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An ever-increasing amount of microplastics enters the environment and affects soil properties and plant growth. Investigating how the interactions between microplastics and soil properties vary across different soil types is crucial. In sandy soil, the subcritical SWR induced by microplastics may affect other soil properties. The objective of this study was to assess the impact of adding three types of microplastics (high-density polyethylene, polyvinyl chloride, and polystyrene) at a concentration of 5% (w/w) to sandy soil on the persistence and severity of SWR, as well as on various soil properties (bulk density, water sorptivity, and hydraulic conductivity) and plant characteristics (fresh and dry weight, maximum photochemical efficiency of PSII, and nutrient content) of radish (Raphanus sativus L.). It was found that microplastic contamination increased the persistence and severity of SWR and decreased soil bulk density, water sorptivity, and hydraulic conductivity. The total biomass measurements did not reveal a significant difference between the microplastic treatments and the control group. This study did not confirm any significant influence of microplastic contamination on the maximum photochemical efficiency of PSII, a measure of crop photosynthesis. Even though the value of photosynthetic efficiency changed with time, the values for all treatments stabilised at the end of the experiment. Microplastic contamination did not significantly alter crops’ nitrogen, phosphorus, potassium, or zinc contents. However, the copper content was reduced in all treatments, and magnesium and iron were reduced in the PVC and PS treatments compared to the control. The microplastic-induced changes in biomass or photosynthetic efficiency do not correspond to the changes in crop element concentrations.

The use of natural alkylresorcinols produced in Estonia (5-methylresorcinol, HONEYOL80 fraction) instead of the expensive resorcinol reduces the cost of the synthesized resins while maintaining their high technological characteristics. Resins based on resorcinol (R), 5-methylresorcinol (5-MR), HONEYOL80, dicyclopentadiene (DCPD), and styrene (S) were synthesized in the presence of an acid catalyst. Their physical and chemical characteristics have also been studied. It was shown that depending on the mole ratio of the components of the formulation, resins with different softening temperatures (66 to 97 °C), ash content of 0.04 to 0.39 wt%, and a low content of volatile components at 105 °C, including moisture, were obtained. The best conditions for the synthesis of resins with a softening point of 94 °C–97 °C are molar ratio of R (5-MR): DCPD: S = 1: 0.5: 0.3 at temperature 135 °C–170 °C, synthesis time 5 h 30 min. The synthesized resins did not require additional processing under a vacuum. The presence of unreacted resorcinol and 5-methylresorcinol (quantitatively and qualitatively) in the final product, the homogeneity, and molecular weight characteristics of the resin composition (qualitatively) were determined by TLC and GPC.

The excessive worldwide production of plastic materials results in omnipresent microplastic pollution. Scientific studies dealing with the impacts of microplastics on aquatic ecosystems focus mainly on the marine environment, documenting the effect on the functional traits of various organisms. Polystyrene, one of the most commonly used plastics, has become a widely used model in this respect. In our study, freshwater shrimps (Neocardina heteropoda) were exposed to virgin polystyrene particles (size 0.5 mm; nominal concentration 8 mgL−1), and their behavioral and physiological responses were compared to control shrimp. The exposed shrimps exhibited modified activity patterns (greater speeds, accelerations and distances moved), accompanied by a lowered standard metabolic rate (SMR). The observed effects differed in their progression from the 7th to 14th day of exposure, from undetectable changes (distance, SMR) to significant differences (speed, acceleration). Significant differences were also detected in the behavioral syndromes expressed by the exposed and controlled shrimps, indicating that the microplastics influence not only the particular traits, but also their functional relationships. As such, our study contributes to the integration of behavioral ecotoxicology in risk assessment, documenting the adverse performance of freshwater invertebrates exposed to microplastics with the potential to transpose the problem to higher levels of the food web.