Greenhouse Farming as a Source of Macroplastic and Microplastics Contamination in Agricultural Soils : A Case Study from Southeast- Hungary

Greenhouse farming is a major source of plastic contamination in agricultural soils because it is characterized by the high production of plastic films that pollute agricultural farmlands with macroplastics and microplastics. Particularly, microplastics can penetrate the agricultural soil and contaminate the soil profile and groundwater. In this case study from Southeast Hungary, we quantified and examined the macroplastic and microplastic contaminants on the soil surface and in the soil profile and groundwater under greenhouse farmland. Random sampling was used to select three areas in a greenhouse farm where macroplastic and microplastics data were collected. For each sampling point, four composite samples were collected from shallow (0–20 cm) and deep (20–40 cm) soils, respectively. Three soil profiles were dug, and samples were collected at intervals of 20 cm. Groundwater samples were also collected from the same profiles at a depth of 100 cm. Microplastics were extracted using predigestion of organic matter with 30%H 2 O 2 and density separation with ZnCl 2 . The total mass of macroplastics in the greenhouse farmland was 6.4 kg/ha. Polyethylene and polyvinyl chloride were the dominant plastic structures, and the dominant sizes were 1–5 and 0.5–1.0 cm, respectively. Overall, the average abundance of microplastics in the greenhouse soil was 450.0 ± 138.4 pieces/kg, and the dominant size structure was 2–3 mm. The average microplastic concentrations at depths of 0–20 and 20–40 cm were 300±93 and 150.0 ± 76.3 pieces/kg, respectively. The average microplastics concentration in the groundwater was 2.3 pieces/L, and fibers were the dominant plastic structure. Given that microplastics were found in greenhouse soil, soil profiles, and groundwater, we recommend the treatment of groundwater from such areas before it is used for human consumption or irrigation as well as careful cleaning and disposal of plastics on greenhouse farmland