We have been busy collecting microplastics samples since lockdown restrictions have been eased. This is how we go about analysing them.
Collecting samples from the beach is really important if we are going to be able to understand the scale and distribution of microplastics and mesoplastics on coastlines around the world. Plotted over time we can also see how changes are occurring. However, collecting the samples if just the beginning. We still have a fair bit to do after that. We recently collected around 150 samples from stretches of coastline at West Wittering and Hayling Island on the South Coast of the UK. Each one of these boxes contains the samples from an area of beach 0.25m x 0.25m square.
With so many samples the first thing we do is count what we have and make sure that we have all the coordinates for the samples. We normally write this on the box along with a sample number. Using the density separation method of sample collection means that all of the samples need to be dried – that is a simple case of opening the lids of the trays and letting them dry out over the course of a few days.
When we analyse the samples it is important to be systematic. We have found that the best way is to set up a work station using reusable white plastic tray which we then surround with cardboard trays. Using tweezers and a magnifying glass we separate what we find. Working methodically and systematically we remove the pieces of mesoplastics and microplastics from the sample using a maginifying glass and tweezers. The time this takes depends on the number of plastic particles, but when it is heavily contaminated this can take up to an hour for a single sample.
Once separated the plastic pieces are divided into catagories dpending on their source, type and colour. Primary microplastics, such as nurdles come in four different varieties and these are also separated. As you go through the samples you start to see patterns emerging. some areas have bio beads, others have lots of grey disk nurdles. As we collect data from around the world we are able to compare these patterns and trends.
The final part of the process is to upload the data onto the central database. This is done using the Big Microplastic Survey app which makes it really easy for anyone to add to our scientific knowledge by participating in this project. We take the various groups of plastics and place them on a piece of paper. We then note the coordinates and put a ruler on the paper before taking a picture and uploading that along with the other information about the location, types of plastics and colours. And yes, the microplastics and mesoplastic in the image all came from an area of beach 0.25m x 0.25m square!
And that’s it! Once you have done that you have made a contribution to our scientific knowledge about the issues of microplastics around the world.