Opinion: we should be doing a lot more with the 1.5 megatonnes of crab and shrimp shells, tails and unused meat than just dumping it
The amount of material left over from crab and shrimp production in Europe every year is the same mass as 60 fully laden container ships. This 1.5 megatonnes of material is all of the bits that we do not consume, mainly consisting of shells, tails and unused meat. At present, most of this material ends up going to landfill or incinerators or is dumped back into our seas.
Although we currently treat this material as a waste product, it is, in fact, a rich source of a range of useful substances. The leftover meat is an excellent source of dietary proteins and beneficial fatty acids. Similarly, the minerals that make up the outer surface of the shells present a source of cheap horticultural stimulants for replenishing mineral contents of soils and for providing nutrients to plants.
Most exciting, though, is the presence of the carbohydrate known as chitin, the second most common polymer produced in nature after cellulose. Being a polymer, it consists of long repeating chains of the same molecule, just like many of the synthetic polymers that we are used to like rubber and plastics. Chitin is produced by such crustaceans as crab and shrimp as a scaffold around which to create their hard protective shells. In combination with its stiffness and rigidity, it is also very resistant to heat, holding its structure to 350℃. Chitin does not dissolve easily and is very chemically resistant, requiring very high concentrations of the strongest acids to degrade it.
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From Tech Insider, how a team from the Royal College of Art and Imperial College London have turned lobster shells into planters, wallets, plastic bags, and more
Once separated from the other useful materials in the crab and shrimp waste streams, chitin is treated to allow it to dissolve in acids no stronger than the vinegar or lemon juice in your kitchen. This makes the polymer much easier to handle. From here, the polymer solution can be poured into a mold of any shape. Once dried, what we end up with is a rigid, durable, chemically resistant and totally biodegradable product. In other words, a bioplastic.
With chitin, we have a naturally sourced material with the physical and chemical properties that makes it tough and durable enough to be a real alternative to many of the fossil-fuel based single-use plastics we currently use. It is safe for human use, totally biodegradable and your compost bin will absolutely love it. It is readily available and cheap to source as it is currently not considered to be worth very much at all.
Of course, this bioplastic is not a sufficient alternative to replace all plastics in the world. Synthetic plastics come in many shapes and sizes, with different molecular structures from different fossil-fuel based sources, with a range of physical and chemical properties and different applications. In producing realistic alternatives, we have to appreciate that many types of green sources have to be utilized such as recycled wood pulp, fisheries waste and seaweeds. Shellfish are only one part of the solution.
Chitin produced from crab and shrimp waste streams serves as an excellent example of the sort of new opportunities which our oceans offer. Unlike most other nations, Ireland is remarkable because we have responsibility over an ocean area ten times the size of our land area. It's a vast natural resource which we are increasingly relying on for products and services we use every day from the fisheries, raw materials and transport sectors.
However, this growth in our utilization of marine sourced materials is now an imperative. We have ever-increasing individual and collective desires to reduce waste and create environmentally friendly materials. We are lucky to be able to so easily turn to our oceans to do this. Knowing as we all do about the scale of the problem of plastic waste polluting the marine area worldwide, there is a surely a certain satisfaction in addressing this problem using materials that the marine resource itself provides.
It is time for us to recognise and embrace the immense influence and effects that the oceans can have in our daily lives
Our marine resources will play an increasingly important role in Ireland's economy in the coming decades, especially in the materials and products we use in our daily lives. Thanks in many ways to the great communicators, naturalists and conservationists of the last century such as Jacques Cousteau and David Attenborough, we have become intimately aware of the influence and effects that our lives have on the marine environment. Now, more than ever, it is time for us to recognise and embrace the immense influence and effects that the oceans can have in our daily lives.
When we recognise this, real change can start to take hold. The potential in our oceans becomes much more real as we become more open to using materials from these sources. A demand can grow and business can take effect. As an island nation, each of us can play an active role in these changes and we can be proud of their global impacts. As our island moves ever forward, it's important that we take a moment to stop and listen to the waves and remember where we have come from.
The views expressed here are those of the author and do not represent or reflect the views of RTÉ