Nitrogen is not only a basic constituent element of life, but it is also one of the key elements causing eutrophication. It has an important effect on nutritional status and water quality in lakes and reservoirs. Inorganic nitrogen, including ammonia (NH 4 þ ) and nitrate (NO 3 À ), often occurs following nitrification and denitrification reactions in a multiphase interface with the change of dissolved oxygen (DO) and redox. In addition, the extent of heavy metals is diffused from sediments to overlying water. It may cause potential harm to the water quality of the reservoir. This chapter is separated into two parts: (1) The release of nitrogen and phosphorus from sediment is investigated in typical Chinese reservoirs; (2) The release of metals from sediment is investigated in typical Chinese reservoirs.