Synthetic Polymers, commonly known as plastics, have made themselves a permanent part of the marine environment for the first time in the long history of planetary seas. No sediment or ice core will reveal ancient deposits of these materials or the biological consequences associated with high concentrations of synthetic polymers in the planet’s pre-historic ocean. However, current ice and sediment cores do reveal an abundance of these recently deposited anthropogenic polymers. Only a broad combination of traditional fields of scientific inquiry is adequate to uncover the effects of, and explore responses to this new pollutant. It seems a pity that a field of study, rather than springing from insights into natural phenomena, arises from new ways that natural phenomena are compromised.
Reports of plastics in the marine environment began to appear in the early 1970s. In 1972, J.B. Colton of the National Marine Fisheries Service in Rhode Island, and E.J. Carpenter of Woods Hole, wrote articles that were published in Science speculating that the problem was likely to get worse and that toxic, non-polymeric compounds in plastics, known as plasticizers, could be delivered to marine organisms with potential effect. Carpenter and Colton’s speculations were correct – probably more so than they imagined. The quantity of plastics in ocean waters has increased enormously, and toxic plastic additives, as well as toxicants concentrated by plastics from the surrounding seawater have been documented in many marine species.
The rapid expansion of the use of synthetic polymers over the last half century has been such that the characterization of the current era as the “Age of Plastics,” seems appropriate. There is no real mystery as to why plastics have become the predominant material of the current epoch. The value of the material is truly surprising. It can substitute for nearly every traditional material, from textiles to metal at reduced cost and weight, and offers qualities unknown in naturally occurring substances. The plastic industry creates an infinity of new applications and products, with growth trending sharply upward and showing no signs of slowing in the foreseeable future. Laser printing using plastic “ink” will guarantee expanded use of polymeric feedstocks for the creation of three dimensional objects as widely divergent as bookmarks and houses, both of which I have seen manufactured by this technology.
Although the majority of plastics produced today use finite petroleum resources, the carbon backbone of synthetic polymers can be fashioned from switchgrass, soybeans, corn, sugar cane or other renewable resources—price alone determines industry’s preference. The fact that synthetic polymers can be made from row crops (so called biopolymers) need have nothing to do with their biodegradability. Olefins are still olefins and acrylates are still acrylates, and behave like their petroleum fabricated counterparts. Furthermore biodegradability standards are not applicable in the marine environment and marine degradability requires a separate standard. Marine degradable plastics, such as polyhydroxyalkanoates (PHAs), have been found to fully degrade in both seawater and marine sediments in my lab, but have a negligible market share, and are not yet poised to make rapid headway into the consumer plastics market. The difficulty of recycling plastics has made profitable recovery for nearly all plastics a major problem, which in turn results in failure to provide take-back infrastructure and results in haphazard discard and loss to the environment.
Given the proliferation of plastics into all spheres of human activity, and their increasing use value in the developing world, the phenomena associated with plastic pollution of the marine environment will continue to merit scientific investigation. Such studies, however, are hampered by the lack of basic geospatial and quantitative data. Estimates abound based on limited sampling and modeling, but the ocean is the biggest habitat on the planet by far and knowledge of its plastic pollution will require new methods of data acquisition. The role of citizens in the monitoring of plastic pollution will increase in the coming years, and the truly “big” data they document must become part of the science of plastic pollution. Citizen science has also been termed “participatory research,” which results in the collection of scientifically useful information by volunteer researchers. It includes observations, simple experiments and crowd-sourced data collection.
The detection of the main plastic feedstock, plastic resin beads and nibs, sometimes called “nurdles,” in marine samples from the North Atlantic taken in the 1970s focused attention on this material. Subsequent studies by Dr. Hideshige Takada of Tokyo University of Agriculture and Technology revealed that these pellets, floating in the marine environment (especially the olefins polyethylene and polypropylene), could accumulate up to a million times the levels of certain persistent organic pollutants from the surrounding seawater. Dr. Takada was able to link this to studies of mussels that accumulate the same pollutants and found that the pellets washed up on shorelines, and collected from beaches, were a good proxy for the kinds of data produced by the filter feeding molluscs. This presented an opportunity for data to be gathered by citizen volunteers around the globe. Dr. Takada wrote an editorial in 2006 for Marine Pollution Bulletin 52:12 entitled: “Call for pellets! International Pellet Watch Global Monitoring of POPs using beached plastic resin pellets.” This has proved to be an excellent strategy, which has recovered thousands of pellets from 80 groups and individuals representing 50 countries. The total cost of data collection for this study, which gave levels of PCBs, DDTs and six other persistent organic pollutants, was negligible – mostly postage stamps – and resulted in a very nice picture of where pollutants are concentrated in coastal zones around the world. This kind of effort can be expanded to include quantitative data on plastics polluting coastal and marine environments. Simplified protocols using smartphone apps give photographic and geographic data to accompany reports from volunteers. The “Marine Debris Tracker,” developed by University of Georgia assistant professors Jenna Jambeck and Kyle Johnsen has been downloaded 10,000 times and has the ability to log photos and geographical positions for different categories of debris. It received a boost, when it was named among “Apps we can’t live without” at a 2014 Apple Worldwide Developers Conference.
What is the level of detail than can be expected from volunteer citizen scientists? Or is the more relevant question, how can the level of detail be expanded by taking input from the spatially divergent masses? Point source pollution requires heavier documentation by professionals in order to back up regulation. No enterprise will submit to costly curtailment of its business practices without a fight, and in order to win that fight, regulators must produce unassailable data. By definition, non-point source pollution is not caused by a single industry or entity and therefore requires political will rather than legal wrangling over data – although that may be part of the political equation – and is thus less in need of research findings of fact produced by professional scientists.
Citizens cannot be expected to employ expensive equipment or spend inordinate amounts of time in pursuit of highly detailed and delimited data, but they can produce copious amounts of observations of phenomena in their own vicinity. The ease of photo documentation and transmission these days provides an easy way to confirm their accuracy, especially in the field of plastic pollution, where the pollutant is often readily visible.
Conferences that bring together data gatherers and users of the data are valuable ways to make sure the data being gathered is useful and accurate. At this year’s Southern California Academy of Sciences Symposium, 19 of 134 submissions dealt specifically with citizen science. Titles included: “MPA Watch: Citizen Scientists Monitoring Human Coastal and Marine Resource Use of Marine Protected Areas,” “Citizen Science: Finding a Match for the Multi-Agency Rocky Intertidal Network (MARINe),” and “Whale MAPP: Citizen Scientists Contribute and Map Marine Mammal Sightings.” Bringing citizen scientists to symposia held by professional scientists insures that the democratization of science, which leads to an increase in the quantity of data, does not lead to a decrease in quality. In a world where humanity’s activities are impacting essential planetary systems, our need to know is too broad and the means to produce meaningful data is too accessible not to see a surge in crowd sourced data. This can be especially important in the field of marine debris, where cleanup and remediation schemes need to be targeted where most needed.
While most citizen efforts are concentrated in coastal areas and on land, a growing number of yachtsmen are looking for ways to make their voyaging contribute to the stewardship of the ocean on which they love to sail. In 2007, my organization, Algalita Marine Research and Education (AMRE) instituted a “Traveling Trawls” program with 8 different trawl types, designed by Dr. Marcus Eriksen, using simplified protocols that we loaned, and in some cases sold to sailors, marine scientists and organizations around the world based on their specific needs and capabilities. The equipment and sampling/sorting protocols are sent to the citizen scientists after an “Equipment Responsibility” contract is signed, which includes an agreement to produce and share data obtained from the samples they obtain. In this way, we aim to expand our online database, and produce useful information on the spatial extent of oceanic plastic pollution.
Questions that need answering include:
(1) How much marine debris is in the world ocean, on the world’s beaches or in the world’s rivers and lakes?
(2) Where are the concentrations of recoverable debris highest?
(3) What is the composition and type of plastic in marine debris?
(4) What species are hitch hiking on marine debris?
(5) What animals and how many of them are impacted by marine debris?
(6) What cleanup schemes are working?
(7) What prevention strategies are working?
(8) What is the total quantity of debris recovered worldwide?
(9) How are island nations coping with increased debris and what is the ratio of on island generated debris to off island sources?
Improved understanding of the quantities, types and location of marine debris must of course be coupled with removing what is already there. An important question then arises as to how to display the data on marine debris so that it can best be attacked by cleanup efforts. The information will need to include the types and quantities of debris so that appropriate technologies can be employed. As an example, let me give the history of a particular cleanup and recycling effort I know something about. Method-Home cleaning products is headquartered in San Francisco, California. Their Co-Founder and CEO, Adam Lowry contacted me about the possibility of using plastic from the North Pacific Convergence Zone, aka the Great Pacific Garbage Patch, in a recycled plastic bottle for soap. He requested samples of the plastics that may be found there in order for his fabricators to test their suitability for such a purpose. I gave him some objects to assay, but informed him that I thought it would be much more economical to use beached plastic litter as a feedstock rather than go fetch it from the remotest part of the world ocean. He then began testing plastics from both California and Hawaii. What he determined was that the majority of Hawaiian beached plastic litter was not of local origin and was composed mainly of High Density Polyethylene (HDPE), which was suitable for his soap bottles. The beached plastic from California, however, which was subject to frequent inputs from local population centers, contained so many resin types that separation costs were excessive and the quantities of HDPE were proportionally much less, so the decision was made to fabricate the bottles from Hawaiian beached debris collected by his employees and volunteers and shipped to the mainland in a container. The bottles made from this debris with some virgin HDPE resin added to improve the quality of the finished product are gray in color and are now on store shelves at major retailers.
Another example is from a different strategy for making use of plastic marine debris and involves a method for pyrolysis of marine debris by a company in Japan, the Blest Corporation. I met with the company’s representatives when I was in Japan for the release of my book, Plastic Ocean in Japanese. This company fabricates units that take plastic waste and liquefy it by heating in a closed metal cylinder in the absence of oxygen and then refines the liquid into kerosene and other distillation petroleum products, a technology known as pyrolysis. While they can use both high and low density polyethylene, polystyrene and polypropylene in their units, they cannot take the typical water bottle made of polyethylene terephthalate (PET), and all inputs to their machine must be clean. Although the company has models of their design suitable for home as well as industrial use, sorting and cleaning remain the biggest impediments to recycling of plastic waste, which reaffirms the conclusion that a rational solution lies in designing plastics for ease of recycling coupled with the creation of take-back infrastructure that will minimize the loss of these materials to the environment in the first place.
For the present, it is fortunate that a growing number of pioneering scientists, government agencies, non-profit organizations and individuals around the world are engaged in attempting to quantify and understand the consequences of the plague of plastic that contaminates our precious ocean, thus giving “traction” to the considerable effort that will be needed to do something meaningful about it.