Anthropogenic Impact in a Small Mountain Catchment: A Case Study of the Czerwonka Stream (Białka Tatrzańska, Carpathians, Southern Poland)

Białka Tatrzańska is a tourist-oriented locality and one of the largest ski resorts in southern Poland, situated in the Carpathian Mountains. In recent years, dynamic population growth and intensified tourism development have resulted in increasing anthropogenic pressure on the natural environment, including the waters of the Czerwonka Stream, which flows through the central part of the village. The objective of this study was to assess the impact of anthropogenic pressure on changes in water quality along the course of the Czerwonka Stream.

In 2023–2025, systematic monitoring of physicochemical and microbiological parameters of surface waters was conducted within the Czerwonka catchment. Hydrochemical analyses were performed using ion chromatography, determining concentrations of 14 major ions and biogenic compounds (H, Ca, Mg, Na, K, NH₄, Li, HCO₃, SO₄, Cl, NO₃, NO₂, PO₄, F, Br). Microbiological analyses included the determination of fecal indicator bacteria (Escherichia coli and Enterococcus faecalis) using culture-based methods on selective media.

Along the course of the Czerwonka Stream, abrupt increases in electrical conductivity were observed, associated with the influence of numerous point pollution sources. These include effluents from thermal facilities, tourist accommodation infrastructure, household and hotel wastewater treatment plants, as well as surface runoff from ski slopes, including waters derived from technical snowmaking. An additional factor deteriorating water quality is the poorly developed water and wastewater management system, largely based on septic tanks, which are often leaky and prone to overflow.

Identified local pollution hot spots caused increases in electrical conductivity of stream water of up to 560%, while maximum conductivity values recorded in inflowing wastewater reached nearly 9750 µS/cm. The natural hydrochemical type of the Czerwonka Stream, dominated by calcium–bicarbonate waters, undergoes substantial transformation along the stream course, leading to the dominance of chloride and sodium ions. Concurrently, a marked increase in fecal indicator bacteria was observed, with Escherichia coli predominating and a significant contribution of Enterococcus faecalis, clearly indicating anthropogenic sources of contamination.

This research was partially funded by BANIA SP. Z O O (eng. Ltd.) (project number - K/KDU/000942).