When we talk about marine litter we talk mainly about two sources: land and sea. Sea-based sources are what you might expect, ships, drilling platforms mostly, and are fairly well regulated in terms of discharge and disposal. Not to say they don’t contribute, but it is estimated that only 20% of marine debris comes from sea-based sources.
That leaves 80% coming from land based sources. A lot of emphasis is put on coastal cities and high tourist areas to better manage their litter and waste, but it is important to remember that litter anywhere has the potential to end up in the ocean. Maybe it is time to stop framing this problem as an “marine” issue (which may alienate inland areas) and start to talk about it as a litter/environmental issue. Because you can drop a water bottle from a boat off Florida, or ditch a bag on a highway in Kansas, and both will likely end up in the same place.
A recent study modeled the influx of plastic into the ocean from the world’s major rivers and found that 2.41 million tons of plastic enters the ocean from inland sources and is carried to the sea by rivers. Not surprisingly, the worst polluting rivers are in Asia (the Ocean Conservancy reported earlier this year that five asian countries contribute over half of the oceans plastic).
The model looks at population centers in major watersheds, waste management, and seasonal rain patterns to predict when, where and how much trash is being flushed into the ocean. Though likely an underestimate, because the model was verified with studies that did not look at all sizes of plastic coming out of a watershed (especially micro and nano particles), it is an important reminder that even though the litter accumulates and causes harm in the ocean, the solutions must be implemented within watersheds as well as coastal communities.
Read the article here