Results of biotesting of bottom deposits of some lakes in Khanty-Mansi Autonomous okrug - Yugra
This paper is based on information about toxicity study of bottom deposits of lakes located on the territory of oil fields of Khanty-Mansi Autonomous District - Yugra (Lakes Toykhlor, Peschanoye, Sykhtymlor, Piltanlor, Kalach, Okunevo, Leningradskoye, Vilyent, and Malyak-Pasolskoye) and beyond the area of human impact in Novoagansk district (conventionally background Lake Matylor). At the phase of exponential growth we used laboratory culture of Paramecium caudatum as the test object. The performed evaluation of acute and chronic toxic effect of water extracts of bottom deposit samples drawn in the littoral and profundal zone of the lakes showed both inhibiting and stimulating effects of the media in question on the number of the test Paramecium culture. At the same time, in some cases littoral samples (Lakes Vilyent, Matylor, and Sykhtymlor) turned out to be more toxic, while in other cases profundal samples were more toxic (Lake Okunevo). By their pollution degree these lakes were divided into classes of clean, polluted, contaminated, and severely contaminated lakes according to a bottom deposit classification with the mean toxicity index.