Semenova I.N., Kuzhina G.Sh., Seregina Y.Y., Yagafarova G.A., Zulkarnaev A.B., Musin Kh.G.
USE OF PLANT TEST SYSTEMS TO ASSESS THE TOXICITY OF BOTTOM SEDIMENTS ^{[№ 10 ' 2015]}
This article is devoted to research the variability of heavy metals (Cu, Zn, Fe, Cd, Pb, Co, Ni, Mn) in sediments of r. Belaja on the territory of the Republic of Bashkortostan of Beloretsk district. The study of metals in their average content in the sediment form the following decreasing number of elements: Fe>Mn> Zn> Ni> Cu>Pb> Co> Cd. The concentration of Cu, Zn, Cd, Fe, Ni, Co in the sediments of the river exceeded the value of background: сopper — in the 6–15 times, zinc — in the 13–20 times, cadmium — in the 10–13 times, nickel — in the 1.5 times, iron — in the 9–11 times, cobalt — in the 155–185 times, lead — in the 1.6 times. The concentration of manganese in all soils studied watercourse was within the geochemical background. Total index of contamination ranged from 201 to 243. The evaluation of the toxicity of the river sediments were determined by bioassay using the seeds of Lepidium sativum L., Raphanus sativus L., Triticum aestivum L. Learned test systems according to the degree of sensitivity can be arranged in the following decreasing series: Lepidium sativum L. > Raphanus sativus L. > Triticum aestivum L. The greatest sensitivity to contamination had such a test responses as seed germination and seedling root length. In this paper, the connection between the content of heavy metals in bottom sediments exceeding the geochemical background, and a manifestation of the properties of the indicator: increase in the concentration of copper and nickel inhibits seed germination, root length, and seedling dry weight of the plant model. The use of these plant test systems allowed to conclude that the studied soils of r. Belaja are moderately toxic pollution degree, except for the alignment after the confluence r. Tirlyan characterized by narrow riverbed and, as a consequence, increase the speed of its flow with a predominance of the processes leaching of toxic elements from the sediments.