| 摘要: |
| 海洋微塑料是全球共同面对的环境问题和挑战,然而目前海洋微塑料从源到汇的输运和沉积过程及影响机制尚不明确。已有研究发现微塑料颗粒的垂向沉降过程受到海洋雪等水体悬浮物质的影响,但是目前相关研究只局限于定性的观察分析。在实验室中模拟含有海洋雪的近岸水体环境,使细颗粒微塑料(PS微球、PVC颗粒)与海洋雪产生碰撞、聚集,观测微塑料或微塑料-海洋雪聚集体的沉降过程。研究结果表明,水体中含有海洋雪时,一方面海洋雪会促进微塑料颗粒自身的聚集,形成更大的聚集体;另一方面由于海洋雪包裹微塑料形成松散的聚集体,导致平均沉速减小。50 μm以下的微塑料其沉降过程受海洋雪的影响较大,平均沉速减小35%以上;微塑料密度越大,受海洋雪的影响越小,平均沉速减小10%以下。沉降速率的减缓,意味着微塑料在水柱中的停留时间增加,处于不同深度的水生生物可能有更多时间和概率与微塑料接触,增加了鱼类等水生生物摄入微塑料的风险。 |
| 关键词: 近岸水体 微塑料 海洋雪 沉降速度 |
| DOI：10.11693/hyhz20211100295 |
| 分类号:X55 |
| 基金项目:国家重点研发计划,2021YFB2601100号;国家自然科学基金联合基金重点项目,U1906231号;国家自然科学基金项目,51579171号。 |
附件 |
|
| EXPERIMENTAL STUDY ON THE EFFECT OF MARINE SNOW ON THE SETTLING OF MICROPLASTICS IN NEARSHORE WATERS |
|
ZHANG Jin-Feng1,2, LIANG Jia-Xiong1, QI Hang1
|
|
1.State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300350, China;2.Key laboratory of Earthquake Engineering Simulation and Seismic Resilience, China Earthquake Administration (Tianjin University), Tianjin 300350, China
|
| Abstract: |
| Marine microplastic pollution is a global environmental problem and challenge, however, the transport and deposition processes and impact mechanisms of microplastics from source to sink are still unclear. It is found that the vertical settling process of microplastics is influenced by suspended substances such as marine snow in water column. However, available studies are limited to qualitative observation and analysis. The nearshore waters containing marine snow were simulated in the laboratory, in which fine-grained microplastics (PS and PVC) collided and aggregated with marine snow, and then the settling process of microplastics or microplastic-marine snow aggregates were observed. Results show that marine snow could promote the aggregation of microplastic particles and form larger aggregates to accelerate the settling of microplastic. On the other hand, the average settling velocity decreased because the marine snow could wrap microplastics to form loose aggregates. The settling process of microplastics below 50 µm was more influenced by marine snow, and the average settling velocity was reduced by more than 35%. The higher the density of microplastics, the less they were affected by marine snow, and the average settling velocity was reduced by less than 10%. The decrease in settling velocity means that the residence time of microplastics in the water column increases, and aquatic organisms at different depths may have more time and probability to contact with microplastics, increasing the risk of microplastic ingestion by fish and other aquatic organisms. |
| Key words: nearshore waters microplastics marine snow settling velocity |
