And that makes cleaning it up a lot easier.

It is a somewhat sad sight: beautiful sandy beaches that are full of dumped, mostly plastic waste. Our Dutch coast cannot escape it either. In a new study researchers have mapped the tens of thousands of kilos of waste that wash up on Dutch beaches. And that makes it possible not only to predict where and when new waste will appear, but also to clean it up in a more targeted way.

Tens of thousands of pounds

Tens of thousands of kilos of waste?! Unfortunately yes. The researchers worked with a dataset of six years of beach cleanups from the North Sea Foundation. These are summer events where volunteers clean up trash on the beach. The data shows that there is currently between 17,000 and 30,000 kilograms of waste on Dutch beaches. “That is an average of 20 to 80 kilos of waste per kilometer of beach,” emphasizes researcher Mikael Kaandorp.

Waste collected by Mikael Kaandorp on the beach on Texel in March 2021. Image: Utrecht University

The coast at Castricum and Bergen in particular appears to be a true collection point for beach waste. “There is relatively less waste on the beach in Zeeland,” explains Kaandorp. “The coast there is more erratic in shape and borders less directly on the North Sea. We therefore think that the waste is more likely to wash back into the sea there because the tide is more variable there.” Less waste is also washed up on the beach in the north and on the Wadden Islands. “The sea current and wind in the Netherlands mainly comes from the southwest,” Kaandorp continues. “The Wadden Islands simply have less coast that focuses on that.”

Origin

The researchers were even able to find out where the washed up plastic waste comes from. “We found a strong relationship between how old the plastic waste is and how much distance it has traveled,” said Kaandorp. “The newest plastic usually comes from the Netherlands, some older plastic from the Channel or the English coast and a small part comes from further away; from France or even Scotland.” Fishermen in particular appear to pollute the waters. For example, forty percent of the plastic waste on Dutch beaches comes from fisheries.

Weather

Thanks to the study, we now know how much waste ends up on Dutch beaches from the sea. The researchers then combined this data with current weather data. Because in this way the team could determine under which circumstances a lot of waste washes ashore. That knowledge now even makes it possible to look ahead.

To predict

It means that scientists can now predict when Dutch beaches will be inundated with waste. And we can then use that to our advantage. “If you expect, based on the weather forecasts, that a lot of waste will wash up on a certain day and a certain location, you can already make a call to clear it up,” explains research leader Erik van Sebille. “That is extremely important, because it is much easier to clear up waste on the beach than in the sea.”

Winter

Although the model gives a good idea of ​​when we can expect a lot of waste on Dutch beaches, the accuracy still needs to be refined a bit. “Waste is mainly cleaned up when the weather is nice,” says Kaandorp. “So we don’t have that much data on the amount of waste in bad weather conditions. This may mean that our model is less accurate for the winter season. So we hereby call on you to organize large-scale beach cleanups more often in the fall and winter.”

The next step for the researchers is to release their developed model in areas other than the Dutch coastline. “Our coastline is relatively simple,” says Van Sebille. “It’s a fairly straight line, with mostly sandy beaches. We now want to apply our model to more complex areas, such as the Galapagos Islands. The sea currents around that archipelago are more complex, and the coastline there is much more erratic and varied.”