Assessing trophic state of surface waters of Służewiecki Stream (Warsaw)

Abstract Phosphorus (P) is one of the key nutrient compounds for phytoplankton grow. In the conducted work, eutrophication indexes were used for the assessment of eutrophication level of water course (Służewiecki Stream) and the waters of nearby lakes (Bottom Berensewicz’s Pond, Wyścigi Pond, Wilanowskie Lake). Calculating eutrophication indexes were based on the most important indicators which is crucial for eutrophication process: total phosphorus (TP), total nitrogen (TN), chlorophyll a (Chl( a )) and water transparency. The research revealed that the concentration of phosphorus and nitrogen in the analysed waters determined intensity of trophic processes. The average concentration of both indicators was high: 0.81 mg/l TP and 6.8 mg/l TN. During this research, two approaches were used: trophic state index (TSI) and trophic level index (TLI). TSI (TP) in Służewiecki Stream were, respectively: 83 and 6.5 whilst for standing waters (lake and ponds) 87 and 6.6. Both indexes indicated high trophic state and confirmed that eutrophication is a serious endangerment for analysed surface waters. Calculated indexes used in the assessment were sufficient and effective for sustainable water protection and management of water quality in Służewiecki Stream and in standing waters.