Microplastic sampling (IMAGE) Kyushu University Caption Dr Okubo looking through a microscope studying microplastic samples. Plastic fragments less than 5 mm in length are categorized as microplastics. Credit Kyushu University/Asahi Kasei Corporation Usage Restrictions Only for media and non-commercial use. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.