Plastic pollution has become a major environmental problem, while the products of its degradation, microplastics (MPs), appear everywhere on Earth. Data on MPs in agricultural soils have appeared lately, but a significant knowledge gap exists regarding forest soils. In Serbia, municipal waste is often dumped in forests, creating environmental problems that have not been documented. To explore the impact of waste dumping and MPs on forest fluvisols, we evaluated MPs from topsoils of three waste dumps and adequate visibly plastic non-contaminated forest sites located in alluviums of the largest rivers in Serbia. For assessing the influence of environmental factors on soil MPs, samples were taken in three forest vegetational seasons, in two years. The impact of MPs on soil structure, chemistry, and microbial respiration (MR) was examined. Undisturbed soil columns from uncontaminated sites with added known MP particles were used to estimate the dynamic of MP transfer through the topsoil. Large aggregate formation, soil coarse sand content, specific mass, porosity, and available P, but not MR were affected by contamination. Seasonal and annual environmental changes significantly influenced the behavior of MPs in forest luvisols. MPs effectively penetrated the deeper layers of soil columns within 3 months, with strong accumulation in the 0–10 cm layer.
Crop production in plastic greenhouses is one of the major sources of plastic pollution worldwide. The main hypothesis of this study is that the regular use of mulch film in greenhouses leads to the cumulative accumulation of microplastic particles (MPs) in the soil, which ultimately leads to changes in the soil properties. Therefore, the main objective of this study was to identify the possible changes in the physical, chemical, and biological properties of soil in greenhouses in three regions of Serbia. The following chemical parameters were determined: electrical conductivity, soil acidity, cation exchange capacity (CEC), total carbon (TC) and nitrogen (TN) content, plant-available phosphorus and potassium content, and trace element content. The following physical parameters were determined: particle size distribution, volumetric mass, specific mass, and porosity; the biological parameters that were determined were microbial respiration and labile carbon. The obtained data were processed using network analysis (NA) to identify the complex relationships between MP content and soil parameters. The NA results support the main findings that the presence of microplastics leads to the destruction of soil structure, which reduces bulk density and increases soil porosity. A strong positive correlation of MPs with soil particles < 0.02 mm and a negative correlation with CEC were found. In the Danube Valley, soil respiration was 78% higher in the open ground compared to a plastic greenhouse. The results contribute to a better understanding of the influence of MPs on soil properties and its ecological functions.
As land plastic pollution has piled up in recent decades, small products of its degradation, microplastics (MPs), have emerged as a rapidly growing problem in soil environments. The first step in MP evaluation from soils is the extraction of MP particles, and it appears to be a particularly difficult substrate to work with. Aggregate formation and the presence of other organic particles of similar sizes appeared as challenges in constructing an efficient and trustworthy protocol for MP extraction from soils. Density separation-based methods are usually applied and finding efficient cost- and environment-friendly solutions is of high importance, while data comparability is a key factor in increasing general knowledge on the topic. Here, we propose an environmentally friendly protocol based on density separation using sucrose solution. Its efficiency for MP extraction from soil was tested and validated. Protocol validation showed that its use in the extraction of PE was efficient for all examined MP sizes (>32 μm) and PVC >500 μm with high recovery rates, while the extraction of PVC >125 μm is justified since sucrose solution is practically cost-free and completely environmentally safe. Result validation indicates that the proposed protocol has high potential for MP extraction from difficult soil samples.
Plastic is a major organic pollutant globally but has only recently been recognized for its recalcitrant nature and resistance to degradation. Although vast amounts of plastic debris are overwhelming the planet, the search for solutions to its degradation has only recently begun. One of the most well-known agents of plastic biodegradation is the larvae of Tenebrio molitor, which can alter the structure of polymers like polystyrene. However, while this insect can cause deterioration, its frass, which still consists of polystyrene microplastics, remains a problem. We investigated whether this frass could be further degraded by strains of white rot fungi, specifically Pleurotus eryngii and Trametes versicolor. We introduced two PS derivatives (styrofoam and stirodure) to the fungi in liquid media and evaluated oxidative metabolism enzymes (laccase, Mn-peroxidase, lignin-peroxidase) activities, and the phenolic products of the potential aromatic polymer degradation in the media. Finally, we evaluated FTIR spectra to determine if we could detect changes in polystyrene molecule degradation. Both fungi produced high amounts of enzymes, particularly when the polystyrene was present. Large quantities of phenolic substances were simultaneously detected, some associated with polystyrene degradation. FTIR spectra of different polystyrene products confirmed species-specific mechanisms for their degradation by experimental fungal strains.
The paper covers research in the fields of urban forestry and environmental ecology. The research results on ecological factors in forest habitats in the periurban zone of Belgrade are presented. The studied complex is classified into forests with a priority protective function and forests intended for recreation and cultural functions. The paper aims to assess the ecological potential of habitats in relation to the purpose and ecosystem services of forests. Based on the research results, it will be possible to reconstruct parts of the forest complex that are underutilizing the habitat's potential. The climate character was determined based on the climate index using the Thornthwaite method. Based on air temperatures and precipitation amounts (2002- 2016), the soil moisture deficit and surplus, potential and actual evapotranspiration, aridity and humidity indices, and the climate index were calculated. The habitat is characterized as: a habitat of submontane beech forest (Fagetum submontanum) on eutric brown soil on loamy sediments; a habitat of Hungarian and Turkey oak forest with manna ash (Quercetum frainetto-cerridis ornetosum) on eutric brown soil on loamy sediments, and a habitat of a typical Hungarian and Turkey oak forest (Quercetum frainetto-cerridis typicum) on illimerized eutric brown soil on loamy sediments. The objective of management is to develop silvicultural measures that facilitate the regeneration of introduced tree species. Key words: Ecological conditions, Belgrade forests, environment, reconstruction.