When you walk along the beach, it can be a lot of fun to keep your eye out for beautiful rocks. Whether you are a geologist by trade or you just like the natural beauty that rocks provide, this is something that millions of people enjoy when walking along the shore.

Unfortunately, the rocks in some places in the world are becoming not only less attractive but also potentially dangerous due to the fact that they are binding with plastic waste from the ocean. This process, dubbed plasticrusts, was first reported in 2016. Portuguese scientists found rocks with unusual colorings on the island of Madeira, which is located off the coast of Africa. A closer study revealed that the unusual color came from plastic that had encrusted the rocks.

Since then, there have been many additional reports of rocks being found that are embedded with plastic in locations around the world. Fernanda Avelar Santos is a geologist at the Federal University of Paraná. He spoke with Reuters, saying:

“This is new and terrifying at the same time, because pollution has reached geology.”

The plastic comes from the ocean, where it is left behind by humans on boats either intentionally or by accident. It can also make its way into the ocean from rivers or other parts of the land where careless people contribute to this pollution.

After floating in the ocean for a long period of time, the plastic washes up on shore and comes to rest on the rocks. From there, the plastic melts in the heat of the sun and then binds itself to the rocks themselves. In some cases, the plastic simply melts onto the rocks, but in others, it can actually chemically fuse with the rocks, making it very difficult to clean off.

To see examples of these disturbing plastic rocks, check out this video:

The full extent of the impact that these plastic-infused rocks will have on the surrounding environment. At a minimum, it is likely that the plastic will slowly erode off the rocks, leaving particles of microplastic left to further contaminate the surrounding water. There have also been reports of snails grazing on the plasticrust, and some research suggests that the snails can’t tell the difference between the plastic and the algae that they would normally eat. Their consumption of plastic will likely cause issues not just for the snails, but also for whatever animals eat the snails.

With trillions of pieces of plastic floating in the oceans, and more being added each day, this is not a problem that is going to go away anytime soon. Plastics have only been widely used for around a century, and they are already considered one of the biggest ecological problems ever faced.

Hopefully, humans will find a way to not just reduce the use of plastics, but to keep them out of the oceans as well.

If you thought that was interesting, you might like to read about a quantum computer simulation that has “reversed time” and physics may never be the same.