青岛近岸野生牡蛎及海滩沉积物中的微塑料季节性分布特征及其关联性

Seasonal distribution characteristics and correlation of microplastics in coastal wild oysters and beach sediments in Qingdao

作为人类活动密集的城市近岸海洋环境中的微塑料污染日益突出,受到持续、广泛关注。为评估海洋微塑料污染带来的生态风险,在青岛近岸采集夏、秋、冬3个季节的牡蛎(Ostrea gigas tnunb)及海滩沉积物样品,分别采用碱性消解法、密度浮选法提取牡蛎体内和海滩沉积物中的微塑料,分析该区域内海洋微塑料的季节性分布特征以及牡蛎和沉积物中微塑料的关联性。结果显示:牡蛎体内与沉积物中微塑料丰度的季节性变化趋势具有一致性,表现为夏季>冬季>秋季;在3个季节中,牡蛎体内的微塑料丰度均显著高于沉积物中的丰度,是沉积物中的3~4倍;总体上,牡蛎体内和海滩沉积物中均以粒径<1 mm的纤维状微塑料为主,无明显的季节性变化;牡蛎体内与沉积物中微塑料的颜色总体上保持一致,以透明、蓝色为主;显微红外光谱显示,微塑料的聚合物种类有聚酯纤维、腈纶、人造丝、纤维素、聚丙烯-聚乙烯共聚物。基于牡蛎体内与沉积物中微塑料丰度随季节变化的一致性和微塑料物理特征上的相似性,建议将牡蛎作为青岛近岸海洋微塑料污染的指示生物。本研究可为青岛近岸海产品中微塑料的潜在风险评估及海洋微塑料污染的监测治理提供参考。

Marine microplastics in coastal regions,where human activity is intense,have attracted widespread attention.In this paper,the distribution,composition,and seasonal variation of marine microplastics in oysters and sediments of Zhanqiao Pier are studied.The results showed that the variation trend of microplastic abundance in oysters and sediments is consistent,with the tendency that summer>winter>autumn.In all three seasons,the abundance of microplastics in oysters was significantly higher than that in sediments,which was 3-4 times that in the sediment.Overall,Microplastics in oysters and sediments are mainly fibers,<1 mm,with no obvious seasonal change.In general,the color of microplastics in oysters and beach sediments is mainly transparent and blue.Micro-FTIR shows that the polymers of microplastics include polyester,acrylic,rayon,cellulose,and polypropylene-polyethylene copolymer.Based on the consistency of the abundance of microplastics in oysters and sediments with seasonal changes and the similarity of the physical characteristics of microplastics,it is suggested that oysters should be used as marine microplastics indicators in the Qingdao coast.This study can provide a reference for the risk assessment and monitoring of marine microplastics pollution in Qingdao inshore marine products.