The contemporal ecological status of the Big Vasilievskoe lake

Changes in the chemical composition of water and in the trophic state of the lake B.Vasilievskoe since 1991/92 were analyzed. The chemical composition of water has changed from calcium-bicarbonate to sodium-bicarbonate type over the past 20 years; total mineralization of water increased 1.4-fold. The trophic state of the lake in 2013 is hypertrophic according to all three major indicators. Comparison of the changes that have occurred in the lake B.Vasilievskoe with two other Vasilievsky lakes fails to show any positive effect of the introduction of chlorella ("algolization") on the ecological conditions of the lake B. Vasilievskoe, so rehabilitations measures are still needed.