Microplastics in agricultural soils on the coastal plain: Spatial characteristics, influencing factors and sources

Yujie Zhou; Zhenyi Jia; Gunghui Zheng; Long Chen; Qi Zhang; Bo Su; Shenglu Zhou

doi:10.1016/j.scitotenv.2023.165948

Microplastics in agricultural soils on the coastal plain: Spatial characteristics, influencing factors and sources

Sci Total Environ. 2023 Nov 25:901:165948. doi: 10.1016/j.scitotenv.2023.165948. Epub 2023 Aug 1.

Authors

Yujie Zhou¹, Zhenyi Jia², Gunghui Zheng³, Long Chen⁴, Qi Zhang⁴, Bo Su⁴, Shenglu Zhou⁵

Affiliations

¹ School of Geographic Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China; School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210046, China.
² College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004, China.
³ School of Geographic Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China.
⁴ School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210046, China.
⁵ School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing 210046, China. Electronic address: zhousl@nju.edu.cn.

PMID: 37532042
DOI: 10.1016/j.scitotenv.2023.165948

Abstract

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 (R² = 0.65, P < 0.01) displayed the greatest and most significant fit with MDII, followed by clothing POIs (R² = 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.

Keywords: Coastal farmland; Influencing factors; Soil microplastics; Source appointment; Spatial distribution.