Assessment of water quality and nutrient balance of a small lake in urban landscape – case study of Rusałka lake in the Wielkopolskie Lakeland

Abstract

Abstract Assessment of water quality and nutrient balance of a small lake in urban landscape - case study of Rusałka lake in the Wielkopolskie Lakeland. In this work based on the results of laboratory analysis of water samples, the water status of lake and as well as water fl owing and out of the lake, during growing season of 2011-2012 and 2016-2017 were assessed. The water samples for physico-chemical analysis were collected once a month from three control points and following parameter were analyzed for: oxygen conditions and organic pollutants (oxygen, BOD5, COD), acidification (pH), salinity (EC) and nutrients concentration (N-NO3, N-NO2, N-NH4 i P-PO43-). The state of the waters of Rusałka lake and Bogdanka river upstream the lake and downstream the lake qualified for III-V grade of quality. This was mainly due to high value of COD and BOD5indices. The main sources of nutrients in the lake’s water were the non-point sources. Yearly introduction of fish, fishing and leisure activities around lake as well as real estate development in the catchment led to the degradation of the quality of the water in Rusałka lake.