Can bioplastics damp down marine littering?
In recent times the problem of marine littering gained worldwide attention becoming one of the greatest resource management challenges. Marine debris is reported to be gathering in vast masses in the oceanic gyres creating a grievous problem and serious threat to aquatic life and subsequently to humanity. Numerous papers describing and estimating occurrence, possible sources, sinks as well as forms and amounts of plastic debris polluting marine environment are being published. Approximately 280 Mt of variable types of plastic is produced annually around the globe (1). Existing estimations say that roughly 10% of annual plastic production could be entering into the sea, which greatly exceeds the mass of recycled plastic traded globally each year (2). Annually held coastal cleanups bring the information that substantial parts of the gathered plastic garbage are packaging products and food service items. Most abundant polymers found are mainly commodity plastics like PE, PP, PS and PET (3). The scientific community concentrates also on existence of microplastic parts (originated from e.g. scrubbers in cosmetics or straight as a plastic pellet substrate) in marine environment (4).
Regardless of described above objectives and solutions still little research is directed to standardization and evaluation of conducted tests. Existing ASTM D7081 standard covers only non-floating products made from plastics that are designed to biodegrade in aerobic marine environment or anaerobic marine sediments. They must demonstrate disintegration and inherent biodegradation during marine water exposure and not exhibit any adverse environmental impacts on marine life. D6691 test method provides a description of the testing procedures that simulate the marine environment and a method by which to determine the degree and rate of aerobic biodegradation of materials exposed to the indigenous population of sea water. Both standards measure carbon dioxide formation and its evolution from plastic undergoing biodegradation. However, both require testing temperature at 30°C, which is a result of pragmatic approach needed to keep test evaluation in a reasonable time. Taking into consideration the fact, that global average sea surface temperature is around 16.3°C (13) both standards are practically non-applicable to real life conditions and as such serve only as approximation. Scientists are developing also individual methods and make attempts to establish tests for the behavior of biopolymers in various conditions occurring at sea and seashore (14) (15) (16) (17).
Gathered information on marine debris, shortcomings of existing standards associated with the problem and still unanswered questions of biopolymers behavior while subjected to marine habitat, gives the IfBB sufficient reason to undertake steps towards answering these issues. Within the scope of our work we intend to expand existing knowledge on plastic products ending up their existence in marine environment as a dangerous waste concerning the amounts of the plastic types in different applications and their origins. Overmore we intend to develop a standard or individual method for testing the behavior of biopolymers in the sea. We are also eager to determine whether the utilization of biodegradable (chemically novel) biopolymers could contribute as a part of a solution to the described problem of marine littering. Is their utilization as a substitution for commodity plastic products in applications that occur as marine litter possible and expedient? Therefore it has to be investigated if there are any biopolymers capable of undergoing degradation in marine environment at temperatures close to real life conditions, what chemical outputs result from such a degradation and the time elapsing while the degradation process takes place. A further field to investigate is what happens to biopolymers in the digestive system of fish and other aquatic organisms. These will be the topics the IfBB would like to face in its research work in order to help decreasing the plastic waste stream polluting our seas.
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