Flood events play a substantial role in the circulation of catchment phosphate (PO 4 3À ). The purpose of the research was to analyze the factors determining PO 4 3À hysteresis patterns (direction and width) during four types of floods: short and long rainfall floods and snowmelt floods on frozen and thawed soil. The research took place in small catchments (forested, agricultural, mixed-use) in the Carpathian Foothills in Poland. Anticlockwise hysteresis was identified in the forested catchment during short and long rainfall floods. Under the same conditions, the clockwise direction was observed in the agricultural catchment. In the mixed-use catchment, the direction of PO 4 3À hysteresis loops was various, driven by the share of water flowing from each part of the catchment. For snowmelt floods, the PO 4 3À hysteresis pattern was similar in all the streams studied (usually clockwise). The direction of PO 4 3À hysteresis loops depends on water circulation patterns, which are determined by the different influx times of particular runoff components. The stream recharge mechanism during a flood event is affected both by the factor initiating the event (precipitation, snowmelt) as well as by land use in the given catchment. Hysteresis loop width was determined by the pool of PO 4 3À in a given catchment during the time period immediately preceding a flood event as well as by the quantity of PO 4 3À flushed out of the soil. The greater a catchment's pool of PO 4 3À and the greater its ability to flush PO 4 3À out of the soil and into surface flow, the wider the hysteresis loops. a i a -floods caused by short rainfalls, i b -floods caused by long rainfalls, ii asnowmelt and rain-on-snow events with the soil frozen, ii bsnowmelt and rain-on-snow events with the soil thawed. nnumber of samples. 3680 J. SIWEK, J. P. SIWEK AND M. ŻELAZNY

The aim of this 2-year study was to examine the temporal changes in the concentration of microbiological indicators of water contamination and selected physicochemical parameters within the Białka river and its selected tributaries in the vicinity of the largest ski station in Białka Tatrzańska. The study involved 24 series of sampling in eight sites throughout the Białka river and on its selected tributaries. Temperature, pH, and electrical conductivity (EC 25°C ) were measured onsite. The microbiological assays included the numbers of mesophilic and psychrophilic bacteria, Staphylococcus spp. and Salmonella spp., as well as coliforms, thermotolerant (fecal) coliforms, Escherichia coli, Enterococcus faecalis, and sulfate-reducing Clostridium. The chemical analyses were conducted to determine the concentration of NH 4 + , NO 2 − , NO 3 − , and PO 4 3−. The analyses showed that contrary to common opinion, waters of the Białka river are strongly polluted in some sections. Seasonal variation in the prevalence of microbial indicators of fecal pollution was found, and the largest numbers of microorganisms were observed in winter ski season, followed by summer holidays. Similar seasonal pattern was observed in the examined chemical parameters. There was also very strong spatial variation within the tested microbial and chemical parameters, indicating the presence of pollution hotspots in the course of the Białka river. The employed principal component analysis revealed the presence of two main pollution sources, mainly affecting the quality of river water, i.e., fecal contamination of human origin and the natural source in the form of surface runoff and soil leaching. These factors, depending on the location of the sampling site, occurred in different configurations.

This study was aimed to determine the spatial variation in anthropogenic pressure exerted on surface water in the Podhale region (southern Poland), which is one of the most popular tourist destinations in Poland. The assessment was based on the dynamics and relationships between microbiological and chemical indicators of water quality throughout the major rivers of this region—Dunajec, Czarny Dunajec, Biały Dunajec, and Białka. Another aim was to assess the effect of land use on the quality of water in the studied rivers. The study was conducted over 1 year at 21 sampling sites distributed from the uppermost sections of rivers in the Tatra National Park through main tourist resorts until mouths of the considered rivers to the Czorsztyńskie Lake. Microbiological analysis comprised the prevalence of total and fecal types of coliforms and Escherichia coli, mesophilic, and psychrophilic bacteria. Chemical assays determined the concentrations of Na+, K+, NH4 +, Cl−, NO3 −, and PO4 3−. Temperature, electrical conductivity, and pH were measured onsite. It was demonstrated that there is a significant relationship between the predominant types of land use within individual catchments, which results in evident differences in the pollution of waters between the catchments. The results showed that increased share of built-up areas and arable land results in significant deterioration of water quality. Thus, waters of Czarny Dunajec were the cleanest, while Biały Dunajec was the most heavily contaminated. Also, spatial diversity in water quality was shown—the cleanest waters were sampled in the Tatra National Park and the pollution increased with the course of rivers. Point sources of pollution such as effluents from treatment plants or discharge of untreated sewage from households proved to be more important than non-point sources, such as surface runoff. Moreover, the important role of the Czorsztyńskie Lake in the purification of water was demonstrated.

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