One　of　the　necessary　ways　to　control　water　pollution　of　Taihu　Lake　is　to　dredge　its　polluted　sediments.　Owing　to　our　country＇s　current　economic　and　technical　limitations　as　well　as　the　enormous　quantity　of　contaminated　dredged　sediments,　the　underneath　cohesive　soil　layers　without　any　treatment　are　directly　selected　as　impervious　barrier　of　the　Xuelang　confined　disposal　facility　(CDF).　In　order　to　prevent　contaminants　in　dredged　sediments　from　polluting　surrounding　environment　and　groundwater　during　dumping,　a　comprehensive　experimental　study　for　evaluating　the　ability　of　these　soil　layers　to　retard　infiltration　and　transportation　of　main　contaminants　(total　nitrogen,　ammonia　nitrogen,　nitrite　nitrogen,　total　phosphorus,　chemical　oxygen　demand　(COD))　in　dredged　sediments　has　been　made　using　permeability　test,　static　adsorption　test,　dynamic　soil　column　test　and　so　on.　It　is　shown　that　the　clay　layers　beneath　the　Xuelang　CDF　are　capable　to　adsorb　and　retard　the　main　contaminants　greatly.