Article in local newspaper

Our research on microplastics was featured in a recent article in de Mare the newspaper of Leiden University. For the article, please click here



Visit from 8-10 year old “university students”

Recently we were visited by students from Transvaal University,  an enrichment programme for low-income children in Transvaal neighborhood in the city of The Hague. Transvaal University is an initiative of the primary school ‘Het Galjoen’ and  community centre ‘Boerenplein’ in the Transvaal district in The Hague.  Every Saturday morning a class of fifteen eager students are taught a variety of different (socially oriented) subjects in order to enhance the talents and skill-sets of these children. I gave a workshop on microplastic and plastic pollution in the aquatic systems, and linked it to possible effects on fish. As part of the class we dissected a fish with the kids, and discussed how plastics and other pollutants can cause harm to organisms.



Kids and plastics…

Together with kids aged 9-12 I conducted a beach clean-up Ameland, the Netherlands. Ameland is located in the north of the Netherlands, and is a scarcely populated area. The goal of the collection was to show them how much plastic can be found on a beach… even when it appears to be very clean when you look at the beach from a distance. We collected several garbage bags full of plastic (and other) waste within 30 minutes. Next we identified some of the plastics using a standardized guide.

We found, among other items, the following:

  • Shopping bags
  • Garbage bags
  • Drink bottles
  • Caps/lids
  • Pens
  • Beach toys
  • Straws
  • Ropes, strings and fibers
  • Nets
  • Fishing lines

We discussed how these plastics could impact the environment, including a paper on garbage in sperm whales, and the amount of “invisible”microplastics. A follow-up series of mini-lectures at school will focus in more depth about this issue… to be continued!

Paper published with optimized protocol for sampling and extracting microplastic from sand samples

Aiken Besley, a recent graduate from Leiden University College, managed to publish his work in the international journal Marine Pollution Bulletin.

His undergraduate research focused on standardizing extraction and sampling methods for microplatics on beaches. A range of studies have found significant levels of microplastics in beach sand. However, he highlighted that there is a considerable amount of methodological variability among these studies. This variation makes it difficult, and often impossible, to compare across studies, as there is no standard procedure for sampling or extraction of microplastics. He identified key variations in sampling and extraction procedures across the literature through a detailed review. He found that sampling depth, sampling location, number of repeat extractions, and settling times are the critical parameters of variation.

Next, using a case-study he determined whether and to what extent these differences impact study outcomes. By investigating the common practices identified in the literature with the case-study, he provides a standard operating procedure for sampling and extracting microplastics from beach sand.

The full article can be found here.

Aiken Besley in the lab working  on optimizing the extraction of microplastics from beaches

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!