## 2 Materials and Methods  
### Pre-Survey Study  
This section is designed to recognize the most concentrated HMs in the drinking water and the nearby drainage water to be used in the experiment. Firstly, five samples (1-5) were collected; the first sample was collected from the drain that received the discharge from a factory of dyed clothes, and the other four samples (from 2-5) were collected from tap water from houses adjacent to the clothes dye factory in the Northern Nile Delta, Egypt (30\({}^{\circ}\)45\({}^{\prime}\)40\({}^{\prime\prime}\), N3\({}^{\circ}\)06\({}^{\prime}\)53\({}^{\prime\prime}\) E). The samples were analyzed for Cu, Mn, Ni, Pb, Cd, and Zn. The metal values were higher in Cu, Mn, and Zn, but they were non-detected or not sensible for other metals (Table 1). The low detection limits (LODs) of Cd, Ni, and Pb were 0.015, 0.035, and, 0.045 respectively. The samples were collected as follows:  
1. A sample from an outlet drain of a clothes dye factory;
2. A sample from a pump 60 m from the drain, with a pump depth of 42 m;
3. A sample from a pump 200 m away from the factory;
4. A sample from a house 500 m away from the factory;
5. A sample from a house 1 km away from the factory.  
Ten other samples (from 6-15) were collected from houses at different distances, and a variation was found in their results. However, Mn was higher than the permissible limits of drinking water [14,29] in eight samples, Zn values were higher in four samples, and Cu was lower than those limits (although Cu was higher than the other examined metals) (Table 1). The samples were collected as follows:  
1. A sample from the water station treatment before treatment and after about 3 km from the water intake from the Nile;
2. A sample from the water station after treatment;
3. A sample from a house 200 m away from the station;  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample Number** & **Cu** & **Mn** & **Zn** \\ \hline
**1** & 1.63 & 7.15 & 5.07 \\
**2** & nd * & 0.56 & 0.88 \\
**3** & 0.12 & 0.32 & 0.64 \\
**4** & 0.06 & 0.90 & 0.95 \\
**5** & 0.05 & 0.32 & 0.72 \\
**6** & 1.50 & 2.08 & 4.38 \\
**7** & 1.15 & 0.58 & 2.45 \\
**8** & 1.03 & 0.85 & 4.48 \\
**9** & 0.73 & 0.30 & 1.68 \\
**10** & 0.73 & 0.70 & 3.35 \\
**11** & 0.55 & 0.68 & 2.33 \\
**12** & 0.78 & 0.95 & 3.25 \\
**13** & 0.78 & 0.28 & 3.00 \\
**14** & 0.20 & 0.53 & 3.30 \\
**15** & 0.15 & 4.55 & 1.83 \\
**Permissible Limits of WHO (2011)** & 2.0 & 0.4 & 3.0 \\
**Permissible Limits of EMH (2011)** & 2.0 & 0.4 & 3.0 \\ \hline \hline \end{tabular}  
* **nd**: non-detected.  
\end{table}
Table 1: The concentrations of Cu, Mn, and Zn (mg L\({}^{-1}\)) in the drinking water samples from the study area.  
A sample from a house 400 m away from the station;  
A sample from a house 600 m away from the station;  
A sample from a house 800 m away from the station;  
A sample from a house 1000 m away from the station;  
A sample of a house 1200 m away from the station;  
A sample from a house 1400 m away from the station;  
A sample from a house 1600 m away from the station.  
Heavy Metals Analysis  
Two-litres of water samples were collected in triplicate and were filtered. One of them was acidified by HNO3 (2%) and was concentrated at 64 \({}^{\circ}\)C into 50 mL for metals analysis using Graphite Furnace-Atomic Absorption Spectrometry (GBC Avanta E, Victoria, Australia) [30]. According to the results, the most concentrated metals were Cu, Mn, and Zn, and so they are the only ones mentioned in Table 1.