[Meta-analysis of the Occurrence Characteristics and Influencing Factors of Microplastics in Agricultural Soil in China]

The potential threat of soil microplastics （MPs, particle sizes smaller than 5 mm） to the agricultural environment and food security production has become a hot issue, but there are few systematic studies on the characteristics and influencing factors of MP pollution in agricultural soil in China. Based on the data of soil MPs and related environmental factors （temperature, precipitation, soil pH, and organic carbon） and social and economic factors （permanent population, gross regional product per capita, gross industrial product per capita, and cultivated land area per capita） extracted from 6 694 samples from 85 published studies from 2020 to 2023, meta-analysis was performed. The characteristics of MPs pollution in agricultural soil and the key factors affecting the accumulation of MPs in soil in six administrative regions of China were analyzed. The results showed that soil MPs had six colors： （semi-） transparent, black, white, yellow, blue, green, and red. There were five kinds of shapes： fragment, fiber, film, particle, and foam. The particle size was between 0.01 and 5.0 mm. There were nine types of MPs： polyethylene （PE）, polypropylene （PP）, polystyrene （PS）, polyester （PES）, polyethylene terephthalate （PET）, polyvinyl chloride （PVC）, rayon （RY）, polyacrylonitrile （PAN）, and polyamide （PA）. The abundance gradient of soil MPs in different regions was as follows： South-central region > Northwest region > Southwest region > East China region > North China region > Northeast region. The （semi-） transparent （27.6%）, fragmented （32.2%）, 0.01~0.5 mm （66.3%）, and PE （37%） types of MPs had the highest detection rates. The characteristics of soil MPs are the result of natural environmental factors （temperature, precipitation, soil pH, organic carbon） and social factors （permanent population, gross regional product per capita, gross industrial product per capita, cultivated land area per capita）.