During our crossing of the Atlantic Ocean from the Cape Verde Islands to St. Lucia in the Carribbean in January / February of this year (2015) I took six samples of sea water to let them analysed for microplastic by Adventure and Science who have a laboratory in Maine where my samples and those of many other sailors who crossed the Atlantic on a similar route.
I learned about this project from Marjo and Edwin of Oceanconservation when I met them in Las Palmas on Gran Canaria in December 2014.
In this map you can see where the samples were taken and how many pieces of microplastic they contained. Map of microplastic samples
Here a short description of how the samples were analysed: (Taken from the e-mail informing me about the results):
„First, let me briefly explain the process that the samples go through in the lab. After Abby receives your 1L bottles of water at her lab in Maine, she vacuum pumps the sample over a gridded 0.45 micrometer filter (meaning a filter that lets through only pieces smaller than 0.45 micrometers). After the sample has dried for a minimum of 24 hours, the counting process begins. Using a microscope at 40x magnification, Abby looks for pieces of microplastic (>5mm). The filter is systematically counted, moving along the grid lines, and each plastic piece is categorized based on shape (round, filament/microfiber, angular, other) and color (blue, red, green, black, transparent/white, other). The volume of water is recorded and the final count for the sample is divided by the quantity of water, which helps to standardize the results, because often samples are not exactly one liter of water.
To date, 94% (399) of the 426 samples collected have contained microplastic. Over 8,300 microplastic fragments have been counted. On average, we are finding 17 plastic pieces per liter of water. You can check out the number of plastic at each of your sampling sites on the map on our microplastics page. “
And this are the results of my samples:
Grand Canary Island to Cape Verde Islands
Sampling platform: Sailboat
„Jan Prahm collected 6 samples while sailing across the Atlantic from Grand Canary island to Cape Verde. In total, 152 microplastics were counted, with an average of 20 pieces per liter and a maximum of 62 pieces per liter. All 4 of the samples had at least 1 piece of plastic. 146 of the 152 pieces were fibrous/filamentous. 50 pieces were transparent/white, 50 were blue, 28 were red, 19 were black, 4 were other colors (including some blue/transparent pieces), and 1 was green.“
What is the problem of microplastics and where do they come from?