Global soil microplastic monitoring data

We systematically compiled existing global datasets documenting microplastic occurrence in soil environments worldwide. Environmental and socio-economic factors of the sampling sites were obtained from open-source datasets. Studies and datasets included in these databases were selected according to several criteria: (1) soils should be sampled in the field, while cultured or experimentally treated soils were excluded; (2) studies that focused only on specific MP types (e.g., tire MPs) or specific pollution sources were excluded; (3) at least one aspect of MP data should be reported, including abundance, size, shape, color, or polymer compositions; (4) abundance should be expressed as items per kilogram of dry soil (items/kg), or it can be converted to this form; (5) studies with a detection size limit greater than 0.1 mm were excluded to enhance the comparability of the dataset. In addition to MP abundance and characteristics, the extracted information also included: (1) sampling and site description (e.g., site location, sampling depth, sampling number, and land-use types); (2) processing and analytical methods (e.g., extraction solution density, detection size limit, and identification method). Finally, we got 1247 independent records of soil MP monitoring data from 153 articles, encompassing 5129 sampling sites in 28 countries