How microscopes and trashbags have been keeping us busy

By Lone Mokkenstorm, Lucia Guaita and Froukje Lots, BSc students at Leiden University.

It’s already our 4th week in the Caribbean, and we’ve gotten quite some work done! Long days of microscope work in the lab have provided us with the results of 14 beaches across the Caribbean, and we’ve been working hard on our new side project too.

How many plastics do you think we found on average in 50 grams of sand from this fine beach on St. Barths?


The right answer is: 14 pieces of plastic! Most of the plastic we find under the microscope are fibres, but sometimes we find some other interesting plastic pieces as well:

And then there’s our side project: every five days, we hike to Zeelandia Beach and clean up all meso (5-25 mm) or macro (>25 mm) debris (also called “garbage”) we can find. It’s not a pretty job, especially not if the sun is shining bright on our heads and the sand is burning our feet, but it’s interesting what we find every time. The aim is to try and understand at which rate waste accumulates on the beach and what it consists of: is it mainly marine debris stranded on the shore, or garbage from the nearby dump that washed down from the cliff?

It’s ironic that, in the end, we have to bring the stuff we found to the dump anyway: there is a recycling plant on the island, but it hasn’t been functional ever since they put it in place. When walking to Zeelandia, you can see piles of lonely recycling bins, waiting to be used… It shows that whatever the outcomes of our research will be, the core of solving the micro- and macroplastic problems should be addressing and solving political and financial issues first.

Thanks for reading. We will keep you posted!

An update from the Golden Rock

The past week, we have been collecting sand on the islands of Anguilla, St. Martin, St. Eustatius and St. Barthélemy. It was one big adventure, resulting in major sunburns, two big suitcases filled with 30 kgs of sand and several border securities laughing at our big, blue bucket and peeling skin.

Although we were far distanced from the rainy and cold weather in The Netherlands, we had to face other challenges whilst sampling in this part of Europe: we had to scare away tourists, sample around 17th century old ruins, climb a mountain to the other side of St. Barthélemy and try not to get lost with the not-so-detailed free tourist map we stole from a taxi driver.

As we speak, we are setting up the lab in our “homebase,” at the Caribbean Netherlands Science Institute in St. Eustatius to start the extractions. When we get back, we will proceed with the global and Dutch samples as well! Want to be part of our global project?  Make sure to check out the sampling instructions, and don’t hesitate to shoot us a message on Facebook!



Road trips, Caribbean islands and many, many bags of sand

By Lone Mokkenstorm – BSc student Leiden University College

If someone would have told me a project in an Environmental Science course would eventually evolve into a capstone, I wouldn’t have believed it. Now, a year later, Lucia, Froukje and me have been working in the lab for weeks, extracting plastic particles from sand samples and even preparing for capstone research overseas.

Last February, we rented a car to take sand samples along the Dutch coast. It turned into a road trip that involved two days, a boat, an island and ten beaches. We even climbed the most muddy dike in The Netherlands, looking for  mud and dressed in a wading suit! After this adventure, third year student Aiken Besley taught us the extraction procedure he used for his research. The past few weeks we have been working on the extraction of these samples from the Dutch coast. The results will hopefully give us more insights into distributions and concentrations on the national scale as well as the potential factors that influence them.

The results will be compared with the research we will be doing in The Caribbean in June. The Caribbean Netherlands Science Institute (CNSI) on St. Eustatius will host us for 5 weeks. We will take samples on this island as well as the surrounding islands Anguilla, St. Martin and St. Barthelemy.  In the institute’s lab, we will quantify the microplastic concentrations of these samples. The dynamics in an insular coastal system are of a very different kind than in the coastal system of The Netherlands and it would be certainly interesting to see how this affects microplastic distributions.

Soon we will be starting with the global samples as well. The more than 40 samples we have gotten so far from LUC students and staff are amazingly diverse, and we would like to encourage everyone to contribute to this project coming summer as well. All you need is some ziplock bags, a spoon and a (phone with a) camera. Interested? Check out the sampling instructions and the map of the destinations we have covered so far!

Although we understand everyone is eager to know how many microplastics were found in the samples  that were brought back last summer, there is a reason why we prioritized the Dutch samples: they form the basis of the research. Right now our priority is to get our methodology straight with samples we could potentially replicate if anything goes wrong. Wouldn’t want your sample from the US to be flushed down the sink, right?

If anything, we will keep you up to date on this blog with any results as well as the progress regarding the Caribbean adventures. Also, please get in touch if you would you like to contribute to our global project or if you have any questions!


Microplastics in Scheveningen

by Lone Mokkenstorm, BSc student at Leiden University College

Photo 1

One of the strengths of LUC’s educational program is that it encourages you to go out in the field and experience the theories you study in the classroom. This semester, Thijs Bosker’s Environmental Science class worked on a field project on the beaches around The Hague. The aim was to quantify the amount of plastics in the region’s coastal areas and to determine if there were any distribution patterns. The class was divided in four research teams and each was assigned coordinates of a sample site somewhere between the pier of Scheveningen and Meijendel, the water purification site.

Plastic is a very durable material and its use has increased tremendously over the past few decades. Plastics in the environment originate for example from industry, sanitary products, and waste. In our research, we distinguished between micro- and macroplastics. Macroplastics are bigger than 5 mm, and basically form the litter you can see lying around on the beaches. Microplastics, however, are trickier: they are smaller than 5 mm and are hard to distinguish from sand particles. However, exactly this small size is what makes them so hazardous for the environment — and us!

Microplastics enter the environment in several ways, for example through surface runoff, sewage systems, or macroplastics breaking down into smaller particles. They are easily consumed by coastal and aquatic organisms. Apart from the fact that they can block an organism’s digestion system, plastics often contain toxic substances (persistent organic pollutants, or POP’s). These POP’s accumulate more with every step in the food chain, and can eventually end up on our plates. Several European countries have recently issued a joint call to ban microplastics from cosmetic products in order to improve the quality of some seafood products, such as the famous Dutch mussels.

As this is a relatively new area of study, scientists have yet to identify all the sources of these plastics, as well as their exact negative health impacts. Even if we know the impacts are hazardous, more research has to be done before this can be taken into account in policies.

beach2On the beach, we sieved the sand with a 5 mm sieve to filter out all shells and driftwood. Afterwards, we let the sand dry for 48 hours and sieved it with two other sieves to distinguish small and bigger microplastics.

The results of our project confirmed this once again. We found more plastics on the sites that werefarthest away from the pier in Scheveningen — which is not exactly what you would expect to be the case, given the amount of human activity and tourism in that area. More questions arose the moment we saw the graphs: Which mechanisms could cause this? Is there another source of plastics? What are the potential impacts if any of those plastics would end up in the water purification pond in Meijendel? An ecological problem that initially seemed straightforward ended up to be more complex than we thought.

Therefore, this hands-on science experience taught us a lot. Everything that could go wrong did indeed go wrong: we tried to sieve wet sand, got lost somewhere in Meijendel, and we found the opposite of what we expected to. It proved that science is a matter of trial and error, and this is something you can’t learn in a classroom. Despite all uncertainties, I do feel that we contributed within this young area of study, concerning an issue that is to be perceived on a local level, whilst impacting health and environment globally.

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Extractions underway

The extraction of samples is underway. We are currently processing the samples which we have received. Three undergraudate students, Lone Mokkenstorm, Lucia Guaita and Froukje Lots are conducting a Research Clinic on the topic. In addition to extracting the samples, they will collect additional samples along the Dutch coast: updates to follow.

Beach sampling pictures

We have received samples from all over the world over the last, in fact from each continent except Antarctica (any takers)? Sampling locations include: Cambodia, Canada, The Caribbean, Spain, Indonesia, Norway, Island, Australia and Zanzibar. Some pictures of the collections can be found below.




St. Martin
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