Soil oxidoreductase activity in conditions of oil contamination and phytoremediation

Abstract

The effect of oil pollution and phytoremediation with Zea mays L. and Vicia faba var. Minor on soil oxidoreductase activity was investigated. The experiment was carried out under field conditions. Soil was artificially contaminated by oil at rate 4.2 % (50 ml of oil per 1 kg of soil). Soil sampling was performed at 10th, 22th, 30th days (the firs experiment stage) before sowing plants and seedlings emergence and at 65th, 95th days (second experiment stage) with plants vegetation. Results showed that soil catalase activity (CA) was reduced during the first experiment stage and increased later under oil contamination conditions compared to control. The reduction of soil enzyme activity can be related to inhibition of soil microbial activity by hydrocarbons toxic influence. On the other hand recovery of enzyme activity can be due to decrease of toxicity of soil conditions over time. A two-way analysis of variance yielded a main effect for the phytoremediation (p<0,01), such that the average CA was significantly higher for soil with plants than for unplanted soil. The interaction effect was significant between oil contamination and phytoremediation with Z. mays (p<0,01), indicating that the plants’ effect was greater in the oil contamination condition than without oil contamination. Soil dehydrogenase activity (DA) in oil contamination conditions decreased during all experiment compared to control. A main effect of phytoremediation on DA was significant (p<0,05), the interaction effect between oil contamination and phytoremediation was significant too (p<0,05). Interaction effect between oil contamination and phytoremediation can indicate improving conditions for microbial activity in the rooting zone. The plant’s exudates may create more feasible conditions for utilisation of carbohydrates by microorganisms. Polyphenol oxidase (PPOA) activity decreased on the 95th day in oil contaminated soil compared to control. PPOA was stimulated by Z. mays and V. faba plants in soil without oil, and only by Z. mays in oil contaminated soil. Soil phytoremediation treatment was related to the increase of enzyme activity. Such plants can be feasible for oil contaminated soil remediation.

Comparison of the efficiency of phytoremediation of soil contaminated with different types of oil products

“…-phytoremediation of soil with petroleum products uses natural processes and ecosystems for cleaning. This method contributes to the preservation of biodiversity and environmental sustainability [8,9].…”