# Transmission of Heavy Metals in River Water and Self-Purification Capacity of Ile River
## 2 Materials and Methods
### Analytical Methods  
Heavy metals in filtered water samples were determined using the flame atomic absorption spectrometric method with an AA-7000 spectrophotometer (Shimadzu, Kyoto, Japan), equipped with a hollow cathode lamp and a titanium burner operating on an acetylene-air mixture, following the procedure described by [PERSON] [32]). The analysis was carried out in accordance with ST RK ISO 8288-2005 \"Water Quality\", which was harmonized with ISO 8288:1986 [33]. The elements analyzed included cobalt, nickel, copper, zinc, cadmium, and lead. Prior to analysis, water samples were filtered through 0.45 \(\upmu\)m membrane filters and acidified with concentrated nitric acid to pH < 2 to preserve the samples. The filtered and \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Sampling Point**} & \multicolumn{2}{c}{**Coordinates**} & \multirow{2}{*}{**Distance from Month, km**} \\ \cline{2-3} \cline{5-4}  & **Latitude (N)** & & **Longitude (E)** \\ \hline \multicolumn{3}{c}{Ile River} \\ \hline HP Dobyn & 43\({}^{\circ}\)45\({}^{\prime}\)31.27\({}^{\prime\prime}\) N & 80\({}^{\circ}\)13\({}^{\prime}\)53.45\({}^{\prime\prime}\) E & 723 \\
164 km upstream of Kapchagay HPP & 43\({}^{\circ}\)50\({}^{\prime}\)15.28\({}^{\prime\prime}\) N & 78\({}^{\circ}\)49\({}^{\prime}\)43.07\({}^{\prime\prime}\) E & 607 \\
37 km downstream of Kapchagay HPP & 44\({}^{\circ}\)75\({}^{\prime}\)36.69\({}^{\prime\prime}\) N & 76\({}^{\circ}\)59\({}^{\prime\prime}\)5.09\({}^{\prime\prime}\) E & 434 \\ HP Ushzharma & 43\({}^{\circ}\)44\({}^{\prime}\)14.24\({}^{\prime\prime}\) N & 77\({}^{\circ}\)84.62\({}^{\prime\prime}\) E & 264 \\ HP Kokzhide & 45\({}^{\circ}\)5\({}^{\prime}\)22.43\({}^{\prime\prime}\) N & 75\({}^{\circ}\)27\({}^{\prime}\)3.40\({}^{\prime\prime}\) E & 35 \\ \hline \multicolumn{3}{c}{Kapchagay Reservoir} \\ \hline Point 1 & 43\({}^{\circ}\)53\({}^{\prime}\)17.64\({}^{\prime\prime}\) N & 77\({}^{\circ}\)8\({}^{\prime}\)24.94\({}^{\prime\prime}\) E & 311 \\ Point 2 & 43\({}^{\circ}\)47\({}^{\prime}\)45.34\({}^{\prime\prime}\) N & 77\({}^{\circ}\)8\({}^{\prime}\)38.58\({}^{\prime\prime}\) E & 320 \\ Point 3 & 43\({}^{\circ}\)56\({}^{\prime}\)3.82\({}^{\prime\prime}\) N & 77\({}^{\circ}\)22\({}^{\prime}\)56.08\({}^{\prime\prime}\) E & 328 \\ Point 4 & 43\({}^{\circ}\)51\({}^{\prime}\)9.43\({}^{\prime\prime}\) N & 77\({}^{\circ}\)22\({}^{\prime}\)3.29\({}^{\prime\prime}\) E & 331 \\ Point 5 & 43\({}^{\circ}\)46\({}^{\prime}\)25.57\({}^{\prime\prime}\) N & 77\({}^{\circ}\)21\({}^{\prime}\)22.46\({}^{\prime\prime}\) E & 334 \\ Point 6 & 43\({}^{\circ}\)51\({}^{\prime}\)15.97\({}^{\prime\prime}\) N & 77\({}^{\circ}\)42\({}^{\prime}\)43.07\({}^{\prime\prime}\) E & 350 \\ Point 7 & 43\({}^{\circ}\)47\({}^{\prime}\)57.07\({}^{\prime\prime}\) N & 77\({}^{\circ}\)41\({}^{\prime}\)1.26\({}^{\prime\prime}\) E & 353 \\ Point 8 & 43\({}^{\circ}\)44\({}^{\prime}\)29.07\({}^{\prime\prime}\) N & 77\({}^{\circ}\)40\({}^{\prime}\)36.31\({}^{\prime\prime}\) E & 358 \\ Point 9 & 43\({}^{\circ}\)47\({}^{\prime}\)37.82\({}^{\prime\prime}\) N & 77\({}^{\circ}\)55\({}^{\prime}\)19.78\({}^{\prime\prime}\) E & 367 \\ Point 10 & 43\({}^{\circ}\)49\({}^{\prime}\)37.26\({}^{\prime\prime}\) N & 78\({}^{\circ}\)6\({}^{\prime}\)3.65\({}^{\prime\prime}\) E & 377 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Coordinates of water sampling points in the Ile River basin. preserved samples were stored in clean 1 L polyethylene bottles, which had been pre-rinsed with deionized water. Calibration was performed using certified standard solutions of heavy metals and each element was measured in triplicate to ensure accuracy. The detection limits of the AA-7000 instrument were as follows: Cu--0.001 mg/L; Zn--0.001 mg/L; Pb--0.003 mg/L; Cd--0.0005 mg/L; Co--0.001 mg/L; Ni--0.001 mg/L. The measurement accuracy ranged from \(\pm\)5% to \(\pm\)10%, depending on concentration.