Zhou Yujie, Jia Zhenyi, Zheng Gunghui, Chen Long, Zhang Qi, Su Bo, Zhou Shenglu
School of Geographic Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China; School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210046, China.
College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China.
Sci Total Environ. 2023 Nov 25;901:165948. doi: 10.1016/j.scitotenv.2023.165948. Epub 2023 Aug 1.
Farmland is a major sink for microplastics (MPs), but research on MPs in coastal plain soil, particularly their occurrence in agricultural areas with changing coastlines, is limited. Here, we investigated the distribution, influencing factors and sources of MPs in a typical agricultural county near the southeast coast of China considering different human activities and soil property changes. The average MP concentration in farmland soils was 314 items/kg, ranging from 70.2 to 851.3 items/kg. MPs increased first and then decreased from inland to the coast, and this trend was greatly affected by coastline expansion. Bulk density, clay and textile points of interest (POIs) are the major factors affecting MPs in farmland. Network analysis was used to divide the whole MP community into two modules, and the average similarity between each MP community and the other 25.5 MP communities was >0.5. Overall, the similarity of the MP community tended to decrease with increasing geographical distance (P < 0.01). In the soil environmental factors group, bulk density and clay affected the total MP abundance, accounting for 14.7 % and 9.4 % of MPs, respectively. After fitting 8 types of POIs and the total MP diversity integrated index (MDII) of farmland, washing POIs (R = 0.65, P < 0.01) displayed the greatest and most significant fit with MDII, followed by clothing POIs (R = 0.29, P < 0.01). The MDII-POI results showed that the major POI sources of soil MPs were clothing manufacturing and washing POIs. Unlike in urban areas, automobile service POIs, packaging POIs and textile POIs had no significant relationship with the MDII, which may be related to the population and economic development scale. The results emphasize the importance of investigating MP occurrence and sources in coastal agricultural areas to promote the effective management of MPs and plastic emissions in land-sea transition zones.
农田是微塑料（MPs）的主要汇，但关于沿海平原土壤中微塑料的研究，尤其是其在海岸线变化的农业地区的存在情况，却很有限。在此，我们考虑了不同的人类活动和土壤性质变化，对中国东南沿海附近一个典型农业县的微塑料分布、影响因素和来源进行了调查。农田土壤中微塑料的平均浓度为314个/千克，范围在70.2至851.3个/千克之间。微塑料从内陆到海岸先增加后减少，这种趋势受海岸线扩张的影响很大。容重、黏土和纺织类兴趣点（POIs）是影响农田中微塑料的主要因素。网络分析用于将整个微塑料群落划分为两个模块，每个微塑料群落与其他25.5个微塑料群落的平均相似度>0.5。总体而言，微塑料群落的相似度倾向于随着地理距离的增加而降低（P<0.01）。在土壤环境因素组中，容重和黏土影响微塑料的总丰度，分别占微塑料的14.7%和9.4%。在对8种类型的兴趣点与农田微塑料总多样性综合指数（MDII）进行拟合后，洗涤类兴趣点（R=0.65，P<0.01）与MDII的拟合度最高且最显著，其次是服装类兴趣点（R=0.29，P<0.01）。MDII-兴趣点结果表明，土壤微塑料的主要兴趣点来源是服装制造和洗涤类兴趣点。与城市地区不同，汽车服务类兴趣点、包装类兴趣点和纺织类兴趣点与MDII没有显著关系，这可能与人口和经济发展规模有关。研究结果强调了调查沿海农业地区微塑料的存在情况和来源对于促进陆海过渡带微塑料及塑料排放有效管理的重要性。
