School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; National Field Observation and Research Station of Erhai Lake Ecosystem, Yunnan 671000, China.
J Hazard Mater. 2022 Aug 15;436:129312. doi: 10.1016/j.jhazmat.2022.129312. Epub 2022 Jun 7.
The coastal zone is being under the threat by accumulation of microplastics (MPs), with much of MPs ending up on the beachhead. Oil spills, which frequently happen in coastal zones due to oil pipe leakage or oil drilling, may affect the behavior of MPs in the beachheads. Herein, sea water and sea sand were collected from three different coastal beachheads including Bohai Sea (BS), East Sea (ES), and South Sea (SS), China, to investigate how the oil spills affect the dispersion and transport of MPs in sea water and sand. The oil spills greatly enhanced the dispersion of MPs in all three sea waters by forming MPs-oil-dispersant agglomerates, which increased the electrostatic repulsion and steric hindrance between MPs particles. Accordingly, the aggregation rates of MPs were reduced from 1.7-8.86 nm min to 0.39-1.29 nm min. The lowest salinity and highest dissolved organic carbon content in SS sea water favored the highest dispersion of MPs, compared to BS and ES sea water. The improved dispersion of MPs with oil spills enhanced their transport in sea sand with an increase of effluent rates from 0-18.8 % to 5.78-42.2 % for BS and from 30.5-45.2 % to 35.0-60.0 % for SS one. However, the transport of MPs in ES sea sand was lower than 3.62 %, even with oil spills, which was attributed to the strong adsorption of MPs by the rich Fe/Al oxides in ES sea sand through electric attraction. Modeling also showed that oil spills increased the migration rate of 10 mg g MPs accumulated in the surface 0-1 cm sea sand from 6.50-13.8 cm year to 8.17-16.7 cm year after 1500 mm rainfall for 3 years, and the strongest transport of MPs was observed in SS sea sand, with the highest cumulative flux and the longest maximum migration depth as 0.089-0.120 mg/cm and 50 cm, respectively. These results indicated that the dispersion and transport of MPs can be enhanced by oil spills, but regulated by sea water salinity for MPs dispersion and sea sand Fe/Al oxides for MPs transport, which advanced our understanding of the transport and transformation of MPs in coastal zones.
沿海地区正受到微塑料（MPs）积累的威胁，其中大部分 MPs 最终出现在滩头。由于石油管道泄漏或石油钻探，沿海地区经常发生溢油事故，这可能会影响滩头 MPs 的行为。在此，从中国渤海（BS）、东海（ES）和南海（SS）三个不同的沿海滩头采集海水和海砂，研究溢油如何影响 MPs 在海水中和海砂中的分散和迁移。溢油通过形成 MPs-油-分散剂团聚体，极大地促进了所有三种海水中 MPs 的分散，增加了 MPs 颗粒之间的静电排斥和空间位阻。因此， MPs 的聚集速率从 1.7-8.86nmmin 降低到 0.39-1.29nmmin。SS 海水的最低盐度和最高溶解有机碳含量有利于 MPs 的最高分散，与 BS 和 ES 海水相比。溢油导致 MPs 分散度提高，从而增加了 BS 和 SS 海砂中 MPs 的输送率，从 0-18.8%增加到 5.78-42.2%和 30.5-45.2%增加到 35.0-60.0%。然而，ES 海砂中的 MPs 输送率低于 3.62%，即使有溢油，这归因于 ES 海砂中丰富的 Fe/Al 氧化物通过静电吸引对 MPs 的强烈吸附。模拟还表明，溢油使在表面 0-1cm 海砂中积累的 10mg/g MPs 的迁移率从 6.50-13.8cm 年增加到 1500mm 降雨 3 年后的 8.17-16.7cm 年，在 SS 海砂中观察到 MPs 的最强迁移，累积通量最高，最大迁移深度最长，分别为 0.089-0.120mg/cm 和 50cm。这些结果表明，溢油可以增强 MPs 的分散和迁移，但受海水盐度影响 MPs 的分散和海砂 Fe/Al 氧化物影响 MPs 的迁移，这提高了我们对沿海地区 MPs 迁移和转化的理解。
