Effect of PET microplastics on the growth, digestive enzymes, and intestinal flora of the sea cucumber Apostichopus japonicus

Marine microplastic (MP) pollution is becoming a serious problem and their potentially toxic effects on marine organisms have attracted much attention. Sea cucumber is very important for the safety and health of marine ecosystems. However, there have been relatively few studies on the effects of microplastic pollution on sea cucumbers at environmentally-related concentrations and under controlled conditions. Therefore, this study evaluated the effects of polyethylene terephthalate (PET) microplastics (particle sizes: 0.5–45 μm, 2–200 μm, and 20–300 μm; and three concentration levels for each particle size, approximately 103, 104, and 105 particles/kg) on the basic biological indicators, intestinal digestive enzymes, and intestinal flora of Apostichopus japonicus after a 28-day feeding experiment. This study showed that environmentally-related and high concentrations of microplastics had little effect on A. japonicus. This study provides valuable reference information about the effects of marine microplastic pollution on sea cucumbers.