Please do not think I am mad or bitter at you all. It's proablly true that dredging the pond bottom will be the fasttest but even if you were to remove all the pollutants on the bottom of the lake wouldn't there still be an amount of pollutants that are in the fish and plants that have absorbed some of those pollutants ? My point is that the conntinueous removal of the pollutants would remove some amount of them and even at a slow rate it would be removal non-the less.