Assessment of the Quality of Bottom Sediments in the Middle Reaches of the Yenisei River by Allium test

Abstract

The harmful potential of bulk bottom sediments of the Yenisei River has been assessed by the Allium test. Sediment samples have been taken in ten sites on a plot of about 100 km in length in the middle reaches of the Yenisei River affected by urban activity of the city of Krasnoyarsk and industrial plants. The samples of sediments differ considerably in the content of potentially toxic substances (heavy metals, artificial radionuclides, and organic pollutants) and nutrients and in physical properties. We use the mean length of onion root as an indicator of general toxicity, the mitotic index as an indicator of cytotoxicity, and the percentage of anatelophase cells in the apical root meristem with abnormal chromosomes as an indicator of genotoxicity. Both the stimulation and inhibition of indicator endpoints are revealed in sediment samples of the Yenisei River relative to the control (artificial sediments). An increased genotoxicity is recorded in the sample of sediments contaminated by a mixture of organic and chemical toxicants. A significant positive correlation between the percentage of abnormal cells and the content of copper and petrochemicals in the samples is revealed. No extremely strong reactions of onion endpoints to the quality of sediment samples are revealed, which is probably related to relatively low contamination of the sediments studied. This is in agreement with the data of chemical analyses. Based on the testing results, we can conclude that the endpoints of the Allium test are sensitive enough to the quality of bottom sediments of the Yenisei River and can be used for their biotesting.