The issue of plastic contamination in the world’s marine environment has been gaining more public attention in recent years. The Ellen MacArthur Foundation has said the volume of plastic in the ocean will exceed that of fish by 2050, and a United Nations Environment Program reported that even plastics marked as biodegradable do not degrade rapidly in the ocean. Additionally, there are recent scientific reports that marine plastic accumulates toxins, while biofouling with algae also makes it attractive to fish.
Ramani Narayan, a distinguished professor at Michigan State University in the Department of Chemical Engineering and Materials Science, spoke recently with SeafoodSource about the issue. His research includes design and engineering of sustainable, bio-based and biodegradable plastics and its precursors. His career positions and appointments include: scientific chair of the Biodegradable Products Institute (BPI), North America; director of the Society of Plastic Engineers Bioplastics Special Interest Group; and positions on several committees related to plastic at the International Standards Organization (ISO). He also holds several patents.
SeafoodSource: You promote carbon capture as a value proposition for bio-based plastics. With the U.S. leaving the Paris climate accord, will carbon capture continue to be a priority? Is there likely to be any regulatory incentive for using bioplastics, assuming it costs more?
Narayan: U.S. states still have dominant power over what is done and what is not done. If you look at California and Washington states, carbon capture is still an important goal. However, even in these states, end-of-life strategies will be a higher priority than bio-plastics.
Regarding feedstocks, this is mostly corn and soybeans from the Midwest states, and President Trump needs these states politically. In the U.S., this is the driver. The ethanol mandate was not taken off by Trump, even though he has rolled back restrictions on oil and gas exploration, and is bringing back coal. I’m very comfortable that big landowners that push for incentives will continue to do so.
[Editor’s note: Last month, Trump renewed the Renewable Fuel Standard program, which mandates blending ethanol in gasoline, for an additional two years.]
SeafoodSource: Would bioplastics have the same drawbacks as ethanol – diverting food to plastic use, and generating excess carbon in the farming, transport, and processing of the corn?
Narayan: You need to decouple plastics and fuel. Only five percent of the arable land would be needed to grow the crops to convert to bioplastic. The amount is low in comparison with fuel use – it would have little impact on food. Also, the chemicals used to make plastic are partly byproducts of food/feed production. Making fuller use of byproducts helps to stabilize food prices, as rises in raw material costs are spread out among more products. The argument that biofuels compete with food uses – I think it’s a red herring.
SeafoodSource: You have made the point that bioplastics are not necessarily biodegradable (or “utilizable”). Is there any advantage to bioplastics with regard to bio-utilization?
Narayan: No, these are separate issues – bio-based plastics and bio-degradable plastics. For the latter, the focus is mainly on end-of-life strategies. Today, if I make a product, I must have an end-of-life strategy to go with it. Some states – California, Washington, Maine – have regulations requiring compostable plastics diversion.
SeafoodSource: You say that some claims are made that a plastic is biodegradable, when in fact the plastic is just broken up to small pieces without being utilized by organisms. You mention a goal of 90 percent bio-utilization as measured by carbon dioxide release. Are any official standards using this as the requirement?
Narayan: Yes, in the U.S.A., there are ASTM standards; in the E.U., they have EN 13432; there are also ISO standards; and in Japan, there is an organization, JBPA, the Japan BioPlastics Association.
In order to claim biodegradability, two things must happen: the plastic must meet this 90 percent standard, but there must also be disposal systems available. There are companies that promote additives which will break down plastics – eventually, this is true – but the information on the amount of time it takes is missing. And the system is missing. So, it breaks down into small pieces and migrates to the ocean where plankton grows on it and it is consumed by fish. There is indiscriminate acceptance of bio-degradability claims.
SeafoodSource: You have written that the ocean is not a disposal environment. Then, what is your recommendation for keeping plastic out of the ocean? Specifically, with regard to bio-degradability, does breaking plastic down to small pieces just make it easier for it to be carried, blown or washed into the ocean?
Narayan: The Ellen MacArthur Foundation has said, “You must close the loop.” Dumping is not a solution. Biodegradability as a solution to marine plastic is not acceptable. The solution has to happen well before.
In our Science article, we wrote that most marine plastic comes from mismanaged waste in the developing world – mainly in Asia: India, China, Sri Lanka, and so on. So, we have to work upstream to implement proper waste management. There are some NGOs working on this issue, such as the Ocean Conservancy. There are also efforts to make items used at sea, like buoys, nets, and pots biodegradable in a marine environment, to address the problem of lost gear, and these efforts are of value.
