高安定性ナノプラスチックの複雑な環境マトリックスにおける長期追跡と定量化

Micro- and nano-plastics (MNPs) pose a significant environmental threat, with considerable research focused on their impact on aquatic ecosystems. However, long-term tracking and quantification in complex environments remain challenging. To address this, we synthesized core-shell nanoplastics (EU@PS) using Eu chelates as a dual-functional tracer for reliable, long-term quantitative tracking via both mass spectrometry and fluorescence imaging in water, sediment and organisms. EU@PS exhibit high sensitivity, with a detection limit of approximately 0.5 μg/L (2*10 ⁴ particles/mL) in single-particle ICP-MS mode. Critically, the Eu core demonstrated exceptional stability, retaining over 83.1 % of its mass after 28 days of exposure and unaffected by ultraviolet light. In a microcosm experiment, we tracked the partitioning dynamics between water and sediment and bioaccumulation in D. magna. More than 95 % of the particles settled in sediment within 10 days at 1 and 10 mg/L concentrations, with a sedimentation rate constant of 0.20/day. Fluorescence imaging confirmed particle accumulation primarily in the gut of D. magna, reaching a concentration of 4.8 μg/g even at a low exposure concentration of 50 μg/L. This study provides a stable method for tracking the environmental fate of nanoplastics, highlighting the importance of tracer stability in environmental studies.