Microplastics in permanent soil observation

Within this data repository we stored the research data of a recent manuscript entiteld: "Microplastics in permanent soil observation samples: Spatial hotspots and temporal variability in soils" by C.J. Weber, J.E. Bastijans, K. Lügger and C. Heller (2023) More information can be found in the abstract provided below. You fill find two .csv datsets containing sampling area information and microplastic (>300 µm) concentrations. Sample material from permanent soil observation (PSO) areas have been provided by the Hessian State Agency for Nature Conservation, Environment and Geology Boden-Dauerbeobachtung (hlnug.de). Coordinates (Gauß-Krüger, zone 3) of sampling site locations are available as a .txt file. Please note that coorinates have been zeroed in last digit due to data protection of property owners! Manuscript abstract Microplastic (MP) contamination of soils has been reported globally and entail a bundle of negative effects on soil functions. However, spatial representative and temporal MP data considering different soils and land uses is lacking globally so far. We used archived topsoil samples from a public authority permanent soil observation programme to investigate spatio-temporal trends of MP contamination on the example of the federal state Hesse (Germany). Within samples covering a time span of maximum 16 years (2003/2004-2014/2015 and 2019), we found widespread MP (>300 µm) contamination (mean 34.66±24.08 p kg-1) from mainly PE and synthetic rubber polymers. Our results show highest MP concentrations in grassland and forest soils against cropland soils. Furthermore, archived soil samples from permanent soil observation programmes enable the identification of spatial contamination hotspots in rural areas and a high variability of MP concentrations over time. No significant temporal trend within MP concentrations could be found. Given the spatial representativeness and independency against MP sources, our results suggest a ubiquitous and independent MP contamination of topsoils, leading to a rough and conservative estimation of 5.92*109 MP particles entailed in agricultural soils in Germany. Based on our results we recommend the usage of archived soil samples for soil related MP research and a treading of current gaps of underrepresented grassland and forest soils.