Abstract
We examined the cytotoxicity evaluation of the plastic marine debris collected in the coasts of Southwest Japan using in vitro tests, primarily the colony-forming assay （CFA） with V79 cells; the test system was based on Annex B of ISO10993-5. In approximately 30% of samples（9 of 29 samples） , the cytotoxicities were detected by the CFA, with IC50 values in the range of 18–74%. In 5 samples in which cytotoxicities were detected by the CFA, cell viability assays with TK6 cells also showed cytotoxicities. Among the samples tested, “moderate” level of cytotoxicity is the level indicating the mucosal tissue inflammation potential, which might negatively influence the physiological condition of marine based organisms via uptake into the body. In addition, we showed that floating microplastics can be evaluated using the CFA. This is the first study to determine the in vitro cytotoxicities of plastic marine debris using an international standard test method and quantitatively determine the cytotoxicities of plastic marine debris.
