Biodegradable plastics are not the answer to reducing marine litter report 2
2018-03-29 09:28:04 Industry News
In 2014, a study by UNEP and partners estimated that about 280 million tonnes of plastic is produced globally each year and only a very small percentage is recycled. Instead, some of that plastic ends up in the world's oceans, costing several billion dollars annually in environmental damage to marine ecosystems.
In recent years, concern has reportedly grown over microplastics, which are particles up to five millimetres in diameter, either manufactured or created when plastic breaks down. Their ingestion has been widely reported in marine organisms, including seabirds, fish, mussels, worms and zooplankton.
The new report aimed to verify a thesis that plastics considered “biodegradable” may play an important role in reducing these negative environmental impacts.
It finds that plastics most commonly used for general applications, such as polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC) are not biodegradable in marine environments. Polymers, which biodegrade under favourable conditions on land, are much slower to break up in the ocean and their widespread adoption is likely to contribute to marine litter and consequent undesirable consequences for marine ecosystems.
The study also analyzes the environmental impacts of oxo-degradable plastics, enriched with a pro oxidant, such as manganese, which precipitates their fragmentation. It found that in marine environments the fragmentation is fairly slow and can take up to 5 years, during which the plastic objects continue to litter the ocean.
According to UNEP, oxo-degradable plastics can pose a threat to marine ecosystems even after fragmentation. The report says it should be assumed that microplastics created in the fragmentation process remain in the ocean, where they can be ingested by marine organisms and facilitate the transport of harmful microbes, pathogens and algal species.