It is well known that most plastics are virtually indestructible. They are, as the saying goes, forever. Sadly, today our oceans are littered with enormous quantities of plastic, much of it in now notorious vast gyres. We all know that plastics should not be thrown overboard. However, the recent development of so-called “biodegradable" plastic bags might suggest that this is a product which can be safely discharged at sea. But read on.
The label “biodegradable” notwithstanding, a recent United Nations study has concluded that on the balance of available scientific evidence found in peer-reviewed literature, this is not the case. The report is entitled “Biodegradable Plastics and Marine Litter: Misconceptions, Concerns and Impacts on Marine Environments”. It can be found at: http://unep.org/gpa/documents/publications/BiodegradablePlastics.pdf.
The reason for the report’s conclusion is that biodegradation of “biodegradable” plastic depends, first, upon action triggered by microbes found in soil, but not in the sea, and, secondly, requires prolonged temperatures higher than those typically found at sea.
Hence, what might be biodegradable on land, is not in our oceans. Accordingly, the Environment of the Sea Committee encourages sailors to treat plastic bags labeled “biodegradable” as they would any other plastic bags and under no circumstances throw them overboard.
Thanks to Ted Parish of the Chesapeake station for calling our attention to this.