Changes in Stormwater Quality and Heavy Metals Content along the Rainfall–Runoff Process in an Urban Catchment

Stormwater quality in an urban watershed can be influenced by several factors, including land use patterns, atmospheric deposition, and human activities. The objective of this study was to investigate spatial and temporal changes in stormwater quality and heavy metal content during the rainfall–runoff in an urban sub-catchment (30 ha) in the town of Olsztyn (NE Poland). Samples were collected from six locations along the rainfall–runoff pathway, including the following direct rainfall and runoff locations: roof runoff, surface runoff, storm collector, and the river. Parameters such as pH, specific conductivity, fluorescent dissolved organic matter (fDOM), total dissolved solids (TDS), and turbidity were measured in situ, while samples were analyzed for heavy metal content (Cu, Cr, Fe, Ni, Zn, and Pb) in the lab (ICP-OES). The results showed significant changes in water quality along the runoff. The highest concentrations of heavy metals were found in samples from a stormwater collector and surface runoff, particularly in winter and spring, due to the increased deposition of air pollutants and salt washout from roads. This study highlights the importance of monitoring stormwater quality and heavy metals in urban watersheds in terms of impacts on the river ecosystem as a recipient of stormwater. Solutions such as green infrastructure and stormwater management are proposed to mitigate the impacts of urbanization on water quality and protect the aquatic environment

Płytki ceramiczne. Badania mikroskopowe tekstur w odniesieniu do wytrzymałości na zginanie

Płytki gresowe są wytwarzane głównie z glinki kaolinowej, kwarcu i skaleni. Wiele właściwości technicznych, w tym odporność na zginanie, są związane z teksturą materiału w skali mikroskopowej. Najważniejszymi cechami są: zawartość, rozmiar i kształt różnych ziaren, w tym większych ziaren kwarcu, kryształów mullitu, fazy amorficznej bogatej w krzemionką i porowatości. Zrozumienie zależności pomiędzy mikrostrukturą a odpornością na zginanie może prowadzić do opracowania efektywniejszych metod wytwarzania cieńszych płytek o większych wymiarach.Porcelain tiles are sintered ceramic material made mainly from ball clays, quartz and feldspars. Many technical feateurs, including bending strength, are related to the microtexture of porcelain stoneware. Most important features are content, size and shape of different grains. These include large particles of filler (quartz), mullite crystals, a silica-rich amorphous phase and porosity. The understanding of the relationship between the microstructure and the bending strength of porcelain stoneware can lead to the development the manufacturing of thinner tiles with higher dimensions