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Detecting microplastics in beach sand

An inconvenient truth

One of the main reasons I bought my microscope is the ability to do my own exploratory research. One of the things that I wanted to look into for a long time has been microplastics. It’s been a relatively unknown area of research for a while, but has now become mainstream because of the alarming results published in the last couple of years.

To get a sense of the field, I decided that my first look would be into beach sand. With me living only a 20 minute walk from the beach and still barely going there, this seemed like a healthy and accessible option. So one night while avoiding my necessary holiday packing I decided to take home a scoop of humid sand a couple of meters from the low tide.

The next step is concentrating the plastics so I dont have to play “where is waldo”(is this a trademarked term?). Some very interesting research has been done with substances that light up under UV and only stains plastics, but my then current budget didn’t allow for that. I’ve since decided that it’s something I want to look into further. A more primitive way to separate plastics from sand is to depend on buoyancy. To make sure all plastics are floating, I read some discussions where the recommendation was to use saturated saline water, so that’s the method I used here.

After a bit of stirring a bunch of very fine objects had collected at the surface. I bought some coffee filters, but was afraid that I would lose a lot of the very little material I had. Then I remembered the trick to break surface tension by using the marangoni effect, and with a little dab of soap on the surface all objects were now concentrated in one spot. With the microscope glass almost fully submerged close to the concentrated area, the objects were attracted to the slide and stuck to it when I got it out.

Microscopic sea creature, 100 times magnification

Microscopic sea creature 100x magnification

One of the first things waiting for me was this microscopic sea creature. I could take the trouble identifying it, but that’s not what I was looking for so I won’t.

Navigating in a grid pattern over the slide I found tens of synthetic fibers, the most easily identifiable microplastics because of their bright colours;

Synthetic fiber microplastic in beach sand

Synthetic fiber microplastic in beach sand 100x magnification

And some more clustered below:

Synthetic fibers microplastic in beach sand

Synthetic fibers microplastic in beach sand 40x magnification

Horrifying right? if it’s that easy to find microplastics in just one tiny scoop of sand, how much of it is out there and makes it onto our plate? We’ll see in my next post.

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