Along with the new technological accomplishments and accelerated development of industry, 21st century also raised certain environmental issues that have to be further tackled by environmental protection and industrial ecology. Plastic masses (polymers) are today present at every turn. However, the pollution caused by improper management of plastics and plastic waste is manifested from macroscopic levels (disposal in nature, environmental disturbance ...) to those microscopic (accumulation of microplastics (MP) in entire food chains of environmental organisms). MPs are considered plastic particles smaller than 5 mm that were formed by various physical processes as a result of improper management of plastic waste. As such, MP has shown a toxic effect on environmental organisms through a series of experimental results. However, the effect of MPs remains the focus of various global studies. In this work, toxicological studies of the effects of MP-PVC, which includes sizes <300 μm; 300-500 μm; 500-700 μm and concentrations 50 mg/L; 250 mg/L; 500 mg/L: 750 mg/L; 1000 mg/L, were performed in order to inhibit the growth of microalgae Scenedesmus sp. based on the change in the logarithmic number of living cells (log CFU). In addition to the logarithmic number of living cells, a potential change in morphological shape was monitored. The test results showed that the inhibition of microalgae growth is largely conditioned by indicators such as the size and concentration of MP-PVC particles. The highest inhibition percentage (10.50%) was shown by particle sizes <300 μm, 300-500 μm and concentrations of 750 mg/L and 1000 mg/L. No change in morphological shape was observed.