by Lone Mokkenstorm, BSc student at Leiden University College
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.
On 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.
Repost from engagethehague.nl