A Look Back at Plastic Pollution Research

What we’ve learned in the last 50 years.

Lately, it feels like plastic is everywhere. It seems a different news story comes out nearly every week about plastic pollution in a new geographic location or found within another organ of the human body. Some may perceive the issue as a new problem that we are only just beginning to understand the true extent of, but in reality, both anecdotal and scientific records of plastic pollution are decades old.

In fact, one of the first mentions of plastic pollution in a published scientific paper was in 1969. Then, scientists reported that Laysan Albatrosses had ingested plastic on the northwest Hawaiian Islands. Just a couple of years later, plastic pollution was reported by scientists studying sargassum seaweed in the Sargasso Sea. Since these first records, there has been over 50 years of research, with exponential growth of scientific papers published over the last two decades. So, what have we learned along the way?

The first four decades (1960 – 2000): An ocean problem and an eyesore

Following the first published records of plastic pollution in the late 1960s, research slowly increased. Scientists began dedicating studies to the topic, documenting plastic in the oceans, understanding the full geographic extent of the problem and how far reaching it really was. Plastics were documented in benthic sediments along the coast of Great Britain, floating in the Mediterranean sea and in the open ocean, as well as remote sites such as the Aleutian Islands in Alaska. At this time, studies identified fishing gear, litter, and mismanaged waste as sources of plastics to the environment. Other major sources were not yet clear. At this time, potential threats of plastic pollution to wildlife were perceived. For example, research documented instances of plastic ingestion by seabirds and were concerned about physical effects. It was also suggested that there may be a toxic link between plastic ingestion and pollutants, such as polychlorinated biphenyl (PCBs) in seabirds. Still, the number of studies on this and other potential impacts were quite limited.

The 2000s: A microplastic soup

In 2004, focus shifted towards a smaller form of plastic. Professor Richard Thompson from the University of Plymouth in the UK coined a new term, microplastic. This was used to describe small plastic particles (<5 mm in size) that were being found in ocean sediments and surface waters, and a call was made for more research to better understand the prevalence, fate, and effects of plastic in the ocean, including microplastics. In 2009, a research cruise to the North Pacific Gyre reported the oceanic surface waters looking like a soup of floating microplastics with large plastic objects within it. This research highlighted the fact that plastic is not only ubiquitous, but it is persistent – breaking apart into smaller pieces over time, rather than breaking down. Our understanding of the broader impacts of plastic pollution on marine life also expanded, including entanglement within and ingestion of plastic by seabirds, fish, and invertebrates. We also began identifying the link between plastic pollution and chemical pollution, with plastic debris transporting and releasing toxic chemicals into the environment.

With increasing research, it became possible to draw links between the rate of global plastic production, and the amount of plastic that was ending up in the environment. These findings demonstrated that not only are we producing and using too much plastic, but that we need to prevent pollution at the source before it breaks up into microplastics in the environment and threatens the health and survival of wildlife. Even with this significant jump in knowledge, questions remained about the true scale of plastic emissions to the ocean, how plastics move through ecosystems, where they accumulate, and the breadth of impacts on wildlife.

The 2010s: A global problem with widespread impacts

From 2010-2020, there was exponential growth in the number of research papers aiming to better understand the sources, fate, and effects of plastic and microplastic pollution. It soon became clear that plastic pollution was present and persistent across all global ecosystems, from remote mountains and islands, to the deep sea. The first long-term dataset on plastic debris was also published in 2010, using surface water samples collected across the North Atlantic Ocean. Previously, marine pollution had been the focus of almost all plastic pollution research, but now rivers and lakes were increasingly being recognised as major transport pathways and sinks of plastics. In the 2010s we also learned more about the impacts of plastic pollution on wildlife, including the broader impacts of ingestion, such as the potential for plastic particles to accumulate and transfer toxic chemicals into the bodies of animals. Not only was this a concern for the health and survival of wildlife, it also highlighted a potential threat to human health through the presence of microplastics in seafood.

In 2015 and 2017, two research papers caught the attention of the global media. The first was a global estimate of plastic waste entering the ocean from land, led by Dr. Jenna Jambeck. Researchers estimated that about 8 million metric tonnes of plastic waste entered the ocean in 2010, from 192 coastal countries. This number was shocking and truly demonstrated the sheer scale of plastic pollution around the world. The second paper led by Dr. Roland Geyer presented estimates and trends of plastic production, use and waste management from 1950 to 2015. This study reported that 8,300 million tonnes of plastic had been produced during this time, with 79% ending up in landfills or in the environment. Both research papers demonstrated how the rate of plastic production was overwhelming our attempts to manage plastic waste, leading to plastic pollution. They encouraged the global community to continue learning about this topic and better understand ways we could prevent further harm.

2020 Onwards: Using science to inform solutions

In the last few years, increasing attention is being paid to nanoplastics (particles <1um, smaller than the width of a human hair) and their ability to pass through cell walls and the blood-brain barrier. Improved laboratory techniques are increasingly revealing the presence of both micro and nanoplastics in different parts of the human body and demonstrating that the threat from plastic pollution is not just to wildlife, it affects humans too.

The year 2020 also brought about a shift in perspective, when two papers were published providing updated estimates of global plastic emissions to the ocean and freshwater ecosystems. These studies investigated the efficacy of different interventions to mitigate plastic pollution on global scales, and the message from both studies was clear – plastic pollution is a significant planetary threat, which will only worsen if we continue with business as usual. To avoid this fate, immediate, ambitious and collaborative global action is needed. This progressed the research focus from understanding the extent of the problem, to identifying appropriate solutions.

The future of plastic pollution research

Over the last fifty years, our understanding of plastic pollution has progressed from seeing it as simply an eyesore, to understanding the vast extent of sources, sinks, and impacts. We have identified prominent global sources such as mismanaged waste, single-use plastics and shedding of microplastics from textiles and tires. We understand that plastic pollution can travel great distances with wind and water currents, from rivers and coastlines to the open ocean, and that it accumulates in different environments such as coastlines, surface waters and deep-sea sediments. We are aware of the wide-reaching consequences it has to both the environment and humans, from ecosystem disruption and exacerbating climate change, to threatening human health, food safety, and the security of global economies.

There has also been a shift from quantifying and understanding the problem to using what we know to identify appropriate solutions based on local scenarios and contexts. Countries, cities and local municipalities are listening to the science and making positive progress towards ending plastic pollution – developing monitoring programs, risk assessments and targets, introducing bans on single-use plastics, working to improve waste management systems, redesigning plastics to be more recyclable and less toxic, and cleaning up plastic pollution to prevent further harm.

At times plastic pollution may feel like an overwhelming crisis, but through collective research progress we have learnt an incredible amount in a relatively short time. While there is still much to learn, we now know enough to act. By thinking globally and acting locally, we can use the knowledge we have to solve plastic pollution together.