Environmental contamination by toxic metals and its indication by plant test systems

Abstract

Important modern environmental problem is the accumulation of toxic metals in soils. Urbanized lands of the central and southeastern regions are the most contaminated areas in Ukraine. Lead, zinc, copper, cadmium, nickel and aluminum are the most widespread and toxic metals – soil pollutants. The mobility and bioavailability of heavy metals and aluminum is directly proportional to the acidity of the soil. The north-western region of Ukraine has got the sod-podzolic soils with natural elevated acidity. Urban soils of the rest of our country regions are acidified by emissions of chemical, metallurgical and engineering enterprises. Considering potential danger of toxic metals for living organisms, is an urgent task and selection of model objects for the assessment of biological risks of these substances is of great value. The advantages of plants for monito­ring cyto- and genotoxic soil pollutants have been analyzed. It has been proposed to use seedlings Allium cepa L. as an effective highly sensitive indicating system for screening of metals with cytotoxic and mutagenic activities. Using modified Allium test has established that the effective toxic concentrations of Cu, Zn and Ni are lower than the approved maximum permissible concentration (MPC) of these metals in the soil, accordingly in 23, 12.5 and 8 times. This enabled us to recommend to reconsider MPC for these metals established in Ukraine.

Keywords

• heavy metals
• aluminium
• cytotoxicity
• bioindication
• allium test