Litter from source to sink

Plastic soup is “only” a part of the litter problem. Although this image is very appealing to the imagination, especially when also images are created from plastic islands somewhere in a far-away ocean, it makes you worry,  but it hardly gives you clues to do something about it.

Ban the Bag

Ban the Bag:

Rise above Plastics:

Actions like “BAN THE BAG”, or “RISE ABOVE PLASTICS” give some kind of psychological relief for all those people who want to do something, but you can be sceptical about the overall effect of these actions. Littering starts when people already have a product and leave it in the environment. So, these actions address “plastics” and not “litter”.

Sure, it brings awareness to the problem with the public and it urges politicians to put the issue on their agendas. That is true and so these actions are a good thing in itself. But for a solution we must do better!

The road from source to sink can be long and windy (see this video: The Majestic Plastic Bag). But it also shows clearly that there are numerous moments where it is possible to intercept litter reaching its final destination in the ocean.

I like to approach the problem from a technological more scientific point of view. Understanding the issues, bring logic and data in the discussion and act from an analysis of the situation. For that purpose I have drawn up a diagram of the flow of litter from source to sink.

River Litter Transport Model

The process starts (blue box on the middle-left) when someone owns a product, wants to get rid of it or loses it. When not discarded properly for reuse, recycling or whatever, litter starts a (sometimes) long way to a final destination.

river litter transport model

river litter transport model

(please click on the picture if you want a better resolution)

The blue arrows represent recovery and recycling processes, the red lines are emissions and the yellow arrows describe the flow of litter from source to sink when products or parts are released in the environment.

The red boxes represent the final destinations of litter on land, in the sediment of a river, on the bottom of the sea or on a remote beach. The purple boxes indicate the possibilities for ingestion by animals or organisms and the green boxes represent the decomposition (eg. composting of paper or rusting of metal ) as a natural process.

What is the value of this model?

First of all you can see that there are a number of possibilities (red arrows) where waste can enter the environment. It can be thrown away on land, into a river, into the sea or left on a beach. Awareness and action campaigns can be directed at these emissions, technical solutions can be developed to prevent emissions like sewer overflows, organisational measures can be implemented to empty waste bins in time, etc.

The preferred route for disposal is the dark blue line upwards into some kind of a waste management system, although from there it should not leak back into the environment as an emission (birds picking from waste dumps or overflowing sewer systems). You can favour recycling, but from the perspective of preventing litter entering the oceans any recovery option is a good one (even incineration, when done properly).

You can also see the possibilities to recover litter from the environment (recover from land, riverbanks, beaches or recover litter from the bottom of the seas or from the sea-surface). It is a matter of economics, local circumstances and efficiency to choose for the best opportunity to intercept litter in one of these places. But anything recovered will not end up in one of the described sinks.

There are two circular movements in the picture. First the intermittent deposition of litter from the river onto the riverbank and the other from the seas onto the beaches. This immediately makes it clear how important constant beach-cleans and cleaning of river banks are in preventing litter to end up in one of the sinks. As long as litter is emitted in the environment, clean-ups are a vital ingredient of preventing litter from reaching the sinks.

Fishing for Litter (

Once litter has been transported by the river from land into the sea, the possibilities to capture it are drastically reduced. Only the very buoyant particles and products will remain somewhere near the sea surface and might get deposited on a beach by the wind or  currents, the rest will disappear below the surface in the water column to end up for ever on the bottom of the sea or enter the food chain in some way. It is practically impossible to recover from there, although attempts are made (Fishing for Litter).

My conclusion from this diagram is that the river is the last practical place to intercept litter before it disappears in the vastness of the seas. It should be more easy to catch litter from a river than from an ocean, we should only be innovative to find ways to do that!

But, even if you have not risen above plastics, there is no excuse not to dispose your waste in the proper way!


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