I have discovered an old oil spill that probably happened in the 60's. The vein is about 5 inches thick and is 4 feet deep covered with silt. I am currently removing the silt during the dry weather here in Oklahoma and just found it while digging. It seems to be contained to about 5 feet wide and 40 feet long. If I remove it from the property how will I seal the soil to prevent it spoiling my water? Any chemicals to add that will neutilize the water and soil. I have a small amount of water still in the old pond and at least a dozen nice fish still remain. I could move them to another pond on the property. Help :p