Microplastics in the Soil Profile and Groundwater of Greenhouse Farmlands of Southeast- Hungary

Soil profile and groundwater under greenhouse farming are susceptible to microplastics contamination due to high generation of plastic waste. Natural and anthropogenic processes such as, infiltration, presence of cracks and farm management practices favor the vertical penetration of contaminants from the soil surface to soil depths and groundwater aquifers. In this study, we quantify and characterized the microplastics in the soil profiles and groundwater of greenhouse farmlands from Southern Hungary. We selected six soils profiles on the plots of greenhouses in the greenhouse farmlands of two cities, which have not been in use for about 3 years and 15-20 years respectively. Six soil profiles were dug, and samples were collected at intervals of 20 and 40 cm. Groundwater samples were also collected from the same profiles at a depth of 100 cm and below 4 meters. Microplastics were extracted from the groundwater by vacuum filtration process, while, predigestion of organic matter with 30%H2O2 and density separation with ZnCl2 was used to extract microplastics in the soil profile samples. Microplastic contamination was detected in the soil profile, thought; its distribution is not uniform. However, microplastics were also recorded in five of the six drilled areas, the average microplastics concentration in the groundwater was 2.5 pieces/L, and fibers were the dominant plastic structure. Given that microplastics were found in 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.