The Subsequent Effects of Soil Pollution by Petroleum Products and Its Bioremediation on the Antioxidant Response and Content of Elements in <i>Vicia faba</i> Plants

Petroleum-derived substances (PDSs), which are one of the most significant sources of energy, have become key factors that affect soils and, consequently, plants. The aim of this study was to determine the subsequent effects of soil contamination by PDSs such as petrol (P), diesel fuel (DF) and used engine oil (EO), in addition to its bioremediation using a ZB-01 biopreparation, on the activities of antioxidising enzymes as well as on the content of antioxidants in the leaves of Vicia faba L. The effects on the growth of the plants and their chemical composition were also determined. The results showed that as many as five years after contamination, engine oil and diesel fuel adversely affected the growth of plants. PDSs caused a significant increase in the activity of peroxidase and an increase in the content of proline. The contamination of the soil with oils (EO and DF) resulted in a decrease in the content of nutrients (Ca, Mg and P) in the plants. DF also decreased the content of K and N while EO decreased the content of Fe. PDSs also increased the content of lead and cadmium, and some resulted in a decrease in the content of zinc, manganese and copper. The ZB-01 biopreparation generally had a beneficial effect on the growth of plants, and contributed to a lowering of the activities of the analysed antioxidative enzymes as well as the content of antioxidants in plants in the soil that had been contaminated with diesel fuel. Furthermore, it most often caused an increase in the nutrient levels in the leaves of plants. The effect of the ZB-01 biopreparation on the content of heavy metals varied and was dependent on the specific contaminant and metal that were analysed