Size- and shape-dependent effects of polyethylene terephthalate microplastics on the benthic crustacean Artemia...

A large amount of microplastics (MPs) in the marine environment have gradually sunk into the benthic area, and crawling organisms can be easily exposed to the MPs. This study aimed to compare the size- and shape-dependent effects of polyethylene terephthalate (PET) on Artemia franciscana, which crawls on the bottom during the juvenile stage. In this study, the juvenile stage A. franciscana was exposed to three sized fragments (<20 μm, 45-75 μm, and >125 μm) and two fibers (200 μm and 3 mm length) of PET MPs contaminated seawater in a sand-layered system for 48 h. Acute effects on survival, growth rate, gut damage, apoptosis, and swimming activity were observed. The results showed that small edible-sized fragments (< 75 μm) consumed by A. franciscana caused gut damage and inhibited their movement, whereas large-sized fragments (> 125 μm) and fibers (200-3000 μm) induced apoptosis through physical stress. The uptake impacts of small PET MPs and physical effects of fibril shaped PET MPs on A. franciscana suggest that morphology, including size and shape, of PET MPs can be a major factor determining their ecotoxicity to marine benthic organisms.