Microplastics (MPs) and oil pollution are major concerns in oceans. Although their coexistence in oceans and the associated MP-oil-dispersant agglomerates (MODAs) have been reported, limited attention is given to the behavior of the co-contaminants. This study investigated MODA transport in a simulated ocean system and explored related mechanisms under various oil types, salinities, and mineral concentrations. We found that more than 90% of the heavy oil-formed MODAs stayed at the seawater surface, while the light oil-formed MODAs were widely distributed throughout the seawater column. The increased salinity promoted MODAs formed by 7 and 90 μm MPs to transport from the seawater surface to the column. This was elucidated by the Derjaguin–Landau–Verwey–Overbeek theory as more MODAs formed under higher salinities and dispersants kept them stable in the seawater column. Minerals facilitated the sinking of large MP-formed MODAs (e.g., 40 μm) as minerals were adsorbed on the MODA surface, but their impact on small MP-formed MODAs (e.g., 7 μm) was negligible. A MODA-mineral system was proposed to explain their interaction. Rubey′s equation was recommended to predict the sinking velocity of MODAs. This study is the first attempt to reveal MODA transport. Findings will contribute to the model development to facilitate their environmental risk evaluation in oceans.

中文翻译：

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海洋环境中微塑料和分散油共污染物的传输

微塑料 (MP) 和石油污染是海洋中的主要问题。尽管已经报道了它们在海洋中的共存和相关的 MP-油分散剂团聚物 (MODA)，但对共同污染物的行为的关注有限。本研究调查了模拟海洋系统中的 MODA 传输，并探索了各种油类、盐度和矿物浓度下的相关机制。我们发现超过 90% 的重油形成的 MODAs 停留在海水表面，而轻油形成的 MODAs 广泛分布在整个海水柱中。增加的盐度促进由 7 和 90 μm MP 形成的 MODA 从海水表面传输到柱。Derjaguin-Landau-Verwey-Overbeek 理论阐明了这一点，因为在较高盐度和分散剂下形成了更多的 MODA，使它们在海水柱中保持稳定。当矿物质吸附在 MODA 表面时，矿物质促进了大型 MP 形成的 MODA（例如 40 μm）的下沉，但它们对小型 MP 形成的 MODA（例如 7 μm）的影响可以忽略不计。提出了 MODA-矿物系统来解释它们的相互作用。Rubey 方程被推荐用于预测 MODA 的下沉速度。这项研究是揭示 MODA 传输的首次尝试。调查结果将有助于模型开发，以促进其在海洋中的环境风险评估。7 μm) 可以忽略不计。提出了 MODA-矿物系统来解释它们的相互作用。Rubey 方程被推荐用于预测 MODA 的下沉速度。这项研究是揭示 MODA 传输的首次尝试。调查结果将有助于模型开发，以促进其在海洋中的环境风险评估。7 μm) 可以忽略不计。提出了 MODA-矿物系统来解释它们的相互作用。Rubey 方程被推荐用于预测 MODA 的下沉速度。这项研究是揭示 MODA 传输的首次尝试。调查结果将有助于模型开发，以促进其在海洋中的环境风险评估。