Phytobiotesting for the assessment of ecotoxicity of oil-contaminated soils

Abstract

Background. Oil pollution of soils is one of the most common forms of anthropo genic impact, leading to disruption of the functioning of soil ecosystems and a decrease in their biological activity. In this regard, it is an urgent task to develop and apply sensitive, informative and environmentally sound methods for assessing the ecotoxicity of contami nated soils. The purpose of this study was a comprehensive assessment of the phytotoxic and genotoxic effects of oil-contaminated soils using phytobiotesting at model facilities Allium cepa L. and Lemna minor L. Materials and methods. The objects of the study were water extracts from soils with varying degrees of oil pollution (3 and 6%). The Allium test and Lemna test were used as test systems. Phytotoxicity was assessed based on germination, root growth, and morphometric characteristics of plants. The genotoxic effect was determined by the method of anatophase analysis with the calculation of the mitotic index and the frequency of chromosomal aberrations. The morphoanatomic state of Lemna minor L. tissues was stud ied using light microscopy and safranin staining. Results. It has been established that oil pol lution of the soil has a pronounced dose-dependent effect on the growth, cytogenetic and morphoanatomic parameters of test plants. At 3% contamination, inhibition of root for mation, a decrease in the mitotic index, and an increase in the frequency of chromosomal aberrations were observed. At 6% concentration, growth of Allium cepa L. roots was stimulated against the background of a sharp increase in genotoxic effects, as well as pronounced growth inhibition and tissue damage of Lemna minor L. Structural disorders of the epidermis, stomata, and parenchyma cells were revealed, indicating a high level of phytotoxicity of the studied soils. Conclusions. The complex application of Allium and Lemna tests al lows for an objective integrated assessment of the ecotoxicity of oil-contaminated soils and can be recommended for environmental monitoring and bioindication of the state of soil ecosystems.