Biology students investigate microplastics at Marineholmen
By Antonia Areali, Ilyasse Bsaithi, Anne Hareide Lund, Charlotte Nakken, Emily Nicolaysen, Åsne Omdal, Emmeli Rundqvist, Torunn Stople, Rune Storli og Cameron Thompson
Microplastics are emerging contaminants of environmental concern. The study of microplastics is a relatively new field, and there is today much we don’t know about the interactions and potential effects of microplastics. The students of BIO316 Selected Topics in Environmental Toxicology were introduced to the topic through lectures in addition to an sampling excursion in the Marineholmen area and laboratory demonstration for hands-on learning. The two-day student workshop was organized by microplastic experts Tanja Kögel (UiB-BIO/IMR), Amy Lusher (UiB-BIO/NIVA), Marte Haave (UiB-CHEM/Norce), all adjunct professors at UiB, and PhD student Alexander Klevedal Madsen (UiB-BIO).
Beach sampling (Cameron, Ilyasse and Åsne)
Microplastics are pervasive in the marine environment and accumulation on the shoreline can serve as an indicator of their local prevalence. During the microplastics workshop that is part of the BIO316 course, we were randomly sampling the beach at the tideline and above the tideline. We laid out sampling grids and collected all the sand and other materials in the surface. Those samples were brought back to the lab and processed with density separation. Lighter plastic materials float while heavier materials, including sand, sink. The floating portion was removed and microplastic particles were identified. By doing this, we got an overview of methods of sampling and analyzing microplastics.
Marineholmen Sandstrand, facing North. Sampling grids were placed at the tideline and 9 m above the tide line. Each grid was 40 x 40 cm. 3 replicate grids were taken 3 m apart and the samples were pooled.
UiB master student Ilyasse Bsaithi samples the surface layer of sand.
UiB PhD student Cameron Thompson filters the solution of low density plastics and other floating material.
Sediment sampling (Rune and Torunn)
Sediment samples were taken using a Van Veen grab. Sampling was attempted at 3 different locations. The method does not work on hard sediments and only one of the three tries was successful. The successful sample was taken from the pier close to the BI beach. A layer of water was present above the sediment layer in the grab
When we completed the sampling, we moved to the laboratory. There we tried different simple methods to investigate if there was microplastic present in the samples, with good help from professional scientists. No pieces could be identified as plastic with full certainty. We found one piece that looked like fibre, but it was too small for identification. In the end we are left with a feeling that the problem of microplastic is bigger than ever before, and still hard to work with. Those who produce plastic and are responsible for the problem are always ahead of the development of scientific methods to solve the problem. It is therefore important to keep working on developing good methods to identify and quantify plastics in water masses, sediments and biota.
Sampling of sediments taken from the beach close to BI
Closeup of sediment sample
Terrestrial urban samples (Anne and Emmeli)
Our group was supposed to collect terrestrial samples nearby a parking lot. We first collected a sample from a bicycle lane near the parking lot where there was a lot of yellow particles, we were interested in finding out if they were plastic or not. We took the sample by first measuring an area of 40 x 40 cm, which is the usual procedure when taking a terrestrial sample from for example a beach. We then used a brush to collect all the loose material within the measured area and put it in a container.
Sampling near a bicycle lane at Marineholmen
Anne and Emmeli sampling near a bicycle lane at Marineholmen
Sampling near a parking lot at Marineholmen
Urban samples clogging the filters
In the lab, we first tried to separate the plastic from other materials, like stones and organic matter, in the sample. We therefore added a saline solution (NaCl) to the samples so that we got a density gradient. Since plastic often has a lower density than other materials, we assumed that the plastic would settle on top of the water column. First, the samples with the saline solution were stirred for approx. two minutes, then we let the sample settle for approx. 10 minutes. The top water from the samples was then filtered. Since we had such a murky sample, it was difficult to see what might be microplastic in the filter, but by using a microscope we could see that the samples contained some fibres that might be microplastic. The sample from the bicycle lane also contained some yellow particles. One of the yellow particles was then analysed by using a device called near infrared handheld scanner that can detect plastics and what type of plastic it is. The instrument showed that the yellow particle contained PVC with varying degrees of certainty (67%, 66%, and 84%).
From the course we learned a simple method to take a terrestrial sample, and then analyse the sample for microplastic. However, we also learned how difficult it is to produce a proper microplastic sample due the small size of the microplastics and the different properties of different plastic types.