Microplastics have been found pretty much everywhere researchers have thought to look - from 30,000' under the sea at the bottom of the Marianas Trench to almost 30,000' on the slopes of Everest and everywhere in between. Not just floating in the oceans but inside our food supply and in the air we breathe. It is time to move beyond a simplistic 'microplastics are everywhere' to more sophisticated questions. What sort of microplastics are there? How far do they travel? What size are they?
G.A.P.S. 24-25 (Global Atmospheric Plastics Survey) is a series of expeditions aiming to provide a global snapshot of the type, size and distribution of airborne nano- and microplastics. This will serve as a baseline for future research and boundary conditions for models of the atmospheric transport of plastic pollution and the plastic cycle.
Blown around the world in the troposphere, nano- and microplastics settle onto the surface snows of high-altitude glaciers and ice caps. These snows act as a natural repository, preserving this imprint of plastics in the atmosphere until they can be collected by our expeditions.
The sampling process itself is very straightforward and is based on the method we developed during the HLR 2022 expedition. Practically, we found that the most efficient way to sample was for the lead person on a rope to do the actual sampling while the second or third records details of the site. In the photo adjacent, lead climber Richard Kay is taking a sample at the top of the Glacier de Pièce while technical lead Robin Milner is recording details of the site.
Once collected, samples are shipped back to our scientific collaborators at the Helmholtz Centre for Environmental Research in Leipzig. Here they get measured using a technique pioneered for this purpose by Dr. Dušan Materić, who is now Head of the Research Group for Microplastics, Nanoplastics and Elements.
The technique has several stages and is labour-intensive. The low pressure evaporation system used just to prepare the samples is shown opposite. The advantage, however, is that this technique can quantify not just microplastics, but also their much smaller nanoplastic counterparts.
Measuring the plastic content of these snows and knowing the local weather, the research team can infer what is going on in the atmosphere. With samples from glaciers and ice-caps all over the world, we hope that this will provide insight into the global plastic cycle.