Microplastic pollution indexes in the coastal and open ocean areas around Japan

Researchers have made a significant effort to reveal plastic pollution's presence and consequences worldwide; however, there are no standard methods to evaluate the level of microplastic pollution. In this context, pollution index assessment in the marine environments contributes to showing a criteria of pollutants. Therefore, the pollution load index (PLI), the polymer risk index (H), and the pollution risk index (PRI) were estimated based on the MPs abundance and polymer-type information in situ for five areas around Japan's sea. According to H values, the contamination due to MPs presented low to moderate pollution levels in each area. Whereas the PRI classified the pollution levels from low (offshore) to very high (coast). Based on MPs' predicted concentrations for 2030 and 2060, the PRI is expected to increase, reaching a very high-pollution level even for offshore areas. The results of this study emphasize the importance of action to prevent additional plastic pollution and the importance of continued monitoring of the MPs in the environment.