Improving the efficiency of phytoremediation technologies of oil-contaminated soils with the participation of natural sorbents-meliorants

Abstract

Phytremediation is considered to be a promising and environmentally friendly way to restore oil-contaminated soils. However, the multicomponent nature of oil pollution, its low bioavailability, high stability, hydrophobicity, and toxicity require a comprehensive approach to its implementation. The purpose of the study is to investigate the influence of different types of sorbents-meliorants and their complexes with remediation agents on improvement of the efficiency of phytoremediation technologies of oil-contaminated soils. The study established that the most effective plants for phytoremediation of oil-contaminated soils are Vicia faba var. Minor, Pisum sativum L., Avena sativa L., which are the least exposed to toxic effects of oil among the studied crops, and better adapt to the conditions of oil-contaminated soils. The influence of sorbent-meliorants such as glauconite, zeolite, sawdust, and sunflower husk on the process of phytoremediation of oil-contaminated soils (oil content 5%) was studied. It was proven that sunflower husk is the most promising and available agent for accelerating phytoremediation. The study examined the individual and combined influence of mineral fertilisers, biogenic surfactants of microbial origin, and humates on the growth of Avena sativa plants under conditions of oil pollution, as well as on the process of soil restoration. The best results are obtained by application of the above agents in combination with sunflower husk. This complex (sunflower husk + mineral fertilizers + surfactants of microbial origin / humates) has a positive effect on Avena sativa plants – reduces the rate of oxidative stress, which indicates an improvement in the adaptability of plants to oil-contaminated soil; growth parameters increase; plant biomass accumulation; the total content of chlorophyll a+b increases; and there is an improvement in soil properties by reducing the oil content in soil, reducing phytotoxicity, increasing dehydrogenase activity