You may swim in Grand Lake St. Marys this summer but it will still be at your own risk. The message at St. Marys Rotary is that the water quality is heading in the right direction though. Dr. Stephen Jacquemin of Wright State University has been working on conservation efforts for Grand Lake St. Marys for years. He presented to the St. Marys Rotary Club that the progress in removing toxins from the lake has been remarkable.