I Do Not Want to Inhale: Finding microplastics in Shonan Beach

 

So, one fine January morning, scientists for Kanagawa Environmental Research Center gathered us, the registered ESD instructors, in a beach where Shonan Bellmare soccer team trained themselves during off-season. It was a beautiful day. The beach volleyball players engaged in their daily training routine while neighbors brought their pooches for morning stroll. A scientist instructed us, “First we situate 40cm*40cm codrato on beach.” “Please aim the collection point along the line where tide reached max, then retreated. They leave the debris on sand.” OK.

We can recognize
how far the tide came at this point with debris.
Nearer to the sea, the tidal flow washed
the fragments several times and
the beach became “seemingly” smooth and clean.

40cm*40cm was like this.

“Next, please scoop the sand within the square for about 3cm deep, and filter the contents in the sieves. We use a combination of two sieves. Above is a tool of coarser mesh with 4.74mm2. Join up a finer sieve with 2mm2 mesh below. Microplastic has, by definition, the size of 5mm less in its longest length which is often the diagonal. 4.75mm mesh could let pass a particle of this size. The lower sieve would release smaller bits, which would be defined as nanoplastics. Collecting nanoparticles is totally different issue, so we skip it today.” Sure. Let’s start sand play!

Two-story sieve system

Ready …

Go!

On the line where the tide reached max, there were lots of fragments of wood, bamboo, hard pampas grasses, and garbage of apparently artificial materials. At the point where I collected the sand not many glasses, beer cans or cigarette butts were found. Maybe, that’s good news. We collected large trash from a codrato before start scooping. In the first sieve, there remained relatively large fragments of wood and shells, and we returned them to the sand. The below is where our target remained. We damped them in a (Ahem) plastic Ziploc and brought it to the lab.

The “above” sieve.

The “below.”
They contain the thing of probably more than 5mm in size.
But they could go through 4.75mm mesh.

You may think the selection for the point of codrato would measure the level of plastic contamination higher than the average of the beach. Scientists for the Center thought the same thing and they did exhaustive study for the same beach before. “We tried several points if there is the optimum point where we can collect the microplastics in the most efficient way. Our conclusion is statistically speaking there is not much difference among locations in one beach and the amount of sand scooped. This means microplastics are scattered evenly and widely without difference in depth. Operationally, it’s good news. To think about the level of contamination, it’s VERY serious finding.” Oh yeah.

Today’s catch.

We brought the scooped materials to the lab and sorted the contents into organic things and plastics by hand, er, by tweezers to be exact. In our bag, there was no apparent porcelain and glass bits or steel wires, so the “artificial” debris was all plastics. At a glance neon green or the like of artificial coloring was not found much. So, the first impression was “Nah, problem is not serious.” Not so fast, please. The problem was, the originally white or transparent plastics absorbed or were smeared by some chemicals during their stay in water, and changed their color into similar to organic woods or the like. Deception. So, we have to identify the thing which was

a) Unnaturally geometrical, and/or

b) Looked a bit strange. 

Category b) is somehow easier to understand, isn’t it? We just trust our gut instincts. 😉

“A bit strange” things are apparent, don’t you think?

The particle in a) category was tricky as the beach was full of tiny rocks polished into something round tiny pebbles. As we know their origin was huge volcanic rocks created by tectonic movements, like andesites and tonalites, in Tanzawa. So, even when they are tiny, they keeps their characteristics of volcanic mineral. We patiently separated such pebbles from the “catch.” The plastic particles remained after this check was once the contents of beads cushions or beloved teddy bears. The main body of them was already trashed, but the staffing = plastic beads came out from the sac, drained into the stream, and ended up in the beach. During this process, they were exposed to sea water and uv-light which turned their color from white/transparent to something “organic-kind” brown. When left as such in the beach, they will be broken into smaller bits and become nanoplastics, or smaller. As they are small and light, when the wave splash kicks up them with sea water into the atmosphere, they can float in the air and end up at the bottom of the lung of mammals, humans included. Anyone cancer? Stroke? Heart attack?

The pebbles from Tanzawa, and a shell.
I plan to make them into an accessory with resin.

Another “unnaturally” plastics we’ve find looked briefly like some shell of seeds. They have a shape after the contents inside were squeezed out. Scientists told us, “It’s plastic.” Originally, they were slow-release fertilizer used massively even in commercial farms. Inside was active ingredients that seeped into the soil and one day they became empty. After reaching this stage, they started to be washed into water stream over ground, to the river, then to the sea. “Ideally, farmers side dressing their crops according to the conditions of their product. But aging problem is serious for the ag community in our prefecture. The grandparents do not have the stamina to tend their field regularly. So, they apply fertilizer contained in the plastic sac to skip regular dressing.” i.e. The problems are in forests, like Yadoriki community, and end up with the sea contamination of microplastics. Hmmmmmmmmm.

For the remnants of slow-release fertilizer,
the bit shown by the arrow is
the most easily identified in this pile of microplastics.
But here, there are roughly 10 such plastic husk.
Could you identify them?

We can analyze such debris for its chemical properties.

The result. It’s acetylcellulose.

According to the scientist of the Center, for Kanagawa Prefecture the level of microplastic contamination is apparently higher along the coast of Sagami Bay compared with the beaches to the direction of Tokyo Bay. Kanagawa’s beach facing to Tokyo Bay is almost at the exit of the Bay. Moreover, there are not many rivers pouring in. In contrast, Sagami Bay has several rivers that run down the large human settlements. Scientists surmised if the origin of the contamination is from open Pacific Ocean, there cannot be such huge difference among locale. Their conclusion is the problem in the sea is coming from the rivers passing through the land. Forests are lovers for sea. So they say. But …

Of course, we now cannot do away with the plastics for our life. We understand senior farmers need any help to continue their farming life. But, there must be some way to prevent inhaling nanoplastics that could cause any serious diseases eventually … Difficult. At least, let’s be careful before throwing away the tattered teddy bear with plastic beads …

If you find environmental issues in Kanagawa Prefecture, especially in cities and coastlines, please make contact with

Kanagawa Environmental Research Center

神奈川県環境科学センター
1-3-39 Shinomiya, Hiratsuka City, 254-0014
〒254-0014　平塚市四ノ宮1-3-39
Phone: 0463-24-3311
FAX: 0463-24-3300 

https://www.pref.kanagawa.jp/docs/b4f/index.html