## 3 Results and Discussion
### Contents of Pollutants in Roof Runoff
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline
**Parameter** & **Sample** & **KR 1** & **KR 2** & **KR 3** & **KR 4** & **KR 5** & **MOG** \\ \hline \multicolumn{8}{c}{mg/L} \\ \hline P-PO\({}_{4}\) & roof runoff & 0.016 & 0.029 & 0.027 & 0.025 & 0.016 & 0.018 \\  & roof runoff after acid digestion & 0.292 & 0.298 & 0.369 & 0.438 & 0.279 & 0.409 \\ SO\({}_{4}\)\({}^{2-}\) & roof runoff & 0.544 & 8.751 & 0.518 & 1.085 & \(<\)LOQ & 0.701 \\  & roof runoff after acid digestion & 0.590 & 7.316 & \(<\)LOQ & 1.211 & \(<\)LOQ & 0.813 \\ SiO\({}_{2}\) & roof runoff & 0.328 & 0.752 & 0.364 & 0.330 & 0.316 & 0.349 \\  & roof runoff after acid digestion & 0.952 & 1.125 & 0.834 & 2.147 & 0.572 & 2.129 \\ Al & roof runoff & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & 0.0069 \\  & roof runoff after acid digestion & 0.0641 & 0.0354 & 0.0454 & 0.2150 & 0.0187 & 0.1701 \\ Ba & roof runoff & 0.0007 & 0.0066 & 0.0022 & 0.0013 & 0.0042 & 0.0010 \\  & roof runoff after acid digestion & 0.0058 & 0.0093 & 0.0036 & 0.0083 & 0.0059 & 0.0075 \\ Ca & roof runoff & 0.1726 & 2.0801 & 0.2514 & 0.2839 & 0.2602 & 0.3571 \\  & roof runoff after acid digestion & 0.8912 & 4.5606 & 1.2786 & 1.2980 & 0.5058 & 0.8167 \\ Co & roof runoff & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\  & roof runoff after acid digestion & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\ Cu & roof runoff & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\  & roof runoff after acid digestion & 0.0913 & 0.0020 & 0.0049 & 0.0051 & 0.0016 & 0.0067 \\ Fe & roof runoff & \(<\)LOQ & \(<\)LOQ & 0.0127 & 0.0141 & \(<\)LOQ & \(<\)LOQ \\  & roof runoff after acid digestion & 0.4416 & 0.2028 & 0.3465 & 1.0458 & 0.1869 & 0.7817 \\ K & roof runoff & 0.0867 & 1.0708 & 0.3701 & 0.1576 & 0.1395 & 0.1539 \\  & roof runoff after acid digestion & 0.1428 & 0.9583 & 0.4245 & 0.2588 & 0.1416 & 0.2848 \\ Mg & roof runoff & 0.0241 & 0.1175 & 0.0399 & 0.0683 & 0.0513 & 0.0616 \\  & roof runoff after acid digestion & 0.1419 & 0.2235 & 0.2012 & 0.3978 & 0.0800 & 0.1855 \\ Mn & roof runoff & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\  & roof runoff after acid digestion & 0.0122 & 0.0091 & 0.0110 & 0.0225 & 0.0056 & 0.0211 \\ Mo & roof runoff & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & 0.0010 \\  & roof runoff & 0.4682 & 1.4067 & 0.7546 & 0.6873 & 0.5077 & 0.5979 \\ Na & roof runoff after acid digestion & 0.6092 & 1.3551 & 0.6948 & 0.6388 & 0.4671 & 0.5911 \\ Ni & roof runoff & \(<\)LOQ & 0.0010 & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\  & roof runoff after acid digestion & \(<\)LOQ & 0.0014 & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\ Pb & roof runoff & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ & \(<\)LOQ \\  & roof runoff after acid digestion & 0.0067 & 0.0001 & 0.0027 & 0.1306 & \(<\)LOQ & 0.0135 \\ Zn & roof runoff & 0.1033 & 2.5786 & 0.0651 & 0.5040 & 0.1620 & 0.0153 \\  & roof runoff after acid digestion & 0.4390 & 6.2382 & 0.3566 & 1.6012 & 0.2810 & 0.0644 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Contents of the investigated elements identified in the roof samples, without and after acid digestion, from research conducted in the winter of 2020. The analyses of the samples, extracted in concentrated nitric acid, indicated higher contents of the majority of elements, in comparison to their contents in raw samples (Table 3). Only for SO4\({}^{2}\)-, K, and Na in both, raw and filtrated roof runoff samples and in roof runoff samples after filtration and acid digestion, differences in their contents were not clearly visible. Moreover, concentrations of Cr in the roof runoff samples were \(<\)LOQ in both types of samples. All that confirmed the importance of suspended matter in aqueous samples, also in the context of environmental risk from total contents of the investigated elements [101; 102; 103].