Dr. Okubo checking out a microscopic lense studying microplastic samples. Plastic fragments less than 5 mm in length are classified as microplastics. Credit: Kyushu University/Asahi Kasei Corporation
In marine environments from lakes to oceans, plastics are the most abundant type of pollutant. As plastic waste is exposed to the elements they ultimately break down and piece. Plastic waste that has broken down to less than 5 mm in length are called microplastics..
In a previous study, we found that there are about 24 trillion grains of microplastics drifting on the surface area layer of the ocean,” explains Professor Atsuhiko Isobe of Kyushu Universitys Research Institute for Applied Mechanics, who led the research study. Another big question we have is how long microplastics wander through the ocean.”.
Prof Atsuhiko Isobe and gathering the microplastic samples collected from the upper ocean. Credit: Kyushu University/Isobe Lab.
To discover out how old microplastics discovered in the ocean can be, Isobe and his team started by investigating what metrics might be used to determine microplastic age in the first place.
” The most typical material in plastic is called polyethylene. We understand that as polyethylene connects with the environment it, deteriorates and oxidizes,” discusses Rie Okubo, a scientist at Asahi Kasei Corporation and first author of the research study.
Prof Atsuhiko Isobe and team gathering microplastic samples from the upper oceans. The upper ocean is determined down to one meter from the waters surface area. Credit: Kyushu University/Isobe Lab.
Naturally, thats insufficient. Since microplastics are being exposed to the aspects the group also required to standardize how temperature and UV radiation affects plastic deterioration. The group initially performed a series of exposure experiments to polyethylene product and collected information on how various combinations of UV and temperature level impacted the materials molecular weight and carbonyl index.
The group found that UVER– ultraviolet erythemal radiation, a measurement of UV radiation at ground level– and seawater temperature level were the 2 greatest contributors to plastic degradation.
” Once we had this information, we started to apply it to our microplastic samples. “We also collected microplastics from a range of locations.
By examining the gathered microplastics, the group had the ability to 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 assume the reason nearshore microplastics range from 0 to 5 years is since they are being regularly washed ashore and surviving for a longer time. Offshore microplastics on the other hand take longer to reach that part of the ocean, thus why we didnt find microplastics over 3 years old,” Okubo describes. “These overseas microplastics are also likely removed from the upper oceans by settling deeper into the waters.”.
The scientists hope that the new technique will provide much better insights into how microplastics are created and spread in the environment. The data will also assist in developing more precise simulations to track microplastics throughout the ocean.
Isobe concludes, “Our research and understanding of microplastics is still extremely new, and thanks to this data weve acquired a little bit more understanding on the essential science of microplastics. Our next action will be to examine how mechanical stimuli like ocean waves and currents can degrade plastics, so we can collect much more accurate data.
Reference: “Estimation of the age of polyethylene microplastics collected from oceans: Application to the western North Pacific Ocean” by Rie Okubo, Aguru Yamamoto, Akihiro Kurima, Terumi Sakabe, Youichiroh Ide and Atsuhiko Isobe, 10 May 2023, Marine Pollution Bulletin.DOI: 10.1016/ j.marpolbul.2023.114951.
The research study was moneyed by the Japan Society for the Promotion of Science and the Asahi Kasei Corporation.
Microplastic samples gathered from the oceans. Plastic fragments less than 5 mm in length are categorized as microplastics.
A novel approach has been devised by scientists to determine the age of microplastics in the ocean. Their findings expose that offshore microplastics can range from 1 to 3 years of ages, whereas nearshore microplastics can range from 0 to 5 years old.
A new method for figuring out the age of microplastics in the upper oceans has actually been established by a group of scientists from Asahi Kasei Corporation and Kyushu University. This method merges the analysis of plastic oxidation levels with the factor to consider of environmental aspects such as UV direct exposure and ambient temperature level.
Applying their novel approach, the researchers estimated the ages of microplastics collected from nearshore and offshore locations in the North Pacific Ocean. Their results revealed that the nearshore microplastics ranged in age from 0 to 5 years, while those from offshore places were between 1 to 3 years of ages. Their findings were just recently published in the journal, Marine Pollution Bulletin.
Microplastic samples gathered from the oceans. Applying their unique method, the researchers approximated the ages of microplastics gathered from nearshore and overseas locations in the North Pacific Ocean. In a previous research study, we discovered that there are about 24 trillion grains of microplastics floating on the surface area layer of the ocean,” explains Professor Atsuhiko Isobe of Kyushu Universitys Research Institute for Applied Mechanics, who led the research study. Prof Atsuhiko Isobe and crew collecting microplastic samples from the upper oceans. Offshore microplastics on the other hand take longer to reach that part of the ocean, thus why we didnt find microplastics over 3 years old,” Okubo discusses.