An evaluation on microplastic accumulations in Turkish soils under different land uses

Muhittin Onur Akca; Sedat Gündoğdu; Hanife Akca; Rabia Albayrak Delialioğlu; Cenk Aksit; Oguz Can Turgay; Naoki Harada

doi:10.1016/j.scitotenv.2023.168609

An evaluation on microplastic accumulations in Turkish soils under different land uses

Sci Total Environ. 2024 Feb 10:911:168609. doi: 10.1016/j.scitotenv.2023.168609. Epub 2023 Nov 19.

Authors

Muhittin Onur Akca¹, Sedat Gündoğdu², Hanife Akca³, Rabia Albayrak Delialioğlu⁴, Cenk Aksit⁵, Oguz Can Turgay⁶, Naoki Harada⁷

Affiliations

¹ Ankara University, Faculty of Agriculture, Department of Soil Science and Plant Nutrition, 06110 Ankara, Türkiye; Institute of Science and Technology, Niigata University, 950-2181 Niigata, Japan. Electronic address: moakca@ankara.edu.tr.
² Çukurova University, Faculty of Fisheries, Department of Basic Sciences, 01330 Adana, Türkiye.
³ Ankara University, Faculty of Agriculture, Department of Soil Science and Plant Nutrition, 06110 Ankara, Türkiye; Institute of Science and Technology, Niigata University, 950-2181 Niigata, Japan.
⁴ Ankara University, Faculty of Agriculture, Biometry and Genetics Department, 06110 Ankara, Türkiye.
⁵ Republic of Türkiye Ministry of Agriculture and Forestry General Directorate of Agricultural Research And Policies, 06800 Ankara, Türkiye.
⁶ Ankara University, Faculty of Agriculture, Department of Soil Science and Plant Nutrition, 06110 Ankara, Türkiye.
⁷ Institute of Science and Technology, Niigata University, 950-2181 Niigata, Japan.

PMID: 37984660
DOI: 10.1016/j.scitotenv.2023.168609

Abstract

Microplastic (MP) pollution is now widely reported in soil ecosystems. However, the level of this pollution in soil ecosystems has not been sufficiently elucidated. Moreover, there is little understanding of how land use conditions affect the occurrence and distribution of MPs in soils. Therefore, this study examined 55 soil samples (44 agricultural and 11 urban) from the Mediterranean, Aegean, and Marmara regions of Türkiye, representing both agricultural and urban land uses. The samples were analyzed for MP distribution characteristics, such as abundance, shape, size, color, and type. Different types of MPs were detected in the soil samples, and their averages in agricultural and urban soils were 192.7 ± 14.2 and 127.3 ± 21.6 particles kg^-1, respectively. MP abundance in the soil exhibited variations between different land uses, with agricultural areas showing higher levels compared to urban areas. In agricultural soils, MPs were predominantly blue-colored (44.6 %), in the form of fibers (74.9 %), smaller than 1000 μm (66.1 %), and primarily constituted polyethylene (90.8 %). In urban areas, MPs were also blue-colored (54.7 %), had a fiber shape (64.2 %), smaller than 1000 μm (70.6 %), and mostly belonged to the polyethylene category (78.5 %). A significant difference in MP concentrations was observed between agricultural and urban areas, reflecting the influence of distinct land uses on MP levels. Moreover, Principal Component Analysis (PCA) revealed that soil properties, including pH, electrical conductivity, organic matter, aggregate stability, average weight diameter, sand, clay, and silt, emerged as the primary determinants influencing the abundance and size of MPs within the soil. These findings contribute valuable insights into the origins of soil MPs and the intricate connections between MPs and varying soil characteristics across diverse land use categories.

Keywords: Agricultural soil; Plasticulture; Soil pollution; Urban soil.