Changes of water quality of the Osówka stream flowing through ponds Syrenie Stawy in Szczecin (NW -Poland) in selected periods in the years 1994–2014

Abstract

The aim of discernment changes in water quality of stream Osówka flowing through ponds Syrenie Stawy in Szczecin (NW-Poland) conducted in the years 1994–2014 the study of basic water chemistry indices in the Osówka Stream water inflow and outflow area of water in/from ponds Syrenie Stawy, which were used to calculate the value of the National Sanitation Foundation Water Quality Index (NSF-WQI). The NFS-WQI values were calculated on the basis of temperature, pH, dissolved oxygen (as a percentage of water saturation), BOD5and concentration of nitrates and total phosphates carried out in 1994–1995, 1999–2000, 2006–2007 and 2014, i.e. during time periods, and in particular the decrease in the amount of inflowing industrial pollution and the changes of anthropopressure related to the hydrotechnical works of stream Osówka and ponds Syrenie Stawy. In assessing according to the criteria of NFS WQI procedure – studied water quality corresponded good and medium to average quality. On the basis of the values and changes in values of NSF-WQI it has been shown that quality water flowing through ponds Syrenie Stawy in subsequent periods the was getting worse, while self-cleaning effect ofthe waters along the ponds Syrenie Stawy gradually increase, especially after hydrotechnical works. It has been estimatedthat the NSF-WQI procedure to assess the quality and discerning water quality changes in the flow ponds in long-time period, based on the basic physical and chemical water quality indices – can be useful to use in practice.

Keywords

• urban ponds, water quality index NSF-WQI, Osówka Stream, ponds Syrenie Stawy, Szczecin City