To understand the impact of microplastic (MP) pollution to aquatic ecosystems, it is important to identify the mechanisms of interaction with organisms. Exposure experiments, like the study of Sussarellu et al. (1) recently published in PNAS, may provide such insights. However, the results of dose–response experiments must always be interpreted in light of environmental concentrations, and the experimental concentrations examined by Sussarellu et al. (1) and several others (2⇓⇓⇓⇓⇓–8) are orders-of-magnitude higher than those reported from field studies (Fig. 1).
Robin Lenz, Kristina Enders and Torkel Gissel Nielsen, PNAS,