Recycling is still the best way of handling plastic waste in the ocean, despite options to create plastic containers that easily degrade in sea water. These are the findings of a new study conducted by Penn State New Kensington researchers.
Researchers have used a machine learning algorithm to classify more than 110 types of plastics, including commercial and lab-made varieties, to better understand how they might degrade in the ocean.
“One of the things we were interested in finding out is what is going to happen to the large quantity of plastic that is in the ocean,” said Robert Mathers, professor of chemistry at Penn State New Kensington, in a statement. “This study took a wide range of physical property data, in combination with a metric that would quantify the composition of molecular structures and used that to try to figure out the most important aspects of plastic degradation in the ocean.”
According to the Ocean Conservancy, there are more than 150 million metric tons of plastic in the ocean, with 8 million metric tons more entering the ocean each year. The researchers said a number of factors in the ocean can help break down this plastic, including ultraviolet radiation from the sun, wind, waves, sea water, water temperature and bacteria. They found that certain types of plastics did break down quicker than others when subjected to these conditions.
While knowing the molecular structure of the more susceptible plastics could give engineers a chance to develop plastics with less environmental impact, Mathers said that the economics of producing those plastics at scale would still be an issue.
“Others have suggested the possibility of putting a weak link in the molecular structure of a plastic that could accelerate the degradation of that strand of atoms,” said Mathers. “Now, that is a great idea, but, right now, it may not be an economically feasible option. It’s just hard to economically compete with polyethylene and polypropylene, which are the most-used plastics in the world. So, we probably want to keep focusing on recycling because that offers the most immediate help.”
Image credit: Paolo Margari via Flickr