Assessment of microplastics (MPs) in sediment cores is necessary to unveil global plastic pollution since most of the plastic litter might have been stored in sediment columns. In the current study, MPs inventory was determined in a 105 cm sediment core, collected in the Golden Horn Estuary, Sea of Marmara. Radiodating of sediment profile by using naturally occurring ²¹⁰Pb and fission product ¹³⁷Cs allowed us to couple the retrospective of global MP production to sediment MPs inventory. More than 90% of total MPs inventory was found in the deep layer of the sediment column (below 15 cm). Small MPs (20–200 μm) were more abundant than large ones (200–4000 μm). Elevated concentrations of MPs were attributed to industrial and municipal effluent of Istanbul metropolitan. On a local scale, this study suggests that the Golden Horn Estuary was polluted with MPs before the 1950s, and the abundance of MPs reached a maximum in the 1980s. We also propose on a global scale that “the missing” plastics might have been buried in deep sediment and radiodating of sediment is useful to reveal their historical input records.

对沉积物核心中的微塑料 (MP) 进行评估对于揭示全球塑料污染是必要的，因为大多数塑料垃圾可能已储存在沉积物柱中。在当前的研究中，在马尔马拉海金角湾收集的 105 厘米沉积物核心中确定了 MPs 清单。使用天然存在的²¹⁰ Pb 和裂变产物¹³⁷对沉积物剖面进行放射性定年Cs 使我们能够将全球 MP 生产的回顾与沉积物 MP 清单结合起来。在沉积柱的深层（低于 15 厘米）中发现了总 MP 存量的 90% 以上。小 MP（20-200 μm）比大 MP（200-4000 μm）更丰富。国会议员的高浓度归因于伊斯坦布尔大都市的工业和市政污水。在局部范围内，这项研究表明金角湾在 1950 年代之前被 MPs 污染，MPs 的丰度在 1980 年代达到最大值。我们还在全球范围内提出，“丢失的”塑料可能被埋在深层沉积物中，沉积物的放射性测年有助于揭示它们的历史输入记录。