The Object Of The Contract Is The Monitoring Service Of The Network Of Compounds Accumulated In Fish And Sediments. The Work Includes, On The One Hand, The Sampling And Preparation Of Sediment And Fish Samples For The Analysis Of Accumulated Substances, And, On The Other Hand, The Analysis Of Bioaccumulated Compounds In Biota And In Sediments Corresponding To The Control Networks Of Priority And Preferred Substances In Biota And In Sediments Included In The Monitoring And Control Program 2025-2030 (Resolution Ter/3938, On November 6, 3938, Which Is Published The 'Agreement Of The Administration Council Of The' Catalan Agency Of The Water, Which Approves The Program Of Monitoring And Control Of The District Of Fluvial Conca De Catalunya For The Period 2025-2030).