Conclusion Setting up the installation obstracted snails to cutoff the way of snails spreading was the effective measure of control schistosomiasis in lake-swamp areas.
Heavy rains will weaken pollution of the water as the lake has no clean water resource. After cutoff the sewage of the lake, water quality of the lake was improved.
污染源对湖水水质有重要的影响，在切断了外源污染后，水质有所改善，但水体污染依然严重。
3
Although it hovers near the freezing point, cutoff from light and outside nutrients, Lake Vostok is teeming with microorganisms.