## 3 Results
### Chemical Composition and Microbiological Quality of Water in the Remiaszow Stream
The Impact of the Construction and Operation of a Ski Run on the Quality of Water in the Remiaszow Stream  
As shown by the results of ANOVA, the quality of water in the Remiaszow stream during the construction of the ski run differed significantly from the periods before its construction and during its operation in terms of the following parameters: pH, K\({}^{+}\), total _E. coli_, fecal coliforms, fecal _E. coli_. On the other hand, the values of NO\({}_{3}\)\({}^{-}\) in the water differed significantly between the construction period and the period after the construction--during the operation of the ski run (Table 4, Supplementary data). A statistically significant decrease in the pH value of the stream water and increased values of K\({}^{+}\), total _E. coli_, fecal coliforms and fecal _E. coli_ were observed during the construction of the ski run. However, in the later period, the values of these parameters returned to a state similar to those recorded before the ski run construction. In the case of NO\({}_{3}\)\({}^{-}\), the concentrations were the highest during construction, while during the operation of the newly built ski run, they decreased and were even lower than the ones recorded before the construction works began (Figure 2). In the case of the remaining parameters of the stream water, there were no significant differences between the periods before, during and after the construction of the considered ski slope. However, in the case of EC, TDS, Ca\({}^{2+}\), Mg\({}^{2+}\), HCO\({}_{3}\)\({}^{-}\), SO\({}_{4}\)\({}^{2-}\), total coliforms and mesophilic bacteria, a slight increase was observed in the period after the construction, compared to the period before the construction began (Figure 2). On the other hand, the concentrations of Na\({}^{+}\), Cl\({}^{-}\) and the number of psychrophilic bacteria slightly decreased in the stream water. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Feature** & **Unit** & **Mean** & **Median** & **Min** & **Max** & **Q25 \({}^{*}\)** & **Q75 \({}^{*}\)** & **CV \({}^{*}\) [\%]** \\ \hline pH & – & 7.8 & 7.9 & 7.1 & 8.2 & 7.5 & 8.1 & 4.2 \\ EC & \(\upmu\)S/cm & 328.8 & 338.1 & 201.5 & 387.1 & 297.9 & 365.9 & 14.4 \\ TDS & mg/L & 280.9 & 282.7 & 157.7 & 335.2 & 254.1 & 323.4 & 16.3 \\ Ca\({}^{2+}\) & & 54.2 & 54.6 & 33.2 & 62.9 & 49.5 & 59.9 & 13.7 \\ Mg\({}^{2+}\) & & 8.53 & 8.69 & 4.49 & 12.06 & 7.03 & 10.08 & 21.5 \\ Na\({}^{+}\) & & 3.27 & 2.72 & 1.64 & 10.17 & 2.43 & 3.08 & 54.1 \\ K\({}^{+}\) & & 1.02 & 0.98 & 0.73 & 1.55 & 0.92 & 1.06 & 20.0 \\ HCO\({}_{3}\)\({}^{-}\) & & 186.8 & 187.0 & 101.0 & 237.6 & 161.9 & 214.9 & 18.7 \\ SO\({}_{4}\)\({}^{2-}\) & & 21.4 & 21.4 & 11.4 & 35.3 & 19.1 & 24.4 & 24.1 \\ Cl\({}^{-}\) & & 3.08 & 2.09 & 1.13 & 16.20 & 1.43 & 2.73 & 105.4 \\ NO\({}_{3}\)\({}^{-}\) & & 2.46 & 1.85 & 0.81 & 6.02 & 1.38 & 3.51 & 58.5 \\ Total coliforms & CFU/100 mL & 838 & 80 & 0 & 7700 & 1 & 1000 & 209.8 \\ Total _E. coli_ & & 572 & 20 & 0 & 7200 & 0 & 400 & 270.0 \\ Fecal coliforms & & 473 & 8 & 0 & 6900 & 0 & 170 & 305.4 \\ Fecal _E. coli_ & & 508 & 6 & 0 & 5620 & 0 & 550 & 253.3 \\ Mesophilic bacteria. & CFU/mL & 737 & 310 & 15 & 4015 & 60 & 780 & 150.8 \\ Psychrophilic bacteria. & & 10,404 & 3260 & 40 & 88,000 & 420 & 8600 & 211.6 \\ \hline \end{tabular} \({}^{*}\)Q25—lower quartile, 25% of data are below this value; Q75—upper quartile, 25% of data are above this value. CV—coefficient of variation.  
\end{table} 
Table 3: Physico-chemical characteristics, bacteriological indicators of water quality and basic statistics—Remiaszów stream. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Feature** & **F * & _p **_**_ \\ \hline pH & 16.645 & **0.000** \\ EC & 0.793 & 0.466 \\ TDS & 0.460 & 0.638 \\ Ca2+ & 0.475 & 0.628 \\ Mg2+ & 0.301 & 0.743 \\