Role of Chlorella sp. and rhamnolipid 90 in maintaining homeostasis in soil contaminated with bisphenol A

Abstract

Abstract Purpose The knowledge about the impact of BPA on soil health does not correspond to the great interest in its analogues. Therefore, a study was conducted to determine the potentially negative impact of BPA on the biochemical properties of soil. The study also evaluated the effectiveness of two biostimulants in eliminating potential homeostasis disorders caused by BPA. Materials and methods A pot experiment was conducted under supervised conditions. BPA at five contamination levels was added to the soil of the granulometric composition of sandy loam at 0, 0.1, 2, 40 and 800 mg BPA kg−1 of a dry matter (DM) of soil. The biochemical activity of the soil was interpreted through the activity of dehydrogenases (Deh), urease (Ure), catalase (Cat), acid phosphatase (Pac), alkaline phosphatase (Pal), arylsulphatase (Aryl) and β-glucosidase (Glu) whose activity was determined on days 5, 15 and 45 of the study. The biostimulative potential of Chlorella sp. and rhamnolipid 90 (which eliminates the undesirable effects of BPA on the parameters) was expressed with IFB—the factor of the impact of increasing of bisphenol (BP) soil contamination levels. The response of spring barley to increasing BPA pressure was analysed with the plant resistance index (RS). The study was made more comprehensive by determination of the macronutrient content in the plants. Results and discussion The sensitivity of individual enzymes to increasing bisphenol pressure on the 45th day of the experiment can be arranged in the following sequence: Deh > Ure > Glu > Pac > Cat > Aryl > Pal. Biostimulation of soil with Chlorella sp. gave better results than with rhamnolipid 90. A compilation of BPA 800 mg BPA kg−1 DM of soil and Chlorella sp. brought about an increase in the activity of Glu on the 45th day of the experiment and Pac, Pal and Aryl on the 5th day. Only at this contamination level did BPA stimulate the crop growth in all the parallel plots except in those biostimulated by Chlorella sp. Only algae significantly reduced the negative BPA impact on the N, Ca and K content in spring barley. Conclusions The experiment emphasised the significant inhibitory impact of BPA on the biochemical activity of soil which, in consequence, upset the microbial balance of soil processes. Chlorella sp. played a more important role in maintaining the soil homeostasis than rhamnolipid 90, which did not correspond to its negative impact on the yield of spring barley.