significant and long-lasting pollution issues worldwide due to its durability and persistence (Villarrubia-Gómez et al., 2018), being able to last in the environment for hundreds of years. Plastics, namely microplastics (i.e., plastic particles smaller than 5 mm) have become ubiquitous in aquatic environments, and plastic debris is now found in all of the world's regions; it has been documented in remote and previously untouched locations, like the Arctic and Antarctic (Mihai et al 2022). The Great Pacific Garbage Patch (GPGP), situated in the eastern region of the North Pacific Subtropical Gyre, is one of the areas with the highest levels of oceanic plastics, with approximately 45-129 thousand tonnes of plastic debris floating within an area of 1.6 million km2 in this location (Lebreton et al., 2018).

Inadequate waste management practices, combined with the continuous production of new plastic items, contribute to a constant build-up of plastics in various marine and coastal environments (Ramos et al., 2023). Despite ongoing environmental concerns, society continues to maintain a high demand for plastics. Plastics are widely used in food and drink packaging, medicines, cosmetics, detergents, and other products (Wang et al., 2016; Anjana et al., 2020). Plastic invention dates back to the 19th century (Figure 1), but its massive production began in the 1950s (Velez et al., 2019). It is still supported by a linear economy, which is gradually shifting into a circular economy in some regions of the world. In 2020, it was estimated that between 4.8 million and 12.7 million metric tons of plastic waste entered the ocean annually (Jambeck et al., 2015). Although numerous regulations and initiatives are currently in place to mitigate plastic pollution, it has not yet been possible to significantly reduce plastic litter. Furthermore, the COVID-19 epidemic has caused a recent setback in the progress made on reducing plastic use, with plastic consumption increasing dramatically (Govender et al., 2020).

Source: Plastic collective

2. Main threats of marine plastic pollution

Plastic pollution poses significant risks to the marine environment and to the health and wellbeing of both marine life and humans. Several organisms have been harmed by plastic debris, including marine mammals, seabirds, fishes, corals, crustaceans, molluscs, as well as marine plants like macroalgae and seagrass.

Plastic debris can entangle marine organisms, leading to suffocation, drowning, or other fatal injuries, and cause habitat damage. Plastic waste can also be ingested by marine organisms, which can cause injury or death by blocking their digestive system or causing other internal injuries.

The main threats posed by marine plastic pollution are numerous and manifold, and they vary according to the type and size of plastic debris. In general, macro-sized marine debris has more lethal impact compared to smaller particles like micro- and nano-sized debris (Ramos et al., 2023). However, in some cases, small debris (nano and micro) can be lethal by restricting also the feeding ability of smaller planktonic organisms like zooplankton and ichthyoplankton (Botterell et al., 2019). Microplastics may also have biological effects at low concentrations, especially for molluscs, crustaceans, and amphibians.

Moreover, the chemicals and pathogens adsorbed to microplastics and nanoplastics can also cause significant noxious effects (Ramos et al., 2023). Smaller ingested debris particles, including micro and nano particles, can indeed have sublethal effects due to plastic-associated chemicals. Hazardous polymers like polyurethanes, polyacrylonitriles, polyvinyl chloride, epoxy resins, and styrene contain mutagenic and carcinogenic monomers. Plastic additives such as phthalates, bisphenol A, and polybrominated diphenyl ethers leach out, affecting reproduction and causing genetic and hormonal imbalances. Plastics can also adsorb metals and persistent organic pollutants (POPs) like polychlorinated biphenyls and polycyclic aromatic hydrocarbons. These POPs act as endocrine disruptors and carcinogens. Microplastics may serve as carriers of hazardous pollutants, which are then released upon ingestion by marine organisms. Microplastics can also transport pathogenic bacteria as well as alien and invasive species from one region to another, thus causing ecological issues.

Also, plastic pollution can impact the food chain, as smaller organisms ingest microplastics, which are then consumed by larger predators. This can lead to the accumulation of plastic particles in the bodies of these organisms, which can ultimately be passed on to humans who consume seafood.

Furthermore, plastic pollution can also influence the health and wellbeing of humans directly. Plastic waste can wash up on beaches, posing a physical hazard to beachgoers and potentially causing injury. It can also affect the aesthetic appeal of coastal areas, leading to reduced tourism and economic impact. Additionally, plastic pollution can have significant economic costs, as it can damage fishing nets, vessels, and other marine infrastructures.

Source: blog.marinedebris.noaa.gov

3. Solutions to prevent and mitigate plastic pollution

Addressing the growing threat of marine plastic pollution requires teamwork within the science-policy-society interface to combine the know-how of the different actors involved, towards successfully solve the marine litter global environmental crisis. Numerous regulations and initiatives are currently in place to mitigate plastic pollution, such as educational and citizen science projects and environmental NGO initiatives, as well as international policies and agreements, resolutions, and other international instruments, processes, commitments, and treaties that directly or indirectly target marine litter and microplastics (Ramos et al., 2023).

Technological solutions are also being developed and implemented to help tackle plastic pollution. These solutions range from innovative new materials to advanced waste management technologies. One example of an innovative material is biodegradable plastic, which is designed to break down more quickly than traditional plastic, reducing the amount of plastic waste in the environment. In addition to these materials-based solutions, technological advancements in waste management are also being developed to reduce the amount of plastic waste that enters the environment, for example, microplastic capture technologies, which can filter out tiny plastic particles from wastewater before it is discharged into the ocean.

Moreover, some countries have implemented extended producer responsibility (EPR) schemes, which require manufacturers to take responsibility for the end-of-life disposal of their products. This encourages manufacturers to design products that are more easily recyclable or compostable, reducing the amount of waste that enters the environment. Other waste management technologies under development include waste-to-energy technologies, which convert plastic waste into energy, reducing the amount of waste at landfills or incinerators.

Although the great majority of marine litter comes from activities that take place on land, sea-based activities also contribute to pollution, though to a lesser extent. The primary sea-based sources of marine litter are aquaculture, fishing, shipping, and offshore oil and gas platforms. In fact, abandoned, lost, or otherwise discarded fishing gear (ALDFG) is a critical item of plastic marine debris (Richardson et al., 2019), responsible for the entanglement and injury of several marine wildlife (Brown and Macfadyen, 2007). There are several initiatives taking place worldwide to recover ALDFG from the oceans and prevent fishing nets from becoming lost. Tagging fishing nets has been presented as a reliable solution to prevent their loss (Balk and Lindem, 2000), with important technological improvements being made in this field. For example, acoustic tagging with transponders technology, as those developed by the EU funded NetTag project is a reliable technological solution to locate, track and recover fishing gears in case of loss.

NetTag project aimed to reduce and prevent marine litter derived from fisheries, bringing together scientists, engineers and the fisheries industry. The project combined two different types of preventive measures:

NetTag¹ developed new technologies to track fishing gears in case gears got lost, fostering a reduction of lost gears. The technology included low cost, miniature and environmental-friendly acoustic tags and acoustic transceivers for uniquely localization (with fisher’s personal ID) of lost gear and an automated-short-range robotic recovery system. For the later, autonomous underwater vehicle/remotely operated vehicle (AUV/ROV) were adapted to assist in the recovery of the gear. Participant fishers from the NW Iberia Peninsula coast then evaluated the new technology in a dedicated demonstrative field action acknowledging the easiness and usefulness of it.

The project will now have a follow up, the NETTAG+ project, dedicated to develop thre solutions to Prevent, avoid and Mitigate the environmental impacts of fishing gears and associated marine litter. This new project will scale-up the technological solution to locate, track and recover fishing gears in case of loss and expand its applicability to different types of fishing gear and scenarios, namely the Mediterranean Sea. NETTAG+ will also continue to work with the fisheries sector, co-producing activities to promote their role as key-actors to prevent and reduce marine litter. Moreover, NetTag+ will also develop new technology to detect and map ALDFG, facilitating their retrieval and, consequently, reducing their negative impacts.

While technological solutions translate into promising pathways to reducing marine plastic pollution, there are still significant challenges to overcome. One major challenge is the cost of said solutions, which can be unaffordable to some communities and countries. Additionally, the implementation of these technologies requires significant infrastructure and regulatory support, which can be difficult to achieve in many parts of the world.

5. Conclusion

In conclusion, marine plastic pollution is a global concern that poses significant risks to both the marine environment and human health and wellbeing. The status of the problem is bleak, with significant amounts of plastic waste entering the ocean each year. However, several mitigation actions are being implemented targeting the responsible use of plastic and improving the circularity of these materials. It is important to stress that preventing plastic pollution is key to solving the current crisis. Additionally, technological solutions offer promising pathways to reducing this pollution, through innovative new materials and advanced waste management technologies. While challenges remain, continuous research and development in this area could lead to a cleaner and healthier future for our planet.

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