River Litter, serious business

Lessons learned in 2012:

During 2012 we have done our first trawls with the set-up we have developed for measuring the amount of litter that is transported by the Meuse. At the time of the sampling, the conditions of the river were very calm and we did not expect to find very high numbers of items. But it turned out that the results were already very significant. After drying, counting and categorizing the caught items, the conclusion was that the amount of litter in the river was big enough to take the problem of river litter very serious.
We did find a substantial amount of macroplastics and we believe the method we developed is capable of delivering valuable data for assessing the contribution of rivers to the problem of plastic litter in the seas.

Until now, beach sampling was the only method available to assess the volume of litter in a river. Our data shows that a substantial part of litter, mainly the flexible fraction, remains in suspension and will not be found on an river bank, unless it is caught in the vegetation. The real amount of flexibles will probably be much higher than presented here in the slides. It takes some more hydrological analyses to determine the dispersion of these parts in the whole water column, here we have only used the number of flexibles that were present in the upper 70 cm.

It also turned out that a major part of the items are smaller than 25 mm. That does not include them in the category of microplastics (< 5 mm), but they could be small enough to be missed in sampling on a beach.

The presentation below describes the results of the initial trawls and a way of thinking  to approach the problem of river litter, recovery and appropriate legislation as a whole.River Litter Serious Business Dia1River Litter Serious Business Dia2River Litter Serious Business Dia3River Litter Serious Business Dia4River Litter Serious Business Dia5River Litter Serious Business Dia6River Litter Serious Business Dia7River Litter Serious Business Dia8River Litter Serious Business Dia9River Litter Serious Business Dia10River Litter Serious Business Dia11River Litter Serious Business Dia12River Litter Serious Business Dia13River Litter Serious Business Dia14River Litter Serious Business Dia15River Litter Serious Business Dia16River Litter Serious Business Dia17River Litter Serious Business Dia18River Litter Serious Business Dia19River Litter Serious Business Dia20River Litter Serious Business Dia21River Litter Serious Business Dia22River Litter Serious Business Dia23River Litter Serious Business Dia24River Litter Serious Business Dia25River Litter Serious Business Dia26River Litter Serious Business Dia27River Litter Serious Business Dia28River Litter Serious Business Dia29River Litter Serious Business Dia30River Litter Serious Business Dia31River Litter Serious Business Dia32River Litter Serious Business Dia33River Litter Serious Business Dia34River Litter Serious Business Dia35


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: projectgreenbag.com

Rise above Plastics: surfrider-southbay.org

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 (www.newlynharbour.co.uk)

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!

Plastic soup is prepared on land!

Rigid Plastics

While writing this blog I am watching the Giro d’Italia. While everything goes forward, every couple of seconds things go sideways: bidons. Below you see a picture of Tom Boonen getting rid of his drinking bottle (ok, not in the Giro….)

It makes sense that these guys do this with their bottles while racing, but recreational bikers do the same. What happens with these bottles? Here you see one that I found while letting my dog out.

crushed bidon

crushed bidon

A couple of cars must have been driving over it. Where is the cap? Ah, there is one in Meers,

bottle cap

bottle cap

Where is the rest of this bottle? My guess is that it is crushed in tiny fragments and washed away with the rain.

Here we may find a fragment of it…

Cleanup Meuse near Borgharen
Cleanup Meuse near Borgharen

But I think it is more realistic to look for its fragments right here!

micrplastics on river bank Borgharen
microplastics on river bank Borgharen

You can picture the way these pieces have travelled:

Thrown away on a curbside or road, get crushed by cars, separating bottle from cap. Fragmented to a size that makes it easy for transportation by rain. Transported further by sewer systems, passing through purification plants, get transported by smaller creeks towards the Meuse. Get deposited for a while on the bank, but transported further after a high water period until flowing into the sea. Adding some more grammes to the plastic soup.


I follow a plastic bag already for a couple of months. This is how he looked while I first met him on January 1st 2012, being entangled in barbed wire.

plastic bag 1 jan 2012

plastic bag 1 jan 2012

A couple of months later this is how he looked:

plastic bag 12 may 2012

plastic bag 12 may 2012

Slowly disintegrating and showing the characteristic wrinkling of a weathered plastic film:

plastic bag wrinkled

plastic bag wrinkled

And where are the blown off pieces? Maybe here…

plastic nest

plastic nest

There is a general idea that plastics in the oceans get ever smaller through the impact of UV-light and wave-action. But I think the fragmentation is already far on it’s way when litter is still in a river.

So whenever we want to stop plastics flowing into the seas, we better be aware that we have to stop these little particles being transported. But that we can solve on land and we do not have to fish them out of the sea!

Maybe that is some good news