Initial Assessment of Changes in Water Quality in the Wrocław City Moat Reservoirs

Abstract

The aim of the research was to initially assess changes in the physicochemical composition of water in the reservoirs of the city moat (Wrocław) in the context of the analysis of the type of pollutants flowing into the inner-city water reservoirs and in relation to the impact of air quality directly in the vicinity of the reservoirs. As an element of the urban landscape, the inner-city water reservoirs play an important role in improving the local climatic conditions, increasing the biodiversity of the landscape, and eliminating the negative impact of urban heat islands. The measurement campaign was conducted for 11 months. The following parameters were determined in the analyzed water samples: turbidity, pH, electrolytic conductivity, as well as concentrations of nitrogen forms (ammonium nitrogen, nitrite nitrogen, nitrate nitrogen), total phosphorus and sulphates. Additionally, air quality parameters in the direct location of the reservoirs were analyzed, including: concentrations of nitrogen oxides, nitrogen dioxide, sulfur dioxide, humidity level and selected meteorological data, i.e. daily precipitation and average daily air temperature. The average concentrations of nitrogenous forms in the waters of the downtown water reservoir were as follows: ammonium nitrogen 0.155 mg·dm-3, nitrite nitrogen 0.084 mg·dm-3, nitrate nitrogen 1.15 mg·dm-3. The sulphate concentrations showed greater variability 67.805–180.973 mg·dm-3. Based on the conducted observations and analyzes, a statistically significant relationship was found between the quality parameters of water in municipal water reservoirs and external factors such as air quality, and in particular the correlation of air humidity with the concentration of nitrite and nitrate ions in the water. The conducted research confirms the influence of air quality on the levels of pollutants in the waters collected in the urban water reservoir.

Keywords

• ammonium nitrogen
• total phosphorus
• urban water reservoirs
• physicochemical composition of water
• city moat