How Old Is That Microplastic? A New Way To Estimate The Age Of Microplastics In The Upper Ocean
Researchers from Kyushu University and Asahi Kasei Corporation have developed a new way to estimate the age of microplastics found in the upper oceans. The method involves a combination of analyzing plastic oxidation levels with environmental factors such as UV exposure and ambient temperature.
The team applied their new method to estimate the age of microplastics found in nearshore and offshore sites in the North Pacific Ocean. They found that the age of microplastics in nearshore regions ranged from 0 to 5 years old, whereas microplastics from offshore regions ranged from 1 to 3 years old. Their findings were published in the journal, Marine Pollution Bulletin.
In marine environments from lakes to oceans, plastics are the most abundant type of pollutant. As plastic waste is exposed to the elements they eventually break down and fragment. Plastic waste that has broken down to less than 5 mm in length is called ‘microplastics.’
“Microplastic pollution is recognized as a global problem. In a previous study, we found that there are about 24 trillion grains of microplastics floating on the surface layer of the ocean,” explains Professor Atsuhiko Isobe of Kyushu University’s Research Institute for Applied Mechanics, who led the study. “However, there is still little we know about its effects on the environment or on living creatures. Another big question we have is how long microplastics drift through the ocean.”
To find out how old microplastics found in the ocean can be, Isobe and his team began by investigating what metrics could be used to measure microplastic age in the first place.
“The most common material in plastic is called polyethylene. We know that as polyethylene interacts with the environment it, oxidizes and degrades,” explains Rie Okubo, a researcher at Asahi Kasei Corporation and the first author of the study. “This degradation level can be measured using the change in the material’s molecular weight and something called the carbonyl index. When polyethylene degrades its carbonyl index increases and molecular weight decreases.”
Of course, that’s not enough. Since microplastics are being exposed to the elements the team also needed to standardize how temperature and UV radiation affects plastic degradation. The team first conducted a series of exposure experiments to polyethylene material and collected data on how various combinations of UV and temperature affected the material’s molecular weight and carbonyl index.
The team found that UVER—ultraviolet erythemal radiation, a measurement of UV radiation at ground level—and seawater temperature were the two biggest contributors to plastic degradation.
“Once we had this data, we began to apply it to our microplastic samples. All our samples came from the upper ocean, up to one meter from the water surface,” continues Okubo. “We also collected microplastics from a range of areas. Some samples were collected from nearshore to Japan, ranging from 10 to 80 km off the coast. Other samples were collected offshore, in the middle of the North Pacific Ocean and the Philippine Sea.”
By analyzing the collected microplastics, the team could estimate the age of each induvial sample. They found that nearshore microplastics ranged from 0 to 5 years old, whereas offshore samples ranged from 1 to 3 years old.
“We hypothesize the reason why nearshore microplastics range from 0 to 5 years is because they are being frequently washed ashore and ‘surviving’ for a longer time. Offshore microplastics on the other hand take longer to reach that part of the ocean, hence why we didn’t find microplastics over 3 years old,” Okubo explains. “These offshore microplastics are also likely removed from the upper oceans by settling deeper into the waters.”
The researchers hope that the new method will give them better insights into how microplastics are generated and spread in the environment. The data will also help in developing more accurate simulations to track microplastics across the ocean.
Isobe concludes, “Our research and understanding of microplastics is still very new, and thanks to this data we’ve gained a little more understanding of the fundamental science of microplastics. Our next step will be to investigate how mechanical stimuli like ocean waves and currents can degrade plastics so that we can collect even more accurate data.
Marine Insight Academy
Online courses for the Maritime industry!
Enroll For Maritime Courses
- 100 + Free & Premium Courses
- Learn at your own speed
- Earn certificates on completing Premium Courses
- Quizes to evaluate your knowledge
- Interactive videos
Marine Insight Academy
Enroll For Maritime Courses
- 100 + Free & Premium Courses
- Learn at your own speed
- Earn certificates on completing Premium Courses
- Quizes to evaluate your knowledge
- Interactive videos
Disclaimer :
The information contained in this website is for general information purposes only. While we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk.
In no event will we be liable for any loss or damage including without limitation, indirect or consequential loss or damage, or any loss or damage whatsoever arising from loss of data or profits arising out of, or in connection with, the use of this website.
Disclaimer :
The information contained in this website is for general information purposes only. While we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk.
Do you have info to share with us ? Suggest a correction
About Author
Marine Insight News Network is a premier source for up-to-date, comprehensive, and insightful coverage of the maritime industry. Dedicated to offering the latest news, trends, and analyses in shipping, marine technology, regulations, and global maritime affairs, Marine Insight News Network prides itself on delivering accurate, engaging, and relevant information.
About Author
Marine Insight News Network is a premier source for up-to-date, comprehensive, and insightful coverage of the maritime industry. Dedicated to offering the latest news, trends, and analyses in shipping, marine technology, regulations, and global maritime affairs, Marine Insight News Network prides itself on delivering accurate, engaging, and relevant information.
Daily Maritime News, Straight To Your Inbox
Sign Up To Get Daily Newsletters
Join over 60k+ people who read our daily newsletters
By subscribing, you agree to our Privacy Policy and may receive occasional deal communications; you can unsubscribe anytime.
BE THE FIRST TO COMMENT