The plastic ocean

There’s a lot of garbage in the oceans.

Plastics are a visible contributor, as they are light, and easily swept away to the ocean, and once there, they remain visible on the surface.

The garbage patches

The plastic in the ocean tends to congregate in gyres, areas where the currents circle. The largest of these is the Great Pacific Garbage Patch.

Garbage in the Great Pacific Garbage Patch. Credit: The Ocean Cleanup.

The garbage patch was observed by a yacht racer in 1997. Since then it’s become widely known and interest has grown in getting it cleaned up.

Microplastics & nanoplastics

There are plenty of reasons to want to get the plastic out of the ocean. Besides the aesthetics of floating trash, there are the health effects, on both aquatic and human life.

As the plastic stays in the ocean, it breaks into smaller and smaller pieces, known as microplastics (<5 mm in size) or nanoplastics (<100 nanometers in size). These microplastics are consumed by plankton and small fish, and work their way up the food chain. When microplastics become too abundant in the environment, it can lead to digestive problems, and even choking to death for wild animals, according to National Geographic.

The health effects of microplastics on humans are unknown. Polymers tend to be relatively inert, but they attract chemicals like heavy metals, and leftover plasticizers like bisphenol A (BPA), are a cause for concern.

Recently, microplastics have also been observed in human stools in multiple countries. This shows that, regardless of our best intentions, microplastics are in the food chain and in us. For now, it’s a matter of living with it and understanding the risks.

Dissipation

It’s not totally clear how long plastic waste lasts in the ocean, but some research indicates it dissipates quickly after sources of garbage are stopped. This is the conclusion of research conducted by Jan van Franeker of Wageningen University in the Netherlands.

Microplastics observed in seabirds (fulmars) and gyres in the North Sea and Atlantic over the years. Microplastics have decreased significantly since the 1980s. Source.

Another unknown is the mechanism of breakdown for the plastics. Research has shown that the salt content of ocean water plays a bigger role than UV light. Others suggest bioremediation using bacteria to further break down the plastic.

The Ocean Cleanup

Dutch inventor Boyan Slat founded The Ocean Cleanup in 2013 at the age of 18. The non-profit group is dedicated to cleaning plastic out of the oceans, most famously, the Great Pacific Garbage Patch. The group raised over $30 million largely from leaders in the Silicon Valley tech scene and buoyed by plentiful flattering coverage in the media.

Despite the positive reception from the media, The Ocean Cleanup has had its critics. One prominent example was Stiv Wilson of the 5 Gyres Foundation. He wrote an article back in 2013 that criticized Slat’s approach. His basic argument was that the design was structurally and economically impractical.

Slat responded to the critique and cited a 530-page feasibility study written by The Ocean Cleanup. Since this time, Stiv Wilson and the 5 Gyres Foundation have been quiet about The Ocean Cleanup. The 5 Gyres Foundation prefer solutions they see as more practical, like collecting waste at the source and decreasing plastic consumption. On these topics, they advise the UN.

Launch day

The past few months have been a critical time for The Ocean Cleanup. They’ve launched their first production-scale cleanup rig. It consists of a 600 meter long floating tube. The rig is folded into a ‘U’ shape and pointed towards the current to funnel trash into it.

News from the launch is poor. First, in November 2018, the team reported that collection was much slower than expected. This was due to trash not remaining inside the U-shaped rig and current not flowing as expected.

Then in December, the team discovered that the boom had broken. This was roughly 100 days after launch. The decided to tow the rig to Hawaii for repairs. The boom was supposedly designed for a working life of 10 years (link – see 3.6.1), but ended up operating for only about 3% of that time before needing repairs.

The underwhelming results so far vindicate criticism of The Ocean Cleanup. Still, I’m sure they’ll be back with a new plan of action soon. We’ll see if they can live up to the hype.

Sources of garbage

According to research in Science, much of the garbage going into the ocean comes from Asia, particularly China and Indonesia. While developed countries create a lot of waste, it is managed well and stored securely in dumps for the most part. In this research, the United States came in at number 20 out of all countries for estimated contributions to ocean waste.

Thus, recent efforts like banning plastic straws in California and Hawaii are unlikely to help much. Waste in the United States is already pretty well-managed. Instead, collecting garbage at rivers, especially in Asia, is likely to have a bigger impact and be more scalable. Here’s a fun look at what that might look like:

The verdict

The Ocean Cleanup’s main successes have been in earned media coverage and raising awareness of the garbage problem. Their success as a direct contributor to cleaning up has not yet materialized.

Cleaning the ocean up is a worthwhile goal. The main motivation I see is for reasons of natural conservation. In my opinion, the health effects of microplastics on humans are likely to be manageable, and they should disperse once sources of garbage are reined in.

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